/*! JointJS v4.0.1 (2024-02-02) - JavaScript diagramming library


This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? factory(exports) :
	typeof define === 'function' && define.amd ? define(['exports'], factory) :
	(global = global || self, factory(global.joint = {}));
}(this, function (exports) { 'use strict';

	var commonjsGlobal = typeof window !== 'undefined' ? window : typeof global !== 'undefined' ? global : typeof self !== 'undefined' ? self : {};

	function commonjsRequire () {
		throw new Error('Dynamic requires are not currently supported by rollup-plugin-commonjs');
	}

	function unwrapExports (x) {
		return x && x.__esModule && Object.prototype.hasOwnProperty.call(x, 'default') ? x.default : x;
	}

	function createCommonjsModule(fn, module) {
		return module = { exports: {} }, fn(module, module.exports), module.exports;
	}

	function getCjsExportFromNamespace (n) {
		return n && n.default || n;
	}

	var check = function (it) {
	  return it && it.Math == Math && it;
	};

	// https://github.com/zloirock/core-js/issues/86#issuecomment-115759028
	var global_1 =
	  // eslint-disable-next-line no-undef
	  check(typeof globalThis == 'object' && globalThis) ||
	  check(typeof window == 'object' && window) ||
	  check(typeof self == 'object' && self) ||
	  check(typeof commonjsGlobal == 'object' && commonjsGlobal) ||
	  // eslint-disable-next-line no-new-func
	  (function () { return this; })() || Function('return this')();

	var fails = function (exec) {
	  try {
	    return !!exec();
	  } catch (error) {
	    return true;
	  }
	};

	// Detect IE8's incomplete defineProperty implementation
	var descriptors = !fails(function () {
	  return Object.defineProperty({}, 1, { get: function () { return 7; } })[1] != 7;
	});

	'use strict';
	var nativePropertyIsEnumerable = {}.propertyIsEnumerable;
	var getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;

	// Nashorn ~ JDK8 bug
	var NASHORN_BUG = getOwnPropertyDescriptor && !nativePropertyIsEnumerable.call({ 1: 2 }, 1);

	// `Object.prototype.propertyIsEnumerable` method implementation
	// https://tc39.es/ecma262/#sec-object.prototype.propertyisenumerable
	var f = NASHORN_BUG ? function propertyIsEnumerable(V) {
	  var descriptor = getOwnPropertyDescriptor(this, V);
	  return !!descriptor && descriptor.enumerable;
	} : nativePropertyIsEnumerable;

	var objectPropertyIsEnumerable = {
		f: f
	};

	var createPropertyDescriptor = function (bitmap, value) {
	  return {
	    enumerable: !(bitmap & 1),
	    configurable: !(bitmap & 2),
	    writable: !(bitmap & 4),
	    value: value
	  };
	};

	var toString = {}.toString;

	var classofRaw = function (it) {
	  return toString.call(it).slice(8, -1);
	};

	var split = ''.split;

	// fallback for non-array-like ES3 and non-enumerable old V8 strings
	var indexedObject = fails(function () {
	  // throws an error in rhino, see https://github.com/mozilla/rhino/issues/346
	  // eslint-disable-next-line no-prototype-builtins
	  return !Object('z').propertyIsEnumerable(0);
	}) ? function (it) {
	  return classofRaw(it) == 'String' ? split.call(it, '') : Object(it);
	} : Object;

	// `RequireObjectCoercible` abstract operation
	// https://tc39.es/ecma262/#sec-requireobjectcoercible
	var requireObjectCoercible = function (it) {
	  if (it == undefined) { throw TypeError("Can't call method on " + it); }
	  return it;
	};

	// toObject with fallback for non-array-like ES3 strings



	var toIndexedObject = function (it) {
	  return indexedObject(requireObjectCoercible(it));
	};

	var isObject = function (it) {
	  return typeof it === 'object' ? it !== null : typeof it === 'function';
	};

	// `ToPrimitive` abstract operation
	// https://tc39.es/ecma262/#sec-toprimitive
	// instead of the ES6 spec version, we didn't implement @@toPrimitive case
	// and the second argument - flag - preferred type is a string
	var toPrimitive = function (input, PREFERRED_STRING) {
	  if (!isObject(input)) { return input; }
	  var fn, val;
	  if (PREFERRED_STRING && typeof (fn = input.toString) == 'function' && !isObject(val = fn.call(input))) { return val; }
	  if (typeof (fn = input.valueOf) == 'function' && !isObject(val = fn.call(input))) { return val; }
	  if (!PREFERRED_STRING && typeof (fn = input.toString) == 'function' && !isObject(val = fn.call(input))) { return val; }
	  throw TypeError("Can't convert object to primitive value");
	};

	var hasOwnProperty$1 = {}.hasOwnProperty;

	var has = function (it, key) {
	  return hasOwnProperty$1.call(it, key);
	};

	var document$1 = global_1.document;
	// typeof document.createElement is 'object' in old IE
	var EXISTS = isObject(document$1) && isObject(document$1.createElement);

	var documentCreateElement = function (it) {
	  return EXISTS ? document$1.createElement(it) : {};
	};

	// Thank's IE8 for his funny defineProperty
	var ie8DomDefine = !descriptors && !fails(function () {
	  return Object.defineProperty(documentCreateElement('div'), 'a', {
	    get: function () { return 7; }
	  }).a != 7;
	});

	var nativeGetOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;

	// `Object.getOwnPropertyDescriptor` method
	// https://tc39.es/ecma262/#sec-object.getownpropertydescriptor
	var f$1 = descriptors ? nativeGetOwnPropertyDescriptor : function getOwnPropertyDescriptor(O, P) {
	  O = toIndexedObject(O);
	  P = toPrimitive(P, true);
	  if (ie8DomDefine) { try {
	    return nativeGetOwnPropertyDescriptor(O, P);
	  } catch (error) { /* empty */ } }
	  if (has(O, P)) { return createPropertyDescriptor(!objectPropertyIsEnumerable.f.call(O, P), O[P]); }
	};

	var objectGetOwnPropertyDescriptor = {
		f: f$1
	};

	var anObject = function (it) {
	  if (!isObject(it)) {
	    throw TypeError(String(it) + ' is not an object');
	  } return it;
	};

	var nativeDefineProperty = Object.defineProperty;

	// `Object.defineProperty` method
	// https://tc39.es/ecma262/#sec-object.defineproperty
	var f$2 = descriptors ? nativeDefineProperty : function defineProperty(O, P, Attributes) {
	  anObject(O);
	  P = toPrimitive(P, true);
	  anObject(Attributes);
	  if (ie8DomDefine) { try {
	    return nativeDefineProperty(O, P, Attributes);
	  } catch (error) { /* empty */ } }
	  if ('get' in Attributes || 'set' in Attributes) { throw TypeError('Accessors not supported'); }
	  if ('value' in Attributes) { O[P] = Attributes.value; }
	  return O;
	};

	var objectDefineProperty = {
		f: f$2
	};

	var createNonEnumerableProperty = descriptors ? function (object, key, value) {
	  return objectDefineProperty.f(object, key, createPropertyDescriptor(1, value));
	} : function (object, key, value) {
	  object[key] = value;
	  return object;
	};

	var setGlobal = function (key, value) {
	  try {
	    createNonEnumerableProperty(global_1, key, value);
	  } catch (error) {
	    global_1[key] = value;
	  } return value;
	};

	var SHARED = '__core-js_shared__';
	var store = global_1[SHARED] || setGlobal(SHARED, {});

	var sharedStore = store;

	var functionToString = Function.toString;

	// this helper broken in `3.4.1-3.4.4`, so we can't use `shared` helper
	if (typeof sharedStore.inspectSource != 'function') {
	  sharedStore.inspectSource = function (it) {
	    return functionToString.call(it);
	  };
	}

	var inspectSource = sharedStore.inspectSource;

	var WeakMap$1 = global_1.WeakMap;

	var nativeWeakMap = typeof WeakMap$1 === 'function' && /native code/.test(inspectSource(WeakMap$1));

	var isPure = false;

	var shared = createCommonjsModule(function (module) {
	(module.exports = function (key, value) {
	  return sharedStore[key] || (sharedStore[key] = value !== undefined ? value : {});
	})('versions', []).push({
	  version: '3.8.3',
	  mode: isPure ? 'pure' : 'global',
	  copyright: '© 2021 Denis Pushkarev (zloirock.ru)'
	});
	});

	var id = 0;
	var postfix = Math.random();

	var uid = function (key) {
	  return 'Symbol(' + String(key === undefined ? '' : key) + ')_' + (++id + postfix).toString(36);
	};

	var keys = shared('keys');

	var sharedKey = function (key) {
	  return keys[key] || (keys[key] = uid(key));
	};

	var hiddenKeys = {};

	var WeakMap$2 = global_1.WeakMap;
	var set, get, has$1;

	var enforce = function (it) {
	  return has$1(it) ? get(it) : set(it, {});
	};

	var getterFor = function (TYPE) {
	  return function (it) {
	    var state;
	    if (!isObject(it) || (state = get(it)).type !== TYPE) {
	      throw TypeError('Incompatible receiver, ' + TYPE + ' required');
	    } return state;
	  };
	};

	if (nativeWeakMap) {
	  var store$1 = sharedStore.state || (sharedStore.state = new WeakMap$2());
	  var wmget = store$1.get;
	  var wmhas = store$1.has;
	  var wmset = store$1.set;
	  set = function (it, metadata) {
	    metadata.facade = it;
	    wmset.call(store$1, it, metadata);
	    return metadata;
	  };
	  get = function (it) {
	    return wmget.call(store$1, it) || {};
	  };
	  has$1 = function (it) {
	    return wmhas.call(store$1, it);
	  };
	} else {
	  var STATE = sharedKey('state');
	  hiddenKeys[STATE] = true;
	  set = function (it, metadata) {
	    metadata.facade = it;
	    createNonEnumerableProperty(it, STATE, metadata);
	    return metadata;
	  };
	  get = function (it) {
	    return has(it, STATE) ? it[STATE] : {};
	  };
	  has$1 = function (it) {
	    return has(it, STATE);
	  };
	}

	var internalState = {
	  set: set,
	  get: get,
	  has: has$1,
	  enforce: enforce,
	  getterFor: getterFor
	};
	var internalState_1 = internalState.set;
	var internalState_2 = internalState.get;
	var internalState_3 = internalState.has;
	var internalState_4 = internalState.enforce;
	var internalState_5 = internalState.getterFor;

	var redefine = createCommonjsModule(function (module) {
	var getInternalState = internalState.get;
	var enforceInternalState = internalState.enforce;
	var TEMPLATE = String(String).split('String');

	(module.exports = function (O, key, value, options) {
	  var unsafe = options ? !!options.unsafe : false;
	  var simple = options ? !!options.enumerable : false;
	  var noTargetGet = options ? !!options.noTargetGet : false;
	  var state;
	  if (typeof value == 'function') {
	    if (typeof key == 'string' && !has(value, 'name')) {
	      createNonEnumerableProperty(value, 'name', key);
	    }
	    state = enforceInternalState(value);
	    if (!state.source) {
	      state.source = TEMPLATE.join(typeof key == 'string' ? key : '');
	    }
	  }
	  if (O === global_1) {
	    if (simple) { O[key] = value; }
	    else { setGlobal(key, value); }
	    return;
	  } else if (!unsafe) {
	    delete O[key];
	  } else if (!noTargetGet && O[key]) {
	    simple = true;
	  }
	  if (simple) { O[key] = value; }
	  else { createNonEnumerableProperty(O, key, value); }
	// add fake Function#toString for correct work wrapped methods / constructors with methods like LoDash isNative
	})(Function.prototype, 'toString', function toString() {
	  return typeof this == 'function' && getInternalState(this).source || inspectSource(this);
	});
	});

	var path = global_1;

	var aFunction = function (variable) {
	  return typeof variable == 'function' ? variable : undefined;
	};

	var getBuiltIn = function (namespace, method) {
	  return arguments.length < 2 ? aFunction(path[namespace]) || aFunction(global_1[namespace])
	    : path[namespace] && path[namespace][method] || global_1[namespace] && global_1[namespace][method];
	};

	var ceil = Math.ceil;
	var floor = Math.floor;

	// `ToInteger` abstract operation
	// https://tc39.es/ecma262/#sec-tointeger
	var toInteger = function (argument) {
	  return isNaN(argument = +argument) ? 0 : (argument > 0 ? floor : ceil)(argument);
	};

	var min = Math.min;

	// `ToLength` abstract operation
	// https://tc39.es/ecma262/#sec-tolength
	var toLength = function (argument) {
	  return argument > 0 ? min(toInteger(argument), 0x1FFFFFFFFFFFFF) : 0; // 2 ** 53 - 1 == 9007199254740991
	};

	var max = Math.max;
	var min$1 = Math.min;

	// Helper for a popular repeating case of the spec:
	// Let integer be ? ToInteger(index).
	// If integer < 0, let result be max((length + integer), 0); else let result be min(integer, length).
	var toAbsoluteIndex = function (index, length) {
	  var integer = toInteger(index);
	  return integer < 0 ? max(integer + length, 0) : min$1(integer, length);
	};

	// `Array.prototype.{ indexOf, includes }` methods implementation
	var createMethod = function (IS_INCLUDES) {
	  return function ($this, el, fromIndex) {
	    var O = toIndexedObject($this);
	    var length = toLength(O.length);
	    var index = toAbsoluteIndex(fromIndex, length);
	    var value;
	    // Array#includes uses SameValueZero equality algorithm
	    // eslint-disable-next-line no-self-compare
	    if (IS_INCLUDES && el != el) { while (length > index) {
	      value = O[index++];
	      // eslint-disable-next-line no-self-compare
	      if (value != value) { return true; }
	    // Array#indexOf ignores holes, Array#includes - not
	    } } else { for (;length > index; index++) {
	      if ((IS_INCLUDES || index in O) && O[index] === el) { return IS_INCLUDES || index || 0; }
	    } } return !IS_INCLUDES && -1;
	  };
	};

	var arrayIncludes = {
	  // `Array.prototype.includes` method
	  // https://tc39.es/ecma262/#sec-array.prototype.includes
	  includes: createMethod(true),
	  // `Array.prototype.indexOf` method
	  // https://tc39.es/ecma262/#sec-array.prototype.indexof
	  indexOf: createMethod(false)
	};
	var arrayIncludes_1 = arrayIncludes.includes;
	var arrayIncludes_2 = arrayIncludes.indexOf;

	var indexOf = arrayIncludes.indexOf;


	var objectKeysInternal = function (object, names) {
	  var O = toIndexedObject(object);
	  var i = 0;
	  var result = [];
	  var key;
	  for (key in O) { !has(hiddenKeys, key) && has(O, key) && result.push(key); }
	  // Don't enum bug & hidden keys
	  while (names.length > i) { if (has(O, key = names[i++])) {
	    ~indexOf(result, key) || result.push(key);
	  } }
	  return result;
	};

	// IE8- don't enum bug keys
	var enumBugKeys = [
	  'constructor',
	  'hasOwnProperty',
	  'isPrototypeOf',
	  'propertyIsEnumerable',
	  'toLocaleString',
	  'toString',
	  'valueOf'
	];

	var hiddenKeys$1 = enumBugKeys.concat('length', 'prototype');

	// `Object.getOwnPropertyNames` method
	// https://tc39.es/ecma262/#sec-object.getownpropertynames
	var f$3 = Object.getOwnPropertyNames || function getOwnPropertyNames(O) {
	  return objectKeysInternal(O, hiddenKeys$1);
	};

	var objectGetOwnPropertyNames = {
		f: f$3
	};

	var f$4 = Object.getOwnPropertySymbols;

	var objectGetOwnPropertySymbols = {
		f: f$4
	};

	// all object keys, includes non-enumerable and symbols
	var ownKeys = getBuiltIn('Reflect', 'ownKeys') || function ownKeys(it) {
	  var keys = objectGetOwnPropertyNames.f(anObject(it));
	  var getOwnPropertySymbols = objectGetOwnPropertySymbols.f;
	  return getOwnPropertySymbols ? keys.concat(getOwnPropertySymbols(it)) : keys;
	};

	var copyConstructorProperties = function (target, source) {
	  var keys = ownKeys(source);
	  var defineProperty = objectDefineProperty.f;
	  var getOwnPropertyDescriptor = objectGetOwnPropertyDescriptor.f;
	  for (var i = 0; i < keys.length; i++) {
	    var key = keys[i];
	    if (!has(target, key)) { defineProperty(target, key, getOwnPropertyDescriptor(source, key)); }
	  }
	};

	var replacement = /#|\.prototype\./;

	var isForced = function (feature, detection) {
	  var value = data[normalize(feature)];
	  return value == POLYFILL ? true
	    : value == NATIVE ? false
	    : typeof detection == 'function' ? fails(detection)
	    : !!detection;
	};

	var normalize = isForced.normalize = function (string) {
	  return String(string).replace(replacement, '.').toLowerCase();
	};

	var data = isForced.data = {};
	var NATIVE = isForced.NATIVE = 'N';
	var POLYFILL = isForced.POLYFILL = 'P';

	var isForced_1 = isForced;

	var getOwnPropertyDescriptor$1 = objectGetOwnPropertyDescriptor.f;






	/*
	  options.target      - name of the target object
	  options.global      - target is the global object
	  options.stat        - export as static methods of target
	  options.proto       - export as prototype methods of target
	  options.real        - real prototype method for the `pure` version
	  options.forced      - export even if the native feature is available
	  options.bind        - bind methods to the target, required for the `pure` version
	  options.wrap        - wrap constructors to preventing global pollution, required for the `pure` version
	  options.unsafe      - use the simple assignment of property instead of delete + defineProperty
	  options.sham        - add a flag to not completely full polyfills
	  options.enumerable  - export as enumerable property
	  options.noTargetGet - prevent calling a getter on target
	*/
	var _export = function (options, source) {
	  var TARGET = options.target;
	  var GLOBAL = options.global;
	  var STATIC = options.stat;
	  var FORCED, target, key, targetProperty, sourceProperty, descriptor;
	  if (GLOBAL) {
	    target = global_1;
	  } else if (STATIC) {
	    target = global_1[TARGET] || setGlobal(TARGET, {});
	  } else {
	    target = (global_1[TARGET] || {}).prototype;
	  }
	  if (target) { for (key in source) {
	    sourceProperty = source[key];
	    if (options.noTargetGet) {
	      descriptor = getOwnPropertyDescriptor$1(target, key);
	      targetProperty = descriptor && descriptor.value;
	    } else { targetProperty = target[key]; }
	    FORCED = isForced_1(GLOBAL ? key : TARGET + (STATIC ? '.' : '#') + key, options.forced);
	    // contained in target
	    if (!FORCED && targetProperty !== undefined) {
	      if (typeof sourceProperty === typeof targetProperty) { continue; }
	      copyConstructorProperties(sourceProperty, targetProperty);
	    }
	    // add a flag to not completely full polyfills
	    if (options.sham || (targetProperty && targetProperty.sham)) {
	      createNonEnumerableProperty(sourceProperty, 'sham', true);
	    }
	    // extend global
	    redefine(target, key, sourceProperty, options);
	  } }
	};

	var nativeSymbol = !!Object.getOwnPropertySymbols && !fails(function () {
	  // Chrome 38 Symbol has incorrect toString conversion
	  // eslint-disable-next-line no-undef
	  return !String(Symbol());
	});

	var useSymbolAsUid = nativeSymbol
	  // eslint-disable-next-line no-undef
	  && !Symbol.sham
	  // eslint-disable-next-line no-undef
	  && typeof Symbol.iterator == 'symbol';

	var WellKnownSymbolsStore = shared('wks');
	var Symbol$1 = global_1.Symbol;
	var createWellKnownSymbol = useSymbolAsUid ? Symbol$1 : Symbol$1 && Symbol$1.withoutSetter || uid;

	var wellKnownSymbol = function (name) {
	  if (!has(WellKnownSymbolsStore, name)) {
	    if (nativeSymbol && has(Symbol$1, name)) { WellKnownSymbolsStore[name] = Symbol$1[name]; }
	    else { WellKnownSymbolsStore[name] = createWellKnownSymbol('Symbol.' + name); }
	  } return WellKnownSymbolsStore[name];
	};

	// `Object.keys` method
	// https://tc39.es/ecma262/#sec-object.keys
	var objectKeys = Object.keys || function keys(O) {
	  return objectKeysInternal(O, enumBugKeys);
	};

	// `Object.defineProperties` method
	// https://tc39.es/ecma262/#sec-object.defineproperties
	var objectDefineProperties = descriptors ? Object.defineProperties : function defineProperties(O, Properties) {
	  anObject(O);
	  var keys = objectKeys(Properties);
	  var length = keys.length;
	  var index = 0;
	  var key;
	  while (length > index) { objectDefineProperty.f(O, key = keys[index++], Properties[key]); }
	  return O;
	};

	var html = getBuiltIn('document', 'documentElement');

	var GT = '>';
	var LT = '<';
	var PROTOTYPE = 'prototype';
	var SCRIPT = 'script';
	var IE_PROTO = sharedKey('IE_PROTO');

	var EmptyConstructor = function () { /* empty */ };

	var scriptTag = function (content) {
	  return LT + SCRIPT + GT + content + LT + '/' + SCRIPT + GT;
	};

	// Create object with fake `null` prototype: use ActiveX Object with cleared prototype
	var NullProtoObjectViaActiveX = function (activeXDocument) {
	  activeXDocument.write(scriptTag(''));
	  activeXDocument.close();
	  var temp = activeXDocument.parentWindow.Object;
	  activeXDocument = null; // avoid memory leak
	  return temp;
	};

	// Create object with fake `null` prototype: use iframe Object with cleared prototype
	var NullProtoObjectViaIFrame = function () {
	  // Thrash, waste and sodomy: IE GC bug
	  var iframe = documentCreateElement('iframe');
	  var JS = 'java' + SCRIPT + ':';
	  var iframeDocument;
	  iframe.style.display = 'none';
	  html.appendChild(iframe);
	  // https://github.com/zloirock/core-js/issues/475
	  iframe.src = String(JS);
	  iframeDocument = iframe.contentWindow.document;
	  iframeDocument.open();
	  iframeDocument.write(scriptTag('document.F=Object'));
	  iframeDocument.close();
	  return iframeDocument.F;
	};

	// Check for document.domain and active x support
	// No need to use active x approach when document.domain is not set
	// see https://github.com/es-shims/es5-shim/issues/150
	// variation of https://github.com/kitcambridge/es5-shim/commit/4f738ac066346
	// avoid IE GC bug
	var activeXDocument;
	var NullProtoObject = function () {
	  try {
	    /* global ActiveXObject */
	    activeXDocument = document.domain && new ActiveXObject('htmlfile');
	  } catch (error) { /* ignore */ }
	  NullProtoObject = activeXDocument ? NullProtoObjectViaActiveX(activeXDocument) : NullProtoObjectViaIFrame();
	  var length = enumBugKeys.length;
	  while (length--) { delete NullProtoObject[PROTOTYPE][enumBugKeys[length]]; }
	  return NullProtoObject();
	};

	hiddenKeys[IE_PROTO] = true;

	// `Object.create` method
	// https://tc39.es/ecma262/#sec-object.create
	var objectCreate = Object.create || function create(O, Properties) {
	  var result;
	  if (O !== null) {
	    EmptyConstructor[PROTOTYPE] = anObject(O);
	    result = new EmptyConstructor();
	    EmptyConstructor[PROTOTYPE] = null;
	    // add "__proto__" for Object.getPrototypeOf polyfill
	    result[IE_PROTO] = O;
	  } else { result = NullProtoObject(); }
	  return Properties === undefined ? result : objectDefineProperties(result, Properties);
	};

	var UNSCOPABLES = wellKnownSymbol('unscopables');
	var ArrayPrototype = Array.prototype;

	// Array.prototype[@@unscopables]
	// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
	if (ArrayPrototype[UNSCOPABLES] == undefined) {
	  objectDefineProperty.f(ArrayPrototype, UNSCOPABLES, {
	    configurable: true,
	    value: objectCreate(null)
	  });
	}

	// add a key to Array.prototype[@@unscopables]
	var addToUnscopables = function (key) {
	  ArrayPrototype[UNSCOPABLES][key] = true;
	};

	var defineProperty = Object.defineProperty;
	var cache = {};

	var thrower = function (it) { throw it; };

	var arrayMethodUsesToLength = function (METHOD_NAME, options) {
	  if (has(cache, METHOD_NAME)) { return cache[METHOD_NAME]; }
	  if (!options) { options = {}; }
	  var method = [][METHOD_NAME];
	  var ACCESSORS = has(options, 'ACCESSORS') ? options.ACCESSORS : false;
	  var argument0 = has(options, 0) ? options[0] : thrower;
	  var argument1 = has(options, 1) ? options[1] : undefined;

	  return cache[METHOD_NAME] = !!method && !fails(function () {
	    if (ACCESSORS && !descriptors) { return true; }
	    var O = { length: -1 };

	    if (ACCESSORS) { defineProperty(O, 1, { enumerable: true, get: thrower }); }
	    else { O[1] = 1; }

	    method.call(O, argument0, argument1);
	  });
	};

	'use strict';

	var $includes = arrayIncludes.includes;



	var USES_TO_LENGTH = arrayMethodUsesToLength('indexOf', { ACCESSORS: true, 1: 0 });

	// `Array.prototype.includes` method
	// https://tc39.es/ecma262/#sec-array.prototype.includes
	_export({ target: 'Array', proto: true, forced: !USES_TO_LENGTH }, {
	  includes: function includes(el /* , fromIndex = 0 */) {
	    return $includes(this, el, arguments.length > 1 ? arguments[1] : undefined);
	  }
	});

	// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
	addToUnscopables('includes');

	var es_array_includes = {

	};

	var aFunction$1 = function (it) {
	  if (typeof it != 'function') {
	    throw TypeError(String(it) + ' is not a function');
	  } return it;
	};

	// optional / simple context binding
	var functionBindContext = function (fn, that, length) {
	  aFunction$1(fn);
	  if (that === undefined) { return fn; }
	  switch (length) {
	    case 0: return function () {
	      return fn.call(that);
	    };
	    case 1: return function (a) {
	      return fn.call(that, a);
	    };
	    case 2: return function (a, b) {
	      return fn.call(that, a, b);
	    };
	    case 3: return function (a, b, c) {
	      return fn.call(that, a, b, c);
	    };
	  }
	  return function (/* ...args */) {
	    return fn.apply(that, arguments);
	  };
	};

	var call = Function.call;

	var entryUnbind = function (CONSTRUCTOR, METHOD, length) {
	  return functionBindContext(call, global_1[CONSTRUCTOR].prototype[METHOD], length);
	};

	var includes = entryUnbind('Array', 'includes');

	var includes$1 = includes;

	// `ToObject` abstract operation
	// https://tc39.es/ecma262/#sec-toobject
	var toObject = function (argument) {
	  return Object(requireObjectCoercible(argument));
	};

	// `IsArray` abstract operation
	// https://tc39.es/ecma262/#sec-isarray
	var isArray = Array.isArray || function isArray(arg) {
	  return classofRaw(arg) == 'Array';
	};

	var SPECIES = wellKnownSymbol('species');

	// `ArraySpeciesCreate` abstract operation
	// https://tc39.es/ecma262/#sec-arrayspeciescreate
	var arraySpeciesCreate = function (originalArray, length) {
	  var C;
	  if (isArray(originalArray)) {
	    C = originalArray.constructor;
	    // cross-realm fallback
	    if (typeof C == 'function' && (C === Array || isArray(C.prototype))) { C = undefined; }
	    else if (isObject(C)) {
	      C = C[SPECIES];
	      if (C === null) { C = undefined; }
	    }
	  } return new (C === undefined ? Array : C)(length === 0 ? 0 : length);
	};

	var push = [].push;

	// `Array.prototype.{ forEach, map, filter, some, every, find, findIndex, filterOut }` methods implementation
	var createMethod$1 = function (TYPE) {
	  var IS_MAP = TYPE == 1;
	  var IS_FILTER = TYPE == 2;
	  var IS_SOME = TYPE == 3;
	  var IS_EVERY = TYPE == 4;
	  var IS_FIND_INDEX = TYPE == 6;
	  var IS_FILTER_OUT = TYPE == 7;
	  var NO_HOLES = TYPE == 5 || IS_FIND_INDEX;
	  return function ($this, callbackfn, that, specificCreate) {
	    var O = toObject($this);
	    var self = indexedObject(O);
	    var boundFunction = functionBindContext(callbackfn, that, 3);
	    var length = toLength(self.length);
	    var index = 0;
	    var create = specificCreate || arraySpeciesCreate;
	    var target = IS_MAP ? create($this, length) : IS_FILTER || IS_FILTER_OUT ? create($this, 0) : undefined;
	    var value, result;
	    for (;length > index; index++) { if (NO_HOLES || index in self) {
	      value = self[index];
	      result = boundFunction(value, index, O);
	      if (TYPE) {
	        if (IS_MAP) { target[index] = result; } // map
	        else if (result) { switch (TYPE) {
	          case 3: return true;              // some
	          case 5: return value;             // find
	          case 6: return index;             // findIndex
	          case 2: push.call(target, value); // filter
	        } } else { switch (TYPE) {
	          case 4: return false;             // every
	          case 7: push.call(target, value); // filterOut
	        } }
	      }
	    } }
	    return IS_FIND_INDEX ? -1 : IS_SOME || IS_EVERY ? IS_EVERY : target;
	  };
	};

	var arrayIteration = {
	  // `Array.prototype.forEach` method
	  // https://tc39.es/ecma262/#sec-array.prototype.foreach
	  forEach: createMethod$1(0),
	  // `Array.prototype.map` method
	  // https://tc39.es/ecma262/#sec-array.prototype.map
	  map: createMethod$1(1),
	  // `Array.prototype.filter` method
	  // https://tc39.es/ecma262/#sec-array.prototype.filter
	  filter: createMethod$1(2),
	  // `Array.prototype.some` method
	  // https://tc39.es/ecma262/#sec-array.prototype.some
	  some: createMethod$1(3),
	  // `Array.prototype.every` method
	  // https://tc39.es/ecma262/#sec-array.prototype.every
	  every: createMethod$1(4),
	  // `Array.prototype.find` method
	  // https://tc39.es/ecma262/#sec-array.prototype.find
	  find: createMethod$1(5),
	  // `Array.prototype.findIndex` method
	  // https://tc39.es/ecma262/#sec-array.prototype.findIndex
	  findIndex: createMethod$1(6),
	  // `Array.prototype.filterOut` method
	  // https://github.com/tc39/proposal-array-filtering
	  filterOut: createMethod$1(7)
	};
	var arrayIteration_1 = arrayIteration.forEach;
	var arrayIteration_2 = arrayIteration.map;
	var arrayIteration_3 = arrayIteration.filter;
	var arrayIteration_4 = arrayIteration.some;
	var arrayIteration_5 = arrayIteration.every;
	var arrayIteration_6 = arrayIteration.find;
	var arrayIteration_7 = arrayIteration.findIndex;
	var arrayIteration_8 = arrayIteration.filterOut;

	'use strict';

	var $find = arrayIteration.find;



	var FIND = 'find';
	var SKIPS_HOLES = true;

	var USES_TO_LENGTH$1 = arrayMethodUsesToLength(FIND);

	// Shouldn't skip holes
	if (FIND in []) { Array(1)[FIND](function () { SKIPS_HOLES = false; }); }

	// `Array.prototype.find` method
	// https://tc39.es/ecma262/#sec-array.prototype.find
	_export({ target: 'Array', proto: true, forced: SKIPS_HOLES || !USES_TO_LENGTH$1 }, {
	  find: function find(callbackfn /* , that = undefined */) {
	    return $find(this, callbackfn, arguments.length > 1 ? arguments[1] : undefined);
	  }
	});

	// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
	addToUnscopables(FIND);

	var es_array_find = {

	};

	var find = entryUnbind('Array', 'find');

	var find$1 = find;

	// `String.prototype.{ codePointAt, at }` methods implementation
	var createMethod$2 = function (CONVERT_TO_STRING) {
	  return function ($this, pos) {
	    var S = String(requireObjectCoercible($this));
	    var position = toInteger(pos);
	    var size = S.length;
	    var first, second;
	    if (position < 0 || position >= size) { return CONVERT_TO_STRING ? '' : undefined; }
	    first = S.charCodeAt(position);
	    return first < 0xD800 || first > 0xDBFF || position + 1 === size
	      || (second = S.charCodeAt(position + 1)) < 0xDC00 || second > 0xDFFF
	        ? CONVERT_TO_STRING ? S.charAt(position) : first
	        : CONVERT_TO_STRING ? S.slice(position, position + 2) : (first - 0xD800 << 10) + (second - 0xDC00) + 0x10000;
	  };
	};

	var stringMultibyte = {
	  // `String.prototype.codePointAt` method
	  // https://tc39.es/ecma262/#sec-string.prototype.codepointat
	  codeAt: createMethod$2(false),
	  // `String.prototype.at` method
	  // https://github.com/mathiasbynens/String.prototype.at
	  charAt: createMethod$2(true)
	};
	var stringMultibyte_1 = stringMultibyte.codeAt;
	var stringMultibyte_2 = stringMultibyte.charAt;

	var correctPrototypeGetter = !fails(function () {
	  function F() { /* empty */ }
	  F.prototype.constructor = null;
	  return Object.getPrototypeOf(new F()) !== F.prototype;
	});

	var IE_PROTO$1 = sharedKey('IE_PROTO');
	var ObjectPrototype = Object.prototype;

	// `Object.getPrototypeOf` method
	// https://tc39.es/ecma262/#sec-object.getprototypeof
	var objectGetPrototypeOf = correctPrototypeGetter ? Object.getPrototypeOf : function (O) {
	  O = toObject(O);
	  if (has(O, IE_PROTO$1)) { return O[IE_PROTO$1]; }
	  if (typeof O.constructor == 'function' && O instanceof O.constructor) {
	    return O.constructor.prototype;
	  } return O instanceof Object ? ObjectPrototype : null;
	};

	'use strict';







	var ITERATOR = wellKnownSymbol('iterator');
	var BUGGY_SAFARI_ITERATORS = false;

	var returnThis = function () { return this; };

	// `%IteratorPrototype%` object
	// https://tc39.es/ecma262/#sec-%iteratorprototype%-object
	var IteratorPrototype, PrototypeOfArrayIteratorPrototype, arrayIterator;

	if ([].keys) {
	  arrayIterator = [].keys();
	  // Safari 8 has buggy iterators w/o `next`
	  if (!('next' in arrayIterator)) { BUGGY_SAFARI_ITERATORS = true; }
	  else {
	    PrototypeOfArrayIteratorPrototype = objectGetPrototypeOf(objectGetPrototypeOf(arrayIterator));
	    if (PrototypeOfArrayIteratorPrototype !== Object.prototype) { IteratorPrototype = PrototypeOfArrayIteratorPrototype; }
	  }
	}

	var NEW_ITERATOR_PROTOTYPE = IteratorPrototype == undefined || fails(function () {
	  var test = {};
	  // FF44- legacy iterators case
	  return IteratorPrototype[ITERATOR].call(test) !== test;
	});

	if (NEW_ITERATOR_PROTOTYPE) { IteratorPrototype = {}; }

	// 25.1.2.1.1 %IteratorPrototype%[@@iterator]()
	if ((!isPure || NEW_ITERATOR_PROTOTYPE) && !has(IteratorPrototype, ITERATOR)) {
	  createNonEnumerableProperty(IteratorPrototype, ITERATOR, returnThis);
	}

	var iteratorsCore = {
	  IteratorPrototype: IteratorPrototype,
	  BUGGY_SAFARI_ITERATORS: BUGGY_SAFARI_ITERATORS
	};
	var iteratorsCore_1 = iteratorsCore.IteratorPrototype;
	var iteratorsCore_2 = iteratorsCore.BUGGY_SAFARI_ITERATORS;

	var defineProperty$1 = objectDefineProperty.f;



	var TO_STRING_TAG = wellKnownSymbol('toStringTag');

	var setToStringTag = function (it, TAG, STATIC) {
	  if (it && !has(it = STATIC ? it : it.prototype, TO_STRING_TAG)) {
	    defineProperty$1(it, TO_STRING_TAG, { configurable: true, value: TAG });
	  }
	};

	var iterators = {};

	'use strict';
	var IteratorPrototype$1 = iteratorsCore.IteratorPrototype;





	var returnThis$1 = function () { return this; };

	var createIteratorConstructor = function (IteratorConstructor, NAME, next) {
	  var TO_STRING_TAG = NAME + ' Iterator';
	  IteratorConstructor.prototype = objectCreate(IteratorPrototype$1, { next: createPropertyDescriptor(1, next) });
	  setToStringTag(IteratorConstructor, TO_STRING_TAG, false, true);
	  iterators[TO_STRING_TAG] = returnThis$1;
	  return IteratorConstructor;
	};

	var aPossiblePrototype = function (it) {
	  if (!isObject(it) && it !== null) {
	    throw TypeError("Can't set " + String(it) + ' as a prototype');
	  } return it;
	};

	// `Object.setPrototypeOf` method
	// https://tc39.es/ecma262/#sec-object.setprototypeof
	// Works with __proto__ only. Old v8 can't work with null proto objects.
	/* eslint-disable no-proto */
	var objectSetPrototypeOf = Object.setPrototypeOf || ('__proto__' in {} ? function () {
	  var CORRECT_SETTER = false;
	  var test = {};
	  var setter;
	  try {
	    setter = Object.getOwnPropertyDescriptor(Object.prototype, '__proto__').set;
	    setter.call(test, []);
	    CORRECT_SETTER = test instanceof Array;
	  } catch (error) { /* empty */ }
	  return function setPrototypeOf(O, proto) {
	    anObject(O);
	    aPossiblePrototype(proto);
	    if (CORRECT_SETTER) { setter.call(O, proto); }
	    else { O.__proto__ = proto; }
	    return O;
	  };
	}() : undefined);

	'use strict';












	var IteratorPrototype$2 = iteratorsCore.IteratorPrototype;
	var BUGGY_SAFARI_ITERATORS$1 = iteratorsCore.BUGGY_SAFARI_ITERATORS;
	var ITERATOR$1 = wellKnownSymbol('iterator');
	var KEYS = 'keys';
	var VALUES = 'values';
	var ENTRIES = 'entries';

	var returnThis$2 = function () { return this; };

	var defineIterator = function (Iterable, NAME, IteratorConstructor, next, DEFAULT, IS_SET, FORCED) {
	  createIteratorConstructor(IteratorConstructor, NAME, next);

	  var getIterationMethod = function (KIND) {
	    if (KIND === DEFAULT && defaultIterator) { return defaultIterator; }
	    if (!BUGGY_SAFARI_ITERATORS$1 && KIND in IterablePrototype) { return IterablePrototype[KIND]; }
	    switch (KIND) {
	      case KEYS: return function keys() { return new IteratorConstructor(this, KIND); };
	      case VALUES: return function values() { return new IteratorConstructor(this, KIND); };
	      case ENTRIES: return function entries() { return new IteratorConstructor(this, KIND); };
	    } return function () { return new IteratorConstructor(this); };
	  };

	  var TO_STRING_TAG = NAME + ' Iterator';
	  var INCORRECT_VALUES_NAME = false;
	  var IterablePrototype = Iterable.prototype;
	  var nativeIterator = IterablePrototype[ITERATOR$1]
	    || IterablePrototype['@@iterator']
	    || DEFAULT && IterablePrototype[DEFAULT];
	  var defaultIterator = !BUGGY_SAFARI_ITERATORS$1 && nativeIterator || getIterationMethod(DEFAULT);
	  var anyNativeIterator = NAME == 'Array' ? IterablePrototype.entries || nativeIterator : nativeIterator;
	  var CurrentIteratorPrototype, methods, KEY;

	  // fix native
	  if (anyNativeIterator) {
	    CurrentIteratorPrototype = objectGetPrototypeOf(anyNativeIterator.call(new Iterable()));
	    if (IteratorPrototype$2 !== Object.prototype && CurrentIteratorPrototype.next) {
	      if (!isPure && objectGetPrototypeOf(CurrentIteratorPrototype) !== IteratorPrototype$2) {
	        if (objectSetPrototypeOf) {
	          objectSetPrototypeOf(CurrentIteratorPrototype, IteratorPrototype$2);
	        } else if (typeof CurrentIteratorPrototype[ITERATOR$1] != 'function') {
	          createNonEnumerableProperty(CurrentIteratorPrototype, ITERATOR$1, returnThis$2);
	        }
	      }
	      // Set @@toStringTag to native iterators
	      setToStringTag(CurrentIteratorPrototype, TO_STRING_TAG, true, true);
	      if (isPure) { iterators[TO_STRING_TAG] = returnThis$2; }
	    }
	  }

	  // fix Array#{values, @@iterator}.name in V8 / FF
	  if (DEFAULT == VALUES && nativeIterator && nativeIterator.name !== VALUES) {
	    INCORRECT_VALUES_NAME = true;
	    defaultIterator = function values() { return nativeIterator.call(this); };
	  }

	  // define iterator
	  if ((!isPure || FORCED) && IterablePrototype[ITERATOR$1] !== defaultIterator) {
	    createNonEnumerableProperty(IterablePrototype, ITERATOR$1, defaultIterator);
	  }
	  iterators[NAME] = defaultIterator;

	  // export additional methods
	  if (DEFAULT) {
	    methods = {
	      values: getIterationMethod(VALUES),
	      keys: IS_SET ? defaultIterator : getIterationMethod(KEYS),
	      entries: getIterationMethod(ENTRIES)
	    };
	    if (FORCED) { for (KEY in methods) {
	      if (BUGGY_SAFARI_ITERATORS$1 || INCORRECT_VALUES_NAME || !(KEY in IterablePrototype)) {
	        redefine(IterablePrototype, KEY, methods[KEY]);
	      }
	    } } else { _export({ target: NAME, proto: true, forced: BUGGY_SAFARI_ITERATORS$1 || INCORRECT_VALUES_NAME }, methods); }
	  }

	  return methods;
	};

	'use strict';
	var charAt = stringMultibyte.charAt;



	var STRING_ITERATOR = 'String Iterator';
	var setInternalState = internalState.set;
	var getInternalState = internalState.getterFor(STRING_ITERATOR);

	// `String.prototype[@@iterator]` method
	// https://tc39.es/ecma262/#sec-string.prototype-@@iterator
	defineIterator(String, 'String', function (iterated) {
	  setInternalState(this, {
	    type: STRING_ITERATOR,
	    string: String(iterated),
	    index: 0
	  });
	// `%StringIteratorPrototype%.next` method
	// https://tc39.es/ecma262/#sec-%stringiteratorprototype%.next
	}, function next() {
	  var state = getInternalState(this);
	  var string = state.string;
	  var index = state.index;
	  var point;
	  if (index >= string.length) { return { value: undefined, done: true }; }
	  point = charAt(string, index);
	  state.index += point.length;
	  return { value: point, done: false };
	});

	var es_string_iterator = {

	};

	var iteratorClose = function (iterator) {
	  var returnMethod = iterator['return'];
	  if (returnMethod !== undefined) {
	    return anObject(returnMethod.call(iterator)).value;
	  }
	};

	// call something on iterator step with safe closing on error
	var callWithSafeIterationClosing = function (iterator, fn, value, ENTRIES) {
	  try {
	    return ENTRIES ? fn(anObject(value)[0], value[1]) : fn(value);
	  // 7.4.6 IteratorClose(iterator, completion)
	  } catch (error) {
	    iteratorClose(iterator);
	    throw error;
	  }
	};

	var ITERATOR$2 = wellKnownSymbol('iterator');
	var ArrayPrototype$1 = Array.prototype;

	// check on default Array iterator
	var isArrayIteratorMethod = function (it) {
	  return it !== undefined && (iterators.Array === it || ArrayPrototype$1[ITERATOR$2] === it);
	};

	'use strict';




	var createProperty = function (object, key, value) {
	  var propertyKey = toPrimitive(key);
	  if (propertyKey in object) { objectDefineProperty.f(object, propertyKey, createPropertyDescriptor(0, value)); }
	  else { object[propertyKey] = value; }
	};

	var TO_STRING_TAG$1 = wellKnownSymbol('toStringTag');
	var test = {};

	test[TO_STRING_TAG$1] = 'z';

	var toStringTagSupport = String(test) === '[object z]';

	var TO_STRING_TAG$2 = wellKnownSymbol('toStringTag');
	// ES3 wrong here
	var CORRECT_ARGUMENTS = classofRaw(function () { return arguments; }()) == 'Arguments';

	// fallback for IE11 Script Access Denied error
	var tryGet = function (it, key) {
	  try {
	    return it[key];
	  } catch (error) { /* empty */ }
	};

	// getting tag from ES6+ `Object.prototype.toString`
	var classof = toStringTagSupport ? classofRaw : function (it) {
	  var O, tag, result;
	  return it === undefined ? 'Undefined' : it === null ? 'Null'
	    // @@toStringTag case
	    : typeof (tag = tryGet(O = Object(it), TO_STRING_TAG$2)) == 'string' ? tag
	    // builtinTag case
	    : CORRECT_ARGUMENTS ? classofRaw(O)
	    // ES3 arguments fallback
	    : (result = classofRaw(O)) == 'Object' && typeof O.callee == 'function' ? 'Arguments' : result;
	};

	var ITERATOR$3 = wellKnownSymbol('iterator');

	var getIteratorMethod = function (it) {
	  if (it != undefined) { return it[ITERATOR$3]
	    || it['@@iterator']
	    || iterators[classof(it)]; }
	};

	'use strict';








	// `Array.from` method implementation
	// https://tc39.es/ecma262/#sec-array.from
	var arrayFrom = function from(arrayLike /* , mapfn = undefined, thisArg = undefined */) {
	  var O = toObject(arrayLike);
	  var C = typeof this == 'function' ? this : Array;
	  var argumentsLength = arguments.length;
	  var mapfn = argumentsLength > 1 ? arguments[1] : undefined;
	  var mapping = mapfn !== undefined;
	  var iteratorMethod = getIteratorMethod(O);
	  var index = 0;
	  var length, result, step, iterator, next, value;
	  if (mapping) { mapfn = functionBindContext(mapfn, argumentsLength > 2 ? arguments[2] : undefined, 2); }
	  // if the target is not iterable or it's an array with the default iterator - use a simple case
	  if (iteratorMethod != undefined && !(C == Array && isArrayIteratorMethod(iteratorMethod))) {
	    iterator = iteratorMethod.call(O);
	    next = iterator.next;
	    result = new C();
	    for (;!(step = next.call(iterator)).done; index++) {
	      value = mapping ? callWithSafeIterationClosing(iterator, mapfn, [step.value, index], true) : step.value;
	      createProperty(result, index, value);
	    }
	  } else {
	    length = toLength(O.length);
	    result = new C(length);
	    for (;length > index; index++) {
	      value = mapping ? mapfn(O[index], index) : O[index];
	      createProperty(result, index, value);
	    }
	  }
	  result.length = index;
	  return result;
	};

	var ITERATOR$4 = wellKnownSymbol('iterator');
	var SAFE_CLOSING = false;

	try {
	  var called = 0;
	  var iteratorWithReturn = {
	    next: function () {
	      return { done: !!called++ };
	    },
	    'return': function () {
	      SAFE_CLOSING = true;
	    }
	  };
	  iteratorWithReturn[ITERATOR$4] = function () {
	    return this;
	  };
	  // eslint-disable-next-line no-throw-literal
	  Array.from(iteratorWithReturn, function () { throw 2; });
	} catch (error) { /* empty */ }

	var checkCorrectnessOfIteration = function (exec, SKIP_CLOSING) {
	  if (!SKIP_CLOSING && !SAFE_CLOSING) { return false; }
	  var ITERATION_SUPPORT = false;
	  try {
	    var object = {};
	    object[ITERATOR$4] = function () {
	      return {
	        next: function () {
	          return { done: ITERATION_SUPPORT = true };
	        }
	      };
	    };
	    exec(object);
	  } catch (error) { /* empty */ }
	  return ITERATION_SUPPORT;
	};

	var INCORRECT_ITERATION = !checkCorrectnessOfIteration(function (iterable) {
	  Array.from(iterable);
	});

	// `Array.from` method
	// https://tc39.es/ecma262/#sec-array.from
	_export({ target: 'Array', stat: true, forced: INCORRECT_ITERATION }, {
	  from: arrayFrom
	});

	var es_array_from = {

	};

	var from_1 = path.Array.from;

	var from_1$1 = from_1;

	'use strict';

	var $findIndex = arrayIteration.findIndex;



	var FIND_INDEX = 'findIndex';
	var SKIPS_HOLES$1 = true;

	var USES_TO_LENGTH$2 = arrayMethodUsesToLength(FIND_INDEX);

	// Shouldn't skip holes
	if (FIND_INDEX in []) { Array(1)[FIND_INDEX](function () { SKIPS_HOLES$1 = false; }); }

	// `Array.prototype.findIndex` method
	// https://tc39.es/ecma262/#sec-array.prototype.findindex
	_export({ target: 'Array', proto: true, forced: SKIPS_HOLES$1 || !USES_TO_LENGTH$2 }, {
	  findIndex: function findIndex(callbackfn /* , that = undefined */) {
	    return $findIndex(this, callbackfn, arguments.length > 1 ? arguments[1] : undefined);
	  }
	});

	// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
	addToUnscopables(FIND_INDEX);

	var es_array_findIndex = {

	};

	var findIndex = entryUnbind('Array', 'findIndex');

	var findIndex$1 = findIndex;

	var base64 = createCommonjsModule(function (module, exports) {
	(function() {

	    /**
	     * version: 0.3.0
	     * git://github.com/davidchambers/Base64.js.git
	     */

	    var object = 'object' != 'undefined' ? exports : this; // #8: web workers
	    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

	    function InvalidCharacterError(message) {
	        this.message = message;
	    }

	    InvalidCharacterError.prototype = new Error;
	    InvalidCharacterError.prototype.name = 'InvalidCharacterError';

	    // encoder
	    // [https://gist.github.com/999166] by [https://github.com/nignag]
	    object.btoa || (
	        object.btoa = function(input) {
	            var str = String(input);
	            for (
	                // initialize result and counter
	                var block, charCode, idx = 0, map = chars, output = '';
	                // if the next str index does not exist:
	                //   change the mapping table to "="
	                //   check if d has no fractional digits
	                str.charAt(idx | 0) || (map = '=', idx % 1);
	                // "8 - idx % 1 * 8" generates the sequence 2, 4, 6, 8
	                output += map.charAt(63 & block >> 8 - idx % 1 * 8)
	            ) {
	                charCode = str.charCodeAt(idx += 3 / 4);
	                if (charCode > 0xFF) {
	                    throw new InvalidCharacterError('\'btoa\' failed: The string to be encoded contains characters outside of the Latin1 range.');
	                }
	                block = block << 8 | charCode;
	            }
	            return output;
	        });

	    // decoder
	    // [https://gist.github.com/1020396] by [https://github.com/atk]
	    object.atob || (
	        object.atob = function(input) {
	            var str = String(input).replace(/=+$/, '');
	            if (str.length % 4 == 1) {
	                throw new InvalidCharacterError('\'atob\' failed: The string to be decoded is not correctly encoded.');
	            }
	            for (
	                // initialize result and counters
	                var bc = 0, bs, buffer, idx = 0, output = '';
	                // get next character
	                // eslint-disable-next-line no-cond-assign
	                buffer = str.charAt(idx++);
	                // character found in table? initialize bit storage and add its ascii value;
	                ~buffer && (bs = bc % 4 ? bs * 64 + buffer : buffer,
	                // and if not first of each 4 characters,
	                // convert the first 8 bits to one ascii character
	                bc++ % 4) ? output += String.fromCharCode(255 & bs >> (-2 * bc & 6)) : 0
	            ) {
	                // try to find character in table (0-63, not found => -1)
	                buffer = chars.indexOf(buffer);
	            }
	            return output;
	        });

	}());
	});

	// `Number.isNaN` method
	// https://tc39.es/ecma262/#sec-number.isnan
	_export({ target: 'Number', stat: true }, {
	  isNaN: function isNaN(number) {
	    // eslint-disable-next-line no-self-compare
	    return number != number;
	  }
	});

	var es_number_isNan = {

	};

	var isNan = path.Number.isNaN;

	var isNan$1 = isNan;

	var globalIsFinite = global_1.isFinite;

	// `Number.isFinite` method
	// https://tc39.es/ecma262/#sec-number.isfinite
	var numberIsFinite = Number.isFinite || function isFinite(it) {
	  return typeof it == 'number' && globalIsFinite(it);
	};

	// `Number.isFinite` method
	// https://tc39.es/ecma262/#sec-number.isfinite
	_export({ target: 'Number', stat: true }, { isFinite: numberIsFinite });

	var es_number_isFinite = {

	};

	var _isFinite = path.Number.isFinite;

	var _isFinite$1 = _isFinite;

	var MATCH = wellKnownSymbol('match');

	// `IsRegExp` abstract operation
	// https://tc39.es/ecma262/#sec-isregexp
	var isRegexp = function (it) {
	  var isRegExp;
	  return isObject(it) && ((isRegExp = it[MATCH]) !== undefined ? !!isRegExp : classofRaw(it) == 'RegExp');
	};

	var notARegexp = function (it) {
	  if (isRegexp(it)) {
	    throw TypeError("The method doesn't accept regular expressions");
	  } return it;
	};

	var MATCH$1 = wellKnownSymbol('match');

	var correctIsRegexpLogic = function (METHOD_NAME) {
	  var regexp = /./;
	  try {
	    '/./'[METHOD_NAME](regexp);
	  } catch (error1) {
	    try {
	      regexp[MATCH$1] = false;
	      return '/./'[METHOD_NAME](regexp);
	    } catch (error2) { /* empty */ }
	  } return false;
	};

	'use strict';





	// `String.prototype.includes` method
	// https://tc39.es/ecma262/#sec-string.prototype.includes
	_export({ target: 'String', proto: true, forced: !correctIsRegexpLogic('includes') }, {
	  includes: function includes(searchString /* , position = 0 */) {
	    return !!~String(requireObjectCoercible(this))
	      .indexOf(notARegexp(searchString), arguments.length > 1 ? arguments[1] : undefined);
	  }
	});

	var es_string_includes = {

	};

	var includes$2 = entryUnbind('String', 'includes');

	var includes$3 = includes$2;

	'use strict';

	var getOwnPropertyDescriptor$2 = objectGetOwnPropertyDescriptor.f;






	var nativeStartsWith = ''.startsWith;
	var min$2 = Math.min;

	var CORRECT_IS_REGEXP_LOGIC = correctIsRegexpLogic('startsWith');
	// https://github.com/zloirock/core-js/pull/702
	var MDN_POLYFILL_BUG = !isPure && !CORRECT_IS_REGEXP_LOGIC && !!function () {
	  var descriptor = getOwnPropertyDescriptor$2(String.prototype, 'startsWith');
	  return descriptor && !descriptor.writable;
	}();

	// `String.prototype.startsWith` method
	// https://tc39.es/ecma262/#sec-string.prototype.startswith
	_export({ target: 'String', proto: true, forced: !MDN_POLYFILL_BUG && !CORRECT_IS_REGEXP_LOGIC }, {
	  startsWith: function startsWith(searchString /* , position = 0 */) {
	    var that = String(requireObjectCoercible(this));
	    notARegexp(searchString);
	    var index = toLength(min$2(arguments.length > 1 ? arguments[1] : undefined, that.length));
	    var search = String(searchString);
	    return nativeStartsWith
	      ? nativeStartsWith.call(that, search, index)
	      : that.slice(index, index + search.length) === search;
	  }
	});

	var es_string_startsWith = {

	};

	var startsWith = entryUnbind('String', 'startsWith');

	var startsWith$1 = startsWith;

	(function() {

	    if (typeof Uint8Array !== 'undefined' || typeof window === 'undefined') {
	        return;
	    }

	    function subarray(start, end) {
	        return this.slice(start, end);
	    }

	    function set_(array, offset) {

	        if (arguments.length < 2) {
	            offset = 0;
	        }
	        for (var i = 0, n = array.length; i < n; ++i, ++offset) {
	            this[offset] = array[i] & 0xFF;
	        }
	    }

	    // we need typed arrays
	    function TypedArray(arg1) {

	        var result;
	        if (typeof arg1 === 'number') {
	            result = new Array(arg1);
	            for (var i = 0; i < arg1; ++i) {
	                result[i] = 0;
	            }
	        } else {
	            result = arg1.slice(0);
	        }
	        result.subarray = subarray;
	        result.buffer = result;
	        result.byteLength = result.length;
	        result.set = set_;
	        if (typeof arg1 === 'object' && arg1.buffer) {
	            result.buffer = arg1.buffer;
	        }

	        return result;
	    }

	    window.Uint8Array = TypedArray;
	    window.Uint32Array = TypedArray;
	    window.Int32Array = TypedArray;
	})();

	var props = {
	    x: 'x',
	    y: 'y',
	    width: 'w',
	    height: 'h',
	    minimum: 's',
	    maximum: 'l',
	    diagonal: 'd'
	};
	var propsList = Object.keys(props).map(function (key) { return props[key]; }).join('');
	var numberPattern = '[-+]?[0-9]*\\.?[0-9]+(?:[eE][-+]?[0-9]+)?';
	var findSpacesRegex = /\s/g;
	var parseExpressionRegExp = new RegExp(("^(" + numberPattern + "\\*)?([" + propsList + "])(/" + numberPattern + ")?([-+]{1,2}" + numberPattern + ")?$"), 'g');

	function throwInvalid(expression) {
	    throw new Error(("Invalid calc() expression: " + expression));
	}

	function evalCalcExpression(expression, bbox) {
	    var match = parseExpressionRegExp.exec(expression.replace(findSpacesRegex, ''));
	    if (!match) { throwInvalid(expression); }
	    parseExpressionRegExp.lastIndex = 0; // reset regex results for the next run
	    var multiply = match[1];
	    var property = match[2];
	    var divide = match[3];
	    var add = match[4];
	    var x = bbox.x;
	    var y = bbox.y;
	    var width = bbox.width;
	    var height = bbox.height;
	    var value = 0;
	    switch (property) {
	        case props.width: {
	            value = width;
	            break;
	        }
	        case props.height: {
	            value = height;
	            break;
	        }
	        case props.x: {
	            value = x;
	            break;
	        }
	        case props.y: {
	            value = y;
	            break;
	        }
	        case props.minimum: {
	            value = Math.min(height, width);
	            break;
	        }
	        case props.maximum: {
	            value = Math.max(height, width);
	            break;
	        }
	        case props.diagonal: {
	            value = Math.sqrt((height * height) + (width * width));
	            break;
	        }
	    }
	    if (multiply) {
	        // e.g "2*"
	        value *= parseFloat(multiply);
	    }
	    if (divide) {
	        // e.g "/2"
	        value /= parseFloat(divide.slice(1));
	    }
	    if (add) {
	        value += evalAddExpression(add);
	    }
	    return value;
	}

	function evalAddExpression(addExpression) {
	    if (!addExpression) { return 0; }
	    var sign = addExpression[0];
	    switch (sign) {
	        case '+': {
	            return parseFloat(addExpression.substr(1));
	        }
	        case '-': {
	            return -parseFloat(addExpression.substr(1));
	        }
	    }
	    return parseFloat(addExpression);
	}

	function isCalcAttribute(value) {
	    return typeof value === 'string' && value.includes('calc');
	}

	var calcStart = 'calc(';
	var calcStartOffset = calcStart.length;

	function evalCalcAttribute(attributeValue, refBBox) {
	    var value = attributeValue;
	    var startSearchIndex = 0;
	    do {
	        var calcIndex = value.indexOf(calcStart, startSearchIndex);
	        if (calcIndex === -1) { return value; }
	        var calcEndIndex = calcIndex + calcStartOffset;
	        var brackets = 1;
	        findClosingBracket: do {
	            switch (value[calcEndIndex]) {
	                case '(': {
	                    brackets++;
	                    break;
	                }
	                case ')': {
	                    brackets--;
	                    if (brackets === 0) { break findClosingBracket; }
	                    break;
	                }
	                case undefined: {
	                    // Could not find the closing bracket.
	                    throwInvalid(value);
	                }
	            }
	            calcEndIndex++;
	        } while (true);
	        // Get the calc() expression without nested calcs (recursion)
	        var expression = value.slice(calcIndex + calcStartOffset, calcEndIndex);
	        if (isCalcAttribute(expression)) {
	            expression = evalCalcAttribute(expression, refBBox);
	        }
	        // Eval the calc() expression without nested calcs.
	        var calcValue = String(evalCalcExpression(expression, refBBox));
	        // Replace the calc() expression and continue search
	        value = value.slice(0, calcIndex) + calcValue + value.slice(calcEndIndex + 1);
	        startSearchIndex = calcIndex + calcValue.length;
	    } while (true);
	}

	// Declare shorthands to the most used math functions.
	var round = Math.round;
	var floor$1 = Math.floor;
	var PI = Math.PI;

	var scale = {

	    // Return the `value` from the `domain` interval scaled to the `range` interval.
	    linear: function(domain, range, value) {

	        var domainSpan = domain[1] - domain[0];
	        var rangeSpan = range[1] - range[0];
	        return (((value - domain[0]) / domainSpan) * rangeSpan + range[0]) || 0;
	    }
	};

	var normalizeAngle = function(angle) {

	    return (angle % 360) + (angle < 0 ? 360 : 0);
	};

	var snapToGrid = function(value, gridSize) {

	    return gridSize * round(value / gridSize);
	};

	var toDeg = function(rad) {

	    return (180 * rad / PI) % 360;
	};

	var toRad = function(deg, over360) {

	    over360 = over360 || false;
	    deg = over360 ? deg : (deg % 360);
	    return deg * PI / 180;
	};

	// Return a random integer from the interval [min,max], inclusive.
	var random = function(min, max) {

	    if (max === undefined) {
	        // use first argument as max, min is 0
	        max = (min === undefined) ? 1 : min;
	        min = 0;

	    } else if (max < min) {
	        // switch max and min
	        var temp = min;
	        min = max;
	        max = temp;
	    }

	    return floor$1((Math.random() * (max - min + 1)) + min);
	};

	// @return the bearing (cardinal direction) of the line. For example N, W, or SE.

	var cos = Math.cos;
	var sin = Math.sin;
	var atan2 = Math.atan2;

	var bearing = function(p, q) {

	    var lat1 = toRad(p.y);
	    var lat2 = toRad(q.y);
	    var lon1 = p.x;
	    var lon2 = q.x;
	    var dLon = toRad(lon2 - lon1);
	    var y = sin(dLon) * cos(lat2);
	    var x = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dLon);
	    var brng = toDeg(atan2(y, x));

	    var bearings = ['NE', 'E', 'SE', 'S', 'SW', 'W', 'NW', 'N'];

	    var index = brng - 22.5;
	    if (index < 0)
	        { index += 360; }
	    index = parseInt(index / 45);

	    return bearings[index];
	};

	// @return {integer} length without sqrt
	// @note for applications where the exact length is not necessary (e.g. compare only)
	var squaredLength = function(start, end) {

	    var x0 = start.x;
	    var y0 = start.y;
	    var x1 = end.x;
	    var y1 = end.y;
	    return (x0 -= x1) * x0 + (y0 -= y1) * y0;
	};

	var length = function(start, end) {
	    return Math.sqrt(squaredLength(start, end));
	};

	var types = {
	    Point: 1,
	    Line: 2,
	    Ellipse: 3,
	    Rect: 4,
	    Polyline: 5,
	    Polygon: 6,
	    Curve: 7,
	    Path: 8
	};

	/*
	    Point is the most basic object consisting of x/y coordinate.

	    Possible instantiations are:
	    * `Point(10, 20)`
	    * `new Point(10, 20)`
	    * `Point('10 20')`
	    * `Point(Point(10, 20))`
	*/

	var abs = Math.abs;
	var cos$1 = Math.cos;
	var sin$1 = Math.sin;
	var sqrt = Math.sqrt;
	var min$3 = Math.min;
	var max$1 = Math.max;
	var atan2$1 = Math.atan2;
	var round$1 = Math.round;
	var pow = Math.pow;
	var PI$1 = Math.PI;

	var Point = function(x, y) {

	    if (!(this instanceof Point)) {
	        return new Point(x, y);
	    }

	    if (typeof x === 'string') {
	        var xy = x.split(x.indexOf('@') === -1 ? ' ' : '@');
	        x = parseFloat(xy[0]);
	        y = parseFloat(xy[1]);

	    } else if (Object(x) === x) {
	        y = x.y;
	        x = x.x;
	    }

	    this.x = x === undefined ? 0 : x;
	    this.y = y === undefined ? 0 : y;
	};

	// Alternative constructor, from polar coordinates.
	// @param {number} Distance.
	// @param {number} Angle in radians.
	// @param {point} [optional] Origin.
	Point.fromPolar = function(distance, angle, origin) {

	    origin = new Point(origin);
	    var x = abs(distance * cos$1(angle));
	    var y = abs(distance * sin$1(angle));
	    var deg = normalizeAngle(toDeg(angle));

	    if (deg < 90) {
	        y = -y;

	    } else if (deg < 180) {
	        x = -x;
	        y = -y;

	    } else if (deg < 270) {
	        x = -x;
	    }

	    return new Point(origin.x + x, origin.y + y);
	};

	// Create a point with random coordinates that fall into the range `[x1, x2]` and `[y1, y2]`.
	Point.random = function(x1, x2, y1, y2) {

	    return new Point(random(x1, x2), random(y1, y2));
	};

	Point.prototype = {

	    type: types.Point,

	    chooseClosest: function(points) {

	        var n = points.length;
	        if (n === 1) { return new Point(points[0]); }
	        var closest = null;
	        var minSqrDistance = Infinity;
	        for (var i = 0; i < n; i++) {
	            var p = new Point(points[i]);
	            var sqrDistance = this.squaredDistance(p);
	            if (sqrDistance < minSqrDistance) {
	                closest = p;
	                minSqrDistance = sqrDistance;
	            }
	        }
	        return closest;
	    },

	    // If point lies outside rectangle `r`, return the nearest point on the boundary of rect `r`,
	    // otherwise return point itself.
	    // (see Squeak Smalltalk, Point>>adhereTo:)
	    adhereToRect: function(r) {

	        if (r.containsPoint(this)) {
	            return this;
	        }

	        this.x = min$3(max$1(this.x, r.x), r.x + r.width);
	        this.y = min$3(max$1(this.y, r.y), r.y + r.height);
	        return this;
	    },

	    // Compute the angle between vector from me to p1 and the vector from me to p2.
	    // ordering of points p1 and p2 is important!
	    // theta function's angle convention:
	    // returns angles between 0 and 180 when the angle is counterclockwise
	    // returns angles between 180 and 360 to convert clockwise angles into counterclockwise ones
	    // returns NaN if any of the points p1, p2 is coincident with this point
	    angleBetween: function(p1, p2) {

	        var angleBetween = (this.equals(p1) || this.equals(p2)) ? NaN : (this.theta(p2) - this.theta(p1));

	        if (angleBetween < 0) {
	            angleBetween += 360; // correction to keep angleBetween between 0 and 360
	        }

	        return angleBetween;
	    },

	    // Return the bearing between me and the given point.
	    bearing: function(point) {
	        return bearing(this, point);
	    },

	    // Returns change in angle from my previous position (-dx, -dy) to my new position
	    // relative to ref point.
	    changeInAngle: function(dx, dy, ref) {

	        // Revert the translation and measure the change in angle around x-axis.
	        return this.clone().offset(-dx, -dy).theta(ref) - this.theta(ref);
	    },

	    clone: function() {

	        return new Point(this);
	    },

	    // Returns the cross product of this point relative to two other points
	    // this point is the common point
	    // point p1 lies on the first vector, point p2 lies on the second vector
	    // watch out for the ordering of points p1 and p2!
	    // positive result indicates a clockwise ("right") turn from first to second vector
	    // negative result indicates a counterclockwise ("left") turn from first to second vector
	    // zero indicates that the first and second vector are collinear
	    // note that the above directions are reversed from the usual answer on the Internet
	    // that is because we are in a left-handed coord system (because the y-axis points downward)
	    cross: function(p1, p2) {

	        return (p1 && p2) ? (((p2.x - this.x) * (p1.y - this.y)) - ((p2.y - this.y) * (p1.x - this.x))) : NaN;
	    },

	    difference: function(dx, dy) {

	        if ((Object(dx) === dx)) {
	            dy = dx.y;
	            dx = dx.x;
	        }

	        return new Point(this.x - (dx || 0), this.y - (dy || 0));
	    },

	    // Returns distance between me and point `p`.
	    distance: function(p) {
	        return length(this, p);
	    },

	    // Returns the dot product of this point with given other point
	    dot: function(p) {

	        return p ? (this.x * p.x + this.y * p.y) : NaN;
	    },

	    equals: function(p) {

	        return !!p &&
	            this.x === p.x &&
	            this.y === p.y;
	    },

	    // Linear interpolation
	    lerp: function(p, t) {

	        var x = this.x;
	        var y = this.y;
	        return new Point((1 - t) * x + t * p.x, (1 - t) * y + t * p.y);
	    },

	    magnitude: function() {

	        return sqrt((this.x * this.x) + (this.y * this.y)) || 0.01;
	    },

	    // Returns a manhattan (taxi-cab) distance between me and point `p`.
	    manhattanDistance: function(p) {

	        return abs(p.x - this.x) + abs(p.y - this.y);
	    },

	    // Move point on line starting from ref ending at me by
	    // distance distance.
	    move: function(ref, distance) {

	        var theta = toRad((new Point(ref)).theta(this));
	        var offset = this.offset(cos$1(theta) * distance, -sin$1(theta) * distance);
	        return offset;
	    },

	    // Scales x and y such that the distance between the point and the origin (0,0) is equal to the given length.
	    normalize: function(length) {

	        var scale = (length || 1) / this.magnitude();
	        return this.scale(scale, scale);
	    },

	    // Offset me by the specified amount.
	    offset: function(dx, dy) {

	        if ((Object(dx) === dx)) {
	            dy = dx.y;
	            dx = dx.x;
	        }

	        this.x += dx || 0;
	        this.y += dy || 0;
	        return this;
	    },

	    // Returns a point that is the reflection of me with
	    // the center of inversion in ref point.
	    reflection: function(ref) {

	        return (new Point(ref)).move(this, this.distance(ref));
	    },

	    // Rotate point by angle around origin.
	    // Angle is flipped because this is a left-handed coord system (y-axis points downward).
	    rotate: function(origin, angle) {

	        if (angle === 0) { return this; }

	        origin = origin || new Point(0, 0);

	        angle = toRad(normalizeAngle(-angle));
	        var cosAngle = cos$1(angle);
	        var sinAngle = sin$1(angle);

	        var x = (cosAngle * (this.x - origin.x)) - (sinAngle * (this.y - origin.y)) + origin.x;
	        var y = (sinAngle * (this.x - origin.x)) + (cosAngle * (this.y - origin.y)) + origin.y;

	        this.x = x;
	        this.y = y;
	        return this;
	    },

	    round: function(precision) {

	        var f = 1; // case 0
	        if (precision) {
	            switch (precision) {
	                case 1: f = 10; break;
	                case 2: f = 100; break;
	                case 3: f = 1000; break;
	                default: f = pow(10, precision); break;
	            }
	        }

	        this.x = round$1(this.x * f) / f;
	        this.y = round$1(this.y * f) / f;
	        return this;
	    },

	    // Scale point with origin.
	    scale: function(sx, sy, origin) {

	        origin = (origin && new Point(origin)) || new Point(0, 0);
	        this.x = origin.x + sx * (this.x - origin.x);
	        this.y = origin.y + sy * (this.y - origin.y);
	        return this;
	    },

	    snapToGrid: function(gx, gy) {

	        this.x = snapToGrid(this.x, gx);
	        this.y = snapToGrid(this.y, gy || gx);
	        return this;
	    },

	    squaredDistance: function(p) {
	        return squaredLength(this, p);
	    },

	    // Compute the angle between me and `p` and the x axis.
	    // (cartesian-to-polar coordinates conversion)
	    // Return theta angle in degrees.
	    theta: function(p) {

	        p = new Point(p);

	        // Invert the y-axis.
	        var y = -(p.y - this.y);
	        var x = p.x - this.x;
	        var rad = atan2$1(y, x); // defined for all 0 corner cases

	        // Correction for III. and IV. quadrant.
	        if (rad < 0) {
	            rad = 2 * PI$1 + rad;
	        }

	        return 180 * rad / PI$1;
	    },

	    toJSON: function() {

	        return { x: this.x, y: this.y };
	    },

	    // Converts rectangular to polar coordinates.
	    // An origin can be specified, otherwise it's 0@0.
	    toPolar: function(o) {

	        o = (o && new Point(o)) || new Point(0, 0);
	        var x = this.x;
	        var y = this.y;
	        this.x = sqrt((x - o.x) * (x - o.x) + (y - o.y) * (y - o.y)); // r
	        this.y = toRad(o.theta(new Point(x, y)));
	        return this;
	    },

	    toString: function() {

	        return this.x + '@' + this.y;
	    },

	    serialize: function() {

	        return this.x + ',' + this.y;
	    },

	    update: function(x, y) {

	        if ((Object(x) === x)) {
	            y = x.y;
	            x = x.x;
	        }

	        this.x = x || 0;
	        this.y = y || 0;
	        return this;
	    },

	    // Compute the angle between the vector from 0,0 to me and the vector from 0,0 to p.
	    // Returns NaN if p is at 0,0.
	    vectorAngle: function(p) {

	        var zero = new Point(0, 0);
	        return zero.angleBetween(this, p);
	    }
	};

	Point.prototype.translate = Point.prototype.offset;

	// For backwards compatibility:
	var point = Point;

	var max$2 = Math.max;
	var min$4 = Math.min;

	var Line = function(p1, p2) {

	    if (!(this instanceof Line)) {
	        return new Line(p1, p2);
	    }

	    if (p1 instanceof Line) {
	        return new Line(p1.start, p1.end);
	    }

	    this.start = new Point(p1);
	    this.end = new Point(p2);
	};

	Line.prototype = {

	    type: types.Line,

	    // @returns the angle of incline of the line.
	    angle: function() {

	        var horizontalPoint = new Point(this.start.x + 1, this.start.y);
	        return this.start.angleBetween(this.end, horizontalPoint);
	    },

	    bbox: function() {

	        var left = min$4(this.start.x, this.end.x);
	        var top = min$4(this.start.y, this.end.y);
	        var right = max$2(this.start.x, this.end.x);
	        var bottom = max$2(this.start.y, this.end.y);

	        return new Rect(left, top, (right - left), (bottom - top));
	    },

	    // @return the bearing (cardinal direction) of the line. For example N, W, or SE.
	    // @returns {String} One of the following bearings : NE, E, SE, S, SW, W, NW, N.
	    bearing: function() {
	        return bearing(this.start, this.end);
	    },

	    clone: function() {

	        return new Line(this.start, this.end);
	    },

	    // @return {point} the closest point on the line to point `p`
	    closestPoint: function(p) {

	        return this.pointAt(this.closestPointNormalizedLength(p));
	    },

	    closestPointLength: function(p) {

	        return this.closestPointNormalizedLength(p) * this.length();
	    },

	    // @return {number} the normalized length of the closest point on the line to point `p`
	    closestPointNormalizedLength: function(p) {

	        var product = this.vector().dot((new Line(this.start, p)).vector());
	        var cpNormalizedLength = min$4(1, max$2(0, product / this.squaredLength()));

	        // cpNormalizedLength returns `NaN` if this line has zero length
	        // we can work with that - if `NaN`, return 0
	        if (cpNormalizedLength !== cpNormalizedLength) { return 0; } // condition evaluates to `true` if and only if cpNormalizedLength is `NaN`
	        // (`NaN` is the only value that is not equal to itself)

	        return cpNormalizedLength;
	    },

	    closestPointTangent: function(p) {

	        return this.tangentAt(this.closestPointNormalizedLength(p));
	    },

	    // Returns `true` if the point lies on the line.
	    containsPoint: function(p) {

	        var start = this.start;
	        var end = this.end;

	        if (start.cross(p, end) !== 0) { return false; }
	        // else: cross product of 0 indicates that this line and the vector to `p` are collinear

	        var length = this.length();
	        if ((new Line(start, p)).length() > length) { return false; }
	        if ((new Line(p, end)).length() > length) { return false; }
	        // else: `p` lies between start and end of the line

	        return true;
	    },

	    // Divides the line into two at requested `ratio` between 0 and 1.
	    divideAt: function(ratio) {

	        var dividerPoint = this.pointAt(ratio);

	        // return array with two lines
	        return [
	            new Line(this.start, dividerPoint),
	            new Line(dividerPoint, this.end)
	        ];
	    },

	    // Divides the line into two at requested `length`.
	    divideAtLength: function(length) {

	        var dividerPoint = this.pointAtLength(length);

	        // return array with two new lines
	        return [
	            new Line(this.start, dividerPoint),
	            new Line(dividerPoint, this.end)
	        ];
	    },

	    equals: function(l) {

	        return !!l &&
	            this.start.x === l.start.x &&
	            this.start.y === l.start.y &&
	            this.end.x === l.end.x &&
	            this.end.y === l.end.y;
	    },

	    // @return {point} Point where I'm intersecting a line.
	    // @return [point] Points where I'm intersecting a rectangle.
	    // @see Squeak Smalltalk, LineSegment>>intersectionWith:
	    intersect: function(shape, opt) {

	        if (shape && shape.intersectionWithLine) {
	            var intersection = shape.intersectionWithLine(this, opt);

	            // Backwards compatibility
	            if (intersection && (shape instanceof Line)) {
	                intersection = intersection[0];
	            }

	            return intersection;
	        }

	        return null;
	    },

	    intersectionWithLine: function(line) {

	        var pt1Dir = new Point(this.end.x - this.start.x, this.end.y - this.start.y);
	        var pt2Dir = new Point(line.end.x - line.start.x, line.end.y - line.start.y);
	        var det = (pt1Dir.x * pt2Dir.y) - (pt1Dir.y * pt2Dir.x);
	        var deltaPt = new Point(line.start.x - this.start.x, line.start.y - this.start.y);
	        var alpha = (deltaPt.x * pt2Dir.y) - (deltaPt.y * pt2Dir.x);
	        var beta = (deltaPt.x * pt1Dir.y) - (deltaPt.y * pt1Dir.x);

	        if (det === 0 || alpha * det < 0 || beta * det < 0) {
	            // No intersection found.
	            return null;
	        }

	        if (det > 0) {
	            if (alpha > det || beta > det) {
	                return null;
	            }

	        } else {
	            if (alpha < det || beta < det) {
	                return null;
	            }
	        }

	        return [new Point(
	            this.start.x + (alpha * pt1Dir.x / det),
	            this.start.y + (alpha * pt1Dir.y / det)
	        )];
	    },

	    isDifferentiable: function() {

	        return !this.start.equals(this.end);
	    },

	    // @return {double} length of the line
	    length: function() {
	        return length(this.start, this.end);
	    },

	    // @return {point} my midpoint
	    midpoint: function() {

	        return new Point(
	            (this.start.x + this.end.x) / 2,
	            (this.start.y + this.end.y) / 2
	        );
	    },

	    parallel: function(distance) {
	        var l = this.clone();
	        if (!this.isDifferentiable()) { return l; }
	        var start = l.start;
	        var end = l.end;
	        var eRef = start.clone().rotate(end, 270);
	        var sRef = end.clone().rotate(start, 90);
	        start.move(sRef, distance);
	        end.move(eRef, distance);
	        return l;
	    },

	    // @return {point} my point at 't' <0,1>
	    pointAt: function(t) {

	        var start = this.start;
	        var end = this.end;

	        if (t <= 0) { return start.clone(); }
	        if (t >= 1) { return end.clone(); }

	        return start.lerp(end, t);
	    },

	    pointAtLength: function(length) {

	        var start = this.start;
	        var end = this.end;

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        var lineLength = this.length();
	        if (length >= lineLength) { return (fromStart ? end.clone() : start.clone()); }

	        return this.pointAt((fromStart ? (length) : (lineLength - length)) / lineLength);
	    },

	    // @return {number} the offset of the point `p` from the line. + if the point `p` is on the right side of the line, - if on the left and 0 if on the line.
	    pointOffset: function(p) {

	        // Find the sign of the determinant of vectors (start,end), where p is the query point.
	        p = new Point(p);
	        var start = this.start;
	        var end = this.end;
	        var determinant = ((end.x - start.x) * (p.y - start.y) - (end.y - start.y) * (p.x - start.x));

	        return determinant / this.length();
	    },

	    rotate: function(origin, angle) {

	        this.start.rotate(origin, angle);
	        this.end.rotate(origin, angle);
	        return this;
	    },

	    round: function(precision) {

	        this.start.round(precision);
	        this.end.round(precision);
	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        this.start.scale(sx, sy, origin);
	        this.end.scale(sx, sy, origin);
	        return this;
	    },

	    // @return {number} scale the line so that it has the requested length
	    setLength: function(length) {

	        var currentLength = this.length();
	        if (!currentLength) { return this; }

	        var scaleFactor = length / currentLength;
	        return this.scale(scaleFactor, scaleFactor, this.start);
	    },

	    // @return {integer} length without sqrt
	    // @note for applications where the exact length is not necessary (e.g. compare only)
	    squaredLength: function() {
	        return squaredLength(this.start, this.end);
	    },

	    tangentAt: function(t) {

	        if (!this.isDifferentiable()) { return null; }

	        var start = this.start;
	        var end = this.end;

	        var tangentStart = this.pointAt(t); // constrains `t` between 0 and 1

	        var tangentLine = new Line(start, end);
	        tangentLine.translate(tangentStart.x - start.x, tangentStart.y - start.y); // move so that tangent line starts at the point requested

	        return tangentLine;
	    },

	    tangentAtLength: function(length) {

	        if (!this.isDifferentiable()) { return null; }

	        var start = this.start;
	        var end = this.end;

	        var tangentStart = this.pointAtLength(length);

	        var tangentLine = new Line(start, end);
	        tangentLine.translate(tangentStart.x - start.x, tangentStart.y - start.y); // move so that tangent line starts at the point requested

	        return tangentLine;
	    },

	    toString: function() {

	        return this.start.toString() + ' ' + this.end.toString();
	    },

	    serialize: function() {

	        return this.start.serialize() + ' ' + this.end.serialize();
	    },

	    translate: function(tx, ty) {

	        this.start.translate(tx, ty);
	        this.end.translate(tx, ty);
	        return this;
	    },

	    // @return vector {point} of the line
	    vector: function() {

	        return new Point(this.end.x - this.start.x, this.end.y - this.start.y);
	    }
	};

	// For backwards compatibility:
	Line.prototype.intersection = Line.prototype.intersect;


	// For backwards compatibility:
	var line = Line;

	var sqrt$1 = Math.sqrt;
	var round$2 = Math.round;
	var pow$1 = Math.pow;

	var Ellipse = function(c, a, b) {

	    if (!(this instanceof Ellipse)) {
	        return new Ellipse(c, a, b);
	    }

	    if (c instanceof Ellipse) {
	        return new Ellipse(new Point(c.x, c.y), c.a, c.b);
	    }

	    c = new Point(c);
	    this.x = c.x;
	    this.y = c.y;
	    this.a = a;
	    this.b = b;
	};

	Ellipse.fromRect = function(rect) {

	    rect = new Rect(rect);
	    return new Ellipse(rect.center(), rect.width / 2, rect.height / 2);
	};

	Ellipse.prototype = {

	    type: types.Ellipse,

	    bbox: function() {

	        return new Rect(this.x - this.a, this.y - this.b, 2 * this.a, 2 * this.b);
	    },

	    /**
	     * @returns {g.Point}
	     */
	    center: function() {

	        return new Point(this.x, this.y);
	    },

	    clone: function() {

	        return new Ellipse(this);
	    },

	    /**
	     * @param {g.Point} p
	     * @returns {boolean}
	     */
	    containsPoint: function(p) {

	        return this.normalizedDistance(p) <= 1;
	    },

	    equals: function(ellipse) {

	        return !!ellipse &&
	            ellipse.x === this.x &&
	            ellipse.y === this.y &&
	            ellipse.a === this.a &&
	            ellipse.b === this.b;
	    },

	    // inflate by dx and dy
	    // @param dx {delta_x} representing additional size to x
	    // @param dy {delta_y} representing additional size to y -
	    // dy param is not required -> in that case y is sized by dx
	    inflate: function(dx, dy) {
	        if (dx === undefined) {
	            dx = 0;
	        }

	        if (dy === undefined) {
	            dy = dx;
	        }

	        this.a += 2 * dx;
	        this.b += 2 * dy;

	        return this;
	    },

	    intersectionWithLine: function(line) {

	        var intersections = [];
	        var a1 = line.start;
	        var a2 = line.end;
	        var rx = this.a;
	        var ry = this.b;
	        var dir = line.vector();
	        var diff = a1.difference(new Point(this));
	        var mDir = new Point(dir.x / (rx * rx), dir.y / (ry * ry));
	        var mDiff = new Point(diff.x / (rx * rx), diff.y / (ry * ry));

	        var a = dir.dot(mDir);
	        var b = dir.dot(mDiff);
	        var c = diff.dot(mDiff) - 1.0;
	        var d = b * b - a * c;

	        if (d < 0) {
	            return null;
	        } else if (d > 0) {
	            var root = sqrt$1(d);
	            var ta = (-b - root) / a;
	            var tb = (-b + root) / a;

	            if ((ta < 0 || 1 < ta) && (tb < 0 || 1 < tb)) {
	                // if ((ta < 0 && tb < 0) || (ta > 1 && tb > 1)) outside else inside
	                return null;
	            } else {
	                if (0 <= ta && ta <= 1) { intersections.push(a1.lerp(a2, ta)); }
	                if (0 <= tb && tb <= 1) { intersections.push(a1.lerp(a2, tb)); }
	            }
	        } else {
	            var t = -b / a;
	            if (0 <= t && t <= 1) {
	                intersections.push(a1.lerp(a2, t));
	            } else {
	                // outside
	                return null;
	            }
	        }

	        return intersections;
	    },

	    // Find point on me where line from my center to
	    // point p intersects my boundary.
	    // @param {number} angle If angle is specified, intersection with rotated ellipse is computed.
	    intersectionWithLineFromCenterToPoint: function(p, angle) {

	        p = new Point(p);

	        if (angle) { p.rotate(new Point(this.x, this.y), angle); }

	        var dx = p.x - this.x;
	        var dy = p.y - this.y;
	        var result;

	        if (dx === 0) {
	            result = this.bbox().pointNearestToPoint(p);
	            if (angle) { return result.rotate(new Point(this.x, this.y), -angle); }
	            return result;
	        }

	        var m = dy / dx;
	        var mSquared = m * m;
	        var aSquared = this.a * this.a;
	        var bSquared = this.b * this.b;

	        var x = sqrt$1(1 / ((1 / aSquared) + (mSquared / bSquared)));
	        x = dx < 0 ? -x : x;

	        var y = m * x;
	        result = new Point(this.x + x, this.y + y);

	        if (angle) { return result.rotate(new Point(this.x, this.y), -angle); }
	        return result;
	    },

	    /**
	     * @param {g.Point} point
	     * @returns {number} result < 1 - inside ellipse, result == 1 - on ellipse boundary, result > 1 - outside
	     */
	    normalizedDistance: function(point) {

	        var x0 = point.x;
	        var y0 = point.y;
	        var a = this.a;
	        var b = this.b;
	        var x = this.x;
	        var y = this.y;

	        return ((x0 - x) * (x0 - x)) / (a * a) + ((y0 - y) * (y0 - y)) / (b * b);
	    },

	    round: function(precision) {

	        var f = 1; // case 0
	        if (precision) {
	            switch (precision) {
	                case 1: f = 10; break;
	                case 2: f = 100; break;
	                case 3: f = 1000; break;
	                default: f = pow$1(10, precision); break;
	            }
	        }

	        this.x = round$2(this.x * f) / f;
	        this.y = round$2(this.y * f) / f;
	        this.a = round$2(this.a * f) / f;
	        this.b = round$2(this.b * f) / f;
	        return this;
	    },

	    /** Compute angle between tangent and x axis
	     * @param {g.Point} p Point of tangency, it has to be on ellipse boundaries.
	     * @returns {number} angle between tangent and x axis
	     */
	    tangentTheta: function(p) {

	        var refPointDelta = 30;
	        var x0 = p.x;
	        var y0 = p.y;
	        var a = this.a;
	        var b = this.b;
	        var center = this.bbox().center();
	        var m = center.x;
	        var n = center.y;

	        var q1 = x0 > center.x + a / 2;
	        var q3 = x0 < center.x - a / 2;

	        var y, x;
	        if (q1 || q3) {
	            y = x0 > center.x ? y0 - refPointDelta : y0 + refPointDelta;
	            x = (a * a / (x0 - m)) - (a * a * (y0 - n) * (y - n)) / (b * b * (x0 - m)) + m;

	        } else {
	            x = y0 > center.y ? x0 + refPointDelta : x0 - refPointDelta;
	            y = (b * b / (y0 - n)) - (b * b * (x0 - m) * (x - m)) / (a * a * (y0 - n)) + n;
	        }

	        return (new Point(x, y)).theta(p);

	    },

	    toString: function() {

	        return (new Point(this.x, this.y)).toString() + ' ' + this.a + ' ' + this.b;
	    }
	};

	// For backwards compatibility:
	var ellipse = Ellipse;

	var abs$1 = Math.abs;
	var cos$2 = Math.cos;
	var sin$2 = Math.sin;
	var min$5 = Math.min;
	var max$3 = Math.max;
	var round$3 = Math.round;
	var pow$2 = Math.pow;

	var Rect = function(x, y, w, h) {

	    if (!(this instanceof Rect)) {
	        return new Rect(x, y, w, h);
	    }

	    if ((Object(x) === x)) {
	        y = x.y;
	        w = x.width;
	        h = x.height;
	        x = x.x;
	    }

	    this.x = x === undefined ? 0 : x;
	    this.y = y === undefined ? 0 : y;
	    this.width = w === undefined ? 0 : w;
	    this.height = h === undefined ? 0 : h;
	};

	Rect.fromEllipse = function(e) {

	    e = new Ellipse(e);
	    return new Rect(e.x - e.a, e.y - e.b, 2 * e.a, 2 * e.b);
	};

	Rect.fromPointUnion = function() {
	    var points = [], len = arguments.length;
	    while ( len-- ) points[ len ] = arguments[ len ];


	    if (points.length === 0) { return null; }

	    var p = new Point();
	    var minX, minY, maxX, maxY;
	    minX = minY = Infinity;
	    maxX = maxY = -Infinity;

	    for (var i = 0; i < points.length; i++) {
	        p.update(points[i]);
	        var x = p.x;
	        var y = p.y;

	        if (x < minX) { minX = x; }
	        if (x > maxX) { maxX = x; }
	        if (y < minY) { minY = y; }
	        if (y > maxY) { maxY = y; }
	    }

	    return new Rect(minX, minY, maxX - minX, maxY - minY);
	};

	Rect.fromRectUnion = function() {
	    var rects = [], len = arguments.length;
	    while ( len-- ) rects[ len ] = arguments[ len ];


	    if (rects.length === 0) { return null; }

	    var r = new Rect();
	    var minX, minY, maxX, maxY;
	    minX = minY = Infinity;
	    maxX = maxY = -Infinity;

	    for (var i = 0; i < rects.length; i++) {
	        r.update(rects[i]);
	        var x = r.x;
	        var y = r.y;
	        var mX = x + r.width;
	        var mY = y + r.height;

	        if (x < minX) { minX = x; }
	        if (mX > maxX) { maxX = mX; }
	        if (y < minY) { minY = y; }
	        if (mY > maxY) { maxY = mY; }
	    }

	    return new Rect(minX, minY, maxX - minX, maxY - minY);
	};

	Rect.prototype = {

	    type: types.Rect,

	    // Find my bounding box when I'm rotated with the center of rotation in the center of me.
	    // @return r {rectangle} representing a bounding box
	    bbox: function(angle) {
	        return this.clone().rotateAroundCenter(angle);
	    },

	    rotateAroundCenter: function(angle) {
	        if (!angle) { return this; }
	        var ref = this;
	        var width = ref.width;
	        var height = ref.height;
	        var theta = toRad(angle);
	        var st = abs$1(sin$2(theta));
	        var ct = abs$1(cos$2(theta));
	        var w = width * ct + height * st;
	        var h = width * st + height * ct;
	        this.x += (width - w) / 2;
	        this.y += (height - h) / 2;
	        this.width = w;
	        this.height = h;
	        return this;
	    },

	    bottomLeft: function() {

	        return new Point(this.x, this.y + this.height);
	    },

	    bottomLine: function() {

	        return new Line(this.bottomLeft(), this.bottomRight());
	    },

	    bottomMiddle: function() {

	        return new Point(this.x + this.width / 2, this.y + this.height);
	    },

	    center: function() {

	        return new Point(this.x + this.width / 2, this.y + this.height / 2);
	    },

	    clone: function() {

	        return new Rect(this);
	    },

	    // @return {bool} true if point p is inside me.
	    containsPoint: function(p) {
	        
	        if (!(p instanceof Point)) {
	            p = new Point(p);
	        }
	        return p.x >= this.x && p.x <= this.x + this.width && p.y >= this.y && p.y <= this.y + this.height;
	    },

	    // @return {bool} true if rectangle `r` is inside me.
	    containsRect: function(r) {

	        var r0 = new Rect(this).normalize();
	        var r1 = new Rect(r).normalize();
	        var w0 = r0.width;
	        var h0 = r0.height;
	        var w1 = r1.width;
	        var h1 = r1.height;

	        if (!w0 || !h0 || !w1 || !h1) {
	            // At least one of the dimensions is 0
	            return false;
	        }

	        var x0 = r0.x;
	        var y0 = r0.y;
	        var x1 = r1.x;
	        var y1 = r1.y;

	        w1 += x1;
	        w0 += x0;
	        h1 += y1;
	        h0 += y0;

	        return x0 <= x1 && w1 <= w0 && y0 <= y1 && h1 <= h0;
	    },

	    corner: function() {

	        return new Point(this.x + this.width, this.y + this.height);
	    },

	    // @return {boolean} true if rectangles are equal.
	    equals: function(r) {

	        var mr = (new Rect(this)).normalize();
	        var nr = (new Rect(r)).normalize();
	        return mr.x === nr.x && mr.y === nr.y && mr.width === nr.width && mr.height === nr.height;
	    },

	    // inflate by dx and dy, recompute origin [x, y]
	    // @param dx {delta_x} representing additional size to x
	    // @param dy {delta_y} representing additional size to y -
	    // dy param is not required -> in that case y is sized by dx
	    inflate: function(dx, dy) {

	        if (dx === undefined) {
	            dx = 0;
	        }

	        if (dy === undefined) {
	            dy = dx;
	        }

	        this.x -= dx;
	        this.y -= dy;
	        this.width += 2 * dx;
	        this.height += 2 * dy;

	        return this;
	    },

	    // @return {rect} if rectangles intersect, {null} if not.
	    intersect: function(r) {

	        var myOrigin = this.origin();
	        var myCorner = this.corner();
	        var rOrigin = r.origin();
	        var rCorner = r.corner();

	        // No intersection found
	        if (rCorner.x <= myOrigin.x ||
	            rCorner.y <= myOrigin.y ||
	            rOrigin.x >= myCorner.x ||
	            rOrigin.y >= myCorner.y) { return null; }

	        var x = max$3(myOrigin.x, rOrigin.x);
	        var y = max$3(myOrigin.y, rOrigin.y);

	        return new Rect(x, y, min$5(myCorner.x, rCorner.x) - x, min$5(myCorner.y, rCorner.y) - y);
	    },

	    intersectionWithLine: function(line) {

	        var r = this;
	        var rectLines = [r.topLine(), r.rightLine(), r.bottomLine(), r.leftLine()];
	        var points = [];
	        var dedupeArr = [];
	        var pt, i;

	        var n = rectLines.length;
	        for (i = 0; i < n; i++) {

	            pt = line.intersect(rectLines[i]);
	            if (pt !== null && dedupeArr.indexOf(pt.toString()) < 0) {
	                points.push(pt);
	                dedupeArr.push(pt.toString());
	            }
	        }

	        return points.length > 0 ? points : null;
	    },

	    // Find point on my boundary where line starting
	    // from my center ending in point p intersects me.
	    // @param {number} angle If angle is specified, intersection with rotated rectangle is computed.
	    intersectionWithLineFromCenterToPoint: function(p, angle) {

	        p = new Point(p);
	        var center = new Point(this.x + this.width / 2, this.y + this.height / 2);
	        var result;

	        if (angle) { p.rotate(center, angle); }

	        // (clockwise, starting from the top side)
	        var sides = [
	            this.topLine(),
	            this.rightLine(),
	            this.bottomLine(),
	            this.leftLine()
	        ];
	        var connector = new Line(center, p);

	        for (var i = sides.length - 1; i >= 0; --i) {
	            var intersection = sides[i].intersection(connector);
	            if (intersection !== null) {
	                result = intersection;
	                break;
	            }
	        }
	        if (result && angle) { result.rotate(center, -angle); }
	        return result;
	    },

	    leftLine: function() {

	        return new Line(this.topLeft(), this.bottomLeft());
	    },

	    leftMiddle: function() {

	        return new Point(this.x, this.y + this.height / 2);
	    },

	    maxRectScaleToFit: function(rect, origin) {

	        rect = new Rect(rect);
	        origin || (origin = rect.center());

	        var sx1, sx2, sx3, sx4, sy1, sy2, sy3, sy4;
	        var ox = origin.x;
	        var oy = origin.y;

	        // Here we find the maximal possible scale for all corner points (for x and y axis) of the rectangle,
	        // so when the scale is applied the point is still inside the rectangle.

	        sx1 = sx2 = sx3 = sx4 = sy1 = sy2 = sy3 = sy4 = Infinity;

	        // Top Left
	        var p1 = rect.topLeft();
	        if (p1.x < ox) {
	            sx1 = (this.x - ox) / (p1.x - ox);
	        }
	        if (p1.y < oy) {
	            sy1 = (this.y - oy) / (p1.y - oy);
	        }
	        // Bottom Right
	        var p2 = rect.bottomRight();
	        if (p2.x > ox) {
	            sx2 = (this.x + this.width - ox) / (p2.x - ox);
	        }
	        if (p2.y > oy) {
	            sy2 = (this.y + this.height - oy) / (p2.y - oy);
	        }
	        // Top Right
	        var p3 = rect.topRight();
	        if (p3.x > ox) {
	            sx3 = (this.x + this.width - ox) / (p3.x - ox);
	        }
	        if (p3.y < oy) {
	            sy3 = (this.y - oy) / (p3.y - oy);
	        }
	        // Bottom Left
	        var p4 = rect.bottomLeft();
	        if (p4.x < ox) {
	            sx4 = (this.x - ox) / (p4.x - ox);
	        }
	        if (p4.y > oy) {
	            sy4 = (this.y + this.height - oy) / (p4.y - oy);
	        }

	        return {
	            sx: min$5(sx1, sx2, sx3, sx4),
	            sy: min$5(sy1, sy2, sy3, sy4)
	        };
	    },

	    maxRectUniformScaleToFit: function(rect, origin) {

	        var scale = this.maxRectScaleToFit(rect, origin);
	        return min$5(scale.sx, scale.sy);
	    },

	    // Move and expand me.
	    // @param r {rectangle} representing deltas
	    moveAndExpand: function(r) {

	        this.x += r.x || 0;
	        this.y += r.y || 0;
	        this.width += r.width || 0;
	        this.height += r.height || 0;
	        return this;
	    },

	    // Normalize the rectangle; i.e., make it so that it has a non-negative width and height.
	    // If width < 0 the function swaps the left and right corners,
	    // and it swaps the top and bottom corners if height < 0
	    // like in http://qt-project.org/doc/qt-4.8/qrectf.html#normalized
	    normalize: function() {

	        var newx = this.x;
	        var newy = this.y;
	        var newwidth = this.width;
	        var newheight = this.height;
	        if (this.width < 0) {
	            newx = this.x + this.width;
	            newwidth = -this.width;
	        }
	        if (this.height < 0) {
	            newy = this.y + this.height;
	            newheight = -this.height;
	        }
	        this.x = newx;
	        this.y = newy;
	        this.width = newwidth;
	        this.height = newheight;
	        return this;
	    },

	    // Offset me by the specified amount.
	    offset: function(dx, dy) {

	        // pretend that this is a point and call offset()
	        // rewrites x and y according to dx and dy
	        return Point.prototype.offset.call(this, dx, dy);
	    },

	    origin: function() {

	        return new Point(this.x, this.y);
	    },

	    // @return {point} a point on my boundary nearest to the given point.
	    // @see Squeak Smalltalk, Rectangle>>pointNearestTo:
	    pointNearestToPoint: function(point) {

	        point = new Point(point);
	        if (this.containsPoint(point)) {
	            var side = this.sideNearestToPoint(point);
	            switch (side) {
	                case 'right':
	                    return new Point(this.x + this.width, point.y);
	                case 'left':
	                    return new Point(this.x, point.y);
	                case 'bottom':
	                    return new Point(point.x, this.y + this.height);
	                case 'top':
	                    return new Point(point.x, this.y);
	            }
	        }
	        return point.adhereToRect(this);
	    },

	    rightLine: function() {

	        return new Line(this.topRight(), this.bottomRight());
	    },

	    rightMiddle: function() {

	        return new Point(this.x + this.width, this.y + this.height / 2);
	    },

	    round: function(precision) {

	        var f = 1; // case 0
	        if (precision) {
	            switch (precision) {
	                case 1: f = 10; break;
	                case 2: f = 100; break;
	                case 3: f = 1000; break;
	                default: f = pow$2(10, precision); break;
	            }
	        }

	        this.x = round$3(this.x * f) / f;
	        this.y = round$3(this.y * f) / f;
	        this.width = round$3(this.width * f) / f;
	        this.height = round$3(this.height * f) / f;
	        return this;
	    },

	    // Scale rectangle with origin.
	    scale: function(sx, sy, origin) {

	        origin = this.origin().scale(sx, sy, origin);
	        this.x = origin.x;
	        this.y = origin.y;
	        this.width *= sx;
	        this.height *= sy;
	        return this;
	    },

	    // @return {string} (left|right|top|bottom) side which is nearest to point
	    // @see Squeak Smalltalk, Rectangle>>sideNearestTo:
	    sideNearestToPoint: function(point) {

	        point = new Point(point);
	        var distToLeft = point.x - this.x;
	        var distToRight = (this.x + this.width) - point.x;
	        var distToTop = point.y - this.y;
	        var distToBottom = (this.y + this.height) - point.y;
	        var closest = distToLeft;
	        var side = 'left';

	        if (distToRight < closest) {
	            closest = distToRight;
	            side = 'right';
	        }
	        if (distToTop < closest) {
	            closest = distToTop;
	            side = 'top';
	        }
	        if (distToBottom < closest) {
	            // closest = distToBottom;
	            side = 'bottom';
	        }
	        return side;
	    },

	    snapToGrid: function(gx, gy) {

	        var origin = this.origin().snapToGrid(gx, gy);
	        var corner = this.corner().snapToGrid(gx, gy);
	        this.x = origin.x;
	        this.y = origin.y;
	        this.width = corner.x - origin.x;
	        this.height = corner.y - origin.y;
	        return this;
	    },

	    toJSON: function() {

	        return { x: this.x, y: this.y, width: this.width, height: this.height };
	    },

	    topLine: function() {

	        return new Line(this.topLeft(), this.topRight());
	    },

	    topMiddle: function() {

	        return new Point(this.x + this.width / 2, this.y);
	    },

	    topRight: function() {

	        return new Point(this.x + this.width, this.y);
	    },

	    toString: function() {

	        return this.origin().toString() + ' ' + this.corner().toString();
	    },

	    // @return {rect} representing the union of both rectangles.
	    union: function(rect) {

	        return Rect.fromRectUnion(this, rect);
	    },

	    update: function(x, y, w, h) {

	        if ((Object(x) === x)) {
	            y = x.y;
	            w = x.width;
	            h = x.height;
	            x = x.x;
	        }

	        this.x = x || 0;
	        this.y = y || 0;
	        this.width = w || 0;
	        this.height = h || 0;
	        return this;
	    }
	};

	Rect.prototype.bottomRight = Rect.prototype.corner;

	Rect.prototype.topLeft = Rect.prototype.origin;

	Rect.prototype.translate = Rect.prototype.offset;

	// For backwards compatibility:
	var rect = Rect;

	function parsePoints(svgString) {

	    // Step 1: Discard surrounding spaces
	    var trimmedString = svgString.trim();
	    if (trimmedString === '') { return []; }

	    var points = [];

	    // Step 2: Split at commas (+ their surrounding spaces) or at multiple spaces
	    // ReDoS mitigation: Have an anchor at the beginning of each alternation
	    // Note: This doesn't simplify double (or more) commas - causes empty coords
	    // This regex is used by `split()`, so it doesn't need to use /g
	    var coords = trimmedString.split(/\b\s*,\s*|,\s*|\s+/);

	    var numCoords = coords.length;
	    for (var i = 0; i < numCoords; i += 2) {
	        // Step 3: Convert each coord to number
	        // Note: If the coord cannot be converted to a number, it will be `NaN`
	        // Note: If the coord is empty ("", e.g. from ",," input), it will be `0`
	        // Note: If we end up with an odd number of coords, the last point's second coord will be `NaN`
	        points.push({ x: +coords[i], y: +coords[i + 1] });
	    }
	    return points;
	}

	function clonePoints(points) {
	    var numPoints = points.length;
	    if (numPoints === 0) { return []; }
	    var newPoints = [];
	    for (var i = 0; i < numPoints; i++) {
	        var point = points[i].clone();
	        newPoints.push(point);
	    }
	    return newPoints;
	}

	// Returns a convex-hull polyline from this polyline.
	// Implements the Graham scan (https://en.wikipedia.org/wiki/Graham_scan).
	// Output polyline starts at the first element of the original polyline that is on the hull, then continues clockwise.
	// Minimal polyline is found (only vertices of the hull are reported, no collinear points).
	function convexHull(points) {

	    var abs = Math.abs;

	    var i;
	    var n;

	    var numPoints = points.length;
	    if (numPoints === 0) { return []; } // if points array is empty

	    // step 1: find the starting point - point with the lowest y (if equality, highest x)
	    var startPoint;
	    for (i = 0; i < numPoints; i++) {
	        if (startPoint === undefined) {
	            // if this is the first point we see, set it as start point
	            startPoint = points[i];

	        } else if (points[i].y < startPoint.y) {
	            // start point should have lowest y from all points
	            startPoint = points[i];

	        } else if ((points[i].y === startPoint.y) && (points[i].x > startPoint.x)) {
	            // if two points have the lowest y, choose the one that has highest x
	            // there are no points to the right of startPoint - no ambiguity about theta 0
	            // if there are several coincident start point candidates, first one is reported
	            startPoint = points[i];
	        }
	    }

	    // step 2: sort the list of points
	    // sorting by angle between line from startPoint to point and the x-axis (theta)

	    // step 2a: create the point records = [point, originalIndex, angle]
	    var sortedPointRecords = [];
	    for (i = 0; i < numPoints; i++) {

	        var angle = startPoint.theta(points[i]);
	        if (angle === 0) {
	            angle = 360; // give highest angle to start point
	            // the start point will end up at end of sorted list
	            // the start point will end up at beginning of hull points list
	        }

	        var entry = [points[i], i, angle];
	        sortedPointRecords.push(entry);
	    }

	    // step 2b: sort the list in place
	    sortedPointRecords.sort(function(record1, record2) {
	        // returning a negative number here sorts record1 before record2
	        // if first angle is smaller than second, first angle should come before second

	        var sortOutput = record1[2] - record2[2];  // negative if first angle smaller
	        if (sortOutput === 0) {
	            // if the two angles are equal, sort by originalIndex
	            sortOutput = record2[1] - record1[1]; // negative if first index larger
	            // coincident points will be sorted in reverse-numerical order
	            // so the coincident points with lower original index will be considered first
	        }

	        return sortOutput;
	    });

	    // step 2c: duplicate start record from the top of the stack to the bottom of the stack
	    if (sortedPointRecords.length > 2) {
	        var startPointRecord = sortedPointRecords[sortedPointRecords.length - 1];
	        sortedPointRecords.unshift(startPointRecord);
	    }

	    // step 3a: go through sorted points in order and find those with right turns
	    // we want to get our results in clockwise order
	    var insidePoints = {}; // dictionary of points with left turns - cannot be on the hull
	    var hullPointRecords = []; // stack of records with right turns - hull point candidates

	    var currentPointRecord;
	    var currentPoint;
	    var lastHullPointRecord;
	    var lastHullPoint;
	    var secondLastHullPointRecord;
	    var secondLastHullPoint;
	    while (sortedPointRecords.length !== 0) {

	        currentPointRecord = sortedPointRecords.pop();
	        currentPoint = currentPointRecord[0];

	        // check if point has already been discarded
	        // keys for insidePoints are stored in the form 'point.x@point.y@@originalIndex'
	        if (insidePoints.hasOwnProperty(currentPointRecord[0] + '@@' + currentPointRecord[1])) {
	            // this point had an incorrect turn at some previous iteration of this loop
	            // this disqualifies it from possibly being on the hull
	            continue;
	        }

	        var correctTurnFound = false;
	        while (!correctTurnFound) {

	            if (hullPointRecords.length < 2) {
	                // not enough points for comparison, just add current point
	                hullPointRecords.push(currentPointRecord);
	                correctTurnFound = true;

	            } else {
	                lastHullPointRecord = hullPointRecords.pop();
	                lastHullPoint = lastHullPointRecord[0];
	                secondLastHullPointRecord = hullPointRecords.pop();
	                secondLastHullPoint = secondLastHullPointRecord[0];

	                var crossProduct = secondLastHullPoint.cross(lastHullPoint, currentPoint);

	                if (crossProduct < 0) {
	                    // found a right turn
	                    hullPointRecords.push(secondLastHullPointRecord);
	                    hullPointRecords.push(lastHullPointRecord);
	                    hullPointRecords.push(currentPointRecord);
	                    correctTurnFound = true;

	                } else if (crossProduct === 0) {
	                    // the three points are collinear
	                    // three options:
	                    // there may be a 180 or 0 degree angle at lastHullPoint
	                    // or two of the three points are coincident
	                    var THRESHOLD = 1e-10; // we have to take rounding errors into account
	                    var angleBetween = lastHullPoint.angleBetween(secondLastHullPoint, currentPoint);
	                    if (abs(angleBetween - 180) < THRESHOLD) { // rounding around 180 to 180
	                        // if the cross product is 0 because the angle is 180 degrees
	                        // discard last hull point (add to insidePoints)
	                        //insidePoints.unshift(lastHullPoint);
	                        insidePoints[lastHullPointRecord[0] + '@@' + lastHullPointRecord[1]] = lastHullPoint;
	                        // reenter second-to-last hull point (will be last at next iter)
	                        hullPointRecords.push(secondLastHullPointRecord);
	                        // do not do anything with current point
	                        // correct turn not found

	                    } else if (lastHullPoint.equals(currentPoint) || secondLastHullPoint.equals(lastHullPoint)) {
	                        // if the cross product is 0 because two points are the same
	                        // discard last hull point (add to insidePoints)
	                        //insidePoints.unshift(lastHullPoint);
	                        insidePoints[lastHullPointRecord[0] + '@@' + lastHullPointRecord[1]] = lastHullPoint;
	                        // reenter second-to-last hull point (will be last at next iter)
	                        hullPointRecords.push(secondLastHullPointRecord);
	                        // do not do anything with current point
	                        // correct turn not found

	                    } else if (abs(((angleBetween + 1) % 360) - 1) < THRESHOLD) { // rounding around 0 and 360 to 0
	                        // if the cross product is 0 because the angle is 0 degrees
	                        // remove last hull point from hull BUT do not discard it
	                        // reenter second-to-last hull point (will be last at next iter)
	                        hullPointRecords.push(secondLastHullPointRecord);
	                        // put last hull point back into the sorted point records list
	                        sortedPointRecords.push(lastHullPointRecord);
	                        // we are switching the order of the 0deg and 180deg points
	                        // correct turn not found
	                    }

	                } else {
	                    // found a left turn
	                    // discard last hull point (add to insidePoints)
	                    //insidePoints.unshift(lastHullPoint);
	                    insidePoints[lastHullPointRecord[0] + '@@' + lastHullPointRecord[1]] = lastHullPoint;
	                    // reenter second-to-last hull point (will be last at next iter of loop)
	                    hullPointRecords.push(secondLastHullPointRecord);
	                    // do not do anything with current point
	                    // correct turn not found
	                }
	            }
	        }
	    }
	    // at this point, hullPointRecords contains the output points in clockwise order
	    // the points start with lowest-y,highest-x startPoint, and end at the same point

	    // step 3b: remove duplicated startPointRecord from the end of the array
	    if (hullPointRecords.length > 2) {
	        hullPointRecords.pop();
	    }

	    // step 4: find the lowest originalIndex record and put it at the beginning of hull
	    var lowestHullIndex; // the lowest originalIndex on the hull
	    var indexOfLowestHullIndexRecord = -1; // the index of the record with lowestHullIndex
	    n = hullPointRecords.length;
	    for (i = 0; i < n; i++) {

	        var currentHullIndex = hullPointRecords[i][1];

	        if (lowestHullIndex === undefined || currentHullIndex < lowestHullIndex) {
	            lowestHullIndex = currentHullIndex;
	            indexOfLowestHullIndexRecord = i;
	        }
	    }

	    var hullPointRecordsReordered = [];
	    if (indexOfLowestHullIndexRecord > 0) {
	        var newFirstChunk = hullPointRecords.slice(indexOfLowestHullIndexRecord);
	        var newSecondChunk = hullPointRecords.slice(0, indexOfLowestHullIndexRecord);
	        hullPointRecordsReordered = newFirstChunk.concat(newSecondChunk);

	    } else {
	        hullPointRecordsReordered = hullPointRecords;
	    }

	    var hullPoints = [];
	    n = hullPointRecordsReordered.length;
	    for (i = 0; i < n; i++) {
	        hullPoints.push(hullPointRecordsReordered[i][0]);
	    }

	    return hullPoints;
	}

	var Polyline = function(points) {

	    if (!(this instanceof Polyline)) {
	        return new Polyline(points);
	    }

	    if (typeof points === 'string') {
	        return new Polyline.parse(points);
	    }

	    this.points = (Array.isArray(points) ? points.map(Point) : []);
	};

	Polyline.parse = function(svgString) {
	    return new Polyline(parsePoints(svgString));
	};

	Polyline.fromRect = function(rect) {
	    return new Polyline([
	        rect.topLeft(),
	        rect.topRight(),
	        rect.bottomRight(),
	        rect.bottomLeft(),
	        rect.topLeft() ]);
	};

	Polyline.prototype = {

	    type: types.Polyline,

	    bbox: function() {

	        var x1 = Infinity;
	        var x2 = -Infinity;
	        var y1 = Infinity;
	        var y2 = -Infinity;

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty

	        for (var i = 0; i < numPoints; i++) {

	            var point = points[i];
	            var x = point.x;
	            var y = point.y;

	            if (x < x1) { x1 = x; }
	            if (x > x2) { x2 = x; }
	            if (y < y1) { y1 = y; }
	            if (y > y2) { y2 = y; }
	        }

	        return new Rect(x1, y1, x2 - x1, y2 - y1);
	    },

	    clone: function() {
	        return new Polyline(clonePoints(this.points));
	    },

	    closestPoint: function(p) {

	        var cpLength = this.closestPointLength(p);

	        return this.pointAtLength(cpLength);
	    },

	    closestPointLength: function(p) {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return 0; } // if points array is empty
	        if (numPoints === 1) { return 0; } // if there is only one point

	        var cpLength;
	        var minSqrDistance = Infinity;
	        var length = 0;
	        var n = numPoints - 1;
	        for (var i = 0; i < n; i++) {

	            var line = new Line(points[i], points[i + 1]);
	            var lineLength = line.length();

	            var cpNormalizedLength = line.closestPointNormalizedLength(p);
	            var cp = line.pointAt(cpNormalizedLength);

	            var sqrDistance = cp.squaredDistance(p);
	            if (sqrDistance < minSqrDistance) {
	                minSqrDistance = sqrDistance;
	                cpLength = length + (cpNormalizedLength * lineLength);
	            }

	            length += lineLength;
	        }

	        return cpLength;
	    },

	    closestPointNormalizedLength: function(p) {

	        var cpLength = this.closestPointLength(p);
	        if (cpLength === 0) { return 0; } // shortcut

	        var length = this.length();
	        if (length === 0) { return 0; } // prevents division by zero

	        return cpLength / length;
	    },

	    closestPointTangent: function(p) {

	        var cpLength = this.closestPointLength(p);

	        return this.tangentAtLength(cpLength);
	    },

	    // Returns `true` if the area surrounded by the polyline contains the point `p`.
	    // Implements the even-odd SVG algorithm (self-intersections are "outside").
	    // (Uses horizontal rays to the right of `p` to look for intersections.)
	    // Closes open polylines (always imagines a final closing segment).
	    containsPoint: function(p) {

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return false; } // shortcut (this polyline has no points)

	        var x = p.x;
	        var y = p.y;

	        // initialize a final closing segment by creating one from last-first points on polyline
	        var startIndex = numPoints - 1; // start of current polyline segment
	        var endIndex = 0; // end of current polyline segment
	        var numIntersections = 0;
	        var segment = new Line();
	        var ray = new Line();
	        var rayEnd = new Point();
	        for (; endIndex < numPoints; endIndex++) {
	            var start = points[startIndex];
	            var end = points[endIndex];
	            if (p.equals(start)) { return true; } // shortcut (`p` is a point on polyline)
	            // current polyline segment
	            segment.start = start;
	            segment.end = end;
	            if (segment.containsPoint(p)) { return true; } // shortcut (`p` lies on a polyline segment)

	            // do we have an intersection?
	            if (((y <= start.y) && (y > end.y)) || ((y > start.y) && (y <= end.y))) {
	                // this conditional branch IS NOT entered when `segment` is collinear/coincident with `ray`
	                // (when `y === start.y === end.y`)
	                // this conditional branch IS entered when `segment` touches `ray` at only one point
	                // (e.g. when `y === start.y !== end.y`)
	                // since this branch is entered again for the following segment, the two touches cancel out

	                var xDifference = (((start.x - x) > (end.x - x)) ? (start.x - x) : (end.x - x));
	                if (xDifference >= 0) {
	                    // segment lies at least partially to the right of `p`
	                    rayEnd.x = x + xDifference;
	                    rayEnd.y = y; // right
	                    ray.start = p;
	                    ray.end = rayEnd;
	                    if (segment.intersect(ray)) {
	                        // an intersection was detected to the right of `p`
	                        numIntersections++;
	                    }
	                } // else: `segment` lies completely to the left of `p` (i.e. no intersection to the right)
	            }

	            // move to check the next polyline segment
	            startIndex = endIndex;
	        }

	        // returns `true` for odd numbers of intersections (even-odd algorithm)
	        return ((numIntersections % 2) === 1);
	    },

	    close: function() {
	        var ref = this;
	        var start = ref.start;
	        var end = ref.end;
	        var points = ref.points;
	        if (start && end && !start.equals(end)) {
	            points.push(start.clone());
	        }
	        return this;
	    },

	    lengthPoints: function() {
	        return this.points;
	    },

	    convexHull: function() {
	        return new Polyline(convexHull(this.points));
	    },

	    // Checks whether two polylines are exactly the same.
	    // If `p` is undefined or null, returns false.
	    equals: function(p) {

	        if (!p) { return false; }

	        var points = this.points;
	        var otherPoints = p.points;

	        var numPoints = points.length;
	        if (otherPoints.length !== numPoints) { return false; } // if the two polylines have different number of points, they cannot be equal

	        for (var i = 0; i < numPoints; i++) {

	            var point = points[i];
	            var otherPoint = p.points[i];

	            // as soon as an inequality is found in points, return false
	            if (!point.equals(otherPoint)) { return false; }
	        }

	        // if no inequality found in points, return true
	        return true;
	    },

	    intersectionWithLine: function(l) {
	        var line = new Line(l);
	        var intersections = [];
	        var points = this.lengthPoints();
	        var l2 = new Line();
	        for (var i = 0, n = points.length - 1; i < n; i++) {
	            l2.start = points[i];
	            l2.end = points[i + 1];
	            var int = line.intersectionWithLine(l2);
	            if (int) { intersections.push(int[0]); }
	        }
	        return (intersections.length > 0) ? intersections : null;
	    },

	    isDifferentiable: function() {

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return false; }

	        var line = new Line();
	        var n = numPoints - 1;
	        for (var i = 0; i < n; i++) {
	            line.start = points[i];
	            line.end = points[i + 1];
	            // as soon as a differentiable line is found between two points, return true
	            if (line.isDifferentiable()) { return true; }
	        }

	        // if no differentiable line is found between pairs of points, return false
	        return false;
	    },

	    length: function() {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return 0; } // if points array is empty

	        var length = 0;
	        var n = numPoints - 1;
	        for (var i = 0; i < n; i++) {
	            length += points[i].distance(points[i + 1]);
	        }

	        return length;
	    },

	    pointAt: function(ratio) {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty
	        if (numPoints === 1) { return points[0].clone(); } // if there is only one point

	        if (ratio <= 0) { return points[0].clone(); }
	        if (ratio >= 1) { return points[numPoints - 1].clone(); }

	        var polylineLength = this.length();
	        var length = polylineLength * ratio;

	        return this.pointAtLength(length);
	    },

	    pointAtLength: function(length) {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty
	        if (numPoints === 1) { return points[0].clone(); } // if there is only one point

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        var l = 0;
	        var n = numPoints - 1;
	        for (var i = 0; i < n; i++) {
	            var index = (fromStart ? i : (n - 1 - i));

	            var a = points[index];
	            var b = points[index + 1];
	            var line = new Line(a, b);
	            var d = a.distance(b);

	            if (length <= (l + d)) {
	                return line.pointAtLength((fromStart ? 1 : -1) * (length - l));
	            }

	            l += d;
	        }

	        // if length requested is higher than the length of the polyline, return last endpoint
	        var lastPoint = (fromStart ? points[numPoints - 1] : points[0]);
	        return lastPoint.clone();
	    },

	    round: function(precision) {

	        var points = this.points;
	        var numPoints = points.length;

	        for (var i = 0; i < numPoints; i++) {
	            points[i].round(precision);
	        }

	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        var points = this.points;
	        var numPoints = points.length;

	        for (var i = 0; i < numPoints; i++) {
	            points[i].scale(sx, sy, origin);
	        }

	        return this;
	    },

	    simplify: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var points = this.points;
	        if (points.length < 3) { return this; } // we need at least 3 points

	        // TODO: we may also accept startIndex and endIndex to specify where to start and end simplification

	        // Due to the nature of the algorithm, we do not use 0 as the default value for `threshold`
	        // because of the rounding errors that can occur when comparing distances.
	        var threshold = opt.threshold || 1e-10; // = max distance of middle point from chord to be simplified

	        // start at the beginning of the polyline and go forward
	        var currentIndex = 0;
	        // we need at least one intermediate point (3 points) in every iteration
	        // as soon as that stops being true, we know we reached the end of the polyline
	        while (points[currentIndex + 2]) {
	            var firstIndex = currentIndex;
	            var middleIndex = (currentIndex + 1);
	            var lastIndex = (currentIndex + 2);

	            var firstPoint = points[firstIndex];
	            var middlePoint = points[middleIndex];
	            var lastPoint = points[lastIndex];

	            var chord = new Line(firstPoint, lastPoint); // = connection between first and last point
	            var closestPoint = chord.closestPoint(middlePoint); // = closest point on chord from middle point
	            var closestPointDistance = closestPoint.distance(middlePoint);
	            if (closestPointDistance <= threshold) {
	                // middle point is close enough to the chord = simplify
	                // 1) remove middle point:
	                points.splice(middleIndex, 1);
	                // 2) in next iteration, investigate the newly-created triplet of points
	                //    - do not change `currentIndex`
	                //    = (first point stays, point after removed point becomes middle point)
	            } else {
	                // middle point is far from the chord
	                // 1) preserve middle point
	                // 2) in next iteration, move `currentIndex` by one step:
	                currentIndex += 1;
	                //    = (point after first point becomes first point)
	            }
	        }

	        // `points` array was modified in-place
	        return this;
	    },

	    tangentAt: function(ratio) {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty
	        if (numPoints === 1) { return null; } // if there is only one point

	        if (ratio < 0) { ratio = 0; }
	        if (ratio > 1) { ratio = 1; }

	        var polylineLength = this.length();
	        var length = polylineLength * ratio;

	        return this.tangentAtLength(length);
	    },

	    tangentAtLength: function(length) {

	        var points = this.lengthPoints();
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty
	        if (numPoints === 1) { return null; } // if there is only one point

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        var lastValidLine; // differentiable (with a tangent)
	        var l = 0; // length so far
	        var n = numPoints - 1;
	        for (var i = 0; i < n; i++) {
	            var index = (fromStart ? i : (n - 1 - i));

	            var a = points[index];
	            var b = points[index + 1];
	            var line = new Line(a, b);
	            var d = a.distance(b);

	            if (line.isDifferentiable()) { // has a tangent line (line length is not 0)
	                if (length <= (l + d)) {
	                    return line.tangentAtLength((fromStart ? 1 : -1) * (length - l));
	                }

	                lastValidLine = line;
	            }

	            l += d;
	        }

	        // if length requested is higher than the length of the polyline, return last valid endpoint
	        if (lastValidLine) {
	            var ratio = (fromStart ? 1 : 0);
	            return lastValidLine.tangentAt(ratio);
	        }

	        // if no valid line, return null
	        return null;
	    },

	    toString: function() {

	        return this.points + '';
	    },

	    translate: function(tx, ty) {

	        var points = this.points;
	        var numPoints = points.length;

	        for (var i = 0; i < numPoints; i++) {
	            points[i].translate(tx, ty);
	        }

	        return this;
	    },

	    // Return svgString that can be used to recreate this line.
	    serialize: function() {

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return ''; } // if points array is empty

	        var output = '';
	        for (var i = 0; i < numPoints; i++) {

	            var point = points[i];
	            output += point.x + ',' + point.y + ' ';
	        }

	        return output.trim();
	    }
	};

	Object.defineProperty(Polyline.prototype, 'start', {
	    // Getter for the first point of the polyline.

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty

	        return this.points[0];
	    },
	});

	Object.defineProperty(Polyline.prototype, 'end', {
	    // Getter for the last point of the polyline.

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        var points = this.points;
	        var numPoints = points.length;
	        if (numPoints === 0) { return null; } // if points array is empty

	        return this.points[numPoints - 1];
	    },
	});

	var abs$2 = Math.abs;
	var sqrt$2 = Math.sqrt;
	var min$6 = Math.min;
	var max$4 = Math.max;
	var pow$3 = Math.pow;

	var Curve = function(p1, p2, p3, p4) {

	    if (!(this instanceof Curve)) {
	        return new Curve(p1, p2, p3, p4);
	    }

	    if (p1 instanceof Curve) {
	        return new Curve(p1.start, p1.controlPoint1, p1.controlPoint2, p1.end);
	    }

	    this.start = new Point(p1);
	    this.controlPoint1 = new Point(p2);
	    this.controlPoint2 = new Point(p3);
	    this.end = new Point(p4);
	};

	// Curve passing through points.
	// Ported from C# implementation by Oleg V. Polikarpotchkin and Peter Lee (http://www.codeproject.com/KB/graphics/BezierSpline.aspx).
	// @param {array} points Array of points through which the smooth line will go.
	// @return {array} curves.
	Curve.throughPoints = (function() {

	    // Get open-ended Bezier Spline Control Points.
	    // @param knots Input Knot Bezier spline points (At least two points!).
	    // @param firstControlPoints Output First Control points. Array of knots.length - 1 length.
	    // @param secondControlPoints Output Second Control points. Array of knots.length - 1 length.
	    function getCurveControlPoints(knots) {

	        var firstControlPoints = [];
	        var secondControlPoints = [];
	        var n = knots.length - 1;
	        var i;

	        // Special case: Bezier curve should be a straight line.
	        if (n == 1) {
	            // 3P1 = 2P0 + P3
	            firstControlPoints[0] = new Point(
	                (2 * knots[0].x + knots[1].x) / 3,
	                (2 * knots[0].y + knots[1].y) / 3
	            );

	            // P2 = 2P1 – P0
	            secondControlPoints[0] = new Point(
	                2 * firstControlPoints[0].x - knots[0].x,
	                2 * firstControlPoints[0].y - knots[0].y
	            );

	            return [firstControlPoints, secondControlPoints];
	        }

	        // Calculate first Bezier control points.
	        // Right hand side vector.
	        var rhs = [];

	        // Set right hand side X values.
	        for (i = 1; i < n - 1; i++) {
	            rhs[i] = 4 * knots[i].x + 2 * knots[i + 1].x;
	        }

	        rhs[0] = knots[0].x + 2 * knots[1].x;
	        rhs[n - 1] = (8 * knots[n - 1].x + knots[n].x) / 2.0;

	        // Get first control points X-values.
	        var x = getFirstControlPoints(rhs);

	        // Set right hand side Y values.
	        for (i = 1; i < n - 1; ++i) {
	            rhs[i] = 4 * knots[i].y + 2 * knots[i + 1].y;
	        }

	        rhs[0] = knots[0].y + 2 * knots[1].y;
	        rhs[n - 1] = (8 * knots[n - 1].y + knots[n].y) / 2.0;

	        // Get first control points Y-values.
	        var y = getFirstControlPoints(rhs);

	        // Fill output arrays.
	        for (i = 0; i < n; i++) {
	            // First control point.
	            firstControlPoints.push(new Point(x[i], y[i]));

	            // Second control point.
	            if (i < n - 1) {
	                secondControlPoints.push(new Point(
	                    2 * knots [i + 1].x - x[i + 1],
	                    2 * knots[i + 1].y - y[i + 1]
	                ));

	            } else {
	                secondControlPoints.push(new Point(
	                    (knots[n].x + x[n - 1]) / 2,
	                    (knots[n].y + y[n - 1]) / 2
	                ));
	            }
	        }

	        return [firstControlPoints, secondControlPoints];
	    }

	    // Solves a tridiagonal system for one of coordinates (x or y) of first Bezier control points.
	    // @param rhs Right hand side vector.
	    // @return Solution vector.
	    function getFirstControlPoints(rhs) {

	        var n = rhs.length;
	        // `x` is a solution vector.
	        var x = [];
	        var tmp = [];
	        var b = 2.0;

	        x[0] = rhs[0] / b;

	        // Decomposition and forward substitution.
	        for (var i = 1; i < n; i++) {
	            tmp[i] = 1 / b;
	            b = (i < n - 1 ? 4.0 : 3.5) - tmp[i];
	            x[i] = (rhs[i] - x[i - 1]) / b;
	        }

	        for (i = 1; i < n; i++) {
	            // Backsubstitution.
	            x[n - i - 1] -= tmp[n - i] * x[n - i];
	        }

	        return x;
	    }

	    return function(points) {

	        if (!points || (Array.isArray(points) && points.length < 2)) {
	            throw new Error('At least 2 points are required');
	        }

	        var controlPoints = getCurveControlPoints(points);

	        var curves = [];
	        var n = controlPoints[0].length;
	        for (var i = 0; i < n; i++) {

	            var controlPoint1 = new Point(controlPoints[0][i].x, controlPoints[0][i].y);
	            var controlPoint2 = new Point(controlPoints[1][i].x, controlPoints[1][i].y);

	            curves.push(new Curve(points[i], controlPoint1, controlPoint2, points[i + 1]));
	        }

	        return curves;
	    };
	})();

	Curve.prototype = {

	    type: types.Curve,

	    // Returns a bbox that tightly envelops the curve.
	    bbox: function() {

	        var start = this.start;
	        var controlPoint1 = this.controlPoint1;
	        var controlPoint2 = this.controlPoint2;
	        var end = this.end;

	        var x0 = start.x;
	        var y0 = start.y;
	        var x1 = controlPoint1.x;
	        var y1 = controlPoint1.y;
	        var x2 = controlPoint2.x;
	        var y2 = controlPoint2.y;
	        var x3 = end.x;
	        var y3 = end.y;

	        var points = new Array(); // local extremes
	        var tvalues = new Array(); // t values of local extremes
	        var bounds = [new Array(), new Array()];

	        var a, b, c, t;
	        var t1, t2;
	        var b2ac, sqrtb2ac;

	        for (var i = 0; i < 2; ++i) {

	            if (i === 0) {
	                b = 6 * x0 - 12 * x1 + 6 * x2;
	                a = -3 * x0 + 9 * x1 - 9 * x2 + 3 * x3;
	                c = 3 * x1 - 3 * x0;

	            } else {
	                b = 6 * y0 - 12 * y1 + 6 * y2;
	                a = -3 * y0 + 9 * y1 - 9 * y2 + 3 * y3;
	                c = 3 * y1 - 3 * y0;
	            }

	            if (abs$2(a) < 1e-12) { // Numerical robustness
	                if (abs$2(b) < 1e-12) { // Numerical robustness
	                    continue;
	                }

	                t = -c / b;
	                if ((0 < t) && (t < 1)) { tvalues.push(t); }

	                continue;
	            }

	            b2ac = b * b - 4 * c * a;
	            sqrtb2ac = sqrt$2(b2ac);

	            if (b2ac < 0) { continue; }

	            t1 = (-b + sqrtb2ac) / (2 * a);
	            if ((0 < t1) && (t1 < 1)) { tvalues.push(t1); }

	            t2 = (-b - sqrtb2ac) / (2 * a);
	            if ((0 < t2) && (t2 < 1)) { tvalues.push(t2); }
	        }

	        var j = tvalues.length;
	        var jlen = j;
	        var mt;
	        var x, y;

	        while (j--) {
	            t = tvalues[j];
	            mt = 1 - t;

	            x = (mt * mt * mt * x0) + (3 * mt * mt * t * x1) + (3 * mt * t * t * x2) + (t * t * t * x3);
	            bounds[0][j] = x;

	            y = (mt * mt * mt * y0) + (3 * mt * mt * t * y1) + (3 * mt * t * t * y2) + (t * t * t * y3);
	            bounds[1][j] = y;

	            points[j] = { X: x, Y: y };
	        }

	        tvalues[jlen] = 0;
	        tvalues[jlen + 1] = 1;

	        points[jlen] = { X: x0, Y: y0 };
	        points[jlen + 1] = { X: x3, Y: y3 };

	        bounds[0][jlen] = x0;
	        bounds[1][jlen] = y0;

	        bounds[0][jlen + 1] = x3;
	        bounds[1][jlen + 1] = y3;

	        tvalues.length = jlen + 2;
	        bounds[0].length = jlen + 2;
	        bounds[1].length = jlen + 2;
	        points.length = jlen + 2;

	        var left = min$6.apply(null, bounds[0]);
	        var top = min$6.apply(null, bounds[1]);
	        var right = max$4.apply(null, bounds[0]);
	        var bottom = max$4.apply(null, bounds[1]);

	        return new Rect(left, top, (right - left), (bottom - top));
	    },

	    clone: function() {

	        return new Curve(this.start, this.controlPoint1, this.controlPoint2, this.end);
	    },

	    // Returns the point on the curve closest to point `p`
	    closestPoint: function(p, opt) {

	        return this.pointAtT(this.closestPointT(p, opt));
	    },

	    closestPointLength: function(p, opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        var localOpt = { precision: precision, subdivisions: subdivisions };

	        return this.lengthAtT(this.closestPointT(p, localOpt), localOpt);
	    },

	    closestPointNormalizedLength: function(p, opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        var localOpt = { precision: precision, subdivisions: subdivisions };

	        var cpLength = this.closestPointLength(p, localOpt);
	        if (!cpLength) { return 0; }

	        var length = this.length(localOpt);
	        if (length === 0) { return 0; }

	        return cpLength / length;
	    },

	    // Returns `t` of the point on the curve closest to point `p`
	    closestPointT: function(p, opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        // does not use localOpt

	        // identify the subdivision that contains the point:
	        var investigatedSubdivision;
	        var investigatedSubdivisionStartT; // assume that subdivisions are evenly spaced
	        var investigatedSubdivisionEndT;
	        var distFromStart; // distance of point from start of baseline
	        var distFromEnd; // distance of point from end of baseline
	        var chordLength; // distance between start and end of the subdivision
	        var minSumDist; // lowest observed sum of the two distances
	        var n = subdivisions.length;
	        var subdivisionSize = (n ? (1 / n) : 0);
	        for (var i = 0; i < n; i++) {

	            var currentSubdivision = subdivisions[i];

	            var startDist = currentSubdivision.start.distance(p);
	            var endDist = currentSubdivision.end.distance(p);
	            var sumDist = startDist + endDist;

	            // check that the point is closest to current subdivision and not any other
	            if (!minSumDist || (sumDist < minSumDist)) {
	                investigatedSubdivision = currentSubdivision;

	                investigatedSubdivisionStartT = i * subdivisionSize;
	                investigatedSubdivisionEndT = (i + 1) * subdivisionSize;

	                distFromStart = startDist;
	                distFromEnd = endDist;

	                chordLength = currentSubdivision.start.distance(currentSubdivision.end);

	                minSumDist = sumDist;
	            }
	        }

	        var precisionRatio = pow$3(10, -precision);

	        // recursively divide investigated subdivision:
	        // until distance between baselinePoint and closest path endpoint is within 10^(-precision)
	        // then return the closest endpoint of that final subdivision
	        while (true) {

	            // check if we have reached at least one required observed precision
	            // - calculated as: the difference in distances from point to start and end divided by the distance
	            // - note that this function is not monotonic = it doesn't converge stably but has "teeth"
	            // - the function decreases while one of the endpoints is fixed but "jumps" whenever we switch
	            // - this criterion works well for points lying far away from the curve
	            var startPrecisionRatio = (distFromStart ? (abs$2(distFromStart - distFromEnd) / distFromStart) : 0);
	            var endPrecisionRatio = (distFromEnd ? (abs$2(distFromStart - distFromEnd) / distFromEnd) : 0);
	            var hasRequiredPrecision = ((startPrecisionRatio < precisionRatio) || (endPrecisionRatio < precisionRatio));

	            // check if we have reached at least one required minimal distance
	            // - calculated as: the subdivision chord length multiplied by precisionRatio
	            // - calculation is relative so it will work for arbitrarily large/small curves and their subdivisions
	            // - this is a backup criterion that works well for points lying "almost at" the curve
	            var hasMinimalStartDistance = (distFromStart ? (distFromStart < (chordLength * precisionRatio)) : true);
	            var hasMinimalEndDistance = (distFromEnd ? (distFromEnd < (chordLength * precisionRatio)) : true);
	            var hasMinimalDistance = (hasMinimalStartDistance || hasMinimalEndDistance);

	            // do we stop now?
	            if (hasRequiredPrecision || hasMinimalDistance) {
	                return ((distFromStart <= distFromEnd) ? investigatedSubdivisionStartT : investigatedSubdivisionEndT);
	            }

	            // otherwise, set up for next iteration
	            var divided = investigatedSubdivision.divide(0.5);
	            subdivisionSize /= 2;

	            var startDist1 = divided[0].start.distance(p);
	            var endDist1 = divided[0].end.distance(p);
	            var sumDist1 = startDist1 + endDist1;

	            var startDist2 = divided[1].start.distance(p);
	            var endDist2 = divided[1].end.distance(p);
	            var sumDist2 = startDist2 + endDist2;

	            if (sumDist1 <= sumDist2) {
	                investigatedSubdivision = divided[0];

	                investigatedSubdivisionEndT -= subdivisionSize; // subdivisionSize was already halved

	                distFromStart = startDist1;
	                distFromEnd = endDist1;

	            } else {
	                investigatedSubdivision = divided[1];

	                investigatedSubdivisionStartT += subdivisionSize; // subdivisionSize was already halved

	                distFromStart = startDist2;
	                distFromEnd = endDist2;
	            }
	        }
	    },

	    closestPointTangent: function(p, opt) {

	        return this.tangentAtT(this.closestPointT(p, opt));
	    },

	    // Returns `true` if the area surrounded by the curve contains the point `p`.
	    // Implements the even-odd algorithm (self-intersections are "outside").
	    // Closes open curves (always imagines a closing segment).
	    // Precision may be adjusted by passing an `opt` object.
	    containsPoint: function(p, opt) {

	        var polyline = this.toPolyline(opt);
	        return polyline.containsPoint(p);
	    },

	    // Divides the curve into two at requested `ratio` between 0 and 1 with precision better than `opt.precision`; optionally using `opt.subdivisions` provided.
	    // For a function that uses `t`, use Curve.divideAtT().
	    divideAt: function(ratio, opt) {

	        if (ratio <= 0) { return this.divideAtT(0); }
	        if (ratio >= 1) { return this.divideAtT(1); }

	        var t = this.tAt(ratio, opt);

	        return this.divideAtT(t);
	    },

	    // Divides the curve into two at requested `length` with precision better than requested `opt.precision`; optionally using `opt.subdivisions` provided.
	    divideAtLength: function(length, opt) {

	        var t = this.tAtLength(length, opt);

	        return this.divideAtT(t);
	    },

	    // Divides the curve into two at point defined by `t` between 0 and 1.
	    // Using de Casteljau's algorithm (http://math.stackexchange.com/a/317867).
	    // Additional resource: https://pomax.github.io/bezierinfo/#decasteljau
	    divideAtT: function(t) {

	        var start = this.start;
	        var controlPoint1 = this.controlPoint1;
	        var controlPoint2 = this.controlPoint2;
	        var end = this.end;

	        // shortcuts for `t` values that are out of range
	        if (t <= 0) {
	            return [
	                new Curve(start, start, start, start),
	                new Curve(start, controlPoint1, controlPoint2, end)
	            ];
	        }

	        if (t >= 1) {
	            return [
	                new Curve(start, controlPoint1, controlPoint2, end),
	                new Curve(end, end, end, end)
	            ];
	        }

	        var dividerPoints = this.getSkeletonPoints(t);

	        var startControl1 = dividerPoints.startControlPoint1;
	        var startControl2 = dividerPoints.startControlPoint2;
	        var divider = dividerPoints.divider;
	        var dividerControl1 = dividerPoints.dividerControlPoint1;
	        var dividerControl2 = dividerPoints.dividerControlPoint2;

	        // return array with two new curves
	        return [
	            new Curve(start, startControl1, startControl2, divider),
	            new Curve(divider, dividerControl1, dividerControl2, end)
	        ];
	    },

	    // Returns the distance between the curve's start and end points.
	    endpointDistance: function() {

	        return this.start.distance(this.end);
	    },

	    // Checks whether two curves are exactly the same.
	    equals: function(c) {

	        return !!c &&
	            this.start.x === c.start.x &&
	            this.start.y === c.start.y &&
	            this.controlPoint1.x === c.controlPoint1.x &&
	            this.controlPoint1.y === c.controlPoint1.y &&
	            this.controlPoint2.x === c.controlPoint2.x &&
	            this.controlPoint2.y === c.controlPoint2.y &&
	            this.end.x === c.end.x &&
	            this.end.y === c.end.y;
	    },

	    // Returns five helper points necessary for curve division.
	    getSkeletonPoints: function(t) {

	        var start = this.start;
	        var control1 = this.controlPoint1;
	        var control2 = this.controlPoint2;
	        var end = this.end;

	        // shortcuts for `t` values that are out of range
	        if (t <= 0) {
	            return {
	                startControlPoint1: start.clone(),
	                startControlPoint2: start.clone(),
	                divider: start.clone(),
	                dividerControlPoint1: control1.clone(),
	                dividerControlPoint2: control2.clone()
	            };
	        }

	        if (t >= 1) {
	            return {
	                startControlPoint1: control1.clone(),
	                startControlPoint2: control2.clone(),
	                divider: end.clone(),
	                dividerControlPoint1: end.clone(),
	                dividerControlPoint2: end.clone()
	            };
	        }

	        var midpoint1 = (new Line(start, control1)).pointAt(t);
	        var midpoint2 = (new Line(control1, control2)).pointAt(t);
	        var midpoint3 = (new Line(control2, end)).pointAt(t);

	        var subControl1 = (new Line(midpoint1, midpoint2)).pointAt(t);
	        var subControl2 = (new Line(midpoint2, midpoint3)).pointAt(t);

	        var divider = (new Line(subControl1, subControl2)).pointAt(t);

	        var output = {
	            startControlPoint1: midpoint1,
	            startControlPoint2: subControl1,
	            divider: divider,
	            dividerControlPoint1: subControl2,
	            dividerControlPoint2: midpoint3
	        };

	        return output;
	    },

	    // Returns a list of curves whose flattened length is better than `opt.precision`.
	    // That is, observed difference in length between recursions is less than 10^(-3) = 0.001 = 0.1%
	    // (Observed difference is not real precision, but close enough as long as special cases are covered)
	    // As a rule of thumb, increasing `precision` by 1 requires 2 more iterations (= levels of division operations)
	    // - Precision 0 (endpointDistance) - 0 iterations => total of 2^0 - 1 = 0 operations (1 subdivision)
	    // - Precision 1 (<10% error) - 2 iterations => total of 2^2 - 1 = 3 operations (4 subdivisions)
	    // - Precision 2 (<1% error) - 4 iterations => total of 2^4 - 1 = 15 operations requires 4 division operations on all elements (15 operations total) (16 subdivisions)
	    // - Precision 3 (<0.1% error) - 6 iterations => total of 2^6 - 1 = 63 operations - acceptable when drawing (64 subdivisions)
	    // - Precision 4 (<0.01% error) - 8 iterations => total of 2^8 - 1 = 255 operations - high resolution, can be used to interpolate `t` (256 subdivisions)
	    // (Variation of 1 recursion worse or better is possible depending on the curve, doubling/halving the number of operations accordingly)
	    getSubdivisions: function(opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        // not using opt.subdivisions
	        // not using localOpt

	        var start = this.start;
	        var control1 = this.controlPoint1;
	        var control2 = this.controlPoint2;
	        var end = this.end;

	        var subdivisions = [new Curve(start, control1, control2, end)];
	        if (precision === 0) { return subdivisions; }

	        // special case #1: point-like curves
	        // - no need to calculate subdivisions, they would all be identical
	        var isPoint = !this.isDifferentiable();
	        if (isPoint) { return subdivisions; }

	        var previousLength = this.endpointDistance();

	        var precisionRatio = pow$3(10, -precision);

	        // special case #2: sine-like curves may have the same observed length in iteration 0 and 1 - skip iteration 1
	        // - not a problem for further iterations because cubic curves cannot have more than two local extrema
	        // - (i.e. cubic curves cannot intersect the baseline more than once)
	        // - therefore starting from iteration = 2 ensures that subsequent iterations do not produce sampling with equal length
	        // - (unless it's a straight-line curve, see below)
	        var minIterations = 2; // = 2*1

	        // special case #3: straight-line curves have the same observed length in all iterations
	        // - this causes observed precision ratio to always be 0 (= lower than `precisionRatio`, which is our exit condition)
	        // - we enforce the expected number of iterations = 2 * precision
	        var isLine = ((control1.cross(start, end) === 0) && (control2.cross(start, end) === 0));
	        if (isLine) {
	            minIterations = (2 * precision);
	        }

	        // recursively divide curve at `t = 0.5`
	        // until we reach `minIterations`
	        // and until the difference between observed length at subsequent iterations is lower than `precision`
	        var iteration = 0;
	        while (true) {
	            iteration += 1;

	            // divide all subdivisions
	            var newSubdivisions = [];
	            var numSubdivisions = subdivisions.length;
	            for (var i = 0; i < numSubdivisions; i++) {

	                var currentSubdivision = subdivisions[i];
	                var divided = currentSubdivision.divide(0.5); // dividing at t = 0.5 (not at middle length!)
	                newSubdivisions.push(divided[0], divided[1]);
	            }

	            // measure new length
	            var length = 0;
	            var numNewSubdivisions = newSubdivisions.length;
	            for (var j = 0; j < numNewSubdivisions; j++) {

	                var currentNewSubdivision = newSubdivisions[j];
	                length += currentNewSubdivision.endpointDistance();
	            }

	            // check if we have reached minimum number of iterations
	            if (iteration >= minIterations) {

	                // check if we have reached required observed precision
	                var observedPrecisionRatio = ((length !== 0) ? ((length - previousLength) / length) : 0);
	                if (observedPrecisionRatio < precisionRatio) {
	                    return newSubdivisions;
	                }
	            }

	            // otherwise, set up for next iteration
	            subdivisions = newSubdivisions;
	            previousLength = length;
	        }
	    },

	    isDifferentiable: function() {

	        var start = this.start;
	        var control1 = this.controlPoint1;
	        var control2 = this.controlPoint2;
	        var end = this.end;

	        return !(start.equals(control1) && control1.equals(control2) && control2.equals(end));
	    },

	    // Returns flattened length of the curve with precision better than `opt.precision`; or using `opt.subdivisions` provided.
	    length: function(opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision; // opt.precision only used in getSubdivisions() call
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        // not using localOpt

	        var length = 0;
	        var n = subdivisions.length;
	        for (var i = 0; i < n; i++) {

	            var currentSubdivision = subdivisions[i];
	            length += currentSubdivision.endpointDistance();
	        }

	        return length;
	    },

	    // Returns distance along the curve up to `t` with precision better than requested `opt.precision`. (Not using `opt.subdivisions`.)
	    lengthAtT: function(t, opt) {

	        if (t <= 0) { return 0; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        // not using opt.subdivisions
	        // not using localOpt

	        var subCurve = this.divide(t)[0];
	        var subCurveLength = subCurve.length({ precision: precision });

	        return subCurveLength;
	    },

	    // Returns point at requested `ratio` between 0 and 1 with precision better than `opt.precision`; optionally using `opt.subdivisions` provided.
	    // Mirrors Line.pointAt() function.
	    // For a function that tracks `t`, use Curve.pointAtT().
	    pointAt: function(ratio, opt) {

	        if (ratio <= 0) { return this.start.clone(); }
	        if (ratio >= 1) { return this.end.clone(); }

	        var t = this.tAt(ratio, opt);

	        return this.pointAtT(t);
	    },

	    // Returns point at requested `length` with precision better than requested `opt.precision`; optionally using `opt.subdivisions` provided.
	    pointAtLength: function(length, opt) {

	        var t = this.tAtLength(length, opt);

	        return this.pointAtT(t);
	    },

	    // Returns the point at provided `t` between 0 and 1.
	    // `t` does not track distance along curve as it does in Line objects.
	    // Non-linear relationship, speeds up and slows down as curve warps!
	    // For linear length-based solution, use Curve.pointAt().
	    pointAtT: function(t) {

	        if (t <= 0) { return this.start.clone(); }
	        if (t >= 1) { return this.end.clone(); }

	        return this.getSkeletonPoints(t).divider;
	    },

	    // Default precision
	    PRECISION: 3,

	    round: function(precision) {

	        this.start.round(precision);
	        this.controlPoint1.round(precision);
	        this.controlPoint2.round(precision);
	        this.end.round(precision);
	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        this.start.scale(sx, sy, origin);
	        this.controlPoint1.scale(sx, sy, origin);
	        this.controlPoint2.scale(sx, sy, origin);
	        this.end.scale(sx, sy, origin);
	        return this;
	    },

	    // Returns a tangent line at requested `ratio` with precision better than requested `opt.precision`; or using `opt.subdivisions` provided.
	    tangentAt: function(ratio, opt) {

	        if (!this.isDifferentiable()) { return null; }

	        if (ratio < 0) { ratio = 0; }
	        else if (ratio > 1) { ratio = 1; }

	        var t = this.tAt(ratio, opt);

	        return this.tangentAtT(t);
	    },

	    // Returns a tangent line at requested `length` with precision better than requested `opt.precision`; or using `opt.subdivisions` provided.
	    tangentAtLength: function(length, opt) {

	        if (!this.isDifferentiable()) { return null; }

	        var t = this.tAtLength(length, opt);

	        return this.tangentAtT(t);
	    },

	    // Returns a tangent line at requested `t`.
	    tangentAtT: function(t) {

	        if (!this.isDifferentiable()) { return null; }

	        if (t < 0) { t = 0; }
	        else if (t > 1) { t = 1; }

	        var skeletonPoints = this.getSkeletonPoints(t);

	        var p1 = skeletonPoints.startControlPoint2;
	        var p2 = skeletonPoints.dividerControlPoint1;

	        var tangentStart = skeletonPoints.divider;

	        var tangentLine = new Line(p1, p2);
	        tangentLine.translate(tangentStart.x - p1.x, tangentStart.y - p1.y); // move so that tangent line starts at the point requested

	        return tangentLine;
	    },

	    // Returns `t` at requested `ratio` with precision better than requested `opt.precision`; optionally using `opt.subdivisions` provided.
	    tAt: function(ratio, opt) {

	        if (ratio <= 0) { return 0; }
	        if (ratio >= 1) { return 1; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        var localOpt = { precision: precision, subdivisions: subdivisions };

	        var curveLength = this.length(localOpt);
	        var length = curveLength * ratio;

	        return this.tAtLength(length, localOpt);
	    },

	    // Returns `t` at requested `length` with precision better than requested `opt.precision`; optionally using `opt.subdivisions` provided.
	    // Uses `precision` to approximate length within `precision` (always underestimates)
	    // Then uses a binary search to find the `t` of a subdivision endpoint that is close (within `precision`) to the `length`, if the curve was as long as approximated
	    // As a rule of thumb, increasing `precision` by 1 causes the algorithm to go 2^(precision - 1) deeper
	    // - Precision 0 (chooses one of the two endpoints) - 0 levels
	    // - Precision 1 (chooses one of 5 points, <10% error) - 1 level
	    // - Precision 2 (<1% error) - 3 levels
	    // - Precision 3 (<0.1% error) - 7 levels
	    // - Precision 4 (<0.01% error) - 15 levels
	    tAtLength: function(length, opt) {

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        var localOpt = { precision: precision, subdivisions: subdivisions };

	        // identify the subdivision that contains the point at requested `length`:
	        var investigatedSubdivision;
	        var investigatedSubdivisionStartT; // assume that subdivisions are evenly spaced
	        var investigatedSubdivisionEndT;
	        //var baseline; // straightened version of subdivision to investigate
	        //var baselinePoint; // point on the baseline that is the requested distance away from start
	        var baselinePointDistFromStart; // distance of baselinePoint from start of baseline
	        var baselinePointDistFromEnd; // distance of baselinePoint from end of baseline
	        var l = 0; // length so far
	        var n = subdivisions.length;
	        var subdivisionSize = 1 / n;
	        for (var i = 0; i < n; i++) {
	            var index = (fromStart ? i : (n - 1 - i));

	            var currentSubdivision = subdivisions[i];
	            var d = currentSubdivision.endpointDistance(); // length of current subdivision

	            if (length <= (l + d)) {
	                investigatedSubdivision = currentSubdivision;

	                investigatedSubdivisionStartT = index * subdivisionSize;
	                investigatedSubdivisionEndT = (index + 1) * subdivisionSize;

	                baselinePointDistFromStart = (fromStart ? (length - l) : ((d + l) - length));
	                baselinePointDistFromEnd = (fromStart ? ((d + l) - length) : (length - l));

	                break;
	            }

	            l += d;
	        }

	        if (!investigatedSubdivision) { return (fromStart ? 1 : 0); } // length requested is out of range - return maximum t
	        // note that precision affects what length is recorded
	        // (imprecise measurements underestimate length by up to 10^(-precision) of the precise length)
	        // e.g. at precision 1, the length may be underestimated by up to 10% and cause this function to return 1

	        var curveLength = this.length(localOpt);

	        var precisionRatio = pow$3(10, -precision);

	        // recursively divide investigated subdivision:
	        // until distance between baselinePoint and closest path endpoint is within 10^(-precision)
	        // then return the closest endpoint of that final subdivision
	        while (true) {

	            // check if we have reached required observed precision
	            var observedPrecisionRatio;

	            observedPrecisionRatio = ((curveLength !== 0) ? (baselinePointDistFromStart / curveLength) : 0);
	            if (observedPrecisionRatio < precisionRatio) { return investigatedSubdivisionStartT; }
	            observedPrecisionRatio = ((curveLength !== 0) ? (baselinePointDistFromEnd / curveLength) : 0);
	            if (observedPrecisionRatio < precisionRatio) { return investigatedSubdivisionEndT; }

	            // otherwise, set up for next iteration
	            var newBaselinePointDistFromStart;
	            var newBaselinePointDistFromEnd;

	            var divided = investigatedSubdivision.divide(0.5);
	            subdivisionSize /= 2;

	            var baseline1Length = divided[0].endpointDistance();
	            var baseline2Length = divided[1].endpointDistance();

	            if (baselinePointDistFromStart <= baseline1Length) { // point at requested length is inside divided[0]
	                investigatedSubdivision = divided[0];

	                investigatedSubdivisionEndT -= subdivisionSize; // sudivisionSize was already halved

	                newBaselinePointDistFromStart = baselinePointDistFromStart;
	                newBaselinePointDistFromEnd = baseline1Length - newBaselinePointDistFromStart;

	            } else { // point at requested length is inside divided[1]
	                investigatedSubdivision = divided[1];

	                investigatedSubdivisionStartT += subdivisionSize; // subdivisionSize was already halved

	                newBaselinePointDistFromStart = baselinePointDistFromStart - baseline1Length;
	                newBaselinePointDistFromEnd = baseline2Length - newBaselinePointDistFromStart;
	            }

	            baselinePointDistFromStart = newBaselinePointDistFromStart;
	            baselinePointDistFromEnd = newBaselinePointDistFromEnd;
	        }
	    },

	    // Returns an array of points that represents the curve when flattened, up to `opt.precision`; or using `opt.subdivisions` provided.
	    // Flattened length is no more than 10^(-precision) away from real curve length.
	    toPoints: function(opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision; // opt.precision only used in getSubdivisions() call
	        var subdivisions = (opt.subdivisions === undefined) ? this.getSubdivisions({ precision: precision }) : opt.subdivisions;
	        // not using localOpt

	        var points = [subdivisions[0].start.clone()];
	        var n = subdivisions.length;
	        for (var i = 0; i < n; i++) {

	            var currentSubdivision = subdivisions[i];
	            points.push(currentSubdivision.end.clone());
	        }

	        return points;
	    },

	    // Returns a polyline that represents the curve when flattened, up to `opt.precision`; or using `opt.subdivisions` provided.
	    // Flattened length is no more than 10^(-precision) away from real curve length.
	    toPolyline: function(opt) {

	        return new Polyline(this.toPoints(opt));
	    },

	    toString: function() {

	        return this.start + ' ' + this.controlPoint1 + ' ' + this.controlPoint2 + ' ' + this.end;
	    },

	    translate: function(tx, ty) {

	        this.start.translate(tx, ty);
	        this.controlPoint1.translate(tx, ty);
	        this.controlPoint2.translate(tx, ty);
	        this.end.translate(tx, ty);
	        return this;
	    }
	};

	Curve.prototype.divide = Curve.prototype.divideAtT;

	// Local helper function.
	// Add properties from arguments on top of properties from `obj`.
	// This allows for rudimentary inheritance.
	// - The `obj` argument acts as parent.
	// - This function creates a new object that inherits all `obj` properties and adds/replaces those that are present in arguments.
	// - A high-level example: calling `extend(Vehicle, Car)` would be akin to declaring `class Car extends Vehicle`.
	function extend(obj) {
	    var arguments$1 = arguments;

	    // In JavaScript, the combination of a constructor function (e.g. `g.Line = function(...) {...}`) and prototype (e.g. `g.Line.prototype = {...}) is akin to a C++ class.
	    // - When inheritance is not necessary, we can leave it at that. (This would be akin to calling extend with only `obj`.)
	    // - But, what if we wanted the `g.Line` quasiclass to inherit from another quasiclass (let's call it `g.GeometryObject`) in JavaScript?
	    // - First, realize that both of those quasiclasses would still have their own separate constructor function.
	    // - So what we are actually saying is that we want the `g.Line` prototype to inherit from `g.GeometryObject` prototype.
	    // - This method provides a way to do exactly that.
	    // - It copies parent prototype's properties, then adds extra ones from child prototype/overrides parent prototype properties with child prototype properties.
	    // - Therefore, to continue with the example above:
	    //   - `g.Line.prototype = extend(g.GeometryObject.prototype, linePrototype)`
	    //   - Where `linePrototype` is a properties object that looks just like `g.Line.prototype` does right now.
	    //   - Then, `g.Line` would allow the programmer to access to all methods currently in `g.Line.Prototype`, plus any non-overridden methods from `g.GeometryObject.prototype`.
	    //   - In that aspect, `g.GeometryObject` would then act like the parent of `g.Line`.
	    // - Multiple inheritance is also possible, if multiple arguments are provided.
	    // - What if we wanted to add another level of abstraction between `g.GeometryObject` and `g.Line` (let's call it `g.LinearObject`)?
	    //   - `g.Line.prototype = extend(g.GeometryObject.prototype, g.LinearObject.prototype, linePrototype)`
	    //   - The ancestors are applied in order of appearance.
	    //   - That means that `g.Line` would have inherited from `g.LinearObject` that would have inherited from `g.GeometryObject`.
	    //   - Any number of ancestors may be provided.
	    // - Note that neither `obj` nor any of the arguments need to actually be prototypes of any JavaScript quasiclass, that was just a simplified explanation.
	    // - We can create a new object composed from the properties of any number of other objects (since they do not have a constructor, we can think of those as interfaces).
	    //   - `extend({ a: 1, b: 2 }, { b: 10, c: 20 }, { c: 100, d: 200 })` gives `{ a: 1, b: 10, c: 100, d: 200 }`.
	    //   - Basically, with this function, we can emulate the `extends` keyword as well as the `implements` keyword.
	    // - Therefore, both of the following are valid:
	    //   - `Lineto.prototype = extend(Line.prototype, segmentPrototype, linetoPrototype)`
	    //   - `Moveto.prototype = extend(segmentPrototype, movetoPrototype)`

	    var i;
	    var n;

	    var args = [];
	    n = arguments.length;
	    for (i = 1; i < n; i++) { // skip over obj
	        args.push(arguments$1[i]);
	    }

	    if (!obj) { throw new Error('Missing a parent object.'); }
	    var child = Object.create(obj);

	    n = args.length;
	    for (i = 0; i < n; i++) {

	        var src = args[i];

	        var inheritedProperty;
	        var key;
	        for (key in src) {

	            if (src.hasOwnProperty(key)) {
	                delete child[key]; // delete property inherited from parent
	                inheritedProperty = Object.getOwnPropertyDescriptor(src, key); // get new definition of property from src
	                Object.defineProperty(child, key, inheritedProperty); // re-add property with new definition (includes getter/setter methods)
	            }
	        }
	    }

	    return child;
	}

	// Accepts path data string, array of segments, array of Curves and/or Lines, or a Polyline.
	var Path = function(arg) {

	    if (!(this instanceof Path)) {
	        return new Path(arg);
	    }

	    if (typeof arg === 'string') { // create from a path data string
	        return new Path.parse(arg);
	    }

	    this.segments = [];

	    var i;
	    var n;

	    if (!arg) {
	        // don't do anything

	    } else if (Array.isArray(arg) && arg.length !== 0) { // if arg is a non-empty array
	        // flatten one level deep
	        // so we can chain arbitrary Path.createSegment results
	        arg = arg.reduce(function(acc, val) {
	            return acc.concat(val);
	        }, []);

	        n = arg.length;
	        if (arg[0].isSegment) { // create from an array of segments
	            for (i = 0; i < n; i++) {

	                var segment = arg[i];

	                this.appendSegment(segment);
	            }

	        } else { // create from an array of Curves and/or Lines
	            var previousObj = null;
	            for (i = 0; i < n; i++) {

	                var obj = arg[i];

	                if (!((obj instanceof Line) || (obj instanceof Curve))) {
	                    throw new Error('Cannot construct a path segment from the provided object.');
	                }

	                if (i === 0) { this.appendSegment(Path.createSegment('M', obj.start)); }

	                // if objects do not link up, moveto segments are inserted to cover the gaps
	                if (previousObj && !previousObj.end.equals(obj.start)) { this.appendSegment(Path.createSegment('M', obj.start)); }

	                if (obj instanceof Line) {
	                    this.appendSegment(Path.createSegment('L', obj.end));

	                } else if (obj instanceof Curve) {
	                    this.appendSegment(Path.createSegment('C', obj.controlPoint1, obj.controlPoint2, obj.end));
	                }

	                previousObj = obj;
	            }
	        }

	    } else if (arg.isSegment) { // create from a single segment
	        this.appendSegment(arg);

	    } else if (arg instanceof Line) { // create from a single Line
	        this.appendSegment(Path.createSegment('M', arg.start));
	        this.appendSegment(Path.createSegment('L', arg.end));

	    } else if (arg instanceof Curve) { // create from a single Curve
	        this.appendSegment(Path.createSegment('M', arg.start));
	        this.appendSegment(Path.createSegment('C', arg.controlPoint1, arg.controlPoint2, arg.end));

	    } else if (arg instanceof Polyline) { // create from a Polyline
	        if (!(arg.points && (arg.points.length !== 0))) { return; } // if Polyline has no points, leave Path empty

	        n = arg.points.length;
	        for (i = 0; i < n; i++) {

	            var point = arg.points[i];

	            if (i === 0) { this.appendSegment(Path.createSegment('M', point)); }
	            else { this.appendSegment(Path.createSegment('L', point)); }
	        }

	    } else { // unknown object
	        throw new Error('Cannot construct a path from the provided object.');
	    }
	};

	// More permissive than V.normalizePathData and Path.prototype.serialize.
	// Allows path data strings that do not start with a Moveto command (unlike SVG specification).
	// Does not require spaces between elements; commas are allowed, separators may be omitted when unambiguous (e.g. 'ZM10,10', 'L1.6.8', 'M100-200').
	// Allows for command argument chaining.
	// Throws an error if wrong number of arguments is provided with a command.
	// Throws an error if an unrecognized path command is provided (according to Path.segmentTypes). Only a subset of SVG commands is currently supported (L, C, M, Z).
	Path.parse = function(pathData) {

	    if (!pathData) { return new Path(); }

	    var path = new Path();

	    var commandRe = /(?:[a-zA-Z] *)(?:(?:-?\d+(?:\.\d+)?(?:e[-+]?\d+)? *,? *)|(?:-?\.\d+ *,? *))+|(?:[a-zA-Z] *)(?! |\d|-|\.)/g;
	    var commands = pathData.match(commandRe);

	    var numCommands = commands.length;
	    for (var i = 0; i < numCommands; i++) {

	        var command = commands[i];
	        var argRe = /(?:[a-zA-Z])|(?:(?:-?\d+(?:\.\d+)?(?:e[-+]?\d+)?))|(?:(?:-?\.\d+))/g;
	        var args = command.match(argRe);

	        var segment = Path.createSegment.apply(this, args); // args = [type, coordinate1, coordinate2...]
	        path.appendSegment(segment);
	    }

	    return path;
	};

	// Create a segment or an array of segments.
	// Accepts unlimited points/coords arguments after `type`.
	Path.createSegment = function(type) {
	    var arguments$1 = arguments;


	    if (!type) { throw new Error('Type must be provided.'); }

	    var segmentConstructor = Path.segmentTypes[type];
	    if (!segmentConstructor) { throw new Error(type + ' is not a recognized path segment type.'); }

	    var args = [];
	    var n = arguments.length;
	    for (var i = 1; i < n; i++) { // do not add first element (`type`) to args array
	        args.push(arguments$1[i]);
	    }

	    return applyToNew(segmentConstructor, args);
	};

	Path.prototype = {

	    type: types.Path,

	    // Accepts one segment or an array of segments as argument.
	    // Throws an error if argument is not a segment or an array of segments.
	    appendSegment: function(arg) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        // works even if path has no segments

	        var currentSegment;

	        var previousSegment = ((numSegments !== 0) ? segments[numSegments - 1] : null); // if we are appending to an empty path, previousSegment is null
	        var nextSegment = null;

	        if (!Array.isArray(arg)) { // arg is a segment
	            if (!arg || !arg.isSegment) { throw new Error('Segment required.'); }

	            currentSegment = this.prepareSegment(arg, previousSegment, nextSegment);
	            segments.push(currentSegment);

	        } else { // arg is an array of segments
	            // flatten one level deep
	            // so we can chain arbitrary Path.createSegment results
	            arg = arg.reduce(function(acc, val) {
	                return acc.concat(val);
	            }, []);

	            if (!arg[0].isSegment) { throw new Error('Segments required.'); }

	            var n = arg.length;
	            for (var i = 0; i < n; i++) {

	                var currentArg = arg[i];
	                currentSegment = this.prepareSegment(currentArg, previousSegment, nextSegment);
	                segments.push(currentSegment);
	                previousSegment = currentSegment;
	            }
	        }
	    },

	    // Returns the bbox of the path.
	    // If path has no segments, returns null.
	    // If path has only invisible segments, returns bbox of the end point of last segment.
	    bbox: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var bbox;
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            if (segment.isVisible) {
	                var segmentBBox = segment.bbox();
	                bbox = bbox ? bbox.union(segmentBBox) : segmentBBox;
	            }
	        }

	        if (bbox) { return bbox; }

	        // if the path has only invisible elements, return end point of last segment
	        var lastSegment = segments[numSegments - 1];
	        return new Rect(lastSegment.end.x, lastSegment.end.y, 0, 0);
	    },

	    // Returns a new path that is a clone of this path.
	    clone: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        // works even if path has no segments

	        var path = new Path();
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i].clone();
	            path.appendSegment(segment);
	        }

	        return path;
	    },

	    closestPoint: function(p, opt) {

	        var t = this.closestPointT(p, opt);
	        if (!t) { return null; }

	        return this.pointAtT(t);
	    },

	    closestPointLength: function(p, opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var t = this.closestPointT(p, localOpt);
	        if (!t) { return 0; }

	        return this.lengthAtT(t, localOpt);
	    },

	    closestPointNormalizedLength: function(p, opt) {

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var cpLength = this.closestPointLength(p, localOpt);
	        if (cpLength === 0) { return 0; } // shortcut

	        var length = this.length(localOpt);
	        if (length === 0) { return 0; } // prevents division by zero

	        return cpLength / length;
	    },

	    // Private function.
	    closestPointT: function(p, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var closestPointT;
	        var minSquaredDistance = Infinity;
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            var subdivisions = segmentSubdivisions[i];

	            if (segment.isVisible) {
	                var segmentClosestPointT = segment.closestPointT(p, {
	                    precision: precision,
	                    subdivisions: subdivisions
	                });
	                var segmentClosestPoint = segment.pointAtT(segmentClosestPointT);
	                var squaredDistance = (new Line(segmentClosestPoint, p)).squaredLength();

	                if (squaredDistance < minSquaredDistance) {
	                    closestPointT = { segmentIndex: i, value: segmentClosestPointT };
	                    minSquaredDistance = squaredDistance;
	                }
	            }
	        }

	        if (closestPointT) { return closestPointT; }

	        // if no visible segment, return end of last segment
	        return { segmentIndex: numSegments - 1, value: 1 };
	    },

	    closestPointTangent: function(p, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var closestPointTangent;
	        var minSquaredDistance = Infinity;
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            var subdivisions = segmentSubdivisions[i];

	            if (segment.isDifferentiable()) {
	                var segmentClosestPointT = segment.closestPointT(p, {
	                    precision: precision,
	                    subdivisions: subdivisions
	                });
	                var segmentClosestPoint = segment.pointAtT(segmentClosestPointT);
	                var squaredDistance = (new Line(segmentClosestPoint, p)).squaredLength();

	                if (squaredDistance < minSquaredDistance) {
	                    closestPointTangent = segment.tangentAtT(segmentClosestPointT);
	                    minSquaredDistance = squaredDistance;
	                }
	            }
	        }

	        if (closestPointTangent) { return closestPointTangent; }

	        // if no valid segment, return null
	        return null;
	    },

	    // Returns `true` if the area surrounded by the path contains the point `p`.
	    // Implements the even-odd algorithm (self-intersections are "outside").
	    // Closes open paths (always imagines a final closing segment).
	    // Precision may be adjusted by passing an `opt` object.
	    containsPoint: function(p, opt) {

	        var polylines = this.toPolylines(opt);
	        if (!polylines) { return false; } // shortcut (this path has no polylines)

	        var numPolylines = polylines.length;

	        // how many component polylines does `p` lie within?
	        var numIntersections = 0;
	        for (var i = 0; i < numPolylines; i++) {
	            var polyline = polylines[i];
	            if (polyline.containsPoint(p)) {
	                // `p` lies within this polyline
	                numIntersections++;
	            }
	        }

	        // returns `true` for odd numbers of intersections (even-odd algorithm)
	        return ((numIntersections % 2) === 1);
	    },

	    // Divides the path into two at requested `ratio` between 0 and 1 with precision better than `opt.precision`; optionally using `opt.subdivisions` provided.
	    divideAt: function(ratio, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        if (ratio < 0) { ratio = 0; }
	        if (ratio > 1) { ratio = 1; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var pathLength = this.length(localOpt);
	        var length = pathLength * ratio;

	        return this.divideAtLength(length, localOpt);
	    },

	    // Divides the path into two at requested `length` with precision better than requested `opt.precision`; optionally using `opt.subdivisions` provided.
	    divideAtLength: function(length, opt) {

	        var numSegments = this.segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var i;
	        var segment;

	        // identify the segment to divide:

	        var l = 0; // length so far
	        var divided;
	        var dividedSegmentIndex;
	        var lastValidSegment; // visible AND differentiable
	        var lastValidSegmentIndex;
	        var t;
	        for (i = 0; i < numSegments; i++) {
	            var index = (fromStart ? i : (numSegments - 1 - i));

	            segment = this.getSegment(index);
	            var subdivisions = segmentSubdivisions[index];
	            var d = segment.length({ precision: precision, subdivisions: subdivisions });

	            if (segment.isDifferentiable()) { // segment is not just a point
	                lastValidSegment = segment;
	                lastValidSegmentIndex = index;

	                if (length <= (l + d)) {
	                    dividedSegmentIndex = index;
	                    divided = segment.divideAtLength(((fromStart ? 1 : -1) * (length - l)), {
	                        precision: precision,
	                        subdivisions: subdivisions
	                    });
	                    break;
	                }
	            }

	            l += d;
	        }

	        if (!lastValidSegment) { // no valid segment found
	            return null;
	        }

	        // else: the path contains at least one valid segment

	        if (!divided) { // the desired length is greater than the length of the path
	            dividedSegmentIndex = lastValidSegmentIndex;
	            t = (fromStart ? 1 : 0);
	            divided = lastValidSegment.divideAtT(t);
	        }

	        // create a copy of this path and replace the identified segment with its two divided parts:

	        var pathCopy = this.clone();
	        pathCopy.replaceSegment(dividedSegmentIndex, divided);

	        var divisionStartIndex = dividedSegmentIndex;
	        var divisionMidIndex = dividedSegmentIndex + 1;
	        var divisionEndIndex = dividedSegmentIndex + 2;

	        // do not insert the part if it looks like a point
	        if (!divided[0].isDifferentiable()) {
	            pathCopy.removeSegment(divisionStartIndex);
	            divisionMidIndex -= 1;
	            divisionEndIndex -= 1;
	        }

	        // insert a Moveto segment to ensure secondPath will be valid:
	        var movetoEnd = pathCopy.getSegment(divisionMidIndex).start;
	        pathCopy.insertSegment(divisionMidIndex, Path.createSegment('M', movetoEnd));
	        divisionEndIndex += 1;

	        // do not insert the part if it looks like a point
	        if (!divided[1].isDifferentiable()) {
	            pathCopy.removeSegment(divisionEndIndex - 1);
	            divisionEndIndex -= 1;
	        }

	        // ensure that Closepath segments in secondPath will be assigned correct subpathStartSegment:

	        var secondPathSegmentIndexConversion = divisionEndIndex - divisionStartIndex - 1;
	        for (i = divisionEndIndex; i < pathCopy.segments.length; i++) {

	            var originalSegment = this.getSegment(i - secondPathSegmentIndexConversion);
	            segment = pathCopy.getSegment(i);

	            if ((segment.type === 'Z') && !originalSegment.subpathStartSegment.end.equals(segment.subpathStartSegment.end)) {
	                // pathCopy segment's subpathStartSegment is different from original segment's one
	                // convert this Closepath segment to a Lineto and replace it in pathCopy
	                var convertedSegment = Path.createSegment('L', originalSegment.end);
	                pathCopy.replaceSegment(i, convertedSegment);
	            }
	        }

	        // distribute pathCopy segments into two paths and return those:

	        var firstPath = new Path(pathCopy.segments.slice(0, divisionMidIndex));
	        var secondPath = new Path(pathCopy.segments.slice(divisionMidIndex));

	        return [firstPath, secondPath];
	    },

	    // Checks whether two paths are exactly the same.
	    // If `p` is undefined or null, returns false.
	    equals: function(p) {

	        if (!p) { return false; }

	        var segments = this.segments;
	        var otherSegments = p.segments;

	        var numSegments = segments.length;
	        if (otherSegments.length !== numSegments) { return false; } // if the two paths have different number of segments, they cannot be equal

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            var otherSegment = otherSegments[i];

	            // as soon as an inequality is found in segments, return false
	            if ((segment.type !== otherSegment.type) || (!segment.equals(otherSegment))) { return false; }
	        }

	        // if no inequality found in segments, return true
	        return true;
	    },

	    // Accepts negative indices.
	    // Throws an error if path has no segments.
	    // Throws an error if index is out of range.
	    getSegment: function(index) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { throw new Error('Path has no segments.'); }

	        if (index < 0) { index = numSegments + index; } // convert negative indices to positive
	        if (index >= numSegments || index < 0) { throw new Error('Index out of range.'); }

	        return segments[index];
	    },

	    // Returns an array of segment subdivisions, with precision better than requested `opt.precision`.
	    getSegmentSubdivisions: function(opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        // works even if path has no segments

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        // not using opt.segmentSubdivisions
	        // not using localOpt

	        var segmentSubdivisions = [];
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            var subdivisions = segment.getSubdivisions({ precision: precision });
	            segmentSubdivisions.push(subdivisions);
	        }

	        return segmentSubdivisions;
	    },

	    // Returns an array of subpaths of this path.
	    // Invalid paths are validated first.
	    // Returns `[]` if path has no segments.
	    getSubpaths: function() {

	        var validatedPath = this.clone().validate();

	        var segments = validatedPath.segments;
	        var numSegments = segments.length;

	        var subpaths = [];
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            if (segment.isSubpathStart) {
	                // we encountered a subpath start segment
	                // create a new path for segment, and push it to list of subpaths
	                subpaths.push(new Path(segment));

	            } else {
	                // append current segment to the last subpath
	                subpaths[subpaths.length - 1].appendSegment(segment);
	            }
	        }

	        return subpaths;
	    },

	    // Insert `arg` at given `index`.
	    // `index = 0` means insert at the beginning.
	    // `index = segments.length` means insert at the end.
	    // Accepts negative indices, from `-1` to `-(segments.length + 1)`.
	    // Accepts one segment or an array of segments as argument.
	    // Throws an error if index is out of range.
	    // Throws an error if argument is not a segment or an array of segments.
	    insertSegment: function(index, arg) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        // works even if path has no segments

	        // note that these are incremented compared to getSegments()
	        // we can insert after last element (note that this changes the meaning of index -1)
	        if (index < 0) { index = numSegments + index + 1; } // convert negative indices to positive
	        if (index > numSegments || index < 0) { throw new Error('Index out of range.'); }

	        var currentSegment;

	        var previousSegment = null;
	        var nextSegment = null;

	        if (numSegments !== 0) {
	            if (index >= 1) {
	                previousSegment = segments[index - 1];
	                nextSegment = previousSegment.nextSegment; // if we are inserting at end, nextSegment is null

	            } else { // if index === 0
	                // previousSegment is null
	                nextSegment = segments[0];
	            }
	        }

	        if (!Array.isArray(arg)) {
	            if (!arg || !arg.isSegment) { throw new Error('Segment required.'); }

	            currentSegment = this.prepareSegment(arg, previousSegment, nextSegment);
	            segments.splice(index, 0, currentSegment);

	        } else {
	            // flatten one level deep
	            // so we can chain arbitrary Path.createSegment results
	            arg = arg.reduce(function(acc, val) {
	                return acc.concat(val);
	            }, []);

	            if (!arg[0].isSegment) { throw new Error('Segments required.'); }

	            var n = arg.length;
	            for (var i = 0; i < n; i++) {

	                var currentArg = arg[i];
	                currentSegment = this.prepareSegment(currentArg, previousSegment, nextSegment);
	                segments.splice((index + i), 0, currentSegment); // incrementing index to insert subsequent segments after inserted segments
	                previousSegment = currentSegment;
	            }
	        }
	    },

	    intersectionWithLine: function(line, opt) {

	        var intersection = null;
	        var polylines = this.toPolylines(opt);
	        if (!polylines) { return null; }
	        for (var i = 0, n = polylines.length; i < n; i++) {
	            var polyline = polylines[i];
	            var polylineIntersection = line.intersect(polyline);
	            if (polylineIntersection) {
	                intersection || (intersection = []);
	                if (Array.isArray(polylineIntersection)) {
	                    Array.prototype.push.apply(intersection, polylineIntersection);
	                } else {
	                    intersection.push(polylineIntersection);
	                }
	            }
	        }

	        return intersection;
	    },

	    isDifferentiable: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            // as soon as a differentiable segment is found in segments, return true
	            if (segment.isDifferentiable()) { return true; }
	        }

	        // if no differentiable segment is found in segments, return false
	        return false;
	    },

	    // Checks whether current path segments are valid.
	    // Note that d is allowed to be empty - should disable rendering of the path.
	    isValid: function() {

	        var segments = this.segments;
	        var isValid = (segments.length === 0) || (segments[0].type === 'M'); // either empty or first segment is a Moveto
	        return isValid;
	    },

	    // Returns length of the path, with precision better than requested `opt.precision`; or using `opt.segmentSubdivisions` provided.
	    // If path has no segments, returns 0.
	    length: function(opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return 0; } // if segments is an empty array

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision; // opt.precision only used in getSegmentSubdivisions() call
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var length = 0;
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            var subdivisions = segmentSubdivisions[i];
	            length += segment.length({ subdivisions: subdivisions });
	        }

	        return length;
	    },

	    // Private function.
	    lengthAtT: function(t, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return 0; } // if segments is an empty array

	        var segmentIndex = t.segmentIndex;
	        if (segmentIndex < 0) { return 0; } // regardless of t.value

	        var tValue = t.value;
	        if (segmentIndex >= numSegments) {
	            segmentIndex = numSegments - 1;
	            tValue = 1;
	        } else if (tValue < 0) { tValue = 0; }
	        else if (tValue > 1) { tValue = 1; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var subdivisions;
	        var length = 0;
	        for (var i = 0; i < segmentIndex; i++) {

	            var segment = segments[i];
	            subdivisions = segmentSubdivisions[i];
	            length += segment.length({ precisison: precision, subdivisions: subdivisions });
	        }

	        segment = segments[segmentIndex];
	        subdivisions = segmentSubdivisions[segmentIndex];
	        length += segment.lengthAtT(tValue, { precisison: precision, subdivisions: subdivisions });

	        return length;
	    },

	    // Returns point at requested `ratio` between 0 and 1, with precision better than requested `opt.precision`; optionally using `opt.segmentSubdivisions` provided.
	    pointAt: function(ratio, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        if (ratio <= 0) { return this.start.clone(); }
	        if (ratio >= 1) { return this.end.clone(); }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var pathLength = this.length(localOpt);
	        var length = pathLength * ratio;

	        return this.pointAtLength(length, localOpt);
	    },

	    // Returns point at requested `length`, with precision better than requested `opt.precision`; optionally using `opt.segmentSubdivisions` provided.
	    // Accepts negative length.
	    pointAtLength: function(length, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        if (length === 0) { return this.start.clone(); }

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var lastVisibleSegment;
	        var l = 0; // length so far
	        for (var i = 0; i < numSegments; i++) {
	            var index = (fromStart ? i : (numSegments - 1 - i));

	            var segment = segments[index];
	            var subdivisions = segmentSubdivisions[index];
	            var d = segment.length({ precision: precision, subdivisions: subdivisions });

	            if (segment.isVisible) {
	                if (length <= (l + d)) {
	                    return segment.pointAtLength(((fromStart ? 1 : -1) * (length - l)), {
	                        precision: precision,
	                        subdivisions: subdivisions
	                    });
	                }

	                lastVisibleSegment = segment;
	            }

	            l += d;
	        }

	        // if length requested is higher than the length of the path, return last visible segment endpoint
	        if (lastVisibleSegment) { return (fromStart ? lastVisibleSegment.end : lastVisibleSegment.start); }

	        // if no visible segment, return last segment end point (no matter if fromStart or no)
	        var lastSegment = segments[numSegments - 1];
	        return lastSegment.end.clone();
	    },

	    // Private function.
	    pointAtT: function(t) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var segmentIndex = t.segmentIndex;
	        if (segmentIndex < 0) { return segments[0].pointAtT(0); }
	        if (segmentIndex >= numSegments) { return segments[numSegments - 1].pointAtT(1); }

	        var tValue = t.value;
	        if (tValue < 0) { tValue = 0; }
	        else if (tValue > 1) { tValue = 1; }

	        return segments[segmentIndex].pointAtT(tValue);
	    },

	    // Default precision
	    PRECISION: 3,

	    // Helper method for adding segments.
	    prepareSegment: function(segment, previousSegment, nextSegment) {

	        // insert after previous segment and before previous segment's next segment
	        segment.previousSegment = previousSegment;
	        segment.nextSegment = nextSegment;
	        if (previousSegment) { previousSegment.nextSegment = segment; }
	        if (nextSegment) { nextSegment.previousSegment = segment; }

	        var updateSubpathStart = segment;
	        if (segment.isSubpathStart) {
	            segment.subpathStartSegment = segment; // assign self as subpath start segment
	            updateSubpathStart = nextSegment; // start updating from next segment
	        }

	        // assign previous segment's subpath start (or self if it is a subpath start) to subsequent segments
	        if (updateSubpathStart) { this.updateSubpathStartSegment(updateSubpathStart); }

	        return segment;
	    },

	    // Remove the segment at `index`.
	    // Accepts negative indices, from `-1` to `-segments.length`.
	    // Throws an error if path has no segments.
	    // Throws an error if index is out of range.
	    removeSegment: function(index) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { throw new Error('Path has no segments.'); }

	        if (index < 0) { index = numSegments + index; } // convert negative indices to positive
	        if (index >= numSegments || index < 0) { throw new Error('Index out of range.'); }

	        var removedSegment = segments.splice(index, 1)[0];
	        var previousSegment = removedSegment.previousSegment;
	        var nextSegment = removedSegment.nextSegment;

	        // link the previous and next segments together (if present)
	        if (previousSegment) { previousSegment.nextSegment = nextSegment; } // may be null
	        if (nextSegment) { nextSegment.previousSegment = previousSegment; } // may be null

	        // if removed segment used to start a subpath, update all subsequent segments until another subpath start segment is reached
	        if (removedSegment.isSubpathStart && nextSegment) { this.updateSubpathStartSegment(nextSegment); }
	    },

	    // Replace the segment at `index` with `arg`.
	    // Accepts negative indices, from `-1` to `-segments.length`.
	    // Accepts one segment or an array of segments as argument.
	    // Throws an error if path has no segments.
	    // Throws an error if index is out of range.
	    // Throws an error if argument is not a segment or an array of segments.
	    replaceSegment: function(index, arg) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { throw new Error('Path has no segments.'); }

	        if (index < 0) { index = numSegments + index; } // convert negative indices to positive
	        if (index >= numSegments || index < 0) { throw new Error('Index out of range.'); }

	        var currentSegment;

	        var replacedSegment = segments[index];
	        var previousSegment = replacedSegment.previousSegment;
	        var nextSegment = replacedSegment.nextSegment;

	        var updateSubpathStart = replacedSegment.isSubpathStart; // boolean: is an update of subpath starts necessary?

	        if (!Array.isArray(arg)) {
	            if (!arg || !arg.isSegment) { throw new Error('Segment required.'); }

	            currentSegment = this.prepareSegment(arg, previousSegment, nextSegment);
	            segments.splice(index, 1, currentSegment); // directly replace

	            if (updateSubpathStart && currentSegment.isSubpathStart) { updateSubpathStart = false; } // already updated by `prepareSegment`

	        } else {
	            // flatten one level deep
	            // so we can chain arbitrary Path.createSegment results
	            arg = arg.reduce(function(acc, val) {
	                return acc.concat(val);
	            }, []);

	            if (!arg[0].isSegment) { throw new Error('Segments required.'); }

	            segments.splice(index, 1);

	            var n = arg.length;
	            for (var i = 0; i < n; i++) {

	                var currentArg = arg[i];
	                currentSegment = this.prepareSegment(currentArg, previousSegment, nextSegment);
	                segments.splice((index + i), 0, currentSegment); // incrementing index to insert subsequent segments after inserted segments
	                previousSegment = currentSegment;

	                if (updateSubpathStart && currentSegment.isSubpathStart) { updateSubpathStart = false; } // already updated by `prepareSegment`
	            }
	        }

	        // if replaced segment used to start a subpath and no new subpath start was added, update all subsequent segments until another subpath start segment is reached
	        if (updateSubpathStart && nextSegment) { this.updateSubpathStartSegment(nextSegment); }
	    },

	    round: function(precision) {

	        var segments = this.segments;
	        var numSegments = segments.length;

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            segment.round(precision);
	        }

	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        var segments = this.segments;
	        var numSegments = segments.length;

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            segment.scale(sx, sy, origin);
	        }

	        return this;
	    },

	    segmentAt: function(ratio, opt) {

	        var index = this.segmentIndexAt(ratio, opt);
	        if (!index) { return null; }

	        return this.getSegment(index);
	    },

	    // Accepts negative length.
	    segmentAtLength: function(length, opt) {

	        var index = this.segmentIndexAtLength(length, opt);
	        if (!index) { return null; }

	        return this.getSegment(index);
	    },

	    segmentIndexAt: function(ratio, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        if (ratio < 0) { ratio = 0; }
	        if (ratio > 1) { ratio = 1; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var pathLength = this.length(localOpt);
	        var length = pathLength * ratio;

	        return this.segmentIndexAtLength(length, localOpt);
	    },

	    // Accepts negative length.
	    segmentIndexAtLength: function(length, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var lastVisibleSegmentIndex = null;
	        var l = 0; // length so far
	        for (var i = 0; i < numSegments; i++) {
	            var index = (fromStart ? i : (numSegments - 1 - i));

	            var segment = segments[index];
	            var subdivisions = segmentSubdivisions[index];
	            var d = segment.length({ precision: precision, subdivisions: subdivisions });

	            if (segment.isVisible) {
	                if (length <= (l + d)) { return index; }
	                lastVisibleSegmentIndex = index;
	            }

	            l += d;
	        }

	        // if length requested is higher than the length of the path, return last visible segment index
	        // if no visible segment, return null
	        return lastVisibleSegmentIndex;
	    },

	    // Returns a string that can be used to reconstruct the path.
	    // Additional error checking compared to toString (must start with M segment).
	    serialize: function() {

	        if (!this.isValid()) { throw new Error('Invalid path segments.'); }

	        return this.toString();
	    },

	    // Returns tangent line at requested `ratio` between 0 and 1, with precision better than requested `opt.precision`; optionally using `opt.segmentSubdivisions` provided.
	    tangentAt: function(ratio, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        if (ratio < 0) { ratio = 0; }
	        if (ratio > 1) { ratio = 1; }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        var localOpt = { precision: precision, segmentSubdivisions: segmentSubdivisions };

	        var pathLength = this.length(localOpt);
	        var length = pathLength * ratio;

	        return this.tangentAtLength(length, localOpt);
	    },

	    // Returns tangent line at requested `length`, with precision better than requested `opt.precision`; optionally using `opt.segmentSubdivisions` provided.
	    // Accepts negative length.
	    tangentAtLength: function(length, opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var fromStart = true;
	        if (length < 0) {
	            fromStart = false; // negative lengths mean start calculation from end point
	            length = -length; // absolute value
	        }

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;
	        // not using localOpt

	        var lastValidSegment; // visible AND differentiable (with a tangent)
	        var l = 0; // length so far
	        for (var i = 0; i < numSegments; i++) {
	            var index = (fromStart ? i : (numSegments - 1 - i));

	            var segment = segments[index];
	            var subdivisions = segmentSubdivisions[index];
	            var d = segment.length({ precision: precision, subdivisions: subdivisions });

	            if (segment.isDifferentiable()) {
	                if (length <= (l + d)) {
	                    return segment.tangentAtLength(((fromStart ? 1 : -1) * (length - l)), {
	                        precision: precision,
	                        subdivisions: subdivisions
	                    });
	                }

	                lastValidSegment = segment;
	            }

	            l += d;
	        }

	        // if length requested is higher than the length of the path, return tangent of endpoint of last valid segment
	        if (lastValidSegment) {
	            var t = (fromStart ? 1 : 0);
	            return lastValidSegment.tangentAtT(t);
	        }

	        // if no valid segment, return null
	        return null;
	    },

	    // Private function.
	    tangentAtT: function(t) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        var segmentIndex = t.segmentIndex;
	        if (segmentIndex < 0) { return segments[0].tangentAtT(0); }
	        if (segmentIndex >= numSegments) { return segments[numSegments - 1].tangentAtT(1); }

	        var tValue = t.value;
	        if (tValue < 0) { tValue = 0; }
	        else if (tValue > 1) { tValue = 1; }

	        return segments[segmentIndex].tangentAtT(tValue);
	    },

	    toPoints: function(opt) {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; } // if segments is an empty array

	        opt = opt || {};
	        var precision = (opt.precision === undefined) ? this.PRECISION : opt.precision;
	        var segmentSubdivisions = (opt.segmentSubdivisions === undefined) ? this.getSegmentSubdivisions({ precision: precision }) : opt.segmentSubdivisions;

	        var points = [];
	        var partialPoints = [];
	        for (var i = 0; i < numSegments; i++) {
	            var segment = segments[i];
	            if (segment.isVisible) {
	                var currentSegmentSubdivisions = segmentSubdivisions[i];
	                if (currentSegmentSubdivisions.length > 0) {
	                    var subdivisionPoints = currentSegmentSubdivisions.map(function(curve) {
	                        return curve.start;
	                    });
	                    Array.prototype.push.apply(partialPoints, subdivisionPoints);
	                } else {
	                    partialPoints.push(segment.start);
	                }
	            } else if (partialPoints.length > 0) {
	                partialPoints.push(segments[i - 1].end);
	                points.push(partialPoints);
	                partialPoints = [];
	            }
	        }

	        if (partialPoints.length > 0) {
	            partialPoints.push(this.end);
	            points.push(partialPoints);
	        }
	        return points;
	    },

	    toPolylines: function(opt) {

	        var polylines = [];
	        var points = this.toPoints(opt);
	        if (!points) { return null; }
	        for (var i = 0, n = points.length; i < n; i++) {
	            polylines.push(new Polyline(points[i]));
	        }

	        return polylines;
	    },

	    toString: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;

	        var pathData = '';
	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            pathData += segment.serialize() + ' ';
	        }

	        return pathData.trim();
	    },

	    translate: function(tx, ty) {

	        var segments = this.segments;
	        var numSegments = segments.length;

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            segment.translate(tx, ty);
	        }

	        return this;
	    },

	    // Helper method for updating subpath start of segments, starting with the one provided.
	    updateSubpathStartSegment: function(segment) {

	        var previousSegment = segment.previousSegment; // may be null
	        while (segment && !segment.isSubpathStart) {

	            // assign previous segment's subpath start segment to this segment
	            if (previousSegment) { segment.subpathStartSegment = previousSegment.subpathStartSegment; } // may be null
	            else { segment.subpathStartSegment = null; } // if segment had no previous segment, assign null - creates an invalid path!

	            previousSegment = segment;
	            segment = segment.nextSegment; // move on to the segment after etc.
	        }
	    },

	    // If the path is not valid, insert M 0 0 at the beginning.
	    // Path with no segments is considered valid, so nothing is inserted.
	    validate: function() {

	        if (!this.isValid()) { this.insertSegment(0, Path.createSegment('M', 0, 0)); }
	        return this;
	    }
	};

	Object.defineProperty(Path.prototype, 'start', {
	    // Getter for the first visible endpoint of the path.

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; }

	        for (var i = 0; i < numSegments; i++) {

	            var segment = segments[i];
	            if (segment.isVisible) { return segment.start; }
	        }

	        // if no visible segment, return last segment end point
	        return segments[numSegments - 1].end;
	    }
	});

	Object.defineProperty(Path.prototype, 'end', {
	    // Getter for the last visible endpoint of the path.

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        var segments = this.segments;
	        var numSegments = segments.length;
	        if (numSegments === 0) { return null; }

	        for (var i = numSegments - 1; i >= 0; i--) {

	            var segment = segments[i];
	            if (segment.isVisible) { return segment.end; }
	        }

	        // if no visible segment, return last segment end point
	        return segments[numSegments - 1].end;
	    }
	});


	// Local helper function.
	// Use an array of arguments to call a constructor (function called with `new`).
	// Adapted from https://stackoverflow.com/a/8843181/2263595
	// It is not necessary to use this function if the arguments can be passed separately (i.e. if the number of arguments is limited).
	// - If that is the case, use `new constructor(arg1, arg2)`, for example.
	// It is not necessary to use this function if the function that needs an array of arguments is not supposed to be used as a constructor.
	// - If that is the case, use `f.apply(thisArg, [arg1, arg2...])`, for example.
	function applyToNew(constructor, argsArray) {
	    // The `new` keyword can only be applied to functions that take a limited number of arguments.
	    // - We can fake that with .bind().
	    // - It calls a function (`constructor`, here) with the arguments that were provided to it - effectively transforming an unlimited number of arguments into limited.
	    // - So `new (constructor.bind(thisArg, arg1, arg2...))`
	    // - `thisArg` can be anything (e.g. null) because `new` keyword resets context to the constructor object.
	    // We need to pass in a variable number of arguments to the bind() call.
	    // - We can use .apply().
	    // - So `new (constructor.bind.apply(constructor, [thisArg, arg1, arg2...]))`
	    // - `thisArg` can still be anything because `new` overwrites it.
	    // Finally, to make sure that constructor.bind overwriting is not a problem, we switch to `Function.prototype.bind`.
	    // - So, the final version is `new (Function.prototype.bind.apply(constructor, [thisArg, arg1, arg2...]))`

	    // The function expects `argsArray[0]` to be `thisArg`.
	    // - This means that whatever is sent as the first element will be ignored.
	    // - The constructor will only see arguments starting from argsArray[1].
	    // - So, a new dummy element is inserted at the start of the array.
	    argsArray.unshift(null);

	    return new (Function.prototype.bind.apply(constructor, argsArray));
	}

	// Path segment interface:
	var segmentPrototype = {

	    // virtual
	    bbox: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    clone: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    closestPoint: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    closestPointLength: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    closestPointNormalizedLength: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // Redirect calls to closestPointNormalizedLength() function if closestPointT() is not defined for segment.
	    closestPointT: function(p) {

	        if (this.closestPointNormalizedLength) { return this.closestPointNormalizedLength(p); }

	        throw new Error('Neither closestPointT() nor closestPointNormalizedLength() function is implemented.');
	    },

	    // virtual
	    closestPointTangent: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    divideAt: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    divideAtLength: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // Redirect calls to divideAt() function if divideAtT() is not defined for segment.
	    divideAtT: function(t) {

	        if (this.divideAt) { return this.divideAt(t); }

	        throw new Error('Neither divideAtT() nor divideAt() function is implemented.');
	    },

	    // virtual
	    equals: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    getSubdivisions: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    isDifferentiable: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    isSegment: true,

	    isSubpathStart: false, // true for Moveto segments

	    isVisible: true, // false for Moveto segments

	    // virtual
	    length: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // Return a fraction of result of length() function if lengthAtT() is not defined for segment.
	    lengthAtT: function(t) {

	        if (t <= 0) { return 0; }

	        var length = this.length();

	        if (t >= 1) { return length; }

	        return length * t;
	    },

	    nextSegment: null, // needed for subpath start segment updating

	    // virtual
	    pointAt: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    pointAtLength: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // Redirect calls to pointAt() function if pointAtT() is not defined for segment.
	    pointAtT: function(t) {

	        if (this.pointAt) { return this.pointAt(t); }

	        throw new Error('Neither pointAtT() nor pointAt() function is implemented.');
	    },

	    previousSegment: null, // needed to get segment start property

	    // virtual
	    round: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    subpathStartSegment: null, // needed to get Closepath segment end property

	    // virtual
	    scale: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    serialize: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    tangentAt: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    tangentAtLength: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // Redirect calls to tangentAt() function if tangentAtT() is not defined for segment.
	    tangentAtT: function(t) {

	        if (this.tangentAt) { return this.tangentAt(t); }

	        throw new Error('Neither tangentAtT() nor tangentAt() function is implemented.');
	    },

	    // virtual
	    toString: function() {

	        throw new Error('Declaration missing for virtual function.');
	    },

	    // virtual
	    translate: function() {

	        throw new Error('Declaration missing for virtual function.');
	    }
	};

	// usually directly assigned
	// getter for Closepath
	Object.defineProperty(segmentPrototype, 'end', {

	    configurable: true,

	    enumerable: true,

	    writable: true
	});

	// always a getter
	// always throws error for Moveto
	Object.defineProperty(segmentPrototype, 'start', {
	    // get a reference to the end point of previous segment

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        if (!this.previousSegment) { throw new Error('Missing previous segment. (This segment cannot be the first segment of a path; OR segment has not yet been added to a path.)'); }

	        return this.previousSegment.end;
	    }
	});

	// virtual
	Object.defineProperty(segmentPrototype, 'type', {

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        throw new Error('Bad segment declaration. No type specified.');
	    }
	});

	// Path segment implementations:
	var Lineto = function() {
	    var arguments$1 = arguments;


	    var args = [];
	    var n = arguments.length;
	    for (var i = 0; i < n; i++) {
	        args.push(arguments$1[i]);
	    }

	    if (!(this instanceof Lineto)) { // switching context of `this` to Lineto when called without `new`
	        return applyToNew(Lineto, args);
	    }

	    if (n === 0) {
	        throw new Error('Lineto constructor expects a line, 1 point, or 2 coordinates (none provided).');
	    }

	    var outputArray;

	    if (args[0] instanceof Line) { // lines provided
	        if (n === 1) {
	            this.end = args[0].end.clone();
	            return this;

	        } else {
	            throw new Error('Lineto constructor expects a line, 1 point, or 2 coordinates (' + n + ' lines provided).');
	        }

	    } else if (typeof args[0] === 'string' || typeof args[0] === 'number') { // coordinates provided
	        if (n === 2) {
	            this.end = new Point(+args[0], +args[1]);
	            return this;

	        } else if (n < 2) {
	            throw new Error('Lineto constructor expects a line, 1 point, or 2 coordinates (' + n + ' coordinates provided).');

	        } else { // this is a poly-line segment
	            var segmentCoords;
	            outputArray = [];
	            for (i = 0; i < n; i += 2) { // coords come in groups of two

	                segmentCoords = args.slice(i, i + 2); // will send one coord if args.length not divisible by 2
	                outputArray.push(applyToNew(Lineto, segmentCoords));
	            }
	            return outputArray;
	        }

	    } else { // points provided (needs to be last to also cover plain objects with x and y)
	        if (n === 1) {
	            this.end = new Point(args[0]);
	            return this;

	        } else { // this is a poly-line segment
	            var segmentPoint;
	            outputArray = [];
	            for (i = 0; i < n; i += 1) {

	                segmentPoint = args[i];
	                outputArray.push(new Lineto(segmentPoint));
	            }
	            return outputArray;
	        }
	    }
	};

	var linetoPrototype = {

	    clone: function() {

	        return new Lineto(this.end);
	    },

	    divideAt: function(ratio) {

	        var line = new Line(this.start, this.end);
	        var divided = line.divideAt(ratio);
	        return [
	            new Lineto(divided[0]),
	            new Lineto(divided[1])
	        ];
	    },

	    divideAtLength: function(length) {

	        var line = new Line(this.start, this.end);
	        var divided = line.divideAtLength(length);
	        return [
	            new Lineto(divided[0]),
	            new Lineto(divided[1])
	        ];
	    },

	    getSubdivisions: function() {

	        return [];
	    },

	    isDifferentiable: function() {

	        if (!this.previousSegment) { return false; }

	        return !this.start.equals(this.end);
	    },

	    round: function(precision) {

	        this.end.round(precision);
	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        this.end.scale(sx, sy, origin);
	        return this;
	    },

	    serialize: function() {

	        var end = this.end;
	        return this.type + ' ' + end.x + ' ' + end.y;
	    },

	    toString: function() {

	        return this.type + ' ' + this.start + ' ' + this.end;
	    },

	    translate: function(tx, ty) {

	        this.end.translate(tx, ty);
	        return this;
	    }
	};

	Object.defineProperty(linetoPrototype, 'type', {

	    configurable: true,

	    enumerable: true,

	    value: 'L'
	});

	Lineto.prototype = extend(segmentPrototype, Line.prototype, linetoPrototype);

	var Curveto = function() {
	    var arguments$1 = arguments;


	    var args = [];
	    var n = arguments.length;
	    for (var i = 0; i < n; i++) {
	        args.push(arguments$1[i]);
	    }

	    if (!(this instanceof Curveto)) { // switching context of `this` to Curveto when called without `new`
	        return applyToNew(Curveto, args);
	    }

	    if (n === 0) {
	        throw new Error('Curveto constructor expects a curve, 3 points, or 6 coordinates (none provided).');
	    }

	    var outputArray;

	    if (args[0] instanceof Curve) { // curves provided
	        if (n === 1) {
	            this.controlPoint1 = args[0].controlPoint1.clone();
	            this.controlPoint2 = args[0].controlPoint2.clone();
	            this.end = args[0].end.clone();
	            return this;

	        } else {
	            throw new Error('Curveto constructor expects a curve, 3 points, or 6 coordinates (' + n + ' curves provided).');
	        }

	    } else if (typeof args[0] === 'string' || typeof args[0] === 'number') { // coordinates provided
	        if (n === 6) {
	            this.controlPoint1 = new Point(+args[0], +args[1]);
	            this.controlPoint2 = new Point(+args[2], +args[3]);
	            this.end = new Point(+args[4], +args[5]);
	            return this;

	        } else if (n < 6) {
	            throw new Error('Curveto constructor expects a curve, 3 points, or 6 coordinates (' + n + ' coordinates provided).');

	        } else { // this is a poly-bezier segment
	            var segmentCoords;
	            outputArray = [];
	            for (i = 0; i < n; i += 6) { // coords come in groups of six

	                segmentCoords = args.slice(i, i + 6); // will send fewer than six coords if args.length not divisible by 6
	                outputArray.push(applyToNew(Curveto, segmentCoords));
	            }
	            return outputArray;
	        }

	    } else { // points provided (needs to be last to also cover plain objects with x and y)
	        if (n === 3) {
	            this.controlPoint1 = new Point(args[0]);
	            this.controlPoint2 = new Point(args[1]);
	            this.end = new Point(args[2]);
	            return this;

	        } else if (n < 3) {
	            throw new Error('Curveto constructor expects a curve, 3 points, or 6 coordinates (' + n + ' points provided).');

	        } else { // this is a poly-bezier segment
	            var segmentPoints;
	            outputArray = [];
	            for (i = 0; i < n; i += 3) { // points come in groups of three

	                segmentPoints = args.slice(i, i + 3); // will send fewer than three points if args.length is not divisible by 3
	                outputArray.push(applyToNew(Curveto, segmentPoints));
	            }
	            return outputArray;
	        }
	    }
	};

	var curvetoPrototype = {

	    clone: function() {

	        return new Curveto(this.controlPoint1, this.controlPoint2, this.end);
	    },

	    divideAt: function(ratio, opt) {

	        var curve = new Curve(this.start, this.controlPoint1, this.controlPoint2, this.end);
	        var divided = curve.divideAt(ratio, opt);
	        return [
	            new Curveto(divided[0]),
	            new Curveto(divided[1])
	        ];
	    },

	    divideAtLength: function(length, opt) {

	        var curve = new Curve(this.start, this.controlPoint1, this.controlPoint2, this.end);
	        var divided = curve.divideAtLength(length, opt);
	        return [
	            new Curveto(divided[0]),
	            new Curveto(divided[1])
	        ];
	    },

	    divideAtT: function(t) {

	        var curve = new Curve(this.start, this.controlPoint1, this.controlPoint2, this.end);
	        var divided = curve.divideAtT(t);
	        return [
	            new Curveto(divided[0]),
	            new Curveto(divided[1])
	        ];
	    },

	    isDifferentiable: function() {

	        if (!this.previousSegment) { return false; }

	        var start = this.start;
	        var control1 = this.controlPoint1;
	        var control2 = this.controlPoint2;
	        var end = this.end;

	        return !(start.equals(control1) && control1.equals(control2) && control2.equals(end));
	    },

	    round: function(precision) {

	        this.controlPoint1.round(precision);
	        this.controlPoint2.round(precision);
	        this.end.round(precision);
	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        this.controlPoint1.scale(sx, sy, origin);
	        this.controlPoint2.scale(sx, sy, origin);
	        this.end.scale(sx, sy, origin);
	        return this;
	    },

	    serialize: function() {

	        var c1 = this.controlPoint1;
	        var c2 = this.controlPoint2;
	        var end = this.end;
	        return this.type + ' ' + c1.x + ' ' + c1.y + ' ' + c2.x + ' ' + c2.y + ' ' + end.x + ' ' + end.y;
	    },

	    toString: function() {

	        return this.type + ' ' + this.start + ' ' + this.controlPoint1 + ' ' + this.controlPoint2 + ' ' + this.end;
	    },

	    translate: function(tx, ty) {

	        this.controlPoint1.translate(tx, ty);
	        this.controlPoint2.translate(tx, ty);
	        this.end.translate(tx, ty);
	        return this;
	    }
	};

	Object.defineProperty(curvetoPrototype, 'type', {

	    configurable: true,

	    enumerable: true,

	    value: 'C'
	});

	Curveto.prototype = extend(segmentPrototype, Curve.prototype, curvetoPrototype);

	var Moveto = function() {
	    var arguments$1 = arguments;


	    var args = [];
	    var n = arguments.length;
	    for (var i = 0; i < n; i++) {
	        args.push(arguments$1[i]);
	    }

	    if (!(this instanceof Moveto)) { // switching context of `this` to Moveto when called without `new`
	        return applyToNew(Moveto, args);
	    }

	    if (n === 0) {
	        throw new Error('Moveto constructor expects a line, a curve, 1 point, or 2 coordinates (none provided).');
	    }

	    var outputArray;

	    if (args[0] instanceof Line) { // lines provided
	        if (n === 1) {
	            this.end = args[0].end.clone();
	            return this;

	        } else {
	            throw new Error('Moveto constructor expects a line, a curve, 1 point, or 2 coordinates (' + n + ' lines provided).');
	        }

	    } else if (args[0] instanceof Curve) { // curves provided
	        if (n === 1) {
	            this.end = args[0].end.clone();
	            return this;

	        } else {
	            throw new Error('Moveto constructor expects a line, a curve, 1 point, or 2 coordinates (' + n + ' curves provided).');
	        }

	    } else if (typeof args[0] === 'string' || typeof args[0] === 'number') { // coordinates provided
	        if (n === 2) {
	            this.end = new Point(+args[0], +args[1]);
	            return this;

	        } else if (n < 2) {
	            throw new Error('Moveto constructor expects a line, a curve, 1 point, or 2 coordinates (' + n + ' coordinates provided).');

	        } else { // this is a moveto-with-subsequent-poly-line segment
	            var segmentCoords;
	            outputArray = [];
	            for (i = 0; i < n; i += 2) { // coords come in groups of two

	                segmentCoords = args.slice(i, i + 2); // will send one coord if args.length not divisible by 2
	                if (i === 0) { outputArray.push(applyToNew(Moveto, segmentCoords)); }
	                else { outputArray.push(applyToNew(Lineto, segmentCoords)); }
	            }
	            return outputArray;
	        }

	    } else { // points provided (needs to be last to also cover plain objects with x and y)
	        if (n === 1) {
	            this.end = new Point(args[0]);
	            return this;

	        } else { // this is a moveto-with-subsequent-poly-line segment
	            var segmentPoint;
	            outputArray = [];
	            for (i = 0; i < n; i += 1) { // points come one by one

	                segmentPoint = args[i];
	                if (i === 0) { outputArray.push(new Moveto(segmentPoint)); }
	                else { outputArray.push(new Lineto(segmentPoint)); }
	            }
	            return outputArray;
	        }
	    }
	};

	var movetoPrototype = {

	    bbox: function() {

	        return null;
	    },

	    clone: function() {

	        return new Moveto(this.end);
	    },

	    closestPoint: function() {

	        return this.end.clone();
	    },

	    closestPointNormalizedLength: function() {

	        return 0;
	    },

	    closestPointLength: function() {

	        return 0;
	    },

	    closestPointT: function() {

	        return 1;
	    },

	    closestPointTangent: function() {

	        return null;
	    },

	    divideAt: function() {

	        return [
	            this.clone(),
	            this.clone()
	        ];
	    },

	    divideAtLength: function() {

	        return [
	            this.clone(),
	            this.clone()
	        ];
	    },

	    equals: function(m) {

	        return this.end.equals(m.end);
	    },

	    getSubdivisions: function() {

	        return [];
	    },

	    isDifferentiable: function() {

	        return false;
	    },

	    isSubpathStart: true,

	    isVisible: false,

	    length: function() {

	        return 0;
	    },

	    lengthAtT: function() {

	        return 0;
	    },

	    pointAt: function() {

	        return this.end.clone();
	    },

	    pointAtLength: function() {

	        return this.end.clone();
	    },

	    pointAtT: function() {

	        return this.end.clone();
	    },

	    round: function(precision) {

	        this.end.round(precision);
	        return this;
	    },

	    scale: function(sx, sy, origin) {

	        this.end.scale(sx, sy, origin);
	        return this;
	    },

	    serialize: function() {

	        var end = this.end;
	        return this.type + ' ' + end.x + ' ' + end.y;
	    },

	    tangentAt: function() {

	        return null;
	    },

	    tangentAtLength: function() {

	        return null;
	    },

	    tangentAtT: function() {

	        return null;
	    },

	    toString: function() {

	        return this.type + ' ' + this.end;
	    },

	    translate: function(tx, ty) {

	        this.end.translate(tx, ty);
	        return this;
	    }
	};

	Object.defineProperty(movetoPrototype, 'start', {

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        throw new Error('Illegal access. Moveto segments should not need a start property.');
	    }
	});

	Object.defineProperty(movetoPrototype, 'type', {

	    configurable: true,

	    enumerable: true,

	    value: 'M'
	});

	Moveto.prototype = extend(segmentPrototype, movetoPrototype); // does not inherit from any other geometry object

	var Closepath = function() {
	    var arguments$1 = arguments;


	    var args = [];
	    var n = arguments.length;
	    for (var i = 0; i < n; i++) {
	        args.push(arguments$1[i]);
	    }

	    if (!(this instanceof Closepath)) { // switching context of `this` to Closepath when called without `new`
	        return applyToNew(Closepath, args);
	    }

	    if (n > 0) {
	        throw new Error('Closepath constructor expects no arguments.');
	    }

	    return this;
	};

	var closepathPrototype = {

	    clone: function() {

	        return new Closepath();
	    },

	    divideAt: function(ratio) {

	        var line = new Line(this.start, this.end);
	        var divided = line.divideAt(ratio);
	        return [
	            // if we didn't actually cut into the segment, first divided part can stay as Z
	            (divided[1].isDifferentiable() ? new Lineto(divided[0]) : this.clone()),
	            new Lineto(divided[1])
	        ];
	    },

	    divideAtLength: function(length) {

	        var line = new Line(this.start, this.end);
	        var divided = line.divideAtLength(length);
	        return [
	            // if we didn't actually cut into the segment, first divided part can stay as Z
	            (divided[1].isDifferentiable() ? new Lineto(divided[0]) : this.clone()),
	            new Lineto(divided[1])
	        ];
	    },

	    getSubdivisions: function() {

	        return [];
	    },

	    isDifferentiable: function() {

	        if (!this.previousSegment || !this.subpathStartSegment) { return false; }

	        return !this.start.equals(this.end);
	    },

	    round: function() {

	        return this;
	    },

	    scale: function() {

	        return this;
	    },

	    serialize: function() {

	        return this.type;
	    },

	    toString: function() {

	        return this.type + ' ' + this.start + ' ' + this.end;
	    },

	    translate: function() {

	        return this;
	    }
	};

	Object.defineProperty(closepathPrototype, 'end', {
	    // get a reference to the end point of subpath start segment

	    configurable: true,

	    enumerable: true,

	    get: function() {

	        if (!this.subpathStartSegment) { throw new Error('Missing subpath start segment. (This segment needs a subpath start segment (e.g. Moveto); OR segment has not yet been added to a path.)'); }

	        return this.subpathStartSegment.end;
	    }
	});

	Object.defineProperty(closepathPrototype, 'type', {

	    configurable: true,

	    enumerable: true,

	    value: 'Z'
	});

	Closepath.prototype = extend(segmentPrototype, Line.prototype, closepathPrototype);

	var segmentTypes = Path.segmentTypes = {
	    L: Lineto,
	    C: Curveto,
	    M: Moveto,
	    Z: Closepath,
	    z: Closepath
	};

	Path.regexSupportedData = new RegExp('^[\\s\\d' + Object.keys(segmentTypes).join('') + ',.]*$');

	Path.isDataSupported = function(data) {

	    if (typeof data !== 'string') { return false; }
	    return this.regexSupportedData.test(data);
	};

	var bezier = {

	    // Cubic Bezier curve path through points.
	    // @deprecated
	    // @param {array} points Array of points through which the smooth line will go.
	    // @return {array} SVG Path commands as an array
	    curveThroughPoints: function(points) {

	        console.warn('deprecated');

	        return new Path(Curve.throughPoints(points)).serialize();
	    },

	    // Get open-ended Bezier Spline Control Points.
	    // @deprecated
	    // @param knots Input Knot Bezier spline points (At least two points!).
	    // @param firstControlPoints Output First Control points. Array of knots.length - 1 length.
	    // @param secondControlPoints Output Second Control points. Array of knots.length - 1 length.
	    getCurveControlPoints: function(knots) {

	        console.warn('deprecated');

	        var firstControlPoints = [];
	        var secondControlPoints = [];
	        var n = knots.length - 1;
	        var i;

	        // Special case: Bezier curve should be a straight line.
	        if (n == 1) {
	            // 3P1 = 2P0 + P3
	            firstControlPoints[0] = new Point(
	                (2 * knots[0].x + knots[1].x) / 3,
	                (2 * knots[0].y + knots[1].y) / 3
	            );

	            // P2 = 2P1 – P0
	            secondControlPoints[0] = new Point(
	                2 * firstControlPoints[0].x - knots[0].x,
	                2 * firstControlPoints[0].y - knots[0].y
	            );

	            return [firstControlPoints, secondControlPoints];
	        }

	        // Calculate first Bezier control points.
	        // Right hand side vector.
	        var rhs = [];

	        // Set right hand side X values.
	        for (i = 1; i < n - 1; i++) {
	            rhs[i] = 4 * knots[i].x + 2 * knots[i + 1].x;
	        }

	        rhs[0] = knots[0].x + 2 * knots[1].x;
	        rhs[n - 1] = (8 * knots[n - 1].x + knots[n].x) / 2.0;

	        // Get first control points X-values.
	        var x = this.getFirstControlPoints(rhs);

	        // Set right hand side Y values.
	        for (i = 1; i < n - 1; ++i) {
	            rhs[i] = 4 * knots[i].y + 2 * knots[i + 1].y;
	        }

	        rhs[0] = knots[0].y + 2 * knots[1].y;
	        rhs[n - 1] = (8 * knots[n - 1].y + knots[n].y) / 2.0;

	        // Get first control points Y-values.
	        var y = this.getFirstControlPoints(rhs);

	        // Fill output arrays.
	        for (i = 0; i < n; i++) {
	            // First control point.
	            firstControlPoints.push(new Point(x[i], y[i]));

	            // Second control point.
	            if (i < n - 1) {
	                secondControlPoints.push(new Point(
	                    2 * knots [i + 1].x - x[i + 1],
	                    2 * knots[i + 1].y - y[i + 1]
	                ));

	            } else {
	                secondControlPoints.push(new Point(
	                    (knots[n].x + x[n - 1]) / 2,
	                    (knots[n].y + y[n - 1]) / 2)
	                );
	            }
	        }

	        return [firstControlPoints, secondControlPoints];
	    },

	    // Divide a Bezier curve into two at point defined by value 't' <0,1>.
	    // Using deCasteljau algorithm. http://math.stackexchange.com/a/317867
	    // @deprecated
	    // @param control points (start, control start, control end, end)
	    // @return a function that accepts t and returns 2 curves.
	    getCurveDivider: function(p0, p1, p2, p3) {

	        console.warn('deprecated');

	        var curve = new Curve(p0, p1, p2, p3);

	        return function divideCurve(t) {

	            var divided = curve.divide(t);

	            return [{
	                p0: divided[0].start,
	                p1: divided[0].controlPoint1,
	                p2: divided[0].controlPoint2,
	                p3: divided[0].end
	            }, {
	                p0: divided[1].start,
	                p1: divided[1].controlPoint1,
	                p2: divided[1].controlPoint2,
	                p3: divided[1].end
	            }];
	        };
	    },

	    // Solves a tridiagonal system for one of coordinates (x or y) of first Bezier control points.
	    // @deprecated
	    // @param rhs Right hand side vector.
	    // @return Solution vector.
	    getFirstControlPoints: function(rhs) {

	        console.warn('deprecated');

	        var n = rhs.length;
	        // `x` is a solution vector.
	        var x = [];
	        var tmp = [];
	        var b = 2.0;

	        x[0] = rhs[0] / b;

	        // Decomposition and forward substitution.
	        for (var i = 1; i < n; i++) {
	            tmp[i] = 1 / b;
	            b = (i < n - 1 ? 4.0 : 3.5) - tmp[i];
	            x[i] = (rhs[i] - x[i - 1]) / b;
	        }

	        for (i = 1; i < n; i++) {
	            // Backsubstitution.
	            x[n - i - 1] -= tmp[n - i] * x[n - i];
	        }

	        return x;
	    },

	    // Solves an inversion problem -- Given the (x, y) coordinates of a point which lies on
	    // a parametric curve x = x(t)/w(t), y = y(t)/w(t), find the parameter value t
	    // which corresponds to that point.
	    // @deprecated
	    // @param control points (start, control start, control end, end)
	    // @return a function that accepts a point and returns t.
	    getInversionSolver: function(p0, p1, p2, p3) {

	        console.warn('deprecated');

	        var curve = new Curve(p0, p1, p2, p3);

	        return function solveInversion(p) {

	            return curve.closestPointT(p);
	        };
	    }
	};

	var Polygon = function(points) {

	    if (!(this instanceof Polygon)) {
	        return new Polygon(points);
	    }

	    if (typeof points === 'string') {
	        return new Polygon.parse(points);
	    }

	    this.points = (Array.isArray(points) ? points.map(Point) : []);
	};

	Polygon.parse = function(svgString) {
	    return new Polygon(parsePoints(svgString));
	};

	Polygon.fromRect = function(rect) {
	    return new Polygon([
	        rect.topLeft(),
	        rect.topRight(),
	        rect.bottomRight(),
	        rect.bottomLeft()
	    ]);
	};

	Polygon.prototype = extend(Polyline.prototype, {

	    type: types.Polygon,

	    clone: function() {
	        return new Polygon(clonePoints(this.points));
	    },

	    convexHull: function() {
	        return new Polygon(convexHull(this.points));
	    },

	    lengthPoints: function() {
	        var ref = this;
	        var start = ref.start;
	        var end = ref.end;
	        var points = ref.points;
	        if (points.length <= 1 || start.equals(end)) { return points; }
	        return points.concat( [start.clone()]);
	    }

	});

	function exists(shape1, shape2, shape1opt, shape2opt) {
	    switch (shape1.type) {
	        case types.Line: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return lineWithLine(shape1, shape2);
	                }
	            }
	            break;
	        }
	        case types.Ellipse: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return ellipseWithLine(shape1, shape2);
	                }
	                case types.Ellipse: {
	                    return ellipseWithEllipse(shape1, shape2);
	                }
	            }
	            break;
	        }
	        case types.Rect: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return rectWithLine(shape1, shape2);
	                }
	                case types.Ellipse: {
	                    return rectWithEllipse(shape1, shape2);
	                }
	                case types.Rect: {
	                    return rectWithRect(shape1, shape2);
	                }
	            }
	            break;
	        }
	        case types.Polyline: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return polylineWithLine(shape1, shape2);
	                }
	                case types.Ellipse: {
	                    return polylineWithEllipse(shape1, shape2);
	                }
	                case types.Rect: {
	                    return polylineWithRect(shape1, shape2);
	                }
	                case types.Polyline: {
	                    return polylineWithPolyline(shape1, shape2);
	                }
	            }
	            break;
	        }
	        case types.Polygon: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return polygonWithLine(shape1, shape2);
	                }
	                case types.Ellipse: {
	                    return polygonWithEllipse(shape1, shape2);
	                }
	                case types.Rect: {
	                    return polygonWithRect(shape1, shape2);
	                }
	                case types.Polyline: {
	                    return polygonWithPolyline(shape1, shape2);
	                }
	                case types.Polygon: {
	                    return polygonWithPolygon(shape1, shape2);
	                }
	            }
	            break;
	        }
	        case types.Path: {
	            switch (shape2.type) {
	                case types.Line: {
	                    return pathWithLine(shape1, shape2, shape1opt);
	                }
	                case types.Ellipse: {
	                    return pathWithEllipse(shape1, shape2, shape1opt);
	                }
	                case types.Rect: {
	                    return pathWithRect(shape1, shape2, shape1opt);
	                }
	                case types.Polyline: {
	                    return pathWithPolyline(shape1, shape2, shape1opt);
	                }
	                case types.Polygon: {
	                    return pathWithPolygon(shape1, shape2, shape1opt);
	                }
	                case types.Path: {
	                    return pathWithPath(shape1, shape2, shape1opt, shape2opt);
	                }
	            }
	            break;
	        }
	    }
	    // None of the cases above
	    switch (shape2.type) {
	        case types.Ellipse:
	        case types.Rect:
	        case types.Polyline:
	        case types.Polygon:
	        case types.Path: {
	            return exists(shape2, shape1, shape2opt, shape1opt);
	        }
	        default: {
	            throw Error(("The intersection for " + shape1 + " and " + shape2 + " could not be found."));
	        }
	    }
	}

	/* Line */

	function lineWithLine(line1, line2) {
	    var x1 = line1.start.x;
	    var y1 = line1.start.y;
	    var x2 = line1.end.x;
	    var y2 = line1.end.y;
	    var x3 = line2.start.x;
	    var y3 = line2.start.y;
	    var x4 = line2.end.x;
	    var y4 = line2.end.y;
	    var s1x = x2 - x1;
	    var s1y = y2 - y1;
	    var s2x = x4 - x3;
	    var s2y = y4 - y3;
	    var s3x = x1 - x3;
	    var s3y = y1 - y3;
	    var p = s1x * s2y - s2x * s1y;
	    var s = (s1x * s3y - s1y * s3x) / p;
	    var t = (s2x * s3y - s2y * s3x) / p;
	    return s >= 0 && s <= 1 && t >= 0 && t <= 1;
	}

	/* Ellipse */

	function ellipseWithLine(ellipse, line) {
	    var rex = ellipse.a;
	    var rey = ellipse.b;
	    var xe = ellipse.x;
	    var ye = ellipse.y;
	    var x1 = line.start.x - xe;
	    var x2 = line.end.x - xe;
	    var y1 = line.start.y - ye;
	    var y2 = line.end.y - ye;
	    var rex_2 = rex * rex;
	    var rey_2 = rey * rey;
	    var dx = x2 - x1;
	    var dy = y2 - y1;
	    var A = dx * dx / rex_2 + dy * dy / rey_2;
	    var B = 2 * x1 * dx / rex_2 + 2 * y1 * dy / rey_2;
	    var C = x1 * x1 / rex_2 + y1 * y1 / rey_2 - 1;
	    var D = B * B - 4 * A * C;
	    if (D === 0) {
	        var t = -B / 2 / A;
	        return t >= 0 && t <= 1;
	    } else if (D > 0) {
	        var sqrt = Math.sqrt(D);
	        var t1 = (-B + sqrt) / 2 / A;
	        var t2 = (-B - sqrt) / 2 / A;
	        return (t1 >= 0 && t1 <= 1) || (t2 >= 0 && t2 <= 1);
	    }
	    return false;
	}

	function ellipseWithEllipse(ellipse1, ellipse2) {
	    return _ellipsesIntersection(ellipse1, 0, ellipse2, 0);
	}

	/* Rect */

	function rectWithLine(rect, line) {
	    var start = line.start;
	    var end = line.end;
	    var x = rect.x;
	    var y = rect.y;
	    var width = rect.width;
	    var height = rect.height;
	    if (
	        (start.x > x + width && end.x > x + width)
	        || (start.x < x && end.x < x)
	        || (start.y > y + height && end.y > y + height)
	        || (start.y < y && end.y < y)
	    ) {
	        return false;
	    }
	    if (rect.containsPoint(line.start) || rect.containsPoint(line.end)) {
	        return true;
	    }
	    return lineWithLine(rect.topLine(), line)
	        || lineWithLine(rect.rightLine(), line)
	        || lineWithLine(rect.bottomLine(), line)
	        || lineWithLine(rect.leftLine(), line);
	}

	function rectWithEllipse(rect, ellipse) {
	    if (!rectWithRect(rect, Rect.fromEllipse(ellipse))) { return false; }
	    return polygonWithEllipse(Polygon.fromRect(rect), ellipse);
	}

	function rectWithRect(rect1, rect2) {
	    return rect1.x < rect2.x + rect2.width
	        && rect1.x + rect1.width > rect2.x
	        && rect1.y < rect2.y + rect2.height
	        && rect1.y + rect1.height > rect2.y;
	}

	/* Polyline */

	function polylineWithLine(polyline, line) {
	    return _polylineWithLine(polyline, line, { interior: false });
	}

	function polylineWithEllipse(polyline, ellipse) {
	    return _polylineWithEllipse(polyline, ellipse, { interior: false });
	}

	function polylineWithRect(polyline, rect) {
	    return _polylineWithRect(polyline, rect, { interior: false });
	}

	function polylineWithPolyline(polyline1, polyline2) {
	    return _polylineWithPolyline(polyline1, polyline2, { interior: false });
	}

	/* Polygon */

	function polygonWithLine(polygon, line) {
	    return _polylineWithLine(polygon, line, { interior: true });
	}

	function polygonWithEllipse(polygon, ellipse) {
	    return _polylineWithEllipse(polygon, ellipse, { interior: true });
	}

	function polygonWithRect(polygon, rect) {
	    return _polylineWithRect(polygon, rect, { interior: true });
	}

	function polygonWithPolyline(polygon, polyline) {
	    return _polylineWithPolyline(polygon, polyline, { interior: true });
	}

	function polygonWithPolygon(polygon1, polygon2) {
	    return _polylineWithPolygon(polygon1, polygon2, { interior: true });
	}

	/* Path */

	function pathWithLine(path, line, pathOpt) {
	    return path.getSubpaths().some(function (subpath) {
	        var ref = subpath.toPolylines(pathOpt);
	        var polyline = ref[0];
	        var ref$1 = subpath.getSegment(-1);
	        var type = ref$1.type;
	        if (type === 'Z') {
	            return polygonWithLine(polyline, line);
	        } else {
	            return polylineWithLine(polyline, line);
	        }
	    });
	}

	function pathWithEllipse(path, ellipse, pathOpt) {
	    return path.getSubpaths().some(function (subpath) {
	        var ref = subpath.toPolylines(pathOpt);
	        var polyline = ref[0];
	        var ref$1 = subpath.getSegment(-1);
	        var type = ref$1.type;
	        if (type === 'Z') {
	            return polygonWithEllipse(polyline, ellipse);
	        } else {
	            return polylineWithEllipse(polyline, ellipse);
	        }
	    });
	}

	function pathWithRect(path, rect, pathOpt) {
	    return pathWithPolygon(path, Polygon.fromRect(rect), pathOpt);
	}

	function pathWithPolyline(path, polyline, pathOpt) {
	    return _pathWithPolyline(path, polyline, pathOpt, { interior: false });
	}

	function pathWithPolygon(path, polygon, pathOpt) {
	    return _pathWithPolyline(path, polygon, pathOpt, { interior: true });
	}

	function pathWithPath(path1, path2, pathOpt1, pathOpt2) {
	    return path1.getSubpaths().some(function (subpath) {
	        var ref = subpath.toPolylines(pathOpt1);
	        var polyline1 = ref[0];
	        var ref$1 = subpath.getSegment(-1);
	        var type = ref$1.type;
	        if (type === 'Z') {
	            return pathWithPolygon(path2, polyline1, pathOpt2);
	        } else {
	            return pathWithPolyline(path2, polyline1, pathOpt2);
	        }
	    });
	}

	function _polylineWithLine(polyline, line, opt) {
	    if ( opt === void 0 ) opt = {};

	    var interior = opt.interior; if ( interior === void 0 ) interior = false;
	    var thisPoints;
	    if (interior) {
	        if (polyline.containsPoint(line.start)) {
	            // If any point of the polyline lies inside this polygon (interior = true)
	            // there is an intersection (we've chosen the start point)
	            return true;
	        }
	        var start = polyline.start;
	        var end = polyline.end;
	        var points = polyline.points;
	        thisPoints = end.equals(start) ? points : points.concat( [start]);
	    } else {
	        thisPoints = polyline.points;
	    }
	    var length = thisPoints.length;
	    var segment = new Line();
	    for (var i = 0; i < length - 1; i++) {
	        segment.start = thisPoints[i];
	        segment.end = thisPoints[i + 1];
	        if (lineWithLine(line, segment)) {
	            return true;
	        }
	    }
	    return false;
	}

	function _polylineWithEllipse(polyline, ellipse, opt) {
	    if ( opt === void 0 ) opt = {};

	    var start = polyline.start;
	    var end = polyline.end;
	    var points = polyline.points;
	    if (ellipse.containsPoint(start)) {
	        return true;
	    }
	    var thisPoints;
	    var interior = opt.interior; if ( interior === void 0 ) interior = false;
	    if (interior) {
	        if (polyline.containsPoint(ellipse.center())) {
	            // If any point of the ellipse lies inside this polygon (interior = true)
	            // there is an intersection (we've chosen the center point)
	            return true;
	        }
	        thisPoints = end.equals(start) ? points : points.concat( [start]);
	    } else {
	        thisPoints = points;
	    }

	    var length = thisPoints.length;
	    var segment = new Line();
	    for (var i = 0; i < length - 1; i++) {
	        segment.start = thisPoints[i];
	        segment.end = thisPoints[i + 1];
	        if (ellipseWithLine(ellipse, segment)) {
	            return true;
	        }
	    }
	    return false;
	}

	function _polylineWithRect(polyline, rect, opt) {
	    var polygon = Polygon.fromRect(rect);
	    return _polylineWithPolygon(polyline, polygon, opt);
	}

	function _pathWithPolyline(path, polyline1, pathOpt, opt) {
	    return path.getSubpaths().some(function (subpath) {
	        var ref = subpath.toPolylines(pathOpt);
	        var polyline2 = ref[0];
	        var ref$1 = subpath.getSegment(-1);
	        var type = ref$1.type;
	        if (type === 'Z') {
	            return _polylineWithPolygon(polyline1, polyline2, opt);
	        } else {
	            return _polylineWithPolyline(polyline1, polyline2, opt);
	        }
	    });
	}

	function _polylineWithPolyline(polyline1, polyline2, opt) {
	    if ( opt === void 0 ) opt = {};

	    var interior = opt.interior; if ( interior === void 0 ) interior = false;
	    var thisPolyline;
	    if (interior) {
	        var start = polyline2.start;
	        if (polyline1.containsPoint(start)) {
	            // If any point of the polyline lies inside this polygon (interior = true)
	            // there is an intersection (we've chosen the start point)
	            return true;
	        }
	        thisPolyline = polyline1.clone().close();
	    } else {
	        thisPolyline = polyline1;
	    }
	    var otherPoints = polyline2.points;
	    var length = otherPoints.length;
	    var segment = new Line();
	    for (var i = 0; i < length - 1; i++) {
	        segment.start = otherPoints[i];
	        segment.end = otherPoints[i + 1];
	        if (polylineWithLine(thisPolyline, segment)) {
	            return true;
	        }
	    }
	    return false;
	}

	function _polylineWithPolygon(polyline, polygon, opt) {
	    return polygon.containsPoint(polyline.start) || _polylineWithPolyline(polyline, polygon.clone().close(), opt);
	}

	function _ellipsesIntersection(e1, w1, e2, w2) {
	    var cos = Math.cos;
	    var sin = Math.sin;
	    var sinW1 = sin(w1);
	    var cosW1 = cos(w1);
	    var sinW2 = sin(w2);
	    var cosW2 = cos(w2);
	    var sinW1s = sinW1 * sinW1;
	    var cosW1s = cosW1 * cosW1;
	    var sinCos1 = sinW1 * cosW1;
	    var sinW2s = sinW2 * sinW2;
	    var cosW2s = cosW2 * cosW2;
	    var sinCos2 = sinW2 * cosW2;
	    var a1s = e1.a * e1.a;
	    var b1s = e1.b * e1.b;
	    var a2s = e2.a * e2.a;
	    var b2s = e2.b * e2.b;
	    var A1 = a1s * sinW1s + b1s * cosW1s;
	    var A2 = a2s * sinW2s + b2s * cosW2s;
	    var B1 = a1s * cosW1s + b1s * sinW1s;
	    var B2 = a2s * cosW2s + b2s * sinW2s;
	    var C1 = 2 * (b1s - a1s) * sinCos1;
	    var C2 = 2 * (b2s - a2s) * sinCos2;
	    var D1 = (-2 * A1 * e1.x - C1 * e1.y);
	    var D2 = (-2 * A2 * e2.x - C2 * e2.y);
	    var E1 = (-C1 * e1.x - 2 * B1 * e1.y);
	    var E2 = (-C2 * e2.x - 2 * B2 * e2.y);
	    var F1 = A1 * e1.x * e1.x + B1 * e1.y * e1.y + C1 * e1.x * e1.y - a1s * b1s;
	    var F2 = A2 * e2.x * e2.x + B2 * e2.y * e2.y + C2 * e2.x * e2.y - a2s * b2s;

	    C1 = C1 / 2;
	    C2 = C2 / 2;
	    D1 = D1 / 2;
	    D2 = D2 / 2;
	    E1 = E1 / 2;
	    E2 = E2 / 2;

	    var l3 = det3([
	        [A1, C1, D1],
	        [C1, B1, E1],
	        [D1, E1, F1]
	    ]);
	    var l0 = det3([
	        [A2, C2, D2],
	        [C2, B2, E2],
	        [D2, E2, F2]
	    ]);
	    var l2 = 0.33333333 * (det3([
	        [A2, C1, D1],
	        [C2, B1, E1],
	        [D2, E1, F1]
	    ]) + det3([
	        [A1, C2, D1],
	        [C1, B2, E1],
	        [D1, E2, F1]
	    ]) + det3([
	        [A1, C1, D2],
	        [C1, B1, E2],
	        [D1, E1, F2]
	    ]));
	    var l1 = 0.33333333 * (det3([
	        [A1, C2, D2],
	        [C1, B2, E2],
	        [D1, E2, F2]
	    ]) + det3([
	        [A2, C1, D2],
	        [C2, B1, E2],
	        [D2, E1, F2]
	    ]) + det3([
	        [A2, C2, D1],
	        [C2, B2, E1],
	        [D2, E2, F1]
	    ]));

	    var delta1 = det2([
	        [l3, l2],
	        [l2, l1]
	    ]);
	    var delta2 = det2([
	        [l3, l1],
	        [l2, l0]
	    ]);
	    var delta3 = det2([
	        [l2, l1],
	        [l1, l0]
	    ]);

	    var dP = det2([
	        [2 * delta1, delta2],
	        [delta2, 2 * delta3]
	    ]);

	    if (dP > 0 && (l1 > 0 || l2 > 0)) {
	        return false;
	    }
	    return true;
	}

	function det2(m) {
	    return m[0][0] * m[1][1] - m[0][1] * m[1][0];
	}

	function det3(m) {
	    return m[0][0] * m[1][1] * m[2][2] -
	        m[0][0] * m[1][2] * m[2][1] -
	        m[0][1] * m[1][0] * m[2][2] +
	        m[0][1] * m[1][2] * m[2][0] +
	        m[0][2] * m[1][0] * m[2][1] -
	        m[0][2] * m[1][1] * m[2][0];
	}

	var _intersection = ({
		exists: exists,
		lineWithLine: lineWithLine,
		ellipseWithLine: ellipseWithLine,
		ellipseWithEllipse: ellipseWithEllipse,
		rectWithLine: rectWithLine,
		rectWithEllipse: rectWithEllipse,
		rectWithRect: rectWithRect,
		polylineWithLine: polylineWithLine,
		polylineWithEllipse: polylineWithEllipse,
		polylineWithRect: polylineWithRect,
		polylineWithPolyline: polylineWithPolyline,
		polygonWithLine: polygonWithLine,
		polygonWithEllipse: polygonWithEllipse,
		polygonWithRect: polygonWithRect,
		polygonWithPolyline: polygonWithPolyline,
		polygonWithPolygon: polygonWithPolygon,
		pathWithLine: pathWithLine,
		pathWithEllipse: pathWithEllipse,
		pathWithRect: pathWithRect,
		pathWithPolyline: pathWithPolyline,
		pathWithPolygon: pathWithPolygon,
		pathWithPath: pathWithPath
	});

	// Geometry library.
	var intersection = _intersection;

	var g = ({
		intersection: intersection,
		scale: scale,
		normalizeAngle: normalizeAngle,
		snapToGrid: snapToGrid,
		toDeg: toDeg,
		toRad: toRad,
		random: random,
		bezier: bezier,
		Curve: Curve,
		Ellipse: Ellipse,
		ellipse: ellipse,
		Line: Line,
		line: line,
		Path: Path,
		Point: Point,
		point: point,
		Polyline: Polyline,
		Polygon: Polygon,
		Rect: Rect,
		rect: rect,
		types: types
	});

	// code is inspired by https://github.com/lodash/lodash

	/* eslint-disable no-case-declarations */
	// -- helper constants
	var argsTag = '[object Arguments]';
	var arrayTag = '[object Array]';
	var boolTag = '[object Boolean]';
	var dateTag = '[object Date]';
	var errorTag = '[object Error]';
	var funcTag = '[object Function]';
	var mapTag = '[object Map]';
	var numberTag = '[object Number]';
	var nullTag = '[object Null]';
	var objectTag = '[object Object]';
	var regexpTag = '[object RegExp]';
	var setTag = '[object Set]';
	var stringTag = '[object String]';
	var symbolTag = '[object Symbol]';
	var undefinedTag = '[object Undefined]';
	var weakMapTag = '[object WeakMap]';
	var arrayBufferTag = '[object ArrayBuffer]';
	var dataViewTag = '[object DataView]';
	var float32Tag = '[object Float32Array]';
	var float64Tag = '[object Float64Array]';
	var int8Tag = '[object Int8Array]';
	var int16Tag = '[object Int16Array]';
	var int32Tag = '[object Int32Array]';
	var uint8Tag = '[object Uint8Array]';
	var uint8ClampedTag = '[object Uint8ClampedArray]';
	var uint16Tag = '[object Uint16Array]';
	var uint32Tag = '[object Uint32Array]';

	var CLONEABLE_TAGS = {};
	CLONEABLE_TAGS[argsTag] = true;
	CLONEABLE_TAGS[arrayTag] = true;
	CLONEABLE_TAGS[arrayBufferTag] = true;
	CLONEABLE_TAGS[dataViewTag] = true;
	CLONEABLE_TAGS[boolTag] = true;
	CLONEABLE_TAGS[dateTag] = true;
	CLONEABLE_TAGS[float32Tag] = true;
	CLONEABLE_TAGS[float64Tag] = true;
	CLONEABLE_TAGS[int8Tag] = true;
	CLONEABLE_TAGS[int16Tag] = true;
	CLONEABLE_TAGS[int32Tag] = true;
	CLONEABLE_TAGS[mapTag] = true;
	CLONEABLE_TAGS[numberTag] = true;
	CLONEABLE_TAGS[objectTag] = true;
	CLONEABLE_TAGS[regexpTag] = true;
	CLONEABLE_TAGS[setTag] = true;
	CLONEABLE_TAGS[stringTag] = true;
	CLONEABLE_TAGS[symbolTag] = true;
	CLONEABLE_TAGS[uint8Tag] = true;
	CLONEABLE_TAGS[uint8ClampedTag] = true;
	CLONEABLE_TAGS[uint16Tag] = true;
	CLONEABLE_TAGS[uint32Tag] = true;
	CLONEABLE_TAGS[errorTag] = false;
	CLONEABLE_TAGS[funcTag] = false;
	CLONEABLE_TAGS[weakMapTag] = false;

	/** Used to compose unicode character classes. */
	var rsAstralRange = '\\ud800-\\udfff';
	var rsComboMarksRange = '\\u0300-\\u036f';
	var reComboHalfMarksRange = '\\ufe20-\\ufe2f';
	var rsComboSymbolsRange = '\\u20d0-\\u20ff';
	var rsComboMarksExtendedRange = '\\u1ab0-\\u1aff';
	var rsComboMarksSupplementRange = '\\u1dc0-\\u1dff';
	var rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange + rsComboMarksExtendedRange + rsComboMarksSupplementRange;
	var rsDingbatRange = '\\u2700-\\u27bf';
	var rsLowerRange = 'a-z\\xdf-\\xf6\\xf8-\\xff';
	var rsMathOpRange = '\\xac\\xb1\\xd7\\xf7';
	var rsNonCharRange = '\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\xbf';
	var rsPunctuationRange = '\\u2000-\\u206f';
	var rsSpaceRange = ' \\t\\x0b\\f\\xa0\\ufeff\\n\\r\\u2028\\u2029\\u1680\\u180e\\u2000\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008\\u2009\\u200a\\u202f\\u205f\\u3000';
	var rsUpperRange = 'A-Z\\xc0-\\xd6\\xd8-\\xde';
	var rsVarRange = '\\ufe0e\\ufe0f';
	var rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;

	/** Used to compose unicode capture groups. */
	var rsApos = '[\'\u2019]';
	var rsBreak = "[" + rsBreakRange + "]";
	var rsCombo = "[" + rsComboRange + "]";
	var rsDigit = '\\d';
	var rsDingbat = "[" + rsDingbatRange + "]";
	var rsLower = "[" + rsLowerRange + "]";
	var rsMisc = "[^" + rsAstralRange + (rsBreakRange + rsDigit + rsDingbatRange + rsLowerRange + rsUpperRange) + "]";
	var rsFitz = '\\ud83c[\\udffb-\\udfff]';
	var rsModifier = "(?:" + rsCombo + "|" + rsFitz + ")";
	var rsNonAstral = "[^" + rsAstralRange + "]";
	var rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}';
	var rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]';
	var rsUpper = "[" + rsUpperRange + "]";
	var rsZWJ = '\\u200d';

	/** Used to compose unicode regexes. */
	var rsMiscLower = "(?:" + rsLower + "|" + rsMisc + ")";
	var rsMiscUpper = "(?:" + rsUpper + "|" + rsMisc + ")";
	var rsOptContrLower = "(?:" + rsApos + "(?:d|ll|m|re|s|t|ve))?";
	var rsOptContrUpper = "(?:" + rsApos + "(?:D|LL|M|RE|S|T|VE))?";
	var reOptMod = rsModifier + "?";
	var rsOptVar = "[" + rsVarRange + "]?";
	var rsOptJoin = "(?:" + rsZWJ + "(?:" + ([rsNonAstral, rsRegional, rsSurrPair].join('|')) + ")" + (rsOptVar + reOptMod) + ")*";
	var rsOrdLower = '\\d*(?:1st|2nd|3rd|(?![123])\\dth)(?=\\b|[A-Z_])';
	var rsOrdUpper = '\\d*(?:1ST|2ND|3RD|(?![123])\\dTH)(?=\\b|[a-z_])';
	var rsSeq = rsOptVar + reOptMod + rsOptJoin;
	var rsEmoji = "(?:" + ([rsDingbat, rsRegional, rsSurrPair].join('|')) + ")" + rsSeq;

	var reUnicodeWords = RegExp([
	    (rsUpper + "?" + rsLower + "+" + rsOptContrLower + "(?=" + ([rsBreak, rsUpper, '$'].join('|')) + ")"),
	    (rsMiscUpper + "+" + rsOptContrUpper + "(?=" + ([rsBreak, rsUpper + rsMiscLower, '$'].join('|')) + ")"),
	    (rsUpper + "?" + rsMiscLower + "+" + rsOptContrLower),
	    (rsUpper + "+" + rsOptContrUpper),
	    rsOrdUpper,
	    rsOrdLower,
	    (rsDigit + "+"),
	    rsEmoji
	].join('|'), 'g');

	var LARGE_ARRAY_SIZE = 200;
	var HASH_UNDEFINED = '__hash_undefined__';

	// Used to match `toStringTag` values of typed arrays
	var reTypedTag = /^\[object (?:Float(?:32|64)|(?:Int|Uint)(?:8|16|32)|Uint8Clamped)Array\]$/;

	// Used to compose unicode capture groups
	var rsAstral = "[" + rsAstralRange + "]";

	// Used to compose unicode regexes
	var rsNonAstralCombo = "" + rsNonAstral + rsCombo + "?";
	var rsSymbol = "(?:" + ([rsNonAstralCombo, rsCombo, rsRegional, rsSurrPair, rsAstral].join('|')) + ")";

	// Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode)
	var reUnicode = RegExp((rsFitz + "(?=" + rsFitz + ")|" + (rsSymbol + rsSeq)), 'g');

	var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/;
	var reIsPlainProp = /^\w*$/;

	var charCodeOfDot = '.'.charCodeAt(0);
	var reEscapeChar = /\\(\\)?/g;
	var rePropName = RegExp(
	    // Match anything that isn't a dot or bracket.
	    '[^.[\\]]+' + '|' +
	  // Or match property names within brackets.
	  '\\[(?:' +
	    // Match a non-string expression.
	    '([^"\'][^[]*)' + '|' +
	    // Or match strings (supports escaping characters).
	    '(["\'])((?:(?!\\2)[^\\\\]|\\\\.)*?)\\2' +
	  ')\\]'+ '|' +
	  // Or match "" as the space between consecutive dots or empty brackets.
	  '(?=(?:\\.|\\[\\])(?:\\.|\\[\\]|$))'
	    , 'g');
	var reIsUint = /^(?:0|[1-9]\d*)$/;

	var hasUnicodeWord = RegExp.prototype.test.bind(
	    /[a-z][A-Z]|[A-Z]{2}[a-z]|[0-9][a-zA-Z]|[a-zA-Z][0-9]|[^a-zA-Z0-9 ]/
	);

	var MAX_ARRAY_INDEX = 4294967295 - 1;

	/** Used to match words composed of alphanumeric characters. */
	// eslint-disable-next-line no-control-regex
	var reAsciiWord = /[^\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\x7f]+/g;



	// -- helper functions
	var hasUnicode = function (string) {
	    return reUnicode.test(string);
	};

	var unicodeToArray = function (string) {
	    return string.match(reUnicode) || [];
	};

	var asciiToArray = function (string) {
	    return string.split('');
	};

	var stringToArray = function (string) {
	    return hasUnicode(string) ? unicodeToArray(string) : asciiToArray(string);
	};

	var values = function (object) {
	    if (object == null) {
	        return [];
	    }

	    return keys$1(object).map(function (key) { return object[key]; });
	};

	var keys$1 = function (object) {
	    return isArrayLike(object) ? arrayLikeKeys(object) : Object.keys(Object(object));
	};

	var baseKeys = function (object) {
	    if (!isPrototype(object)) {
	        return Object.keys(object);
	    }
	    var result = [];
	    for (var key in Object(object)) {
	        if (hasOwnProperty.call(object, key) && key != 'constructor') {
	            result.push(key);
	        }
	    }

	    return result;
	};

	var arrayLikeKeys = function (value, inherited) {
	    var isArr = Array.isArray(value);
	    var isArg = !isArr && isObjectLike(value) && getTag(value) === argsTag;
	    var isType = !isArr && !isArg && isTypedArray(value);
	    var skipIndexes = isArr || isArg || isType;
	    var length = value.length;
	    var result = new Array(skipIndexes ? length : 0);
	    var index = skipIndexes ? -1 : length;
	    while (++index < length) {
	        result[index] = "" + index;
	    }
	    for (var key in value) {
	        if ((inherited || hasOwnProperty.call(value, key)) &&
	            !(skipIndexes && (
	                // Safari 9 has enumerable `arguments.length` in strict mode.
	                key === 'length' ||
	                // Skip index properties.
	                isIndex(key, length)
	            ))
	        ) {
	            result.push(key);
	        }
	    }
	    return result;
	};

	var assocIndexOf = function (array, key) {
	    var length = array.length;
	    while (length--) {
	        if (eq(array[length][0], key)) {
	            return length;
	        }
	    }
	    return -1;
	};

	var eq = function (value, other) {
	    return value === other || (value !== value && other !== other);
	};

	var isObjectLike = function (value) {
	    return value != null && typeof value == 'object';
	};

	var isIterateeCall = function (value, index, object) {
	    if (!isObject$1(object)) {
	        return false;
	    }
	    var type = typeof index;

	    var isPossibleIteratee = type == 'number' ?
	        (isArrayLike(object) && index > -1 && index < object.length) :
	        (type == 'string' && index in object);

	    if (isPossibleIteratee) {
	        return eq(object[index], value);
	    }
	    return false;
	};

	var isSet = function (value) {
	    return isObjectLike(value) && getTag(value) == setTag;
	};

	var isMap = function (value) {
	    return isObjectLike(value) && getTag(value) == mapTag;
	};

	var isPrototype = function (value) {
	    var Ctor = value && value.constructor;
	    var proto = (typeof Ctor === 'function' && Ctor.prototype) || Object.prototype;

	    return value === proto;
	};

	var assignValue = function (object, key, value) {
	    var objValue = object[key];
	    if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
	        (value === undefined && !(key in object))) {
	        object[key] = value;
	    }
	};

	var copyObject = function (source, props, object) {
	    var index = -1;
	    var length = props.length;

	    while (++index < length) {
	        var key = props[index];
	        assignValue(object, key, source[key]);
	    }
	    return object;
	};

	var isArrayLike = function (value) {
	    return value != null && typeof value !== 'function' && typeof value.length === 'number' &&
	        value.length > -1 && value.length % 1 === 0;
	};

	var isSymbol = function (value) {
	    return typeof value == 'symbol' ||
	        (isObjectLike(value) && getTag(value) === symbolTag);
	};

	var initCloneArray = function (array) {
	    var length = array.length;
	    var result = new array.constructor(length);

	    if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
	        result.index = array.index;
	        result.input = array.input;
	    }

	    return result;
	};

	var copyArray = function (source, array) {
	    var index = -1;
	    var length = source.length;

	    array || (array = new Array(length));
	    while (++index < length) {
	        array[index] = source[index];
	    }
	    return array;
	};

	var getTag = function (value) {
	    if (value == null) {
	        return value === undefined ? undefinedTag : nullTag;
	    }

	    return Object.prototype.toString.call(value);
	};

	var cloneArrayBuffer = function (arrayBuffer) {
	    var result = new arrayBuffer.constructor(arrayBuffer.byteLength);
	    new Uint8Array(result).set(new Uint8Array(arrayBuffer));
	    return result;
	};

	var cloneTypedArray = function (typedArray, isDeep) {
	    var buffer = isDeep ? cloneArrayBuffer(typedArray.buffer) : typedArray.buffer;
	    return new typedArray.constructor(buffer, typedArray.byteOffset, typedArray.length);
	};

	var cloneRegExp = function (regexp) {
	    var result = new regexp.constructor(regexp.source, /\w*$/.exec(regexp));
	    result.lastIndex = regexp.lastIndex;
	    return result;
	};

	var initCloneObject = function (object) {
	    return (typeof object.constructor == 'function' && !isPrototype(object))
	        ? Object.create(Object.getPrototypeOf(object))
	        : {};
	};

	var getSymbols = function (object) {
	    if (object == null) {
	        return [];
	    }

	    object = Object(object);
	    var symbols = Object.getOwnPropertySymbols(object);

	    return symbols.filter(function (symbol) { return propertyIsEnumerable.call(object, symbol); });
	};

	var copySymbols = function (source, object) {
	    return copyObject(source, getSymbols(source), object);
	};

	function cloneDataView(dataView, isDeep) {
	    var buffer = isDeep ? cloneArrayBuffer(dataView.buffer) : dataView.buffer;
	    return new dataView.constructor(buffer, dataView.byteOffset, dataView.byteLength);
	}

	var initCloneByTag = function (object, tag, isDeep) {
	    var Constructor = object.constructor;
	    switch(tag) {
	        case arrayBufferTag:
	            return cloneArrayBuffer(object, isDeep);
	        case boolTag:
	        case dateTag:
	            return new Constructor(+object);
	        case dataViewTag:
	            return cloneDataView(object, isDeep);
	        case float32Tag:
	        case float64Tag:
	        case int8Tag:
	        case int16Tag:
	        case int32Tag:
	        case uint8Tag:
	        case uint8ClampedTag:
	        case uint16Tag:
	        case uint32Tag:
	            return cloneTypedArray(object, isDeep);
	        case mapTag:
	            return new Constructor(object);
	        case numberTag:
	        case stringTag:
	            return new Constructor(object);
	        case regexpTag:
	            return cloneRegExp(object);
	        case setTag:
	            return new Constructor;
	        case symbolTag:
	            return Symbol.prototype.valueOf ? Object(Symbol.prototype.valueOf.call(object)) : {};
	    }
	};

	var isTypedArray = function (value) {
	    return isObjectLike(value) && reTypedTag.test(getTag(value));
	};

	var getAllKeys = function (object) {
	    var result = Object.keys(object);
	    if(!Array.isArray(object) && object != null) {
	        result.push.apply(result, getSymbols(Object(object)));
	    }

	    return result;
	};

	var getSymbolsIn = function (object) {
	    var result = [];
	    while (object) {
	        result.push.apply(result, getSymbols(object));
	        object = Object.getPrototypeOf(Object(object));
	    }

	    return result;
	};

	var getAllKeysIn = function (object) {
	    var result = [];

	    for (var key in object) {
	        result.push(key);
	    }

	    if (!Array.isArray(object)) {
	        result.push.apply(result, getSymbolsIn(object));
	    }

	    return result;
	};

	var getMapData = function (ref, key) {
	    var __data__ = ref.__data__;

	    var data = __data__;
	    return isKeyable(key)
	        ? data[typeof key === 'string' ? 'string' : 'hash']
	        : data.map;
	};

	var equalObjects = function (object, other, equalFunc, stack) {
	    var objProps = getAllKeys(object);
	    var objLength = objProps.length;
	    var othProps = getAllKeys(other);
	    var othLength = othProps.length;

	    if (objLength != othLength) {
	        return false;
	    }
	    var key;
	    var index = objLength;
	    while (index--) {
	        key = objProps[index];
	        if (!(hasOwnProperty.call(other, key))) {
	            return false;
	        }
	    }

	    var objStacked = stack.get(object);
	    var othStacked = stack.get(other);
	    if (objStacked && othStacked) {
	        return objStacked == other && othStacked == object;
	    }
	    var result = true;
	    stack.set(object, other);
	    stack.set(other, object);

	    var compared;
	    var skipCtor;

	    while (++index < objLength) {
	        key = objProps[index];
	        var objValue = object[key];
	        var othValue = other[key];

	        if (!(compared === undefined
	            ? (objValue === othValue || equalFunc(objValue, othValue, stack))
	            : compared
	        )) {
	            result = false;
	            break;
	        }
	        skipCtor || (skipCtor = key == 'constructor');
	    }

	    if (result && !skipCtor) {
	        var objCtor = object.constructor;
	        var othCtor = other.constructor;

	        if (objCtor != othCtor &&
	        ('constructor' in object && 'constructor' in other) &&
	        !(typeof objCtor === 'function' && objCtor instanceof objCtor &&
	            typeof othCtor === 'function' && othCtor instanceof othCtor)) {
	            result = false;
	        }
	    }
	    stack['delete'](object);
	    stack['delete'](other);
	    return result;
	};

	var baseIsEqual = function (value, other, stack) {
	    if (value === other) {
	        return true;
	    }
	    if (value == null || other == null || (!isObjectLike(value) && !isObjectLike(other))) {
	        return value !== value && other !== other;
	    }

	    return baseIsEqualDeep(value, other, baseIsEqual, stack);
	};

	var baseIsEqualDeep = function (object, other, equalFunc, stack) {
	    var objIsArr = Array.isArray(object);
	    var othIsArr = Array.isArray(other);
	    var objTag = objIsArr ? arrayTag : getTag(object);
	    var othTag = othIsArr ? arrayTag : getTag(other);

	    objTag = objTag == argsTag ? objectTag : objTag;
	    othTag = othTag == argsTag ? objectTag : othTag;

	    var objIsObj = objTag == objectTag;
	    var othIsObj = othTag == objectTag;
	    var isSameTag = objTag == othTag;

	    if (isSameTag && !objIsObj) {
	        stack || (stack = new Stack);
	        return (objIsArr || isTypedArray(object))
	            ? equalArrays(object, other, false, equalFunc, stack)
	            : equalByTag(object, other, objTag, equalFunc, stack);
	    }

	    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__');
	    var othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

	    if (objIsWrapped || othIsWrapped) {
	        var objUnwrapped = objIsWrapped ? object.value() : object;
	        var othUnwrapped = othIsWrapped ? other.value() : other;

	        stack || (stack = new Stack);
	        return equalFunc(objUnwrapped, othUnwrapped, stack);
	    }

	    if (!isSameTag) {
	        return false;
	    }

	    stack || (stack = new Stack);
	    return equalObjects(object, other, equalFunc, stack);
	};

	var equalArrays = function (array, other, compareUnordered, equalFunc, stack) {
	    var isPartial = false;
	    var arrLength = array.length;
	    var othLength = other.length;

	    if (arrLength != othLength && !(isPartial && othLength > arrLength)) {
	        return false;
	    }
	    // Assume cyclic values are equal.
	    var arrStacked = stack.get(array);
	    var othStacked = stack.get(other);
	    if (arrStacked && othStacked) {
	        return arrStacked == other && othStacked == array;
	    }
	    var index = -1;
	    var result = true;
	    var seen = compareUnordered ? new SetCache : undefined;

	    stack.set(array, other);
	    stack.set(other, array);

	    var loop = function () {
	        var compared = (void 0);
	        var arrValue = array[index];
	        var othValue = other[index];

	        if (compared !== undefined) {
	            if (compared) {
	                return;
	            }
	            result = false;
	            return 'break';
	        }

	        if (seen) {
	            if (!some(other, function (othValue, othIndex) {
	                if (!cacheHas(seen, othIndex) &&
	            (arrValue === othValue || equalFunc(arrValue, othValue, stack))) {
	                    return seen.push(othIndex);
	                }
	            })) {
	                result = false;
	                return 'break';
	            }
	        } else if (!(
	            arrValue === othValue ||
	            equalFunc(arrValue, othValue, stack)
	        )) {
	            result = false;
	            return 'break';
	        }
	    };

	    while (++index < arrLength) {
	      var returned = loop();

	      if ( returned === 'break' ) break;
	    }
	    stack['delete'](array);
	    stack['delete'](other);
	    return result;
	};

	var some = function (array, predicate) {
	    var index = -1;
	    var length = array == null ? 0 : array.length;

	    while (++index < length) {
	        if (predicate(array[index], index, array)) {
	            return true;
	        }
	    }
	    return false;
	};

	var cacheHas = function (cache, key) {
	    return cache.has(key);
	};

	var compareArrayBufferTag = function (object, other, equalFunc, stack) {
	    if ((object.byteLength != other.byteLength) ||
	                !equalFunc(new Uint8Array(object), new Uint8Array(other), stack)) {
	        return false;
	    }
	    return true;
	};

	var equalByTag = function (object, other, tag, equalFunc, stack) {

	    switch (tag) {
	        case dataViewTag:
	            if ((object.byteLength != other.byteLength) ||
	                (object.byteOffset != other.byteOffset)) {
	                return false;
	            }
	            object = object.buffer;
	            other = other.buffer;
	            return compareArrayBufferTag(object, other, equalFunc, stack);
	        case arrayBufferTag:
	            return compareArrayBufferTag(object, other, equalFunc, stack);
	        case boolTag:
	        case dateTag:
	        case numberTag:
	            return eq(+object, +other);
	        case errorTag:
	            return object.name == other.name && object.message == other.message;
	        case regexpTag:
	        case stringTag:
	            return object == ("" + other);
	        case mapTag:
	            var convert = mapToArray;
	        // Intentional fallthrough
	        // eslint-disable-next-line no-fallthrough
	        case setTag:
	            convert || (convert = setToArray);

	            if (object.size != other.size) {
	                return false;
	            }
	            // Assume cyclic values are equal.
	            var stacked = stack.get(object);
	            if (stacked) {
	                return stacked == other;
	            }

	            // Recursively compare objects (susceptible to call stack limits).
	            stack.set(object, other);
	            var result = equalArrays(convert(object), convert(other), true, equalFunc, stack);
	            stack['delete'](object);
	            return result;
	        case symbolTag:
	            return Symbol.prototype.valueOf.call(object) == Symbol.prototype.valueOf.call(other);
	    }

	    return false;
	};

	var mapToArray = function (map) {
	    var index = -1;
	    var result = Array(map.size);

	    map.forEach(function (value, key) {
	        result[++index] = [key, value];
	    });
	    return result;
	};

	var setToArray = function (set) {
	    var index = -1;
	    var result = new Array(set.size);

	    set.forEach(function (value) {
	        result[++index] = value;
	    });
	    return result;
	};

	var isKey = function (value, object) {
	    if (Array.isArray(value)) {
	        return false;
	    }
	    var type = typeof value;
	    if (type === 'number' || type === 'boolean' || value == null || isSymbol(value)) {
	        return true;
	    }
	    return reIsPlainProp.test(value) || !reIsDeepProp.test(value) ||
	    (object != null && value in Object(object));
	};

	var stringToPath = function (string) {
	    var result = [];
	    if (string.charCodeAt(0) === charCodeOfDot) {
	        result.push('');
	    }
	    string.replace(rePropName, function (match, expression, quote, subString) {
	        var key = match;
	        if (quote) {
	            key = subString.replace(reEscapeChar, '$1');
	        }
	        else if (expression) {
	            key = expression.trim();
	        }
	        result.push(key);
	    });
	    return result;
	};

	var castPath = function (path, object) {
	    if (Array.isArray(path)) {
	        return path;
	    }

	    return isKey(path, object) ? [path] : stringToPath(("" + path));
	};

	var get$1 = function (object, path) {
	    path = castPath(path, object);

	    var index = 0;
	    var length = path.length;

	    while (object != null && index < length) {
	        object = object[toKey(path[index])];
	        index++;
	    }

	    return (index && index == length) ? object : undefined;
	};

	function compareAscending(value, other) {
	    if (value !== other) {
	        var valIsDefined = value !== undefined;
	        var valIsNull = value === null;
	        var valIsReflexive = value === value;
	        var valIsSymbol = isSymbol(value);

	        var othIsDefined = other !== undefined;
	        var othIsNull = other === null;
	        var othIsReflexive = other === other;
	        var othIsSymbol = isSymbol(other);

	        if ((!othIsNull && !othIsSymbol && !valIsSymbol && value > other) ||
	            (valIsSymbol && othIsDefined && othIsReflexive && !othIsNull && !othIsSymbol) ||
	            (valIsNull && othIsDefined && othIsReflexive) ||
	            (!valIsDefined && othIsReflexive) ||
	            !valIsReflexive) {
	            return 1;
	        }
	        if ((!valIsNull && !valIsSymbol && !othIsSymbol && value < other) ||
	            (othIsSymbol && valIsDefined && valIsReflexive && !valIsNull && !valIsSymbol) ||
	            (othIsNull && valIsDefined && valIsReflexive) ||
	            (!othIsDefined && valIsReflexive) ||
	            !othIsReflexive) {
	            return -1;
	        }
	    }
	    return 0;
	}

	function compareMultiple(object, other, orders) {
	    var index = -1;
	    var objCriteria = object.criteria;
	    var othCriteria = other.criteria;
	    var length = objCriteria.length;
	    var ordersLength = orders.length;

	    while (++index < length) {
	        var order = index < ordersLength ? orders[index] : null;
	        var cmpFn = (order && typeof order === 'function') ? order : compareAscending;
	        var result = cmpFn(objCriteria[index], othCriteria[index]);
	        if (result) {
	            if (order && typeof order !== 'function') {
	                return result * (order == 'desc' ? -1 : 1);
	            }
	            return result;
	        }
	    }

	    return object.index - other.index;
	}

	var diff = function (array, values) {
	    var includes = function (array, value) {
	        var length = array == null ? 0 : array.length;
	        return !!length && array.indexOf(value) > -1;
	    };
	    var isCommon = true;
	    var result = [];
	    var valuesLength = values.length;

	    if (!array.length) {
	        return result;
	    }

	    if (values.length >= LARGE_ARRAY_SIZE) {
	        includes = function (cache, key) { return cache.has(key); };
	        isCommon = false;
	        values = new SetCache(values);
	    }

	    outer:
	    for (var key in array) {
	        var value = array[key];
	        var computed = value;

	        value = (value !== 0) ? value : 0;
	        if (isCommon && computed === computed) {
	            var valuesIndex = valuesLength;
	            while (valuesIndex--) {
	                if (values[valuesIndex] === computed) {
	                    continue outer;
	                }
	            }
	            result.push(value);
	        }
	        else if (!includes(values, computed)) {
	            result.push(value);
	        }
	    }

	    return result;
	};

	var intersect = function (arrays) {
	    var includes = function (array, value) {
	        var length = array == null ? 0 : array.length;
	        return !!length && array.indexOf(value) > -1;
	    };
	    var cacheHas = function (cache, key) { return cache.has(key); };
	    var length = arrays[0].length;
	    var othLength = arrays.length;
	    var caches = new Array(othLength);
	    var result = [];

	    var array;
	    var maxLength = Infinity;
	    var othIndex = othLength;

	    while (othIndex--) {
	        array = arrays[othIndex];

	        maxLength = Math.min(array.length, maxLength);
	        caches[othIndex] = length >= 120 && array.length >= 120
	            ? new SetCache(othIndex && array)
	            : undefined;
	    }
	    array = arrays[0];

	    var index = -1;
	    var seen = caches[0];

	    outer:
	    while (++index < length && result.length < maxLength) {
	        var value = array[index];
	        var computed = value;

	        value = (value !== 0) ? value : 0;
	        if (!(seen
	            ? cacheHas(seen, computed)
	            : includes(result, computed)
	        )) {
	            othIndex = othLength;
	            while (--othIndex) {
	                var cache = caches[othIndex];
	                if (!(cache
	                    ? cacheHas(cache, computed)
	                    : includes(arrays[othIndex], computed))
	                ) {
	                    continue outer;
	                }
	            }
	            if (seen) {
	                seen.push(computed);
	            }
	            result.push(value);
	        }
	    }
	    return result;
	};

	var toKey = function (value) {
	    if (typeof value === 'string' || isSymbol(value)) {
	        return value;
	    }
	    var result = "" + value;
	    return (result == '0' && (1 / value) == -Infinity) ? '-0' : result;
	};

	var baseClone = function (value, isDeep, isFlat, isFull, customizer, key, object, stack) {
	    if ( isDeep === void 0 ) isDeep = false;
	    if ( isFlat === void 0 ) isFlat = false;
	    if ( isFull === void 0 ) isFull = true;

	    var result;

	    if (customizer) {
	        result = object ? customizer(value, key, object, stack) : customizer(value);
	    }

	    if (result !== undefined) {
	        return result;
	    }

	    if (!isObject$1(value)) {
	        return value;
	    }

	    var isArr = Array.isArray(value);
	    var tag = getTag(value);

	    if (isArr) {
	        result = initCloneArray(value);

	        if (!isDeep) {
	            return copyArray(value, result);
	        }
	    } else {
	        var isFunc = typeof value === 'function';

	        if (tag === objectTag || tag === argsTag || (isFunc && !object)) {
	            result = (isFlat || isFunc) ? {} : initCloneObject(value);
	            if (!isDeep) {
	                return isFlat ?
	                    copySymbolsIn(value, copyObject(value, Object.keys(value), result)) :
	                    copySymbols(value, Object.assign(result, value));
	            }
	        } else {
	            if (isFunc || !CLONEABLE_TAGS[tag]) {
	                return object ? value : {};
	            }
	            result = initCloneByTag(value, tag, isDeep);
	        }
	    }

	    stack || (stack = new Stack);
	    var stacked = stack.get(value);

	    if (stacked) {
	        return stacked;
	    }

	    stack.set(value, result);

	    if (isMap(value)) {
	        value.forEach(function (subValue, key) {
	            result.set(key, baseClone(subValue, isDeep, isFlat, isFull, customizer, key, value, stack));
	        });

	        return result;
	    }

	    if (isSet(value)) {
	        value.forEach(function (subValue) {
	            result.add(baseClone(subValue, isDeep, isFlat, isFull, customizer, subValue, value, stack));
	        });

	        return result;
	    }

	    if(isTypedArray(value)) {
	        return result;
	    }

	    var keysFunc = isFull
	        ? (isFlat ? getAllKeysIn : getAllKeys)
	        : (isFlat ? keysIn : keys$1);

	    var props =  isArr ? undefined : keysFunc(value);

	    (props || value).forEach(function (subValue, key) {
	        if (props) {
	            key = subValue;
	            subValue = value[key];
	        }

	        assignValue(result, key, baseClone(subValue, isDeep, isFlat, isFull, customizer, key, value, stack));
	    });

	    return result;
	};

	var copySymbolsIn = function (source, object) {
	    return copyObject(source, getSymbolsIn(source), object);
	};

	var parent = function (object, path) {
	    return path.length < 2 ? object : get$1(object, path.slice(0, -1));
	};

	var set$1 = function (object, path, value) {
	    if (!isObject$1(object)) {
	        return object;
	    }
	    path = castPath(path, object);

	    var length = path.length;
	    var lastIndex = length - 1;

	    var index = -1;
	    var nested = object;

	    while (nested != null && ++index < length) {
	        var key = toKey(path[index]);
	        var newValue = value;

	        if (index != lastIndex) {
	            var objValue = nested[key];
	            newValue = undefined;
	            if (newValue === undefined) {
	                newValue = isObject$1(objValue)
	                    ? objValue
	                    : (isIndex(path[index + 1]) ? [] : {});
	            }
	        }
	        assignValue(nested, key, newValue);
	        nested = nested[key];
	    }
	    return object;
	};

	var isIndex = function (value, length) {
	    var type = typeof value;
	    length = length == null ? Number.MAX_SAFE_INTEGER : length;

	    return !!length &&
	    (type === 'number' ||
	        (type !== 'symbol' && reIsUint.test(value))) &&
	        (value > -1 && value % 1 == 0 && value < length);
	};

	var unset = function (object, path) {
	    path = castPath(path, object);
	    object = parent(object, path);
	    var lastSegment = path[path.length - 1];
	    return object == null || delete object[toKey(lastSegment)];
	};

	var isKeyable = function (value) {
	    var type = typeof value;
	    return (type === 'string' || type === 'number' || type === 'symbol' || type === 'boolean')
	        ? (value !== '__proto__')
	        : (value === null);
	};

	var keysIn = function (object) {
	    var result = [];
	    for (var key in object) {
	        result.push(key);
	    }
	    return result;
	};

	var toPlainObject = function (value) {
	    value = Object(value);
	    var result = {};
	    for (var key in value) {
	        result[key] = value[key];
	    }
	    return result;
	};

	var safeGet = function (object, key) {
	    if (key === 'constructor' && typeof object[key] === 'function') {
	        return;
	    }

	    if (key == '__proto__') {
	        return;
	    }

	    return object[key];
	};

	function createAssigner(assigner, isMerge) {
	    if ( isMerge === void 0 ) isMerge = false;

	    return function (object) {
	        var sources = [], len = arguments.length - 1;
	        while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];

	        var index = -1;
	        var length = sources.length;
	        var customizer = length > 1 ? sources[length - 1] : undefined;
	        var guard = length > 2 ? sources[2] : undefined;

	        customizer = (assigner.length > 3 && typeof customizer === 'function')
	            ? (length--, customizer)
	            : isMerge ? function (a, b) {
	                if (Array.isArray(a) && !Array.isArray(b)) {
	                    return b;
	                }
	            } : undefined;

	        if (guard && isIterateeCall(sources[0], sources[1], guard)) {
	            customizer = length < 3 ? undefined : customizer;
	            length = 1;
	        }
	        object = Object(object);
	        while (++index < length) {
	            var source = sources[index];
	            if (source) {
	                assigner(object, source, index, customizer);
	            }
	        }
	        return object;
	    };
	}

	var baseMerge = function (object, source, srcIndex, customizer, stack) {
	    if (object === source) {
	        return;
	    }

	    forIn(source, function (srcValue, key) {
	        if (isObject$1(srcValue)) {
	            stack || (stack = new Stack);
	            baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
	        } else {
	            var newValue = customizer
	                ? customizer(object[key], srcValue, ("" + key), object, source, stack)
	                : undefined;

	            if (newValue === undefined) {
	                newValue = srcValue;
	            }

	            assignMergeValue(object, key, newValue);
	        }
	    }, keysIn);
	};

	var baseMergeDeep = function (object, source, key, srcIndex, mergeFunc, customizer, stack) {
	    var objValue = safeGet(object, key);
	    var srcValue = safeGet(source, key);
	    var stacked = stack.get(srcValue);

	    if (stacked) {
	        assignMergeValue(object, key, stacked);
	        return;
	    }

	    var newValue = customizer
	        ? customizer(objValue, srcValue, ("" + key), object, source, stack)
	        : undefined;

	    var isCommon = newValue === undefined;

	    if (isCommon) {
	        var isArr = Array.isArray(srcValue);
	        var isTyped = !isArr && isTypedArray(srcValue);

	        newValue = srcValue;
	        if (isArr || isTyped) {
	            if (Array.isArray(objValue)) {
	                newValue = objValue;
	            }
	            else if (isObjectLike(objValue) && isArrayLike(objValue)) {
	                newValue = copyArray(objValue);
	            }
	            else if (isTyped) {
	                isCommon = false;
	                newValue = cloneTypedArray(srcValue, true);
	            }
	            else {
	                newValue = [];
	            }
	        }
	        else if (isPlainObject(srcValue) || isArguments(srcValue)) {
	            newValue = objValue;
	            if (isArguments(objValue)) {
	                newValue = toPlainObject(objValue);
	            }
	            else if (typeof objValue === 'function' || !isObject$1(objValue)) {
	                newValue = initCloneObject(srcValue);
	            }
	        }
	        else {
	            isCommon = false;
	        }
	    }
	    if (isCommon) {
	    // Recursively merge objects and arrays (susceptible to call stack limits).
	        stack.set(srcValue, newValue);
	        mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
	        stack['delete'](srcValue);
	    }
	    assignMergeValue(object, key, newValue);
	};

	var assignMergeValue = function (object, key, value) {
	    if ((value !== undefined && !eq(object[key], value)) ||
	        (value === undefined && !(key in object))) {
	        assignValue(object, key, value);
	    }
	};

	function baseFor(object, iteratee, keysFunc) {
	    var iterable = Object(object);
	    var props = keysFunc(object);
	    var length = props.length;
	    var index = -1;

	    while (length--) {
	        var key = props[++index];
	        if (iteratee(iterable[key], key, iterable) === false) {
	            break;
	        }
	    }
	    return object;
	}

	var baseForOwn = function (object, iteratee) {
	    return object && baseFor(object, iteratee, keys$1);
	};

	var baseEach = function (collection, iteratee) {
	    if (collection == null) {
	        return collection;
	    }
	    if (!isArrayLike(collection)) {
	        return baseForOwn(collection, iteratee);
	    }
	    var length = collection.length;
	    var iterable = Object(collection);
	    var index = -1;

	    while (++index < length) {
	        if (iteratee(iterable[index], index, iterable) === false) {
	            break;
	        }
	    }
	    return collection;
	};

	function last(array) {
	    var length = array == null ? 0 : array.length;
	    return length ? array[length - 1] : undefined;
	}

	var createSet = (Set && (1 / setToArray(new Set([undefined,-0]))[1]) == 1 / 0)
	    ? function (values) { return new Set(values); }
	    : function () {};

	function customDefaultsMerge(objValue, srcValue, key, object, source, stack) {
	    if (isObject$1(objValue) && isObject$1(srcValue)) {
	    // Recursively merge objects and arrays (susceptible to call stack limits).
	        stack.set(srcValue, objValue);
	        baseMerge(objValue, srcValue, undefined, customDefaultsMerge, stack);
	        stack['delete'](srcValue);
	    }
	    return objValue;
	}

	function baseOrderBy(collection, iteratees, orders) {
	    if (iteratees.length) {
	        iteratees = iteratees.map(function (iteratee) {
	            if (Array.isArray(iteratee)) {
	                return function (value) { return get$1(value, iteratee.length === 1 ? iteratee[0] : iteratee); };
	            }

	            return iteratee;
	        });
	    } else {
	        iteratees = [function (value) { return value; }];
	    }

	    var criteriaIndex = -1;
	    var eachIndex = -1;

	    var result = isArrayLike(collection) ? new Array(collection.length) : [];

	    baseEach(collection, function (value) {
	        var criteria = iteratees.map(function (iteratee) { return iteratee(value); });

	        result[++eachIndex] = {
	            criteria: criteria,
	            index: ++criteriaIndex,
	            value: value
	        };
	    });

	    return baseSortBy(result, function (object, other) { return compareMultiple(object, other, orders); });
	}

	function baseSortBy(array, comparer) {
	    var length = array.length;

	    array.sort(comparer);
	    while (length--) {
	        array[length] = array[length].value;
	    }
	    return array;
	}

	function isStrictComparable(value) {
	    return value === value && !isObject$1(value);
	}

	function matchesStrictComparable(key, srcValue) {
	    return function (object) {
	        if (object == null) {
	            return false;
	        }
	        return object[key] === srcValue &&
	            (srcValue !== undefined || (key in Object(object)));
	    };
	}

	function hasIn(object, path) {
	    return object != null && hasPath(object, path, baseHasIn);
	}

	function baseMatchesProperty(path, srcValue) {
	    if (isKey(path) && isStrictComparable(srcValue)) {
	        return matchesStrictComparable(toKey(path), srcValue);
	    }
	    return function (object) {
	        var objValue = get$1(object, path);
	        return (objValue === undefined && objValue === srcValue)
	            ? hasIn(object, path)
	            : baseIsEqual(srcValue, objValue);
	    };
	}

	function baseMatches(source) {
	    var matchData = getMatchData(source);
	    if (matchData.length === 1 && matchData[0][2]) {
	        return matchesStrictComparable(matchData[0][0], matchData[0][1]);
	    }
	    return function (object) { return object === source || baseIsMatch(object, source, matchData); };
	}

	function getMatchData(object) {
	    var result = keys$1(object);
	    var length = result.length;

	    while (length--) {
	        var key = result[length];
	        var value = object[key];
	        result[length] = [key, value, isStrictComparable(value)];
	    }
	    return result;
	}

	function baseIsMatch(object, source, matchData, customizer) {
	    var index = matchData.length;
	    var length = index;
	    var noCustomizer = !customizer;

	    if (object == null) {
	        return !length;
	    }
	    var data;
	    var result;
	    object = Object(object);
	    while (index--) {
	        data = matchData[index];
	        if ((noCustomizer && data[2])
	            ? data[1] !== object[data[0]]
	            : !(data[0] in object)
	        ) {
	            return false;
	        }
	    }
	    while (++index < length) {
	        data = matchData[index];
	        var key = data[0];
	        var objValue = object[key];
	        var srcValue = data[1];

	        if (noCustomizer && data[2]) {
	            if (objValue === undefined && !(key in object)) {
	                return false;
	            }
	        } else {
	            var stack = new Stack;
	            if (customizer) {
	                result = customizer(objValue, srcValue, key, object, source, stack);
	            }
	            if (!(result === undefined
	                ? baseIsEqual(srcValue, objValue, stack)
	                : result
	            )) {
	                return false;
	            }
	        }
	    }
	    return true;
	}

	function property(path) {
	    return isKey(path) ? baseProperty(toKey(path)) : basePropertyDeep(path);
	}

	function baseProperty(key) {
	    return function (object) { return object == null ? undefined : object[key]; };
	}

	function basePropertyDeep(path) {
	    return function (object) { return get$1(object, path); };
	}

	function baseIteratee(value) {
	    if (typeof value == 'function') {
	        return value;
	    }
	    if (value == null) {
	        return function (val) { return val; };
	    }
	    if (typeof value == 'object') {
	        return Array.isArray(value)
	            ? baseMatchesProperty(value[0], value[1])
	            : baseMatches(value);
	    }
	    return property(value);
	}

	function getIteratee() {
	    var result = baseIteratee;
	    return arguments.length ? result(arguments[0], arguments[1]) : result;
	}

	var arrayReduce = function (array, iteratee, accumulator, initAccum) {
	    var index = -1;
	    var length = array == null ? 0 : array.length;

	    if (initAccum && length) {
	        accumulator = array[++index];
	    }
	    while (++index < length) {
	        accumulator = iteratee(accumulator, array[index], index, array);
	    }
	    return accumulator;
	};

	var baseReduce = function (collection, iteratee, accumulator, initAccum, eachFunc) {
	    eachFunc(collection, function (value, index, collection) {
	        accumulator = initAccum
	            ? (initAccum = false, value)
	            : iteratee(accumulator, value, index, collection);
	    });
	    return accumulator;
	};

	function reduce(collection, iteratee, accumulator) {
	    var func = Array.isArray(collection) ? arrayReduce : baseReduce;
	    var initAccum = arguments.length < 3;
	    return func(collection, iteratee, accumulator, initAccum, baseEach);
	}

	var isFlattenable = function (value) {
	    return Array.isArray(value) || isArguments(value) ||
	    !!(value && value[Symbol.isConcatSpreadable]);
	};

	function baseFlatten(array, depth, predicate, isStrict, result) {
	    var index = -1;
	    var length = array.length;

	    predicate || (predicate = isFlattenable);
	    result || (result = []);

	    while (++index < length) {
	        var value = array[index];
	        if (depth > 0 && predicate(value)) {
	            if (depth > 1) {
	                // Recursively flatten arrays (susceptible to call stack limits).
	                baseFlatten(value, depth - 1, predicate, isStrict, result);
	            } else {
	                result.push.apply(result, value);
	            }
	        } else if (!isStrict) {
	            result[result.length] = value;
	        }
	    }
	    return result;
	}

	var isArguments = function (value) {
	    return isObjectLike(value) && getTag(value) == '[object Arguments]';
	};

	var basePick = function (object, paths) {
	    return basePickBy(object, paths, function (value, path) { return hasIn(object, path); });
	};

	var basePickBy = function (object, paths, predicate) {
	    var index = -1;
	    var length = paths.length;
	    var result = {};

	    while (++index < length) {
	        var path = paths[index];
	        var value = get$1(object, path);
	        if (predicate(value, path)) {
	            set$1(result, castPath(path, object), value);
	        }
	    }
	    return result;
	};

	var isLength = function (value) {
	    return typeof value == 'number' &&
	        value > -1 && value % 1 == 0 && value <= Number.MAX_SAFE_INTEGER;
	};

	var baseHasIn = function (object, key) {
	    return object != null && key in Object(object);
	};

	var hasPath = function (object, path, hasFunc) {
	    path = castPath(path, object);

	    var index = -1,
	        length = path.length,
	        result = false;

	    while (++index < length) {
	        var key = toKey(path[index]);
	        if (!(result = object != null && hasFunc(object, key))) {
	            break;
	        }
	        object = object[key];
	    }
	    if (result || ++index != length) {
	        return result;
	    }
	    length = object == null ? 0 : object.length;
	    return !!length && isLength(length) && isIndex(key, length) &&
	        (Array.isArray(object) || isArguments(object));
	};

	var asciiWords = function (string) {
	    return string.match(reAsciiWord);
	};

	var unicodeWords = function (string) {
	    return string.match(reUnicodeWords);
	};

	var words = function (string, pattern) {
	    if (pattern === undefined) {
	        var result = hasUnicodeWord(string) ? unicodeWords(string) : asciiWords(string);
	        return result || [];
	    }
	    return string.match(pattern) || [];
	};

	var castSlice = function (array, start, end) {
	    var length = array.length;
	    end = end === undefined ? length : end;
	    return (!start && end >= length) ? array : array.slice(start, end);
	};

	var upperFirst = createCaseFirst('toUpperCase');

	function createCaseFirst(methodName) {
	    return function (string) {
	        if (!string) {
	            return '';
	        }

	        var strSymbols = hasUnicode(string)
	            ? stringToArray(string)
	            : undefined;

	        var chr = strSymbols
	            ? strSymbols[0]
	            : string[0];

	        var trailing = strSymbols
	            ? castSlice(strSymbols, 1).join('')
	            : string.slice(1);

	        return chr[methodName]() + trailing;
	    };
	}

	function matches(source) {
	    return baseMatches(baseClone(source, true));
	}

	// -- helper classes
	var Stack = function Stack(entries) {
	      var data = this.__data__ = new ListCache(entries);
	      this.size = data.size;
	  };

	  Stack.prototype.clear = function clear () {
	      this.__data__ = new ListCache;
	      this.size = 0;
	  };

	  Stack.prototype.delete = function delete$1 (key) {
	      var data = this.__data__;
	      var result = data['delete'](key);

	      this.size = data.size;
	      return result;
	  };

	  Stack.prototype.get = function get (key) {
	      return this.__data__.get(key);
	  };

	  Stack.prototype.has = function has (key) {
	      return this.__data__.has(key);
	  };

	  Stack.prototype.set = function set (key, value) {
	      var data = this.__data__;
	      if (data instanceof ListCache) {
	          var pairs = data.__data__;
	          if (pairs.length < LARGE_ARRAY_SIZE - 1) {
	              pairs.push([key, value]);
	              this.size = ++data.size;
	              return this;
	          }
	          data = this.__data__ = new MapCache(pairs);
	      }
	      data.set(key, value);
	      this.size = data.size;
	      return this;
	  };

	var ListCache = function ListCache(entries) {
	      var index = -1;
	      var length = entries == null ? 0 : entries.length;

	      this.clear();
	      while (++index < length) {
	          var entry = entries[index];
	          this.set(entry[0], entry[1]);
	      }
	  };

	  ListCache.prototype.clear = function clear () {
	      this.__data__ = [];
	      this.size = 0;
	  };

	  ListCache.prototype.delete = function delete$2 (key) {
	      var data = this.__data__;
	      var index = assocIndexOf(data, key);

	      if (index < 0) {
	          return false;
	      }
	      var lastIndex = data.length - 1;
	      if (index == lastIndex) {
	          data.pop();
	      } else {
	          data.splice(index, 1);
	      }
	      --this.size;
	      return true;
	  };

	  ListCache.prototype.get = function get (key) {
	      var data = this.__data__;
	      var index = assocIndexOf(data, key);
	      return index < 0 ? undefined : data[index][1];
	  };

	  ListCache.prototype.has = function has (key) {
	      return assocIndexOf(this.__data__, key) > -1;
	  };

	  ListCache.prototype.set = function set (key, value) {
	      var data = this.__data__;
	      var index = assocIndexOf(data, key);

	      if (index < 0) {
	          ++this.size;
	          data.push([key, value]);
	      } else {
	          data[index][1] = value;
	      }
	      return this;
	  };

	var MapCache = function MapCache(entries) {
	      var index = -1;
	      var length = entries == null ? 0 : entries.length;

	      this.clear();
	      while (++index < length) {
	          var entry = entries[index];
	          this.set(entry[0], entry[1]);
	      }
	  };

	  MapCache.prototype.clear = function clear () {
	      this.size = 0;
	      this.__data__ = {
	          'hash': new Hash,
	          'map': new Map,
	          'string': new Hash
	      };
	  };

	  MapCache.prototype.delete = function delete$3 (key) {
	      var result = getMapData(this, key)['delete'](key);
	      this.size -= result ? 1 : 0;
	      return result;
	  };

	  MapCache.prototype.get = function get (key) {
	      return getMapData(this, key).get(key);
	  };

	  MapCache.prototype.has = function has (key) {
	      return getMapData(this, key).has(key);
	  };

	  MapCache.prototype.set = function set (key, value) {
	      var data = getMapData(this, key);
	      var size = data.size;

	      data.set(key, value);
	      this.size += data.size == size ? 0 : 1;
	      return this;
	  };

	var Hash = function Hash(entries) {
	      var index = -1;
	      var length = entries == null ? 0 : entries.length;

	      this.clear();
	      while (++index < length) {
	          var entry = entries[index];
	          this.set(entry[0], entry[1]);
	      }
	  };

	  Hash.prototype.clear = function clear () {
	      this.__data__ = Object.create(null);
	      this.size = 0;
	  };

	  Hash.prototype.delete = function delete$4 (key) {
	      var result = this.has(key) && delete this.__data__[key];
	      this.size -= result ? 1 : 0;
	      return result;
	  };

	  Hash.prototype.get = function get (key) {
	      var data = this.__data__;
	      var result = data[key];
	      return result === HASH_UNDEFINED ? undefined : result;
	  };

	  Hash.prototype.has = function has (key) {
	      var data = this.__data__;
	      return data[key] !== undefined;
	  };

	  Hash.prototype.set = function set (key, value) {
	      var data = this.__data__;
	      this.size += this.has(key) ? 0 : 1;
	      data[key] = value === undefined ? HASH_UNDEFINED : value;
	      return this;
	  };

	var SetCache = function SetCache(values) {
	      var index = -1;
	      var length = values == null ? 0 : values.length;

	      this.__data__ = new MapCache;
	      while (++index < length) {
	          this.add(values[index]);
	      }
	  };

	  SetCache.prototype.add = function add (value) {
	      this.__data__.set(value, HASH_UNDEFINED);
	      return this;
	  };

	  SetCache.prototype.has = function has (value) {
	      return this.__data__.has(value);
	  };

	SetCache.prototype.push = SetCache.prototype.add;

	// -- top level functions

	var isBoolean = function(value) {
	    var toString = Object.prototype.toString;
	    return value === true || value === false || (!!value && typeof value === 'object' && toString.call(value) === boolTag);
	};

	var isObject$1 = function(value) {
	    return !!value && (typeof value === 'object' || typeof value === 'function');
	};

	var isNumber = function(value) {
	    var toString = Object.prototype.toString;
	    return typeof value === 'number' || (!!value && typeof value === 'object' && toString.call(value) === numberTag);
	};

	var isString = function(value) {
	    var toString = Object.prototype.toString;
	    return typeof value === 'string' || (!!value && typeof value === 'object' && toString.call(value) === stringTag);
	};

	var assign = createAssigner(function (object, source) {
	    if (isPrototype(source) || isArrayLike(source)) {
	        copyObject(source, keys$1(source), object);
	        return;
	    }
	    for (var key in source) {
	        if (hasOwnProperty.call(source, key)) {
	            assignValue(object, key, source[key]);
	        }
	    }
	});

	var mixin = assign;

	var deepMixin = mixin;

	var supplement = function (object) {
	    var sources = [], len = arguments.length - 1;
	    while ( len-- > 0 ) sources[ len ] = arguments[ len + 1 ];

	    var index = -1;
	    var length = sources.length;
	    var guard = length > 2 ? sources[2] : undefined;

	    if (guard && isIterateeCall(sources[0], sources[1], guard)) {
	        length = 1;
	    }

	    while (++index < length) {
	        var source = sources[index];

	        if (source == null) {
	            continue;
	        }

	        var props = Object.keys(source);
	        var propsLength = props.length;
	        var propsIndex = -1;

	        while (++propsIndex < propsLength) {
	            var key = props[propsIndex];
	            var value = object[key];

	            if (value === undefined ||
	                (eq(value, Object.prototype[key]) && !hasOwnProperty.call(object, key))) {
	                object[key] = source[key];
	            }
	        }
	    }

	    return object;
	};

	var defaults = supplement;

	var deepSupplement = function defaultsDeep() {
	    var args = [], len = arguments.length;
	    while ( len-- ) args[ len ] = arguments[ len ];

	    args.push(undefined, customDefaultsMerge);
	    return merge.apply(undefined, args);
	};

	var defaultsDeep = deepSupplement;

	// _.invokeMap
	var invoke = function (collection, path) {
	    var args = [], len = arguments.length - 2;
	    while ( len-- > 0 ) args[ len ] = arguments[ len + 2 ];

	    var index = -1;
	    var isFunc = typeof path === 'function';
	    var result = isArrayLike(collection) ? new Array(collection.length) : [];

	    baseEach(collection, function (value) {
	        result[++index] = isFunc ? path.apply(value, args) : invokeProperty.apply(void 0, [ value, path ].concat( args ));
	    });

	    return result;
	};

	// _.invoke
	var invokeProperty = function (object, path) {
	    var args = [], len = arguments.length - 2;
	    while ( len-- > 0 ) args[ len ] = arguments[ len + 2 ];

	    path = castPath(path, object);
	    object = parent(object, path);
	    var func = object == null ? object : object[toKey(last(path))];
	    return func == null ? undefined : func.apply(object, args);
	};

	var sortedIndex = function (array, value, iteratee) {
	    var low = 0;
	    var high = array == null ? 0 : array.length;
	    if (high == 0) {
	        return 0;
	    }

	    iteratee = getIteratee(iteratee, 2);
	    value = iteratee(value);

	    var valIsNaN = value !== value;
	    var valIsNull = value === null;
	    var valIsSymbol = isSymbol(value);
	    var valIsUndefined = value === undefined;

	    while (low < high) {
	        var setLow = (void 0);
	        var mid = Math.floor((low + high) / 2);
	        var computed = iteratee(array[mid]);
	        var othIsDefined = computed !== undefined;
	        var othIsNull = computed === null;
	        var othIsReflexive = computed === computed;
	        var othIsSymbol = isSymbol(computed);

	        if (valIsNaN) {
	            setLow = othIsReflexive;
	        } else if (valIsUndefined) {
	            setLow = othIsReflexive &&othIsDefined;
	        } else if (valIsNull) {
	            setLow = othIsReflexive && othIsDefined && !othIsNull;
	        } else if (valIsSymbol) {
	            setLow = othIsReflexive && othIsDefined && !othIsNull && !othIsSymbol;
	        } else if (othIsNull || othIsSymbol) {
	            setLow = false;
	        } else {
	            setLow = computed < value;
	        }
	        if (setLow) {
	            low = mid + 1;
	        } else {
	            high = mid;
	        }
	    }
	    return Math.min(high, MAX_ARRAY_INDEX);
	};

	var uniq = function (array, iteratee) {
	    var index = -1;
	    var includes = function (array, value) {
	        var length = array == null ? 0 : array.length;
	        return !!length && array.indexOf(value) > -1;
	    };
	    iteratee = getIteratee(iteratee, 2);
	    var isCommon = true;

	    var length = array.length;
	    var result = [];
	    var seen = result;

	    if (length >= LARGE_ARRAY_SIZE) {
	        var set = iteratee ? null : createSet(array);
	        if (set) {
	            return setToArray(set);
	        }
	        isCommon = false;
	        includes = function (cache, key) { return cache.has(key); };
	        seen = new SetCache;
	    } else {
	        seen = iteratee ? [] : result;
	    }
	    outer:
	    while (++index < length) {
	        var value = array[index];
	        var computed = iteratee ? iteratee(value) : value;

	        value = (value !== 0) ? value : 0;
	        if (isCommon && computed === computed) {
	            var seenIndex = seen.length;
	            while (seenIndex--) {
	                if (seen[seenIndex] === computed) {
	                    continue outer;
	                }
	            }
	            if (iteratee) {
	                seen.push(computed);
	            }
	            result.push(value);
	        }
	        else if (!includes(seen, computed)) {
	            if (seen !== result) {
	                seen.push(computed);
	            }
	            result.push(value);
	        }
	    }
	    return result;
	};

	var clone = function (value) { return baseClone(value); };

	var cloneDeep = function (value) { return baseClone(value, true); };

	var isEmpty = function (value) {
	    if (value == null) {
	        return true;
	    }
	    if (isArrayLike(value) &&
	        (Array.isArray(value) || typeof value === 'string' || typeof value.splice === 'function' ||
	            isTypedArray(value) || isArguments(value))) {
	        return !value.length;
	    }
	    var tag = getTag(value);
	    if (tag == '[object Map]' || tag == '[object Set]') {
	        return !value.size;
	    }
	    if (isPrototype(value)) {
	        return !baseKeys(value).length;
	    }
	    for (var key in value) {
	        if (hasOwnProperty.call(value, key)) {
	            return false;
	        }
	    }
	    return true;
	};
	var isEqual = function (object, other) { return baseIsEqual(object, other); };

	var isFunction = function (value) { return typeof value === 'function'; };

	var isPlainObject = function (value) {
	    if (!isObjectLike(value) || getTag(value) != '[object Object]') {
	        return false;
	    }
	    if (Object.getPrototypeOf(value) === null) {
	        return true;
	    }
	    var proto = value;
	    while (Object.getPrototypeOf(proto) !== null) {
	        proto = Object.getPrototypeOf(proto);
	    }
	    return Object.getPrototypeOf(value) === proto;
	};

	var toArray = function (value) {
	    if (!value) {
	        return [];
	    }

	    if (isArrayLike(value)) {
	        return isString(value) ? stringToArray(value) : copyArray(value);
	    }

	    if (Symbol.iterator && Symbol.iterator in Object(value)) {
	        var iterator = value[Symbol.iterator]();
	        var data;
	        var result = [];

	        while (!(data = iterator.next()).done) {
	            result.push(data.value);
	        }
	        return result;
	    }

	    var tag = getTag(value);
	    var func = tag == mapTag ? mapToArray : (tag == setTag ? setToArray : values);

	    return func(value);
	};

	function debounce(func, wait, opt) {
	    if (typeof func !== 'function') {
	        throw new TypeError('Expected a function');
	    }

	    var lastArgs;
	    var lastThis;
	    var maxWait;
	    var result;
	    var timerId;
	    var lastCallTime;
	    var lastInvokeTime = 0;
	    var leading = false;
	    var maxing = false;
	    var trailing = true;

	    var useRaf = (!wait && wait !== 0 && window && typeof window.requestAnimationFrame === 'function');

	    wait = +wait || 0;

	    if (isObject$1(opt)) {
	        leading = !!opt.leading;
	        maxing = 'maxWait' in opt;
	        maxWait = maxing ? Math.max(+opt.maxWait || 0, wait) : maxWait;
	        trailing = 'trailing' in opt ? !!opt.trailing : trailing;
	    }

	    function invokeFunc(time) {
	        var args = lastArgs;
	        var thisArg = lastThis;

	        lastArgs = lastThis = undefined;
	        lastInvokeTime = time;
	        result = func.apply(thisArg, args);
	        return result;
	    }

	    function startTimer(pendingFunc, wait) {
	        if (useRaf) {
	            window.cancelAnimationFrame(timerId);
	            return window.requestAnimationFrame(pendingFunc);
	        }
	        return setTimeout(pendingFunc, wait);
	    }

	    function cancelTimer(id) {
	        if (useRaf) {
	            return window.cancelAnimationFrame(id);
	        }
	        clearTimeout(id);
	    }

	    function leadingEdge(time) {
	        lastInvokeTime = time;
	        timerId = startTimer(timerExpired, wait);
	        return leading ? invokeFunc(time) : result;
	    }

	    function remainingWait(time) {
	        var timeSinceLastCall = time - lastCallTime;
	        var timeSinceLastInvoke = time - lastInvokeTime;
	        var timeWaiting = wait - timeSinceLastCall;

	        return maxing ? Math.min(timeWaiting, maxWait - timeSinceLastInvoke) : timeWaiting;
	    }

	    function shouldInvoke(time) {
	        var timeSinceLastCall = time - lastCallTime;
	        var timeSinceLastInvoke = time - lastInvokeTime;

	        return (lastCallTime === undefined || (timeSinceLastCall >= wait) || (timeSinceLastCall < 0) ||
	            (maxing && timeSinceLastInvoke >= maxWait));
	    }

	    function timerExpired() {
	        var time = Date.now();
	        if (shouldInvoke(time)) {
	            return trailingEdge(time);
	        }
	        timerId = startTimer(timerExpired, remainingWait(time));
	    }

	    function trailingEdge(time) {
	        timerId = undefined;

	        if (trailing && lastArgs) {
	            return invokeFunc(time);
	        }
	        lastArgs = lastThis = undefined;
	        return result;
	    }

	    function debounced() {
	        var args = [], len = arguments.length;
	        while ( len-- ) args[ len ] = arguments[ len ];

	        var time = Date.now();
	        var isInvoking = shouldInvoke(time);

	        lastArgs = args;
	        lastThis = this;
	        lastCallTime = time;

	        if (isInvoking) {
	            if (timerId === undefined) {
	                return leadingEdge(lastCallTime);
	            }
	            if (maxing) {
	                timerId = startTimer(timerExpired, wait);
	                return invokeFunc(lastCallTime);
	            }
	        }
	        if (timerId === undefined) {
	            timerId = startTimer(timerExpired, wait);
	        }
	        return result;
	    }

	    debounced.cancel = function () {
	        if (timerId !== undefined) {
	            cancelTimer(timerId);
	        }
	        lastInvokeTime = 0;
	        lastArgs = lastCallTime = lastThis = timerId = undefined;
	    };
	    debounced.flush = function () { return timerId === undefined ? result : trailingEdge(Date.now()); };
	    debounced.pending = function () { return timerId !== undefined; };

	    return debounced;
	}

	var groupBy = function (collection, iteratee) {
	    iteratee = getIteratee(iteratee, 2);

	    return reduce(collection, function (result, value, key) {
	        key = iteratee(value);
	        if (hasOwnProperty.call(result, key)) {
	            result[key].push(value);
	        } else {
	            assignValue(result, key, [value]);
	        }
	        return result;
	    }, {});
	};

	var sortBy = function (collection, iteratees) {
	    if ( iteratees === void 0 ) iteratees = [];

	    if (collection == null) {
	        return [];
	    }

	    var length = iteratees.length;
	    if (length > 1 && isIterateeCall(collection, iteratees[0], iteratees[1])) {
	        iteratees = [];
	    } else if (length > 2 && isIterateeCall(iteratees[0], iteratees[1], iteratees[2])) {
	        iteratees = [iteratees[0]];
	    }

	    if (!Array.isArray(iteratees)) {
	        iteratees = [getIteratee(iteratees, 2)];
	    }

	    return baseOrderBy(collection, iteratees.flat(1), []);
	};

	var flattenDeep = function (array) {
	    var length = array == null ? 0 : array.length;
	    return length ? baseFlatten(array, Infinity) : [];
	};

	var without = function (array) {
	  var values = [], len = arguments.length - 1;
	  while ( len-- > 0 ) values[ len ] = arguments[ len + 1 ];

	  return isArrayLike(array) ? diff(array, values) : [];
	};

	var difference = function (array) {
	      var values = [], len = arguments.length - 1;
	      while ( len-- > 0 ) values[ len ] = arguments[ len + 1 ];

	      return isObjectLike(array) && isArrayLike(array) ?
	        diff(array, values.flat(1)) : [];
	};

	var intersection$1 = function () {
	    var arrays = [], len = arguments.length;
	    while ( len-- ) arrays[ len ] = arguments[ len ];

	    var mapped = arrays.map(function (array) { return isObjectLike(array) && isArrayLike(array) ?
	            array : []; }
	    );

	    return mapped.length && mapped[0] === arrays[0] ?
	        intersect(mapped) : [];
	};

	var union = function () {
	    var arrays = [], len = arguments.length;
	    while ( len-- ) arrays[ len ] = arguments[ len ];

	    var array = arrays.flat(1);
	    return uniq(array);
	};

	var has$2 = function (object, key) {
	    if (object == null) {
	        return false;
	    }

	    if (typeof key === 'string') {
	        key = key.split('.');
	    }

	    var index = -1;
	    var value = object;

	    while (++index < key.length) {
	        if (!value || !hasOwnProperty.call(value, key[index])) {
	            return false;
	        }
	        value = value[key[index]];
	    }

	    return true;
	};

	var result = function (object, path, defaultValue) {
	    path = castPath(path, object);

	    var index = -1;
	    var length = path.length;

	    if (!length) {
	        length = 1;
	        object = undefined;
	    }
	    while (++index < length) {
	        var value = object == null ? undefined : object[toKey(path[index])];
	        if (value === undefined) {
	            index = length;
	            value = defaultValue;
	        }
	        object = typeof value === 'function' ? value.call(object) : value;
	    }
	    return object;
	};

	var omit = function (object) {
	    var paths = [], len = arguments.length - 1;
	    while ( len-- > 0 ) paths[ len ] = arguments[ len + 1 ];

	    var result = {};
	    if (object == null) {
	        return result;
	    }
	    var isDeep = false;
	    paths = paths.flat(1).map(function (path) {
	        path = castPath(path, object);
	        isDeep || (isDeep = path.length > 1);
	        return path;
	    });
	    copyObject(object, getAllKeysIn(object), result);
	    if (isDeep) {
	        result = baseClone(result, true, true, true, function (value) { return isPlainObject(value) ? undefined : value; });
	    }
	    var length = paths.length;
	    while (length--) {
	        unset(result, paths[length]);
	    }
	    return result;
	};

	var pick = function (object) {
	    var paths = [], len = arguments.length - 1;
	    while ( len-- > 0 ) paths[ len ] = arguments[ len + 1 ];

	    return object == null ? {} : basePick(object, paths.flat(Infinity));
	};

	var bindAll = function (object) {
	    var methodNames = [], len = arguments.length - 1;
	    while ( len-- > 0 ) methodNames[ len ] = arguments[ len + 1 ];

	    methodNames.flat(1).forEach(function (key) {
	        key = toKey(key);
	        assignValue(object, key, object[key].bind(object));
	    });
	    return object;
	};

	var forIn = function (object, iteratee) {
	    if ( iteratee === void 0 ) iteratee = function (value) { return value; };

	    var index = -1;
	    var iterable = Object(object);
	    var props = isArrayLike(object) ? arrayLikeKeys(object, true) : keysIn(object);
	    var length = props.length;

	    while(length--) {
	        var key = props[++index];
	        if (iteratee(iterable[key], key, iterable) === false) {
	            break;
	        }
	    }
	};

	var camelCase = function (string) {
	  if ( string === void 0 ) string = '';

	  return (
	    words(("" + string).replace(/['\u2019]/g, ''))
	        .reduce(function (result, word, index) {
	            word = word.toLowerCase();
	            return result + (index ? upperFirst(word) : word);
	        }, '')
	);
	};

	var idCounter = 0;

	var uniqueId = function (prefix) {
	    if ( prefix === void 0 ) prefix = '';

	    var id = ++idCounter;
	    return "" + prefix + id;
	};

	var merge = createAssigner(function (object, source, srcIndex, customizer) {
	    baseMerge(object, source, srcIndex, customizer);
	}, true);

	var Data = function Data() {
	    this.map = new WeakMap();
	};

	Data.prototype.has = function has (obj, key) {
	    if (key === undefined) { return this.map.has(obj); }
	    return key in this.map.get(obj);
	};

	Data.prototype.create = function create (obj) {
	    if (!this.has(obj)) { this.map.set(obj, Object.create(null)); }
	    return this.get(obj);
	};

	Data.prototype.get = function get (obj, key) {
	    if (!this.has(obj)) { return undefined; }
	    var data = this.map.get(obj);
	    if (key === undefined) { return data; }
	    return data[key];
	};

	Data.prototype.set = function set (obj, key, value) {
	    if (key === undefined) { return; }
	    var data = this.create(obj);
	    if (typeof key === 'string') {
	        data[key] = value;
	    } else {
	        Object.assign(data, key);
	    }
	};

	Data.prototype.remove = function remove (obj, key) {
	    if (!this.has(obj)) { return; }
	    if (key === undefined) {
	        this.map.delete(obj);
	    } else {
	        var data = this.map.get(obj);
	        delete data[key];
	    }
	};

	var dataPriv = new Data();

	var dataUser = new Data();

	var Event = function(src, props) {
	    // Allow instantiation without the 'new' keyword
	    if (!(this instanceof Event)) {
	        return new Event(src, props);
	    }

	    // Event object
	    if (src && src.type) {
	        this.originalEvent = src;
	        this.type = src.type;

	        // Events bubbling up the document may have been marked as prevented
	        // by a handler lower down the tree; reflect the correct value.
	        this.isDefaultPrevented = src.defaultPrevented
	            ? returnTrue
	            : returnFalse;

	        // Create target properties
	        this.target = src.target;
	        this.currentTarget = src.currentTarget;
	        this.relatedTarget = src.relatedTarget;

	        // Event type
	    } else {
	        this.type = src;
	    }

	    // Put explicitly provided properties onto the event object
	    if (props) {
	        Object.assign(this, props);
	    }

	    // Create a timestamp if incoming event doesn't have one
	    this.timeStamp = (src && src.timeStamp) || Date.now();

	    // Mark it as fixed
	    this.envelope = true;
	};

	// $.Event is based on DOM3 Events as specified by the ECMAScript Language Binding
	// https://www.w3.org/TR/2003/WD-DOM-Level-3-Events-20030331/ecma-script-binding.html
	Event.prototype = {
	    constructor: Event,
	    isDefaultPrevented: returnFalse,
	    isPropagationStopped: returnFalse,
	    isImmediatePropagationStopped: returnFalse,
	    preventDefault: function() {
	        var evt = this.originalEvent;
	        this.isDefaultPrevented = returnTrue;
	        if (evt) {
	            evt.preventDefault();
	        }
	    },
	    stopPropagation: function() {
	        var evt = this.originalEvent;
	        this.isPropagationStopped = returnTrue;
	        if (evt) {
	            evt.stopPropagation();
	        }
	    },
	    stopImmediatePropagation: function() {
	        var evt = this.originalEvent;
	        this.isImmediatePropagationStopped = returnTrue;
	        if (evt) {
	            evt.stopImmediatePropagation();
	        }
	        this.stopPropagation();
	    },
	};

	// Includes all common event props including KeyEvent and MouseEvent specific props
	[
	    'altKey',
	    'bubbles',
	    'cancelable',
	    'changedTouches',
	    'ctrlKey',
	    'detail',
	    'eventPhase',
	    'metaKey',
	    'pageX',
	    'pageY',
	    'shiftKey',
	    'view',
	    'char',
	    'code',
	    'charCode',
	    'key',
	    'keyCode',
	    'button',
	    'buttons',
	    'clientX',
	    'clientY',
	    'offsetX',
	    'offsetY',
	    'pointerId',
	    'pointerType',
	    'screenX',
	    'screenY',
	    'targetTouches',
	    'toElement',
	    'touches',
	    'which' ].forEach(function (name) { return addProp(name); });

	function addProp(name) {
	    Object.defineProperty(Event.prototype, name, {
	        enumerable: true,
	        configurable: true,
	        get: function() {
	            return this.originalEvent ? this.originalEvent[name] : undefined;
	        },
	        set: function(value) {
	            Object.defineProperty(this, name, {
	                enumerable: true,
	                configurable: true,
	                writable: true,
	                value: value,
	            });
	        },
	    });
	}

	function returnTrue() {
	    return true;
	}

	function returnFalse() {
	    return false;
	}

	var document$2 = (typeof window !== 'undefined') ? window.document : null;
	var documentElement = document$2 && document$2.documentElement;

	var rTypeNamespace = /^([^.]*)(?:\.(.+)|)/;

	// Only count HTML whitespace
	// Other whitespace should count in values
	// https://infra.spec.whatwg.org/#ascii-whitespace
	var rNotHtmlWhite = /[^\x20\t\r\n\f]+/g;

	// Define a local copy of $
	var $ = function(selector) {
	    // The $ object is actually just the init constructor 'enhanced'
	    // Need init if $ is called (just allow error to be thrown if not included)
	    return new $.Dom(selector);
	};

	$.fn = $.prototype = {
	    constructor: $,
	    // The default length of a $ object is 0
	    length: 0,
	};

	// A global GUID counter for objects
	$.guid = 1;

	// User data storage
	$.data = dataUser;

	$.merge = function(first, second) {
	    var len = +second.length;
	    var i = first.length;
	    for (var j = 0; j < len; j++) {
	        first[i++] = second[j];
	    }
	    first.length = i;
	    return first;
	};

	$.parseHTML = function(string) {
	    // Inline events will not execute when the HTML is parsed; this includes, for example, sending GET requests for images.
	    var context = document$2.implementation.createHTMLDocument();
	    // Set the base href for the created document so any parsed elements with URLs
	    // are based on the document's URL
	    var base = context.createElement('base');
	    base.href = document$2.location.href;
	    context.head.appendChild(base);

	    context.body.innerHTML = string;
	    // remove scripts
	    var scripts = context.getElementsByTagName('script');
	    for (var i = 0; i < scripts.length; i++) {
	        scripts[i].remove();
	    }
	    return Array.from(context.body.childNodes);
	};

	if (typeof Symbol === 'function') {
	    $.fn[Symbol.iterator] = Array.prototype[Symbol.iterator];
	}

	$.fn.toArray = function() {
	    return Array.from(this);
	};

	// Take an array of elements and push it onto the stack
	// (returning the new matched element set)
	$.fn.pushStack = function(elements) {
	    // Build a new $ matched element set
	    var ret = $.merge(this.constructor(), elements);
	    // Add the old object onto the stack (as a reference)
	    ret.prevObject = this;
	    // Return the newly-formed element set
	    return ret;
	};

	$.fn.find = function(selector) {
	    var ref = this;
	    var el = ref[0];
	    var ret = this.pushStack([]);
	    if (!el) { return ret; }
	    // Early return if context is not an element, document or document fragment
	    var nodeType = el.nodeType;
	    if (nodeType !== 1 && nodeType !== 9 && nodeType !== 11) {
	        return ret;
	    }
	    if (typeof selector !== 'string') {
	        if (el !== selector && el.contains(selector)) {
	            $.merge(ret, [selector]);
	        }
	    } else {
	        $.merge(ret, el.querySelectorAll(selector));
	    }
	    return ret;
	};

	$.fn.add = function(selector, context) {
	    var newElements = $(selector, context).toArray();
	    var prevElements = this.toArray();
	    var ret = this.pushStack([]);
	    $.merge(ret, uniq(prevElements.concat(newElements)));
	    return ret;
	};

	$.fn.addBack = function() {
	    return this.add(this.prevObject);
	};

	$.fn.filter = function(selector) {
	    var matches = [];
	    for (var i = 0; i < this.length; i++) {
	        var node = this[i];
	        if (!node.matches(selector)) { continue; }
	        matches.push(node);
	    }
	    return this.pushStack(matches);
	};

	// A simple way to check for HTML strings
	// Prioritize #id over <tag> to avoid XSS via location.hash (trac-9521)
	// Strict HTML recognition (trac-11290: must start with <)
	// Shortcut simple #id case for speed
	var rQuickExpr = /^(?:\s*(<[\w\W]+>)[^>]*|#([\w-]+))$/;

	function isObviousHtml(input) {
	    return (
	        input[0] === '<' && input[input.length - 1] === '>' && input.length >= 3
	    );
	}

	var Dom = function(selector) {
	    if (!selector) {
	        // HANDLE: $(""), $(null), $(undefined), $(false)
	        return this;
	    }
	    if (typeof selector === 'function') {
	        // HANDLE: $(function)
	        // Shortcut for document ready
	        throw new Error('function not supported');
	    }
	    if (arguments.length > 1) {
	        throw new Error('selector with context not supported');
	    }
	    if (selector.nodeType) {
	        // HANDLE: $(DOMElement)
	        this[0] = selector;
	        this.length = 1;
	        return this;
	    }
	    var match;
	    if (isObviousHtml(selector + '')) {
	        // Handle obvious HTML strings
	        // Assume that strings that start and end with <> are HTML and skip
	        // the regex check. This also handles browser-supported HTML wrappers
	        // like TrustedHTML.
	        match = [null, selector, null];
	    } else if (typeof selector === 'string') {
	        // Handle HTML strings or selectors
	        match = rQuickExpr.exec(selector);
	    } else {
	        // Array-like
	        return $.merge(this, selector);
	    }
	    if (!match || !match[1]) {
	        // HANDLE: $(expr)
	        return $root.find(selector);
	    }
	    // Match html or make sure no context is specified for #id
	    // Note: match[1] may be a string or a TrustedHTML wrapper
	    if (match[1]) {
	        // HANDLE: $(html) -> $(array)
	        $.merge(this, $.parseHTML(match[1]));
	        return this;
	    }
	    // HANDLE: $(#id)
	    var el = document$2.getElementById(match[2]);
	    if (el) {
	        // Inject the element directly into the $ object
	        this[0] = el;
	        this.length = 1;
	    }
	    return this;
	};

	$.Dom = Dom;

	// Give the init function the $ prototype for later instantiation
	Dom.prototype = $.fn;

	// Events

	$.Event = Event;

	$.event = {
	    special: Object.create(null),
	};

	$.event.has = function(elem, eventType) {
	    var events = dataPriv.get(elem, 'events');
	    if (!events) { return false; }
	    if (!eventType) { return true; }
	    return Array.isArray(events[eventType]) && events[eventType].length > 0;
	};

	$.event.on = function(elem, types, selector, data, fn, one) {

	    // Types can be a map of types/handlers
	    if (typeof types === 'object') {
	        // ( types-Object, selector, data )
	        if (typeof selector !== 'string') {
	            // ( types-Object, data )
	            data = data || selector;
	            selector = undefined;
	        }
	        for (var type in types) {
	            $.event.on(elem, type, selector, data, types[type], one);
	        }
	        return elem;
	    }

	    if (data == null && fn == null) {
	        // ( types, fn )
	        fn = selector;
	        data = selector = undefined;
	    } else if (fn == null) {
	        if (typeof selector === 'string') {
	            // ( types, selector, fn )
	            fn = data;
	            data = undefined;
	        } else {
	            // ( types, data, fn )
	            fn = data;
	            data = selector;
	            selector = undefined;
	        }
	    }
	    if (!fn) {
	        return elem;
	    }
	    if (one === 1) {
	        var origFn = fn;
	        fn = function(event) {
	            // Can use an empty set, since event contains the info
	            $().off(event);
	            return origFn.apply(this, arguments);
	        };

	        // Use same guid so caller can remove using origFn
	        fn.guid = origFn.guid || (origFn.guid = $.guid++);
	    }
	    for (var i = 0; i < elem.length; i++) {
	        $.event.add(elem[i], types, fn, data, selector);
	    }
	};

	$.event.add = function(elem, types, handler, data, selector) {
	    // Only attach events to objects for which we can store data
	    if (typeof elem != 'object') {
	        return;
	    }

	    var elemData = dataPriv.create(elem);

	    // Caller can pass in an object of custom data in lieu of the handler
	    var handleObjIn;
	    if (handler.handler) {
	        handleObjIn = handler;
	        handler = handleObjIn.handler;
	        selector = handleObjIn.selector;
	    }

	    // Ensure that invalid selectors throw exceptions at attach time
	    // Evaluate against documentElement in case elem is a non-element node (e.g., document)
	    if (selector) {
	        documentElement.matches(selector);
	    }

	    // Make sure that the handler has a unique ID, used to find/remove it later
	    if (!handler.guid) {
	        handler.guid = $.guid++;
	    }

	    // Init the element's event structure and main handler, if this is the first
	    var events;
	    if (!(events = elemData.events)) {
	        events = elemData.events = Object.create(null);
	    }
	    var eventHandle;
	    if (!(eventHandle = elemData.handle)) {
	        eventHandle = elemData.handle = function(e) {
	            // Discard the second event of a $.event.trigger() and
	            // when an event is called after a page has unloaded
	            return (typeof $ !== 'undefined')
	                ? $.event.dispatch.apply(elem, arguments)
	                : undefined;
	        };
	    }

	    // Handle multiple events separated by a space
	    var typesArr = (types || '').match(rNotHtmlWhite) || [''];
	    var i = typesArr.length;
	    while (i--) {
	        var ref = rTypeNamespace.exec(typesArr[i]);
	        var origType = ref[1];
	        var ns = ref[2]; if ( ns === void 0 ) ns = '';
	        // There *must* be a type, no attaching namespace-only handlers
	        if (!origType) {
	            continue;
	        }

	        var namespaces = ns.split('.').sort();
	        // If event changes its type, use the special event handlers for the changed type
	        var special = $.event.special[origType];
	        // If selector defined, determine special event api type, otherwise given type
	        var type = (special && (selector ? special.delegateType : special.bindType)) || origType;
	        // Update special based on newly reset type
	        special = $.event.special[type];
	        // handleObj is passed to all event handlers
	        var handleObj = Object.assign(
	            {
	                type: type,
	                origType: origType,
	                data: data,
	                handler: handler,
	                guid: handler.guid,
	                selector: selector,
	                namespace: namespaces.join('.'),
	            },
	            handleObjIn
	        );

	        var handlers = (void 0);
	        // Init the event handler queue if we're the first
	        if (!(handlers = events[type])) {
	            handlers = events[type] = [];
	            handlers.delegateCount = 0;

	            // Only use addEventListener if the special events handler returns false
	            if (
	                !special || !special.setup ||
	                    special.setup.call(elem, data, namespaces, eventHandle) === false
	            ) {
	                if (elem.addEventListener) {
	                    elem.addEventListener(type, eventHandle);
	                }
	            }
	        }

	        if (special && special.add) {
	            special.add.call(elem, handleObj);
	            if (!handleObj.handler.guid) {
	                handleObj.handler.guid = handler.guid;
	            }
	        }

	        // Add to the element's handler list, delegates in front
	        if (selector) {
	            handlers.splice(handlers.delegateCount++, 0, handleObj);
	        } else {
	            handlers.push(handleObj);
	        }
	    }
	};

	// Detach an event or set of events from an element
	$.event.remove = function(elem, types, handler, selector, mappedTypes) {

	    var elemData = dataPriv.get(elem);
	    if (!elemData || !elemData.events) { return; }
	    var events = elemData.events;

	    // Once for each type.namespace in types; type may be omitted
	    var typesArr = (types || '').match(rNotHtmlWhite) || [''];
	    var i = typesArr.length;
	    while (i--) {
	        var ref = rTypeNamespace.exec(typesArr[i]);
	        var origType = ref[1];
	        var ns = ref[2]; if ( ns === void 0 ) ns = '';
	        // Unbind all events (on this namespace, if provided) for the element
	        if (!origType) {
	            for (var type in events) {
	                $.event.remove(
	                    elem,
	                    type + typesArr[i],
	                    handler,
	                    selector,
	                    true
	                );
	            }
	            continue;
	        }

	        var special = $.event.special[origType];
	        var type$1 = (special && (selector ? special.delegateType : special.bindType)) || origType;
	        var handlers = events[type$1];
	        if (!handlers || handlers.length === 0) { continue; }

	        var namespaces = ns.split('.').sort();
	        var rNamespace = ns
	            ? new RegExp('(^|\\.)' + namespaces.join('\\.(?:.*\\.|)') + '(\\.|$)')
	            : null;

	        // Remove matching events
	        var origCount = handlers.length;
	        var j = origCount;
	        while (j--) {
	            var handleObj = handlers[j];

	            if (
	                (mappedTypes || origType === handleObj.origType) &&
	                    (!handler || handler.guid === handleObj.guid) &&
	                    (!rNamespace || rNamespace.test(handleObj.namespace)) &&
	                    (!selector ||
	                        selector === handleObj.selector ||
	                        (selector === '**' && handleObj.selector))
	            ) {
	                handlers.splice(j, 1);
	                if (handleObj.selector) {
	                    handlers.delegateCount--;
	                }
	                if (special && special.remove) {
	                    special.remove.call(elem, handleObj);
	                }
	            }
	        }

	        // Remove generic event handler if we removed something and no more handlers exist
	        // (avoids potential for endless recursion during removal of special event handlers)
	        if (origCount && handlers.length === 0) {
	            if (
	                !special || !special.teardown ||
	                    special.teardown.call(elem, namespaces, elemData.handle) === false
	            ) {
	                // This "if" is needed for plain objects
	                if (elem.removeEventListener) {
	                    elem.removeEventListener(type$1, elemData.handle);
	                }
	            }
	            delete events[type$1];
	        }
	    }

	    // Remove data if it's no longer used
	    if (isEmpty(events)) {
	        dataPriv.remove(elem, 'handle');
	        dataPriv.remove(elem, 'events');
	    }
	};

	$.event.dispatch = function(nativeEvent) {

	    var elem = this;
	    // Make a writable $.Event from the native event object
	    var event = $.event.fix(nativeEvent);
	    event.delegateTarget = elem;
	    // Use the fix-ed $.Event rather than the (read-only) native event
	    var args = Array.from(arguments);
	    args[0] = event;

	    var eventsData = dataPriv.get(elem, 'events');
	    var handlers = (eventsData && eventsData[event.type]) || [];
	    var special = $.event.special[event.type];

	    // Call the preDispatch hook for the mapped type, and let it bail if desired
	    if (special && special.preDispatch) {
	        if (special.preDispatch.call(elem, event) === false) { return; }
	    }

	    // Determine handlers
	    var handlerQueue = $.event.handlers.call(elem, event, handlers);

	    // Run delegates first; they may want to stop propagation beneath us
	    var i = 0;
	    var matched;
	    while ((matched = handlerQueue[i++]) && !event.isPropagationStopped()) {
	        event.currentTarget = matched.elem;
	        var j = 0;
	        var handleObj = (void 0);
	        while (
	            (handleObj = matched.handlers[j++]) &&
	                !event.isImmediatePropagationStopped()
	        ) {

	            event.handleObj = handleObj;
	            event.data = handleObj.data;

	            var origSpecial = $.event.special[handleObj.origType];
	            var handler = (void 0);
	            if (origSpecial && origSpecial.handle) {
	                handler = origSpecial.handle;
	            } else {
	                handler = handleObj.handler;
	            }

	            var ret = handler.apply(matched.elem, args);
	            if (ret !== undefined) {
	                if ((event.result = ret) === false) {
	                    event.preventDefault();
	                    event.stopPropagation();
	                }
	            }
	        }
	    }

	    // Call the postDispatch hook for the mapped type
	    if (special && special.postDispatch) {
	        special.postDispatch.call(elem, event);
	    }

	    return event.result;
	};

	$.event.handlers = function(event, handlers) {

	    var delegateCount = handlers.delegateCount;
	    var handlerQueue = [];

	    // Find delegate handlers
	    if (
	        delegateCount &&
	            // Support: Firefox <=42 - 66+
	            // Suppress spec-violating clicks indicating a non-primary pointer button (trac-3861)
	            // https://www.w3.org/TR/DOM-Level-3-Events/#event-type-click
	            // Support: IE 11+
	            // ...but not arrow key "clicks" of radio inputs, which can have `button` -1 (gh-2343)
	            !(event.type === 'click' && event.button >= 1)
	    ) {
	        for (var cur = event.target; cur !== this; cur = cur.parentNode || this) {
	            // Don't check non-elements (trac-13208)
	            // Don't process clicks on disabled elements (trac-6911, trac-8165, trac-11382, trac-11764)
	            if (
	                cur.nodeType === 1 &&
	                    !(event.type === 'click' && cur.disabled === true)
	            ) {
	                var matchedHandlers = [];
	                var matchedSelectors = {};
	                for (var i = 0; i < delegateCount; i++) {
	                    var handleObj = handlers[i];
	                    // Don't conflict with Object.prototype properties (trac-13203)
	                    var sel = handleObj.selector + ' ';
	                    if (matchedSelectors[sel] === undefined) {
	                        matchedSelectors[sel] = cur.matches(sel);
	                    }
	                    if (matchedSelectors[sel]) {
	                        matchedHandlers.push(handleObj);
	                    }
	                }
	                if (matchedHandlers.length) {
	                    handlerQueue.push({
	                        elem: cur,
	                        handlers: matchedHandlers,
	                    });
	                }
	            }
	        }
	    }

	    // Add the remaining (directly-bound) handlers
	    if (delegateCount < handlers.length) {
	        handlerQueue.push({
	            elem: this,
	            handlers: handlers.slice(delegateCount),
	        });
	    }

	    return handlerQueue;
	};

	$.event.fix = function(originalEvent) {
	    return originalEvent.envelope ? originalEvent : new Event(originalEvent);
	};

	// A central reference to the root $(document)
	var $root = $(document$2);

	// Vectorizer.

	var V = (function() {

	    var hasSvg = typeof window === 'object' && !!window.SVGAngle;

	    // SVG support is required.
	    if (!hasSvg) {

	        // Return a function that throws an error when it is used.
	        return function() {
	            throw new Error('SVG is required to use Vectorizer.');
	        };
	    }

	    // XML namespaces.
	    var ns = {
	        svg: 'http://www.w3.org/2000/svg',
	        xmlns: 'http://www.w3.org/2000/xmlns/',
	        xml: 'http://www.w3.org/XML/1998/namespace',
	        xlink: 'http://www.w3.org/1999/xlink',
	        xhtml: 'http://www.w3.org/1999/xhtml'
	    };

	    var SVGVersion = '1.1';

	    // Declare shorthands to the most used math functions.
	    var math = Math;
	    var PI = math.PI;
	    var atan2 = math.atan2;
	    var sqrt = math.sqrt;
	    var min = math.min;
	    var max = math.max;
	    var cos = math.cos;
	    var sin = math.sin;

	    var V = function(el, attrs, children) {

	        // This allows using V() without the new keyword.
	        if (!(this instanceof V)) {
	            return V.apply(Object.create(V.prototype), arguments);
	        }

	        if (!el) { return; }

	        if (V.isV(el)) {
	            el = el.node;
	        }

	        attrs = attrs || {};

	        if (V.isString(el)) {

	            el = el.trim();

	            if (el.toLowerCase() === 'svg') {

	                // Create a new SVG canvas.
	                el = V.createSvgDocument();

	            } else if (el[0] === '<') {

	                // Create element from an SVG string.
	                // Allows constructs of type: `document.appendChild(V('<rect></rect>').node)`.

	                var svgDoc = V.createSvgDocument(el);

	                // Note that `V()` might also return an array should the SVG string passed as
	                // the first argument contain more than one root element.
	                if (svgDoc.childNodes.length > 1) {

	                    // Map child nodes to `V`s.
	                    var arrayOfVels = [];
	                    var i, len;

	                    for (i = 0, len = svgDoc.childNodes.length; i < len; i++) {

	                        var childNode = svgDoc.childNodes[i];
	                        arrayOfVels.push(new V(document.importNode(childNode, true)));
	                    }

	                    return arrayOfVels;
	                }

	                el = document.importNode(svgDoc.firstChild, true);

	            } else {

	                el = document.createElementNS(ns.svg, el);
	            }

	            V.ensureId(el);
	        }

	        this.node = el;

	        this.setAttributes(attrs);

	        if (children) {
	            this.append(children);
	        }

	        return this;
	    };

	    var VPrototype = V.prototype;

	    Object.defineProperty(VPrototype, 'id', {
	        enumerable: true,
	        get: function() {
	            return this.node.id;
	        },
	        set: function(id) {
	            this.node.id = id;
	        }
	    });

	    /**
	     * @param {SVGGElement} toElem
	     * @returns {SVGMatrix}
	     */
	    VPrototype.getTransformToElement = function(target) {
	        var node = this.node;
	        if (V.isSVGGraphicsElement(target) && V.isSVGGraphicsElement(node)) {
	            var targetCTM = V.toNode(target).getScreenCTM();
	            var nodeCTM = node.getScreenCTM();
	            if (targetCTM && nodeCTM) {
	                return targetCTM.inverse().multiply(nodeCTM);
	            }
	        }
	        // Could not get actual transformation matrix
	        return V.createSVGMatrix();
	    };

	    /**
	     * @param {SVGMatrix} matrix
	     * @param {Object=} opt
	     * @returns {Vectorizer|SVGMatrix} Setter / Getter
	     */
	    VPrototype.transform = function(matrix, opt) {

	        var node = this.node;
	        if (V.isUndefined(matrix)) {
	            return V.transformStringToMatrix(this.attr('transform'));
	        }

	        if (opt && opt.absolute) {
	            return this.attr('transform', V.matrixToTransformString(matrix));
	        }

	        var svgTransform = V.createSVGTransform(matrix);
	        node.transform.baseVal.appendItem(svgTransform);
	        return this;
	    };

	    VPrototype.translate = function(tx, ty, opt) {

	        opt = opt || {};
	        ty = ty || 0;

	        var transformAttr = this.attr('transform') || '';
	        var transform = V.parseTransformString(transformAttr);
	        transformAttr = transform.value;
	        // Is it a getter?
	        if (V.isUndefined(tx)) {
	            return transform.translate;
	        }

	        transformAttr = transformAttr.replace(/translate\([^)]*\)/g, '').trim();

	        var newTx = opt.absolute ? tx : transform.translate.tx + tx;
	        var newTy = opt.absolute ? ty : transform.translate.ty + ty;
	        var newTranslate = 'translate(' + newTx + ',' + newTy + ')';

	        // Note that `translate()` is always the first transformation. This is
	        // usually the desired case.
	        this.attr('transform', (newTranslate + ' ' + transformAttr).trim());
	        return this;
	    };

	    VPrototype.rotate = function(angle, cx, cy, opt) {

	        opt = opt || {};

	        var transformAttr = this.attr('transform') || '';
	        var transform = V.parseTransformString(transformAttr);
	        transformAttr = transform.value;

	        // Is it a getter?
	        if (V.isUndefined(angle)) {
	            return transform.rotate;
	        }

	        transformAttr = transformAttr.replace(/rotate\([^)]*\)/g, '').trim();

	        angle %= 360;

	        var newAngle = opt.absolute ? angle : transform.rotate.angle + angle;
	        var newOrigin = (cx !== undefined && cy !== undefined) ? ',' + cx + ',' + cy : '';
	        var newRotate = 'rotate(' + newAngle + newOrigin + ')';

	        this.attr('transform', (transformAttr + ' ' + newRotate).trim());
	        return this;
	    };

	    // Note that `scale` as the only transformation does not combine with previous values.
	    VPrototype.scale = function(sx, sy) {

	        sy = V.isUndefined(sy) ? sx : sy;

	        var transformAttr = this.attr('transform') || '';
	        var transform = V.parseTransformString(transformAttr);
	        transformAttr = transform.value;

	        // Is it a getter?
	        if (V.isUndefined(sx)) {
	            return transform.scale;
	        }

	        transformAttr = transformAttr.replace(/scale\([^)]*\)/g, '').trim();

	        var newScale = 'scale(' + sx + ',' + sy + ')';

	        this.attr('transform', (transformAttr + ' ' + newScale).trim());
	        return this;
	    };

	    // Get SVGRect that contains coordinates and dimension of the real bounding box,
	    // i.e. after transformations are applied.
	    // If `target` is specified, bounding box will be computed relatively to `target` element.
	    VPrototype.bbox = function(withoutTransformations, target) {

	        var box;
	        var node = this.node;
	        var ownerSVGElement = node.ownerSVGElement;

	        // If the element is not in the live DOM, it does not have a bounding box defined and
	        // so fall back to 'zero' dimension element.
	        if (!ownerSVGElement) {
	            return new Rect(0, 0, 0, 0);
	        }

	        try {

	            box = node.getBBox();

	        } catch (e) {

	            // Fallback for IE.
	            box = {
	                x: node.clientLeft,
	                y: node.clientTop,
	                width: node.clientWidth,
	                height: node.clientHeight
	            };
	        }

	        if (withoutTransformations) {
	            return new Rect(box);
	        }

	        var matrix = this.getTransformToElement(target || ownerSVGElement);

	        return V.transformRect(box, matrix);
	    };

	    // Returns an SVGRect that contains coordinates and dimensions of the real bounding box,
	    // i.e. after transformations are applied.
	    // Fixes a browser implementation bug that returns incorrect bounding boxes for groups of svg elements.
	    // Takes an (Object) `opt` argument (optional) with the following attributes:
	    // (Object) `target` (optional): if not undefined, transform bounding boxes relative to `target`; if undefined, transform relative to this
	    // (Boolean) `recursive` (optional): if true, recursively enter all groups and get a union of element bounding boxes (svg bbox fix); if false or undefined, return result of native function this.node.getBBox();
	    VPrototype.getBBox = function(opt) {

	        var options = {};

	        var outputBBox;
	        var node = this.node;
	        var ownerSVGElement = node.ownerSVGElement;

	        // If the element is not in the live DOM, it does not have a bounding box defined and
	        // so fall back to 'zero' dimension element.
	        // If the element is not an SVGGraphicsElement, we could not measure the bounding box either
	        if (!ownerSVGElement || !V.isSVGGraphicsElement(node)) {
	            return new Rect(0, 0, 0, 0);
	        }

	        if (opt) {
	            if (opt.target) { // check if target exists
	                options.target = V.toNode(opt.target); // works for V objects, jquery objects, and node objects
	            }
	            if (opt.recursive) {
	                options.recursive = opt.recursive;
	            }
	        }

	        if (!options.recursive) {
	            try {
	                outputBBox = node.getBBox();
	            } catch (e) {
	                // Fallback for IE.
	                outputBBox = {
	                    x: node.clientLeft,
	                    y: node.clientTop,
	                    width: node.clientWidth,
	                    height: node.clientHeight
	                };
	            }

	            if (!options.target) {
	                // transform like this (that is, not at all)
	                return new Rect(outputBBox);
	            } else {
	                // transform like target
	                var matrix = this.getTransformToElement(options.target);
	                return V.transformRect(outputBBox, matrix);
	            }
	        } else { // if we want to calculate the bbox recursively
	            // browsers report correct bbox around svg elements (one that envelops the path lines tightly)
	            // but some browsers fail to report the same bbox when the elements are in a group (returning a looser bbox that also includes control points, like node.getClientRect())
	            // this happens even if we wrap a single svg element into a group!
	            // this option setting makes the function recursively enter all the groups from this and deeper, get bboxes of the elements inside, then return a union of those bboxes

	            var children = this.children();
	            var n = children.length;

	            if (n === 0) {
	                return this.getBBox({ target: options.target, recursive: false });
	            }

	            // recursion's initial pass-through setting:
	            // recursive passes-through just keep the target as whatever was set up here during the initial pass-through
	            if (!options.target) {
	                // transform children/descendants like this (their parent/ancestor)
	                options.target = this;
	            } // else transform children/descendants like target

	            for (var i = 0; i < n; i++) {
	                var currentChild = children[i];

	                var childBBox;

	                // if currentChild is not a group element, get its bbox with a nonrecursive call
	                if (currentChild.children().length === 0) {
	                    childBBox = currentChild.getBBox({ target: options.target, recursive: false });
	                } else {
	                    // if currentChild is a group element (determined by checking the number of children), enter it with a recursive call
	                    childBBox = currentChild.getBBox({ target: options.target, recursive: true });
	                }

	                if (!outputBBox) {
	                    // if this is the first iteration
	                    outputBBox = childBBox;
	                } else {
	                    // make a new bounding box rectangle that contains this child's bounding box and previous bounding box
	                    outputBBox = outputBBox.union(childBBox);
	                }
	            }

	            return outputBBox;
	        }
	    };

	    // Text() helpers

	    function createTextPathNode(attrs, vel) {
	        attrs || (attrs = {});
	        var textPathElement = V('textPath');
	        var d = attrs.d;
	        if (d && attrs['xlink:href'] === undefined) {
	            // If `opt.attrs` is a plain string, consider it to be directly the
	            // SVG path data for the text to go along (this is a shortcut).
	            // Otherwise if it is an object and contains the `d` property, then this is our path.
	            // Wrap the text in the SVG <textPath> element that points
	            // to a path defined by `opt.attrs` inside the `<defs>` element.
	            var linkedPath = V('path').attr('d', d).appendTo(vel.defs());
	            textPathElement.attr('xlink:href', '#' + linkedPath.id);
	        }
	        if (V.isObject(attrs)) {
	            // Set attributes on the `<textPath>`. The most important one
	            // is the `xlink:href` that points to our newly created `<path/>` element in `<defs/>`.
	            // Note that we also allow the following construct:
	            // `t.text('my text', { textPath: { 'xlink:href': '#my-other-path' } })`.
	            // In other words, one can completely skip the auto-creation of the path
	            // and use any other arbitrary path that is in the document.
	            textPathElement.attr(attrs);
	        }
	        return textPathElement.node;
	    }

	    function annotateTextLine(lineNode, lineAnnotations, opt) {
	        opt || (opt = {});
	        var includeAnnotationIndices = opt.includeAnnotationIndices;
	        var eol = opt.eol;
	        var lineHeight = opt.lineHeight;
	        var baseSize = opt.baseSize;
	        var maxFontSize = 0;
	        var fontMetrics = {};
	        var lastJ = lineAnnotations.length - 1;
	        for (var j = 0; j <= lastJ; j++) {
	            var annotation = lineAnnotations[j];
	            var fontSize = null;
	            if (V.isObject(annotation)) {
	                var annotationAttrs = annotation.attrs;
	                var vTSpan = V('tspan', annotationAttrs);
	                var tspanNode = vTSpan.node;
	                var t = annotation.t;
	                if (eol && j === lastJ) { t += eol; }
	                tspanNode.textContent = t;
	                // Per annotation className
	                var annotationClass = annotationAttrs['class'];
	                if (annotationClass) { vTSpan.addClass(annotationClass); }
	                // If `opt.includeAnnotationIndices` is `true`,
	                // set the list of indices of all the applied annotations
	                // in the `annotations` attribute. This list is a comma
	                // separated list of indices.
	                if (includeAnnotationIndices) { vTSpan.attr('annotations', annotation.annotations); }
	                // Check for max font size
	                fontSize = parseFloat(annotationAttrs['font-size']);
	                if (!isFinite(fontSize)) { fontSize = baseSize; }
	                if (fontSize && fontSize > maxFontSize) { maxFontSize = fontSize; }
	            } else {
	                if (eol && j === lastJ) { annotation += eol; }
	                tspanNode = document.createTextNode(annotation || ' ');
	                if (baseSize && baseSize > maxFontSize) { maxFontSize = baseSize; }
	            }
	            lineNode.appendChild(tspanNode);
	        }

	        if (maxFontSize) { fontMetrics.maxFontSize = maxFontSize; }
	        if (lineHeight) {
	            fontMetrics.lineHeight = lineHeight;
	        } else if (maxFontSize) {
	            fontMetrics.lineHeight = (maxFontSize * 1.2);
	        }
	        return fontMetrics;
	    }

	    var emRegex = /em$/;

	    function convertEmToPx(em, fontSize) {
	        var numerical = parseFloat(em);
	        if (emRegex.test(em)) { return numerical * fontSize; }
	        return numerical;
	    }

	    function calculateDY(alignment, linesMetrics, baseSizePx, lineHeight) {
	        if (!Array.isArray(linesMetrics)) { return 0; }
	        var n = linesMetrics.length;
	        if (!n) { return 0; }
	        var lineMetrics = linesMetrics[0];
	        var flMaxFont = convertEmToPx(lineMetrics.maxFontSize, baseSizePx) || baseSizePx;
	        var rLineHeights = 0;
	        var lineHeightPx = convertEmToPx(lineHeight, baseSizePx);
	        for (var i = 1; i < n; i++) {
	            lineMetrics = linesMetrics[i];
	            var iLineHeight = convertEmToPx(lineMetrics.lineHeight, baseSizePx) || lineHeightPx;
	            rLineHeights += iLineHeight;
	        }
	        var llMaxFont = convertEmToPx(lineMetrics.maxFontSize, baseSizePx) || baseSizePx;
	        var dy;
	        switch (alignment) {
	            case 'middle':
	                dy = (flMaxFont / 2) - (0.15 * llMaxFont) - (rLineHeights / 2);
	                break;
	            case 'bottom':
	                dy = -(0.25 * llMaxFont) - rLineHeights;
	                break;
	            default:
	            case 'top':
	                dy = (0.8 * flMaxFont);
	                break;
	        }
	        return dy;
	    }

	    VPrototype.text = function(content, opt) {

	        if (content && typeof content !== 'string') { throw new Error('Vectorizer: text() expects the first argument to be a string.'); }

	        // Replace all spaces with the Unicode No-break space (http://www.fileformat.info/info/unicode/char/a0/index.htm).
	        // IE would otherwise collapse all spaces into one.
	        content = V.sanitizeText(content);
	        opt || (opt = {});
	        // Should we allow the text to be selected?
	        var displayEmpty = opt.displayEmpty;
	        // End of Line character
	        var eol = opt.eol;
	        // Text along path
	        var textPath = opt.textPath;
	        // Vertical shift
	        var verticalAnchor = opt.textVerticalAnchor;
	        var namedVerticalAnchor = (verticalAnchor === 'middle' || verticalAnchor === 'bottom' || verticalAnchor === 'top');
	        // Horizontal shift applied to all the lines but the first.
	        var x = opt.x;
	        if (x === undefined) { x = this.attr('x') || 0; }
	        // Annotations
	        var iai = opt.includeAnnotationIndices;
	        var annotations = opt.annotations;
	        if (annotations && !V.isArray(annotations)) { annotations = [annotations]; }
	        // Shift all the <tspan> but first by one line (`1em`)
	        var defaultLineHeight = opt.lineHeight;
	        var autoLineHeight = (defaultLineHeight === 'auto');
	        var lineHeight = (autoLineHeight) ? '1.5em' : (defaultLineHeight || '1em');
	        // Clearing the element
	        this.empty();
	        this.attr({
	            // Preserve spaces. In other words, we do not want consecutive spaces to get collapsed to one.
	            'xml:space': 'preserve',
	            // An empty text gets rendered into the DOM in webkit-based browsers.
	            // In order to unify this behaviour across all browsers
	            // we rather hide the text element when it's empty.
	            'display': (content || displayEmpty) ? null : 'none'
	        });

	        // Set default font-size if none
	        var fontSize = parseFloat(this.attr('font-size'));
	        if (!fontSize) {
	            fontSize = 16;
	            if (namedVerticalAnchor || annotations) { this.attr('font-size', fontSize); }
	        }

	        var doc = document;
	        var containerNode;
	        if (textPath) {
	            // Now all the `<tspan>`s will be inside the `<textPath>`.
	            if (typeof textPath === 'string') { textPath = { d: textPath }; }
	            containerNode = createTextPathNode(textPath, this);
	        } else {
	            containerNode = doc.createDocumentFragment();
	        }
	        var offset = 0;
	        var lines = content.split('\n');
	        var linesMetrics = [];
	        var annotatedY;
	        for (var i = 0, lastI = lines.length - 1; i <= lastI; i++) {
	            var dy = lineHeight;
	            var lineClassName = 'v-line';
	            var lineNode = doc.createElementNS(ns.svg, 'tspan');
	            var line = lines[i];
	            var lineMetrics;
	            if (line) {
	                if (annotations) {
	                    // Find the *compacted* annotations for this line.
	                    var lineAnnotations = V.annotateString(line, annotations, {
	                        offset: -offset,
	                        includeAnnotationIndices: iai
	                    });
	                    lineMetrics = annotateTextLine(lineNode, lineAnnotations, {
	                        includeAnnotationIndices: iai,
	                        eol: (i !== lastI && eol),
	                        lineHeight: (autoLineHeight) ? null : lineHeight,
	                        baseSize: fontSize
	                    });
	                    // Get the line height based on the biggest font size in the annotations for this line.
	                    var iLineHeight = lineMetrics.lineHeight;
	                    if (iLineHeight && autoLineHeight && i !== 0) { dy = iLineHeight; }
	                    if (i === 0) { annotatedY = lineMetrics.maxFontSize * 0.8; }
	                } else {
	                    if (eol && i !== lastI) { line += eol; }
	                    lineNode.textContent = line;
	                }
	            } else {
	                // Make sure the textContent is never empty. If it is, add a dummy
	                // character and make it invisible, making the following lines correctly
	                // relatively positioned. `dy=1em` won't work with empty lines otherwise.
	                lineNode.textContent = '-';
	                lineClassName += ' v-empty-line';
	                // 'opacity' needs to be specified with fill, stroke. Opacity without specification
	                // is not applied in Firefox
	                var lineNodeStyle = lineNode.style;
	                lineNodeStyle.fillOpacity = 0;
	                lineNodeStyle.strokeOpacity = 0;
	                if (annotations) {
	                    // Empty line with annotations.
	                    lineMetrics = {};
	                    lineAnnotations = V.findAnnotationsAtIndex(annotations, offset);
	                    var lineFontSize = fontSize;
	                    // Check if any of the annotations overrides the font size.
	                    for (var j = lineAnnotations.length; j > 0; j--) {
	                        var attrs = lineAnnotations[j - 1].attrs;
	                        if (!attrs || !('font-size' in attrs)) { continue; }
	                        var fs = parseFloat(attrs['font-size']);
	                        if (isFinite(fs)) {
	                            lineFontSize = fs;
	                            break;
	                        }
	                    }
	                    if (autoLineHeight) {
	                        if (i > 0) {
	                            dy = lineFontSize * 1.2;
	                        } else {
	                            annotatedY = lineFontSize * 0.8;
	                        }
	                    }
	                    // The font size is important for the native selection box height.
	                    lineNode.setAttribute('font-size', lineFontSize);
	                    lineMetrics.maxFontSize = lineFontSize;
	                }
	            }
	            if (lineMetrics) { linesMetrics.push(lineMetrics); }
	            if (i > 0) { lineNode.setAttribute('dy', dy); }
	            // Firefox requires 'x' to be set on the first line when inside a text path
	            if (i > 0 || textPath) { lineNode.setAttribute('x', x); }
	            lineNode.className.baseVal = lineClassName;
	            containerNode.appendChild(lineNode);
	            offset += line.length + 1;      // + 1 = newline character.
	        }
	        // Y Alignment calculation
	        if (namedVerticalAnchor) {
	            if (annotations) {
	                dy = calculateDY(verticalAnchor, linesMetrics, fontSize, lineHeight);
	            } else if (verticalAnchor === 'top') {
	                // A shortcut for top alignment. It does not depend on font-size nor line-height
	                dy = '0.8em';
	            } else {
	                var rh; // remaining height
	                if (lastI > 0) {
	                    rh = parseFloat(lineHeight) || 1;
	                    rh *= lastI;
	                    if (!emRegex.test(lineHeight)) { rh /= fontSize; }
	                } else {
	                    // Single-line text
	                    rh = 0;
	                }
	                switch (verticalAnchor) {
	                    case 'middle':
	                        dy = (0.3 - (rh / 2)) + 'em';
	                        break;
	                    case 'bottom':
	                        dy = (-rh - 0.3) + 'em';
	                        break;
	                }
	            }
	        } else {
	            if (verticalAnchor === 0) {
	                dy = '0em';
	            } else if (verticalAnchor) {
	                dy = verticalAnchor;
	            } else {
	                // No vertical anchor is defined
	                dy = 0;
	                // Backwards compatibility - we change the `y` attribute instead of `dy`.
	                if (this.attr('y') === null) { this.attr('y', annotatedY || '0.8em'); }
	            }
	        }
	        containerNode.firstChild.setAttribute('dy', dy);
	        // Appending lines to the element.
	        this.append(containerNode);
	        return this;
	    };

	    /**
	     * @public
	     * @param {string} name
	     * @returns {Vectorizer}
	     */
	    VPrototype.removeAttr = function(name) {

	        var trueName = attributeNames[name];

	        var ref = V.qualifyAttr(trueName);
	        var ns = ref.ns;
	        var local = ref.local;
	        var el = this.node;

	        if (ns) {
	            if (el.hasAttributeNS(ns, local)) {
	                el.removeAttributeNS(ns, local);
	            }
	        } else if (el.hasAttribute(trueName)) {
	            el.removeAttribute(trueName);
	        }
	        return this;
	    };

	    VPrototype.attr = function(name, value) {

	        if (V.isUndefined(name)) {

	            // Return all attributes.
	            var attributes = this.node.attributes;
	            var attrs = {};

	            for (var i = 0; i < attributes.length; i++) {
	                attrs[attributes[i].name] = attributes[i].value;
	            }

	            return attrs;
	        }

	        if (V.isString(name) && V.isUndefined(value)) {
	            return this.node.getAttribute(attributeNames[name]);
	        }

	        if (typeof name === 'object') {

	            for (var attrName in name) {
	                if (name.hasOwnProperty(attrName)) {
	                    this.setAttribute(attrName, name[attrName]);
	                }
	            }

	        } else {

	            this.setAttribute(name, value);
	        }

	        return this;
	    };

	    VPrototype.normalizePath = function() {

	        var tagName = this.tagName();
	        if (tagName === 'PATH') {
	            this.attr('d', V.normalizePathData(this.attr('d')));
	        }

	        return this;
	    };

	    VPrototype.remove = function() {

	        if (this.node.parentNode) {
	            this.node.parentNode.removeChild(this.node);
	        }

	        return this;
	    };

	    VPrototype.empty = function() {

	        while (this.node.firstChild) {
	            this.node.removeChild(this.node.firstChild);
	        }

	        return this;
	    };

	    /**
	     * @private
	     * @param {object} attrs
	     * @returns {Vectorizer}
	     */
	    VPrototype.setAttributes = function(attrs) {

	        for (var key in attrs) {
	            if (attrs.hasOwnProperty(key)) {
	                this.setAttribute(key, attrs[key]);
	            }
	        }

	        return this;
	    };

	    VPrototype.append = function(els) {

	        if (!V.isArray(els)) {
	            els = [els];
	        }

	        for (var i = 0, len = els.length; i < len; i++) {
	            this.node.appendChild(V.toNode(els[i])); // lgtm [js/xss-through-dom]
	        }

	        return this;
	    };

	    VPrototype.prepend = function(els) {

	        var child = this.node.firstChild;
	        return child ? V(child).before(els) : this.append(els);
	    };

	    VPrototype.before = function(els) {

	        var node = this.node;
	        var parent = node.parentNode;

	        if (parent) {

	            if (!V.isArray(els)) {
	                els = [els];
	            }

	            for (var i = 0, len = els.length; i < len; i++) {
	                parent.insertBefore(V.toNode(els[i]), node);
	            }
	        }

	        return this;
	    };

	    VPrototype.appendTo = function(node) {
	        V.toNode(node).appendChild(this.node); // lgtm [js/xss-through-dom]
	        return this;
	    };

	    VPrototype.svg = function() {

	        return this.node instanceof window.SVGSVGElement ? this : V(this.node.ownerSVGElement);
	    };

	    VPrototype.tagName = function() {

	        return this.node.tagName.toUpperCase();
	    };

	    VPrototype.defs = function() {
	        var context = this.svg() || this;
	        var defsNode = context.node.getElementsByTagName('defs')[0];
	        if (defsNode) { return V(defsNode); }
	        return V('defs').appendTo(context);
	    };

	    VPrototype.clone = function() {

	        var clone = V(this.node.cloneNode(true/* deep */));
	        // Note that clone inherits also ID. Therefore, we need to change it here.
	        clone.node.id = V.uniqueId();
	        return clone;
	    };

	    VPrototype.findOne = function(selector) {

	        var found = this.node.querySelector(selector);
	        return found ? V(found) : undefined;
	    };

	    VPrototype.find = function(selector) {

	        var vels = [];
	        var nodes = this.node.querySelectorAll(selector);

	        if (nodes) {

	            // Map DOM elements to `V`s.
	            for (var i = 0; i < nodes.length; i++) {
	                vels.push(V(nodes[i]));
	            }
	        }

	        return vels;
	    };

	    // Returns an array of V elements made from children of this.node.
	    VPrototype.children = function() {

	        var children = this.node.childNodes;

	        var outputArray = [];
	        for (var i = 0; i < children.length; i++) {
	            var currentChild = children[i];
	            if (currentChild.nodeType === 1) {
	                outputArray.push(V(children[i]));
	            }
	        }
	        return outputArray;
	    };

	    // Returns the V element from parentNode of this.node.
	    VPrototype.parent = function() {
	        return V(this.node.parentNode) || null;
	    },

	    // Find an index of an element inside its container.
	    VPrototype.index = function() {

	        var index = 0;
	        var node = this.node.previousSibling;

	        while (node) {
	            // nodeType 1 for ELEMENT_NODE
	            if (node.nodeType === 1) { index++; }
	            node = node.previousSibling;
	        }

	        return index;
	    };

	    VPrototype.findParentByClass = function(className, terminator) {

	        var ownerSVGElement = this.node.ownerSVGElement;
	        var node = this.node.parentNode;

	        while (node && node !== terminator && node !== ownerSVGElement) {

	            var vel = V(node);
	            if (vel.hasClass(className)) {
	                return vel;
	            }

	            node = node.parentNode;
	        }

	        return null;
	    };

	    // https://jsperf.com/get-common-parent
	    VPrototype.contains = function(el) {

	        var a = this.node;
	        var b = V.toNode(el);
	        var bup = b && b.parentNode;

	        return (a === bup) || !!(bup && bup.nodeType === 1 && (a.compareDocumentPosition(bup) & 16));
	    };

	    // Convert global point into the coordinate space of this element.
	    VPrototype.toLocalPoint = function(x, y) {

	        var svg = this.svg().node;

	        var p = svg.createSVGPoint();
	        p.x = x;
	        p.y = y;

	        try {

	            var globalPoint = p.matrixTransform(svg.getScreenCTM().inverse());
	            var globalToLocalMatrix = this.getTransformToElement(svg).inverse();

	        } catch (e) {
	            // IE9 throws an exception in odd cases. (`Unexpected call to method or property access`)
	            // We have to make do with the original coordianates.
	            return p;
	        }

	        return globalPoint.matrixTransform(globalToLocalMatrix);
	    };

	    VPrototype.translateCenterToPoint = function(p) {

	        var bbox = this.getBBox({ target: this.svg() });
	        var center = bbox.center();

	        this.translate(p.x - center.x, p.y - center.y);
	        return this;
	    };

	    // Efficiently auto-orient an element. This basically implements the orient=auto attribute
	    // of markers. The easiest way of understanding on what this does is to imagine the element is an
	    // arrowhead. Calling this method on the arrowhead makes it point to the `position` point while
	    // being auto-oriented (properly rotated) towards the `reference` point.
	    // `target` is the element relative to which the transformations are applied. Usually a viewport.
	    VPrototype.translateAndAutoOrient = function(position, reference, target) {

	        position = new Point(position);
	        reference =  new Point(reference);
	        target || (target = this.svg());

	        // Clean-up previously set transformations except the scale. If we didn't clean up the
	        // previous transformations then they'd add up with the old ones. Scale is an exception as
	        // it doesn't add up, consider: `this.scale(2).scale(2).scale(2)`. The result is that the
	        // element is scaled by the factor 2, not 8.
	        var scale = this.scale();
	        this.attr('transform', '');
	        var bbox = this.getBBox({ target: target }).scale(scale.sx, scale.sy);

	        // 1. Translate to origin.
	        var translateToOrigin = V.createSVGTransform();
	        translateToOrigin.setTranslate(-bbox.x - bbox.width / 2, -bbox.y - bbox.height / 2);

	        // 2. Rotate around origin.
	        var rotateAroundOrigin = V.createSVGTransform();
	        var angle = position.angleBetween(reference, position.clone().offset(1, 0));
	        if (angle) { rotateAroundOrigin.setRotate(angle, 0, 0); }

	        // 3. Translate to the `position` + the offset (half my width) towards the `reference` point.
	        var translateFromOrigin = V.createSVGTransform();
	        var finalPosition = position.clone().move(reference, bbox.width / 2);
	        translateFromOrigin.setTranslate(2 * position.x - finalPosition.x, 2 * position.y - finalPosition.y);

	        // 4. Get the current transformation matrix of this node
	        var ctm = this.getTransformToElement(target);

	        // 5. Apply transformations and the scale
	        var transform = V.createSVGTransform();
	        transform.setMatrix(
	            translateFromOrigin.matrix.multiply(
	                rotateAroundOrigin.matrix.multiply(
	                    translateToOrigin.matrix.multiply(
	                        ctm.scale(scale.sx, scale.sy)))));

	        this.attr('transform', V.matrixToTransformString(transform.matrix));

	        return this;
	    };

	    VPrototype.animateAlongPath = function(attrs, path) {

	        path = V.toNode(path);

	        var id = V.ensureId(path);
	        var animateMotion = V('animateMotion', attrs);
	        var mpath = V('mpath', { 'xlink:href': '#' + id });

	        animateMotion.append(mpath);

	        this.append(animateMotion);
	        try {
	            animateMotion.node.beginElement();
	        } catch (e) {
	            // Fallback for IE 9.
	            // Run the animation programmatically if FakeSmile (`http://leunen.me/fakesmile/`) present
	            if (document.documentElement.getAttribute('smiling') === 'fake') {
	                /* global getTargets:true, Animator:true, animators:true id2anim:true */
	                // Register the animation. (See `https://answers.launchpad.net/smil/+question/203333`)
	                var animation = animateMotion.node;
	                animation.animators = [];

	                var animationID = animation.getAttribute('id');
	                if (animationID) { id2anim[animationID] = animation; }

	                var targets = getTargets(animation);
	                for (var i = 0, len = targets.length; i < len; i++) {
	                    var target = targets[i];
	                    var animator = new Animator(animation, target, i);
	                    animators.push(animator);
	                    animation.animators[i] = animator;
	                    animator.register();
	                }
	            }
	        }
	        return this;
	    };


	    // Split a string into an array of tokens.
	    // https://infra.spec.whatwg.org/#ascii-whitespace
	    var noHTMLWhitespaceRegex = /[^\x20\t\r\n\f]+/g;
	    function getTokenList(str) {
	        if (!V.isString(str)) { return []; }
	        return str.trim().match(noHTMLWhitespaceRegex) || [];
	    }

	    VPrototype.hasClass = function(className) {
	        if (!V.isString(className)) { return false; }
	        return this.node.classList.contains(className.trim());
	    };

	    VPrototype.addClass = function(className) {
	        var ref;

	        (ref = this.node.classList).add.apply(ref, getTokenList(className));
	        return this;
	    };

	    VPrototype.removeClass = function(className) {
	        var ref;

	        (ref = this.node.classList).remove.apply(ref, getTokenList(className));
	        return this;
	    };

	    VPrototype.toggleClass = function(className, toAdd) {
	        var tokens = getTokenList(className);
	        for (var i = 0; i < tokens.length; i++) {
	            this.node.classList.toggle(tokens[i], toAdd);
	        }
	        return this;
	    };

	    // Interpolate path by discrete points. The precision of the sampling
	    // is controlled by `interval`. In other words, `sample()` will generate
	    // a point on the path starting at the beginning of the path going to the end
	    // every `interval` pixels.
	    // The sampler can be very useful for e.g. finding intersection between two
	    // paths (finding the two closest points from two samples).
	    VPrototype.sample = function(interval) {

	        interval = interval || 1;
	        var node = this.node;
	        var length = node.getTotalLength();
	        var samples = [];
	        var distance = 0;
	        var sample;
	        while (distance < length) {
	            sample = node.getPointAtLength(distance);
	            samples.push({ x: sample.x, y: sample.y, distance: distance });
	            distance += interval;
	        }
	        return samples;
	    };

	    VPrototype.convertToPath = function() {

	        var path = V('path');
	        path.attr(this.attr());
	        var d = this.convertToPathData();
	        if (d) {
	            path.attr('d', d);
	        }
	        return path;
	    };

	    VPrototype.convertToPathData = function() {

	        var tagName = this.tagName();

	        switch (tagName) {
	            case 'PATH':
	                return this.attr('d');
	            case 'LINE':
	                return V.convertLineToPathData(this.node);
	            case 'POLYGON':
	                return V.convertPolygonToPathData(this.node);
	            case 'POLYLINE':
	                return V.convertPolylineToPathData(this.node);
	            case 'ELLIPSE':
	                return V.convertEllipseToPathData(this.node);
	            case 'CIRCLE':
	                return V.convertCircleToPathData(this.node);
	            case 'RECT':
	                return V.convertRectToPathData(this.node);
	        }

	        throw new Error(tagName + ' cannot be converted to PATH.');
	    };

	    V.prototype.toGeometryShape = function() {
	        var x, y, width, height, cx, cy, r, rx, ry, points, d, x1, x2, y1, y2;
	        switch (this.tagName()) {

	            case 'RECT':
	                x = parseFloat(this.attr('x')) || 0;
	                y = parseFloat(this.attr('y')) || 0;
	                width = parseFloat(this.attr('width')) || 0;
	                height = parseFloat(this.attr('height')) || 0;
	                return new Rect(x, y, width, height);

	            case 'CIRCLE':
	                cx = parseFloat(this.attr('cx')) || 0;
	                cy = parseFloat(this.attr('cy')) || 0;
	                r = parseFloat(this.attr('r')) || 0;
	                return new Ellipse({ x: cx, y: cy }, r, r);

	            case 'ELLIPSE':
	                cx = parseFloat(this.attr('cx')) || 0;
	                cy = parseFloat(this.attr('cy')) || 0;
	                rx = parseFloat(this.attr('rx')) || 0;
	                ry = parseFloat(this.attr('ry')) || 0;
	                return new Ellipse({ x: cx, y: cy }, rx, ry);

	            case 'POLYLINE':
	                points = V.getPointsFromSvgNode(this);
	                return new Polyline(points);

	            case 'POLYGON':
	                points = V.getPointsFromSvgNode(this);
	                if (points.length > 1) { points.push(points[0]); }
	                return new Polyline(points);

	            case 'PATH':
	                d = this.attr('d');
	                if (!Path.isDataSupported(d)) { d = V.normalizePathData(d); }
	                return new Path(d);

	            case 'LINE':
	                x1 = parseFloat(this.attr('x1')) || 0;
	                y1 = parseFloat(this.attr('y1')) || 0;
	                x2 = parseFloat(this.attr('x2')) || 0;
	                y2 = parseFloat(this.attr('y2')) || 0;
	                return new Line({ x: x1, y: y1 }, { x: x2, y: y2 });
	        }

	        // Anything else is a rectangle
	        return this.getBBox();
	    };

	    // Find the intersection of a line starting in the center
	    // of the SVG `node` ending in the point `ref`.
	    // `target` is an SVG element to which `node`s transformations are relative to.
	    // Note that `ref` point must be in the coordinate system of the `target` for this function to work properly.
	    // Returns a point in the `target` coordinate system (the same system as `ref` is in) if
	    // an intersection is found. Returns `undefined` otherwise.
	    VPrototype.findIntersection = function(ref, target) {

	        var svg = this.svg().node;
	        target = target || svg;
	        var bbox = this.getBBox({ target: target });
	        var center = bbox.center();

	        if (!bbox.intersectionWithLineFromCenterToPoint(ref)) { return undefined; }

	        var spot;
	        var tagName = this.tagName();

	        // Little speed up optimization for `<rect>` element. We do not do conversion
	        // to path element and sampling but directly calculate the intersection through
	        // a transformed geometrical rectangle.
	        if (tagName === 'RECT') {

	            var gRect = new Rect(
	                parseFloat(this.attr('x') || 0),
	                parseFloat(this.attr('y') || 0),
	                parseFloat(this.attr('width')),
	                parseFloat(this.attr('height'))
	            );
	            // Get the rect transformation matrix with regards to the SVG document.
	            var rectMatrix = this.getTransformToElement(target);
	            // Decompose the matrix to find the rotation angle.
	            var rectMatrixComponents = V.decomposeMatrix(rectMatrix);
	            // Now we want to rotate the rectangle back so that we
	            // can use `intersectionWithLineFromCenterToPoint()` passing the angle as the second argument.
	            var resetRotation = svg.createSVGTransform();
	            resetRotation.setRotate(-rectMatrixComponents.rotation, center.x, center.y);
	            var rect = V.transformRect(gRect, resetRotation.matrix.multiply(rectMatrix));
	            spot = (new Rect(rect)).intersectionWithLineFromCenterToPoint(ref, rectMatrixComponents.rotation);

	        } else if (tagName === 'PATH' || tagName === 'POLYGON' || tagName === 'POLYLINE' || tagName === 'CIRCLE' || tagName === 'ELLIPSE') {

	            var pathNode = (tagName === 'PATH') ? this : this.convertToPath();
	            var samples = pathNode.sample();
	            var minDistance = Infinity;
	            var closestSamples = [];

	            var i, sample, gp, centerDistance, refDistance, distance;

	            for (i = 0; i < samples.length; i++) {

	                sample = samples[i];
	                // Convert the sample point in the local coordinate system to the global coordinate system.
	                gp = V.createSVGPoint(sample.x, sample.y);
	                gp = gp.matrixTransform(this.getTransformToElement(target));
	                sample = new Point(gp);
	                centerDistance = sample.distance(center);
	                // Penalize a higher distance to the reference point by 10%.
	                // This gives better results. This is due to
	                // inaccuracies introduced by rounding errors and getPointAtLength() returns.
	                refDistance = sample.distance(ref) * 1.1;
	                distance = centerDistance + refDistance;

	                if (distance < minDistance) {
	                    minDistance = distance;
	                    closestSamples = [{ sample: sample, refDistance: refDistance }];
	                } else if (distance < minDistance + 1) {
	                    closestSamples.push({ sample: sample, refDistance: refDistance });
	                }
	            }

	            closestSamples.sort(function(a, b) {
	                return a.refDistance - b.refDistance;
	            });

	            if (closestSamples[0]) {
	                spot = closestSamples[0].sample;
	            }
	        }

	        return spot;
	    };

	    /**
	     * @private
	     * @param {string} name
	     * @param {string} value
	     * @returns {Vectorizer}
	     */
	    VPrototype.setAttribute = function(name, value) {

	        var el = this.node;

	        if (value === null) {
	            this.removeAttr(name);
	            return this;
	        }

	        var trueName = attributeNames[name];

	        var ref = V.qualifyAttr(trueName);
	        var ns = ref.ns;
	        if (ns) {
	            // Attribute names can be namespaced. E.g. `image` elements
	            // have a `xlink:href` attribute to set the source of the image.
	            el.setAttributeNS(ns, trueName, value);
	        } else if (trueName === 'id') {
	            el.id = value;
	        } else {
	            el.setAttribute(trueName, value);
	        }

	        return this;
	    };

	    // Create an SVG document element.
	    // If `content` is passed, it will be used as the SVG content of the `<svg>` root element.
	    V.createSvgDocument = function(content) {

	        if (content) {
	            var XMLString = "<svg xmlns=\"" + (ns.svg) + "\" xmlns:xlink=\"" + (ns.xlink) + "\" version=\"" + SVGVersion + "\">" + content + "</svg>";
	            var ref = V.parseXML(XMLString, { async: false });
	            var documentElement = ref.documentElement;
	            return documentElement;
	        }

	        var svg = document.createElementNS(ns.svg, 'svg');
	        svg.setAttributeNS(ns.xmlns, 'xmlns:xlink', ns.xlink);
	        svg.setAttribute('version', SVGVersion);
	        return svg;
	    };

	    V.createSVGStyle = function(stylesheet) {
	        var ref = V('style', { type: 'text/css' }, [
	            V.createCDATASection(stylesheet)
	        ]);
	        var node = ref.node;
	        return node;
	    },

	    V.createCDATASection = function(data) {
	        if ( data === void 0 ) data = '';

	        var xml = document.implementation.createDocument(null, 'xml', null);
	        return xml.createCDATASection(data);
	    };

	    V.idCounter = 0;

	    // A function returning a unique identifier for this client session with every call.
	    V.uniqueId = function() {

	        return 'v-' + (++V.idCounter);
	    };

	    V.toNode = function(el) {

	        return V.isV(el) ? el.node : (el.nodeName && el || el[0]);
	    };

	    V.ensureId = function(node) {

	        node = V.toNode(node);
	        return node.id || (node.id = V.uniqueId());
	    };

	    // Replace all spaces with the Unicode No-break space (http://www.fileformat.info/info/unicode/char/a0/index.htm).
	    // IE would otherwise collapse all spaces into one. This is used in the text() method but it is
	    // also exposed so that the programmer can use it in case he needs to. This is useful e.g. in tests
	    // when you want to compare the actual DOM text content without having to add the unicode character in
	    // the place of all spaces.
	    V.sanitizeText = function(text) {

	        return (text || '').replace(/ /g, '\u00A0');
	    };

	    V.isUndefined = function(value) {

	        return typeof value === 'undefined';
	    };

	    V.isString = function(value) {

	        return typeof value === 'string';
	    };

	    V.isObject = function(value) {

	        return value && (typeof value === 'object');
	    };

	    V.isArray = Array.isArray;

	    V.parseXML = function(data, opt) {

	        opt = opt || {};

	        var xml;

	        try {
	            var parser = new DOMParser();

	            if (!V.isUndefined(opt.async)) {
	                parser.async = opt.async;
	            }

	            xml = parser.parseFromString(data, 'text/xml');
	        } catch (error) {
	            xml = undefined;
	        }

	        if (!xml || xml.getElementsByTagName('parsererror').length) {
	            throw new Error('Invalid XML: ' + data);
	        }

	        return xml;
	    };

	    // Create an empty object which does not inherit any properties from `Object.prototype`.
	    // This is useful when we want to use an object as a dictionary without having to
	    // worry about inherited properties such as `toString`, `valueOf` etc.
	    var _attributeNames = Object.create(null);

	    // List of attributes for which not to split camel case words.
	    // It contains known SVG attribute names and may be extended with user-defined attribute names.
	    [
	        'baseFrequency',
	        'baseProfile',
	        'clipPathUnits',
	        'contentScriptType',
	        'contentStyleType',
	        'diffuseConstant',
	        'edgeMode',
	        'externalResourcesRequired',
	        'filterRes', // deprecated
	        'filterUnits',
	        'gradientTransform',
	        'gradientUnits',
	        'kernelMatrix',
	        'kernelUnitLength',
	        'keyPoints',
	        'lengthAdjust',
	        'limitingConeAngle',
	        'markerHeight',
	        'markerUnits',
	        'markerWidth',
	        'maskContentUnits',
	        'maskUnits',
	        'numOctaves',
	        'pathLength',
	        'patternContentUnits',
	        'patternTransform',
	        'patternUnits',
	        'pointsAtX',
	        'pointsAtY',
	        'pointsAtZ',
	        'preserveAlpha',
	        'preserveAspectRatio',
	        'primitiveUnits',
	        'refX',
	        'refY',
	        'requiredExtensions',
	        'requiredFeatures',
	        'specularConstant',
	        'specularExponent',
	        'spreadMethod',
	        'startOffset',
	        'stdDeviation',
	        'stitchTiles',
	        'surfaceScale',
	        'systemLanguage',
	        'tableValues',
	        'targetX',
	        'targetY',
	        'textLength',
	        'viewBox',
	        'viewTarget', // deprecated
	        'xChannelSelector',
	        'yChannelSelector',
	        'zoomAndPan' // deprecated
	    ].forEach(function (name) { return _attributeNames[name] = name; });

	    _attributeNames['xlinkShow'] = 'xlink:show';
	    _attributeNames['xlinkRole'] = 'xlink:role';
	    _attributeNames['xlinkActuate'] = 'xlink:actuate';
	    _attributeNames['xlinkHref'] = 'xlink:href';
	    _attributeNames['xlinkType'] = 'xlink:type';
	    _attributeNames['xlinkTitle'] = 'xlink:title';
	    _attributeNames['xmlBase'] = 'xml:base';
	    _attributeNames['xmlLang'] = 'xml:lang';
	    _attributeNames['xmlSpace'] = 'xml:space';

	    var attributeNames = new Proxy(_attributeNames, {
	        get: function get(cache, name) {
	            // The cache is a dictionary of attribute names. See `_attributeNames` above.
	            // If the attribute name is not in the cache, it means that it is not
	            // a camel-case attribute name. In that case, we need to convert
	            // the attribute name to dash-separated words.
	            if (!V.supportCamelCaseAttributes) { return name; }
	            if (name in cache) {
	                return cache[name];
	            }
	            // Convert camel case to dash-separated words.
	            return (cache[name] = name.replace(/[A-Z]/g, '-$&').toLowerCase());
	        }
	    });

	    // Dictionary of attribute names
	    Object.defineProperty(V, 'attributeNames', {
	        enumerable: true,
	        value: attributeNames,
	        writable: false,
	    });

	    // Should camel case attributes be supported?
	    Object.defineProperty(V, 'supportCamelCaseAttributes', {
	        enumerable: true,
	        value: true,
	        writable: true,
	    });

	    /**
	     * @param {string} name
	     * @returns {{ns: string|null, local: string}} namespace and attribute name
	     */
	    V.qualifyAttr = function(name) {

	        if (name.indexOf(':') !== -1) {
	            var combinedKey = name.split(':');
	            return {
	                ns: ns[combinedKey[0]],
	                local: combinedKey[1]
	            };
	        }

	        return {
	            ns: null,
	            local: name
	        };
	    };

	    // Note: This regex allows multiple commas as separator which is incorrect in SVG
	    // This regex is used by `split()`, so it doesn't need to use /g
	    V.transformSeparatorRegex = /[ ,]+/;
	    // Note: All following regexes are more restrictive than SVG specification
	    // ReDoS mitigation: Use an anchor at the beginning of the match
	    // ReDoS mitigation: Avoid backtracking (uses `[^()]+` instead of `.*?`)
	    // ReDoS mitigation: Don't match initial `(` inside repeated part
	    // The following regex needs to use /g (= cannot use capturing groups)
	    V.transformRegex = /\b\w+\([^()]+\)/g;
	    // The following regexes need to use capturing groups (= cannot use /g)
	    V.transformFunctionRegex = /\b(\w+)\(([^()]+)\)/;
	    V.transformTranslateRegex = /\btranslate\(([^()]+)\)/;
	    V.transformRotateRegex = /\brotate\(([^()]+)\)/;
	    V.transformScaleRegex = /\bscale\(([^()]+)\)/;

	    V.transformStringToMatrix = function(transform) {

	        // Initialize result matrix as identity matrix
	        var transformationMatrix = V.createSVGMatrix();

	        // Note: Multiple transform functions are allowed in `transform` string
	        // `match()` returns `null` if none found
	        var transformMatches = transform && transform.match(V.transformRegex);
	        if (!transformMatches) {
	            // Return identity matrix
	            return transformationMatrix;
	        }

	        var numMatches = transformMatches.length;
	        for (var i = 0; i < numMatches; i++) {

	            var transformMatch = transformMatches[i];
	            // Use same regex as above, but with capturing groups
	            // `match()` returns values of capturing groups as `[1]`, `[2]`
	            var transformFunctionMatch = transformMatch.match(V.transformFunctionRegex);
	            if (transformFunctionMatch) {

	                var sx = (void 0), sy = (void 0), tx = (void 0), ty = (void 0), angle = (void 0);
	                var ctm = V.createSVGMatrix();
	                var transformFunction = transformFunctionMatch[1].toLowerCase();
	                var args = transformFunctionMatch[2].split(V.transformSeparatorRegex);
	                switch (transformFunction) {

	                    case 'scale':
	                        sx = parseFloat(args[0]);
	                        sy = (args[1] === undefined) ? sx : parseFloat(args[1]);
	                        ctm = ctm.scaleNonUniform(sx, sy);
	                        break;

	                    case 'translate':
	                        tx = parseFloat(args[0]);
	                        ty = parseFloat(args[1]);
	                        ctm = ctm.translate(tx, ty);
	                        break;

	                    case 'rotate':
	                        angle = parseFloat(args[0]);
	                        tx = parseFloat(args[1]) || 0;
	                        ty = parseFloat(args[2]) || 0;
	                        if (tx !== 0 || ty !== 0) {
	                            ctm = ctm.translate(tx, ty).rotate(angle).translate(-tx, -ty);
	                        } else {
	                            ctm = ctm.rotate(angle);
	                        }
	                        break;

	                    case 'skewx':
	                        angle = parseFloat(args[0]);
	                        ctm = ctm.skewX(angle);
	                        break;

	                    case 'skewy':
	                        angle = parseFloat(args[0]);
	                        ctm = ctm.skewY(angle);
	                        break;

	                    case 'matrix':
	                        ctm.a = parseFloat(args[0]);
	                        ctm.b = parseFloat(args[1]);
	                        ctm.c = parseFloat(args[2]);
	                        ctm.d = parseFloat(args[3]);
	                        ctm.e = parseFloat(args[4]);
	                        ctm.f = parseFloat(args[5]);
	                        break;

	                    default:
	                        continue;
	                }

	                // Multiply current transformation into result matrix
	                transformationMatrix = transformationMatrix.multiply(ctm);
	            }

	        }
	        return transformationMatrix;
	    };

	    V.matrixToTransformString = function(matrix) {
	        matrix || (matrix = true);

	        return 'matrix(' +
	            (matrix.a !== undefined ? matrix.a : 1) + ',' +
	            (matrix.b !== undefined ? matrix.b : 0) + ',' +
	            (matrix.c !== undefined ? matrix.c : 0) + ',' +
	            (matrix.d !== undefined ? matrix.d : 1) + ',' +
	            (matrix.e !== undefined ? matrix.e : 0) + ',' +
	            (matrix.f !== undefined ? matrix.f : 0) +
	            ')';
	    };

	    V.parseTransformString = function(transform) {

	        var translate, rotate, scale;

	        if (transform) {

	            var separator = V.transformSeparatorRegex;

	            // Special handling for `transform` with one or more matrix functions
	            if (transform.trim().indexOf('matrix') >= 0) {

	                // Convert EVERYTHING in `transform` string to a matrix
	                // Will combine ALL matrixes * ALL translates * ALL scales * ALL rotates
	                // Note: In non-matrix case, we only take first one of each (if any)
	                var matrix = V.transformStringToMatrix(transform);
	                var decomposedMatrix = V.decomposeMatrix(matrix);

	                // Extract `translate`, `scale`, `rotate` from matrix
	                translate = [decomposedMatrix.translateX, decomposedMatrix.translateY];
	                scale = [decomposedMatrix.scaleX, decomposedMatrix.scaleY];
	                rotate = [decomposedMatrix.rotation];

	                // Rewrite `transform` string in `translate scale rotate` format
	                var transformations = [];
	                if (translate[0] !== 0 || translate[1] !== 0) {
	                    transformations.push('translate(' + translate + ')');
	                }
	                if (scale[0] !== 1 || scale[1] !== 1) {
	                    transformations.push('scale(' + scale + ')');
	                }
	                if (rotate[0] !== 0) {
	                    transformations.push('rotate(' + rotate + ')');
	                }
	                transform = transformations.join(' ');

	            } else {

	                // Extract `translate`, `rotate`, `scale` functions from `transform` string
	                // Note: We only detect the first match of each (if any)
	                // `match()` returns value of capturing group as `[1]`
	                var translateMatch = transform.match(V.transformTranslateRegex);
	                if (translateMatch) {
	                    translate = translateMatch[1].split(separator);
	                }
	                var rotateMatch = transform.match(V.transformRotateRegex);
	                if (rotateMatch) {
	                    rotate = rotateMatch[1].split(separator);
	                }
	                var scaleMatch = transform.match(V.transformScaleRegex);
	                if (scaleMatch) {
	                    scale = scaleMatch[1].split(separator);
	                }
	            }
	        }

	        var sx = (scale && scale[0]) ? parseFloat(scale[0]) : 1;

	        return {
	            value: transform,
	            translate: {
	                tx: (translate && translate[0]) ? parseInt(translate[0], 10) : 0,
	                ty: (translate && translate[1]) ? parseInt(translate[1], 10) : 0
	            },
	            rotate: {
	                angle: (rotate && rotate[0]) ? parseInt(rotate[0], 10) : 0,
	                cx: (rotate && rotate[1]) ? parseInt(rotate[1], 10) : undefined,
	                cy: (rotate && rotate[2]) ? parseInt(rotate[2], 10) : undefined
	            },
	            scale: {
	                sx: sx,
	                sy: (scale && scale[1]) ? parseFloat(scale[1]) : sx
	            }
	        };
	    };

	    V.deltaTransformPoint = function(matrix, point) {

	        var dx = point.x * matrix.a + point.y * matrix.c + 0;
	        var dy = point.x * matrix.b + point.y * matrix.d + 0;
	        return { x: dx, y: dy };
	    };

	    V.decomposeMatrix = function(matrix) {

	        // @see https://gist.github.com/2052247

	        // calculate delta transform point
	        var px = V.deltaTransformPoint(matrix, { x: 0, y: 1 });
	        var py = V.deltaTransformPoint(matrix, { x: 1, y: 0 });

	        // calculate skew
	        var skewX = ((180 / PI) * atan2(px.y, px.x) - 90);
	        var skewY = ((180 / PI) * atan2(py.y, py.x));

	        return {

	            translateX: matrix.e,
	            translateY: matrix.f,
	            scaleX: sqrt(matrix.a * matrix.a + matrix.b * matrix.b),
	            scaleY: sqrt(matrix.c * matrix.c + matrix.d * matrix.d),
	            skewX: skewX,
	            skewY: skewY,
	            rotation: skewX // rotation is the same as skew x
	        };
	    };

	    // Return the `scale` transformation from the following equation:
	    // `translate(tx, ty) . rotate(angle) . scale(sx, sy) === matrix(a,b,c,d,e,f)`
	    V.matrixToScale = function(matrix) {

	        var a, b, c, d;
	        if (matrix) {
	            a = V.isUndefined(matrix.a) ? 1 : matrix.a;
	            d = V.isUndefined(matrix.d) ? 1 : matrix.d;
	            b = matrix.b;
	            c = matrix.c;
	        } else {
	            a = d = 1;
	        }
	        return {
	            sx: b ? sqrt(a * a + b * b) : a,
	            sy: c ? sqrt(c * c + d * d) : d
	        };
	    };

	    // Return the `rotate` transformation from the following equation:
	    // `translate(tx, ty) . rotate(angle) . scale(sx, sy) === matrix(a,b,c,d,e,f)`
	    V.matrixToRotate = function(matrix) {

	        var p = { x: 0, y: 1 };
	        if (matrix) {
	            p = V.deltaTransformPoint(matrix, p);
	        }

	        return {
	            angle: normalizeAngle(toDeg(atan2(p.y, p.x)) - 90)
	        };
	    };

	    // Return the `translate` transformation from the following equation:
	    // `translate(tx, ty) . rotate(angle) . scale(sx, sy) === matrix(a,b,c,d,e,f)`
	    V.matrixToTranslate = function(matrix) {

	        return {
	            tx: (matrix && matrix.e) || 0,
	            ty: (matrix && matrix.f) || 0
	        };
	    };

	    V.isV = function(object) {

	        return object instanceof V;
	    };

	    // For backwards compatibility:
	    V.isVElement = V.isV;

	    // Element implements `getBBox()`, `getCTM()` and `getScreenCTM()`
	    // https://developer.mozilla.org/en-US/docs/Web/API/SVGGraphicsElement
	    V.isSVGGraphicsElement = function(node) {
	        if (!node) { return false; }
	        node = V.toNode(node);
	        // IE/Edge does not implement SVGGraphicsElement interface, thus check for `getScreenCTM` below
	        return node instanceof SVGElement && typeof node.getScreenCTM === 'function';
	    };

	    var svgDocument = V('svg').node;

	    V.createSVGMatrix = function(matrix) {

	        var svgMatrix = svgDocument.createSVGMatrix();
	        for (var component in matrix) {
	            svgMatrix[component] = matrix[component];
	        }

	        return svgMatrix;
	    };

	    V.createSVGTransform = function(matrix) {

	        if (!V.isUndefined(matrix)) {

	            if (!(matrix instanceof SVGMatrix)) {
	                matrix = V.createSVGMatrix(matrix);
	            }

	            return svgDocument.createSVGTransformFromMatrix(matrix);
	        }

	        return svgDocument.createSVGTransform();
	    };

	    V.createSVGPoint = function(x, y) {

	        var p = svgDocument.createSVGPoint();
	        p.x = x;
	        p.y = y;
	        return p;
	    };

	    V.transformRect = function(r, matrix) {

	        var p = svgDocument.createSVGPoint();

	        p.x = r.x;
	        p.y = r.y;
	        var corner1 = p.matrixTransform(matrix);

	        p.x = r.x + r.width;
	        p.y = r.y;
	        var corner2 = p.matrixTransform(matrix);

	        p.x = r.x + r.width;
	        p.y = r.y + r.height;
	        var corner3 = p.matrixTransform(matrix);

	        p.x = r.x;
	        p.y = r.y + r.height;
	        var corner4 = p.matrixTransform(matrix);

	        var minX = min(corner1.x, corner2.x, corner3.x, corner4.x);
	        var maxX = max(corner1.x, corner2.x, corner3.x, corner4.x);
	        var minY = min(corner1.y, corner2.y, corner3.y, corner4.y);
	        var maxY = max(corner1.y, corner2.y, corner3.y, corner4.y);

	        return new Rect(minX, minY, maxX - minX, maxY - minY);
	    };

	    V.transformPoint = function(p, matrix) {

	        return new Point(V.createSVGPoint(p.x, p.y).matrixTransform(matrix));
	    };

	    V.transformLine = function(l, matrix) {

	        return new Line(
	            V.transformPoint(l.start, matrix),
	            V.transformPoint(l.end, matrix)
	        );
	    };

	    V.transformPolyline = function(p, matrix) {

	        var inPoints = (p instanceof Polyline) ? p.points : p;
	        if (!V.isArray(inPoints)) { inPoints = []; }
	        var outPoints = [];
	        for (var i = 0, n = inPoints.length; i < n; i++) { outPoints[i] = V.transformPoint(inPoints[i], matrix); }
	        return new Polyline(outPoints);
	    };

	    // Convert a style represented as string (e.g. `'fill="blue"; stroke="red"'`) to
	    // an object (`{ fill: 'blue', stroke: 'red' }`).
	    V.styleToObject = function(styleString) {
	        var ret = {};
	        var styles = styleString.split(';');
	        for (var i = 0; i < styles.length; i++) {
	            var style = styles[i];
	            var pair = style.split('=');
	            ret[pair[0].trim()] = pair[1].trim();
	        }
	        return ret;
	    };

	    // Inspired by d3.js https://github.com/mbostock/d3/blob/master/src/svg/arc.js
	    V.createSlicePathData = function(innerRadius, outerRadius, startAngle, endAngle) {

	        var svgArcMax = 2 * PI - 1e-6;
	        var r0 = innerRadius;
	        var r1 = outerRadius;
	        var a0 = startAngle;
	        var a1 = endAngle;
	        var da = (a1 < a0 && (da = a0, a0 = a1, a1 = da), a1 - a0);
	        var df = da < PI ? '0' : '1';
	        var c0 = cos(a0);
	        var s0 = sin(a0);
	        var c1 = cos(a1);
	        var s1 = sin(a1);

	        return (da >= svgArcMax)
	            ? (r0
	                ? 'M0,' + r1
	                + 'A' + r1 + ',' + r1 + ' 0 1,1 0,' + (-r1)
	                + 'A' + r1 + ',' + r1 + ' 0 1,1 0,' + r1
	                + 'M0,' + r0
	                + 'A' + r0 + ',' + r0 + ' 0 1,0 0,' + (-r0)
	                + 'A' + r0 + ',' + r0 + ' 0 1,0 0,' + r0
	                + 'Z'
	                : 'M0,' + r1
	                + 'A' + r1 + ',' + r1 + ' 0 1,1 0,' + (-r1)
	                + 'A' + r1 + ',' + r1 + ' 0 1,1 0,' + r1
	                + 'Z')
	            : (r0
	                ? 'M' + r1 * c0 + ',' + r1 * s0
	                + 'A' + r1 + ',' + r1 + ' 0 ' + df + ',1 ' + r1 * c1 + ',' + r1 * s1
	                + 'L' + r0 * c1 + ',' + r0 * s1
	                + 'A' + r0 + ',' + r0 + ' 0 ' + df + ',0 ' + r0 * c0 + ',' + r0 * s0
	                + 'Z'
	                : 'M' + r1 * c0 + ',' + r1 * s0
	                + 'A' + r1 + ',' + r1 + ' 0 ' + df + ',1 ' + r1 * c1 + ',' + r1 * s1
	                + 'L0,0'
	                + 'Z');
	    };

	    // Merge attributes from object `b` with attributes in object `a`.
	    // Note that this modifies the object `a`.
	    // Also important to note that attributes are merged but CSS classes are concatenated.
	    V.mergeAttrs = function(a, b) {

	        for (var attr in b) {

	            if (attr === 'class') {
	                // Concatenate classes.
	                a[attr] = a[attr] ? a[attr] + ' ' + b[attr] : b[attr];
	            } else if (attr === 'style') {
	                // `style` attribute can be an object.
	                if (V.isObject(a[attr]) && V.isObject(b[attr])) {
	                    // `style` stored in `a` is an object.
	                    a[attr] = V.mergeAttrs(a[attr], b[attr]);
	                } else if (V.isObject(a[attr])) {
	                    // `style` in `a` is an object but it's a string in `b`.
	                    // Convert the style represented as a string to an object in `b`.
	                    a[attr] = V.mergeAttrs(a[attr], V.styleToObject(b[attr]));
	                } else if (V.isObject(b[attr])) {
	                    // `style` in `a` is a string, in `b` it's an object.
	                    a[attr] = V.mergeAttrs(V.styleToObject(a[attr]), b[attr]);
	                } else {
	                    // Both styles are strings.
	                    a[attr] = V.mergeAttrs(V.styleToObject(a[attr]), V.styleToObject(b[attr]));
	                }
	            } else {
	                a[attr] = b[attr];
	            }
	        }

	        return a;
	    };

	    V.annotateString = function(t, annotations, opt) {

	        annotations = annotations || [];
	        opt = opt || {};

	        var offset = opt.offset || 0;
	        var compacted = [];
	        var batch;
	        var ret = [];
	        var item;
	        var prev;

	        for (var i = 0; i < t.length; i++) {

	            item = ret[i] = t[i];

	            for (var j = 0; j < annotations.length; j++) {

	                var annotation = annotations[j];
	                var start = annotation.start + offset;
	                var end = annotation.end + offset;

	                if (i >= start && i < end) {
	                    // Annotation applies.
	                    if (V.isObject(item)) {
	                        // There is more than one annotation to be applied => Merge attributes.
	                        item.attrs = V.mergeAttrs(V.mergeAttrs({}, item.attrs), annotation.attrs);
	                    } else {
	                        item = ret[i] = { t: t[i], attrs: annotation.attrs };
	                    }
	                    if (opt.includeAnnotationIndices) {
	                        (item.annotations || (item.annotations = [])).push(j);
	                    }
	                }
	            }

	            prev = ret[i - 1];

	            if (!prev) {

	                batch = item;

	            } else if (V.isObject(item) && V.isObject(prev)) {
	                // Both previous item and the current one are annotations. If the attributes
	                // didn't change, merge the text.
	                if (JSON.stringify(item.attrs) === JSON.stringify(prev.attrs)) {
	                    batch.t += item.t;
	                } else {
	                    compacted.push(batch);
	                    batch = item;
	                }

	            } else if (V.isObject(item)) {
	                // Previous item was a string, current item is an annotation.
	                compacted.push(batch);
	                batch = item;

	            } else if (V.isObject(prev)) {
	                // Previous item was an annotation, current item is a string.
	                compacted.push(batch);
	                batch = item;

	            } else {
	                // Both previous and current item are strings.
	                batch = (batch || '') + item;
	            }
	        }

	        if (batch) {
	            compacted.push(batch);
	        }

	        return compacted;
	    };

	    V.findAnnotationsAtIndex = function(annotations, index) {

	        var found = [];

	        if (annotations) {

	            annotations.forEach(function(annotation) {

	                if (annotation.start < index && index <= annotation.end) {
	                    found.push(annotation);
	                }
	            });
	        }

	        return found;
	    };

	    V.findAnnotationsBetweenIndexes = function(annotations, start, end) {

	        var found = [];

	        if (annotations) {

	            annotations.forEach(function(annotation) {

	                if ((start >= annotation.start && start < annotation.end) || (end > annotation.start && end <= annotation.end) || (annotation.start >= start && annotation.end < end)) {
	                    found.push(annotation);
	                }
	            });
	        }

	        return found;
	    };

	    // Shift all the text annotations after character `index` by `offset` positions.
	    V.shiftAnnotations = function(annotations, index, offset) {

	        if (annotations) {

	            annotations.forEach(function(annotation) {

	                if (annotation.start < index && annotation.end >= index) {
	                    annotation.end += offset;
	                } else if (annotation.start >= index) {
	                    annotation.start += offset;
	                    annotation.end += offset;
	                }
	            });
	        }

	        return annotations;
	    };

	    V.convertLineToPathData = function(line) {

	        line = V(line);
	        var d = [
	            'M', line.attr('x1'), line.attr('y1'),
	            'L', line.attr('x2'), line.attr('y2')
	        ].join(' ');
	        return d;
	    };

	    V.convertPolygonToPathData = function(polygon) {

	        var points = V.getPointsFromSvgNode(polygon);
	        if (points.length === 0) { return null; }

	        return V.svgPointsToPath(points) + ' Z';
	    };

	    V.convertPolylineToPathData = function(polyline) {

	        var points = V.getPointsFromSvgNode(polyline);
	        if (points.length === 0) { return null; }

	        return V.svgPointsToPath(points);
	    };

	    V.svgPointsToPath = function(points) {

	        for (var i = 0, n = points.length; i < n; i++) {
	            points[i] = points[i].x + ' ' + points[i].y;
	        }

	        return 'M ' + points.join(' L');
	    };

	    V.getPointsFromSvgNode = function(node) {

	        node = V.toNode(node);
	        var points = [];
	        var nodePoints = node.points;
	        if (nodePoints) {
	            for (var i = 0, n = nodePoints.numberOfItems; i < n; i++) {
	                points.push(nodePoints.getItem(i));
	            }
	        }

	        return points;
	    };

	    V.KAPPA = 0.551784;

	    V.convertCircleToPathData = function(circle) {

	        circle = V(circle);
	        var cx = parseFloat(circle.attr('cx')) || 0;
	        var cy = parseFloat(circle.attr('cy')) || 0;
	        var r = parseFloat(circle.attr('r'));
	        var cd = r * V.KAPPA; // Control distance.

	        var d = [
	            'M', cx, cy - r,    // Move to the first point.
	            'C', cx + cd, cy - r, cx + r, cy - cd, cx + r, cy, // I. Quadrant.
	            'C', cx + r, cy + cd, cx + cd, cy + r, cx, cy + r, // II. Quadrant.
	            'C', cx - cd, cy + r, cx - r, cy + cd, cx - r, cy, // III. Quadrant.
	            'C', cx - r, cy - cd, cx - cd, cy - r, cx, cy - r, // IV. Quadrant.
	            'Z'
	        ].join(' ');
	        return d;
	    };

	    V.convertEllipseToPathData = function(ellipse) {

	        ellipse = V(ellipse);
	        var cx = parseFloat(ellipse.attr('cx')) || 0;
	        var cy = parseFloat(ellipse.attr('cy')) || 0;
	        var rx = parseFloat(ellipse.attr('rx'));
	        var ry = parseFloat(ellipse.attr('ry')) || rx;
	        var cdx = rx * V.KAPPA; // Control distance x.
	        var cdy = ry * V.KAPPA; // Control distance y.

	        var d = [
	            'M', cx, cy - ry,    // Move to the first point.
	            'C', cx + cdx, cy - ry, cx + rx, cy - cdy, cx + rx, cy, // I. Quadrant.
	            'C', cx + rx, cy + cdy, cx + cdx, cy + ry, cx, cy + ry, // II. Quadrant.
	            'C', cx - cdx, cy + ry, cx - rx, cy + cdy, cx - rx, cy, // III. Quadrant.
	            'C', cx - rx, cy - cdy, cx - cdx, cy - ry, cx, cy - ry, // IV. Quadrant.
	            'Z'
	        ].join(' ');
	        return d;
	    };

	    V.convertRectToPathData = function(rect) {

	        rect = V(rect);

	        return V.rectToPath({
	            x: parseFloat(rect.attr('x')) || 0,
	            y: parseFloat(rect.attr('y')) || 0,
	            width: parseFloat(rect.attr('width')) || 0,
	            height: parseFloat(rect.attr('height')) || 0,
	            rx: parseFloat(rect.attr('rx')) || 0,
	            ry: parseFloat(rect.attr('ry')) || 0
	        });
	    };

	    // Convert a rectangle to SVG path commands. `r` is an object of the form:
	    // `{ x: [number], y: [number], width: [number], height: [number], top-ry: [number], top-ry: [number], bottom-rx: [number], bottom-ry: [number] }`,
	    // where `x, y, width, height` are the usual rectangle attributes and [top-/bottom-]rx/ry allows for
	    // specifying radius of the rectangle for all its sides (as opposed to the built-in SVG rectangle
	    // that has only `rx` and `ry` attributes).
	    V.rectToPath = function(r) {

	        var d;
	        var x = r.x;
	        var y = r.y;
	        var width = r.width;
	        var height = r.height;
	        var topRx = min(r.rx || r['top-rx'] || 0, width / 2);
	        var bottomRx = min(r.rx || r['bottom-rx'] || 0, width / 2);
	        var topRy = min(r.ry || r['top-ry'] || 0, height / 2);
	        var bottomRy = min(r.ry || r['bottom-ry'] || 0, height / 2);

	        if (topRx || bottomRx || topRy || bottomRy) {
	            d = [
	                'M', x, y + topRy,
	                'v', height - topRy - bottomRy,
	                'a', bottomRx, bottomRy, 0, 0, 0, bottomRx, bottomRy,
	                'h', width - 2 * bottomRx,
	                'a', bottomRx, bottomRy, 0, 0, 0, bottomRx, -bottomRy,
	                'v', -(height - bottomRy - topRy),
	                'a', topRx, topRy, 0, 0, 0, -topRx, -topRy,
	                'h', -(width - 2 * topRx),
	                'a', topRx, topRy, 0, 0, 0, -topRx, topRy,
	                'Z'
	            ];
	        } else {
	            d = [
	                'M', x, y,
	                'H', x + width,
	                'V', y + height,
	                'H', x,
	                'V', y,
	                'Z'
	            ];
	        }

	        return d.join(' ');
	    };

	    // Take a path data string
	    // Return a normalized path data string
	    // If data cannot be parsed, return 'M 0 0'
	    // Highly inspired by Raphael Library (www.raphael.com)
	    V.normalizePathData = (function() {

	        var spaces = '\x09\x0a\x0b\x0c\x0d\x20\xa0\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000\u2028\u2029';
	        var pathCommand = new RegExp('([a-z])[' + spaces + ',]*((-?\\d*\\.?\\d*(?:e[\\-+]?\\d+)?[' + spaces + ']*,?[' + spaces + ']*)+)', 'ig');
	        var pathValues = new RegExp('(-?\\d*\\.?\\d*(?:e[\\-+]?\\d+)?)[' + spaces + ']*,?[' + spaces + ']*', 'ig');

	        var math = Math;
	        var PI = math.PI;
	        var sin = math.sin;
	        var cos = math.cos;
	        var tan = math.tan;
	        var asin = math.asin;
	        var sqrt = math.sqrt;
	        var abs = math.abs;

	        function q2c(x1, y1, ax, ay, x2, y2) {

	            var _13 = 1 / 3;
	            var _23 = 2 / 3;
	            return [(_13 * x1) + (_23 * ax), (_13 * y1) + (_23 * ay), (_13 * x2) + (_23 * ax), (_13 * y2) + (_23 * ay), x2, y2];
	        }

	        function rotate(x, y, rad) {

	            var X = (x * cos(rad)) - (y * sin(rad));
	            var Y = (x * sin(rad)) + (y * cos(rad));
	            return { x: X, y: Y };
	        }

	        function a2c(x1, y1, rx, ry, angle, large_arc_flag, sweep_flag, x2, y2, recursive) {
	            // for more information of where this math came from visit:
	            // http://www.w3.org/TR/SVG11/implnote.html#ArcImplementationNotes
	            var _120 = (PI * 120) / 180;
	            var rad = (PI / 180) * (+angle || 0);
	            var res = [];
	            var xy;

	            if (!recursive) {
	                xy = rotate(x1, y1, -rad);
	                x1 = xy.x;
	                y1 = xy.y;

	                xy = rotate(x2, y2, -rad);
	                x2 = xy.x;
	                y2 = xy.y;

	                var x = (x1 - x2) / 2;
	                var y = (y1 - y2) / 2;
	                var h = ((x * x) / (rx * rx)) + ((y * y) / (ry * ry));

	                if (h > 1) {
	                    h = sqrt(h);
	                    rx = h * rx;
	                    ry = h * ry;
	                }

	                var rx2 = rx * rx;
	                var ry2 = ry * ry;

	                var k = ((large_arc_flag == sweep_flag) ? -1 : 1) * sqrt(abs(((rx2 * ry2) - (rx2 * y * y) - (ry2 * x * x)) / ((rx2 * y * y) + (ry2 * x * x))));

	                var cx = ((k * rx * y) / ry) + ((x1 + x2) / 2);
	                var cy = ((k * -ry * x) / rx) + ((y1 + y2) / 2);

	                var f1 = asin(((y1 - cy) / ry).toFixed(9));
	                var f2 = asin(((y2 - cy) / ry).toFixed(9));

	                f1 = ((x1 < cx) ? (PI - f1) : f1);
	                f2 = ((x2 < cx) ? (PI - f2) : f2);

	                if (f1 < 0) { f1 = (PI * 2) + f1; }
	                if (f2 < 0) { f2 = (PI * 2) + f2; }

	                if (sweep_flag && (f1 > f2)) { f1 = f1 - (PI * 2); }
	                if (!sweep_flag && (f2 > f1)) { f2 = f2 - (PI * 2); }

	            } else {
	                f1 = recursive[0];
	                f2 = recursive[1];
	                cx = recursive[2];
	                cy = recursive[3];
	            }

	            var df = f2 - f1;
	            if (abs(df) > _120) {
	                var f2old = f2;
	                var x2old = x2;
	                var y2old = y2;
	                f2 = f1 + (_120 * ((sweep_flag && (f2 > f1)) ? 1 : -1));
	                x2 = cx + (rx * cos(f2));
	                y2 = cy + (ry * sin(f2));
	                res = a2c(x2, y2, rx, ry, angle, 0, sweep_flag, x2old, y2old, [f2, f2old, cx, cy]);
	            }

	            df = f2 - f1;

	            var c1 = cos(f1);
	            var s1 = sin(f1);
	            var c2 = cos(f2);
	            var s2 = sin(f2);
	            var t = tan(df / 4);
	            var hx = (4 / 3) * (rx * t);
	            var hy = (4 / 3) * (ry * t);
	            var m1 = [x1, y1];
	            var m2 = [x1 + (hx * s1), y1 - (hy * c1)];
	            var m3 = [x2 + (hx * s2), y2 - (hy * c2)];
	            var m4 = [x2, y2];

	            m2[0] = (2 * m1[0]) - m2[0];
	            m2[1] = (2 * m1[1]) - m2[1];

	            if (recursive) {
	                return [m2, m3, m4].concat(res);
	            } else {
	                res = [m2, m3, m4].concat(res).join().split(',');
	                var newres = [];
	                var ii = res.length;
	                for (var i = 0; i < ii; i++) {
	                    newres[i] = (i % 2) ? rotate(res[i - 1], res[i], rad).y : rotate(res[i], res[i + 1], rad).x;
	                }
	                return newres;
	            }
	        }

	        function parsePathString(pathString) {

	            if (!pathString) { return null; }

	            var paramCounts = { a: 7, c: 6, h: 1, l: 2, m: 2, q: 4, s: 4, t: 2, v: 1, z: 0 };
	            var data = [];

	            String(pathString).replace(pathCommand, function(a, b, c) {

	                var params = [];
	                var name = b.toLowerCase();
	                c.replace(pathValues, function(a, b) {
	                    if (b) { params.push(+b); }
	                });

	                if ((name === 'm') && (params.length > 2)) {
	                    data.push([b].concat(params.splice(0, 2)));
	                    name = 'l';
	                    b = ((b === 'm') ? 'l' : 'L');
	                }

	                while (params.length >= paramCounts[name]) {
	                    data.push([b].concat(params.splice(0, paramCounts[name])));
	                    if (!paramCounts[name]) { break; }
	                }
	            });

	            return data;
	        }

	        function pathToAbsolute(pathArray) {

	            if (!Array.isArray(pathArray) || !Array.isArray(pathArray && pathArray[0])) { // rough assumption
	                pathArray = parsePathString(pathArray);
	            }

	            // if invalid string, return 'M 0 0'
	            if (!pathArray || !pathArray.length) { return [['M', 0, 0]]; }

	            var res = [];
	            var x = 0;
	            var y = 0;
	            var mx = 0;
	            var my = 0;
	            var start = 0;
	            var pa0;

	            var ii = pathArray.length;
	            for (var i = start; i < ii; i++) {

	                var r = [];
	                res.push(r);

	                var pa = pathArray[i];
	                pa0 = pa[0];

	                if (pa0 != pa0.toUpperCase()) {
	                    r[0] = pa0.toUpperCase();

	                    var jj;
	                    var j;
	                    switch (r[0]) {
	                        case 'A':
	                            r[1] = pa[1];
	                            r[2] = pa[2];
	                            r[3] = pa[3];
	                            r[4] = pa[4];
	                            r[5] = pa[5];
	                            r[6] = +pa[6] + x;
	                            r[7] = +pa[7] + y;
	                            break;

	                        case 'V':
	                            r[1] = +pa[1] + y;
	                            break;

	                        case 'H':
	                            r[1] = +pa[1] + x;
	                            break;

	                        case 'M':
	                            mx = +pa[1] + x;
	                            my = +pa[2] + y;

	                            jj = pa.length;
	                            for (j = 1; j < jj; j++) {
	                                r[j] = +pa[j] + ((j % 2) ? x : y);
	                            }
	                            break;

	                        default:
	                            jj = pa.length;
	                            for (j = 1; j < jj; j++) {
	                                r[j] = +pa[j] + ((j % 2) ? x : y);
	                            }
	                            break;
	                    }
	                } else {
	                    var kk = pa.length;
	                    for (var k = 0; k < kk; k++) {
	                        r[k] = pa[k];
	                    }
	                }

	                switch (r[0]) {
	                    case 'Z':
	                        x = +mx;
	                        y = +my;
	                        break;

	                    case 'H':
	                        x = r[1];
	                        break;

	                    case 'V':
	                        y = r[1];
	                        break;

	                    case 'M':
	                        mx = r[r.length - 2];
	                        my = r[r.length - 1];
	                        x = r[r.length - 2];
	                        y = r[r.length - 1];
	                        break;

	                    default:
	                        x = r[r.length - 2];
	                        y = r[r.length - 1];
	                        break;
	                }
	            }

	            return res;
	        }

	        function normalize(path) {

	            var p = pathToAbsolute(path);
	            var attrs = { x: 0, y: 0, bx: 0, by: 0, X: 0, Y: 0, qx: null, qy: null };

	            function processPath(path, d, pcom) {

	                var nx, ny;

	                if (!path) { return ['C', d.x, d.y, d.x, d.y, d.x, d.y]; }

	                if (!(path[0] in { T: 1, Q: 1 })) {
	                    d.qx = null;
	                    d.qy = null;
	                }

	                switch (path[0]) {
	                    case 'M':
	                        d.X = path[1];
	                        d.Y = path[2];
	                        break;

	                    case 'A':
	                        if (parseFloat(path[1]) === 0 || parseFloat(path[2]) === 0) {
	                            // https://www.w3.org/TR/SVG/paths.html#ArcOutOfRangeParameters
	                            // "If either rx or ry is 0, then this arc is treated as a
	                            // straight line segment (a "lineto") joining the endpoints."
	                            path = ['L', path[6], path[7]];
	                        } else {
	                            path = ['C'].concat(a2c.apply(0, [d.x, d.y].concat(path.slice(1))));
	                        }
	                        break;

	                    case 'S':
	                        if (pcom === 'C' || pcom === 'S') { // In 'S' case we have to take into account, if the previous command is C/S.
	                            nx = (d.x * 2) - d.bx;          // And reflect the previous
	                            ny = (d.y * 2) - d.by;          // command's control point relative to the current point.
	                        } else {                            // or some else or nothing
	                            nx = d.x;
	                            ny = d.y;
	                        }
	                        path = ['C', nx, ny].concat(path.slice(1));
	                        break;

	                    case 'T':
	                        if (pcom === 'Q' || pcom === 'T') { // In 'T' case we have to take into account, if the previous command is Q/T.
	                            d.qx = (d.x * 2) - d.qx;        // And make a reflection similar
	                            d.qy = (d.y * 2) - d.qy;        // to case 'S'.
	                        } else {                            // or something else or nothing
	                            d.qx = d.x;
	                            d.qy = d.y;
	                        }
	                        path = ['C'].concat(q2c(d.x, d.y, d.qx, d.qy, path[1], path[2]));
	                        break;

	                    case 'Q':
	                        d.qx = path[1];
	                        d.qy = path[2];
	                        path = ['C'].concat(q2c(d.x, d.y, path[1], path[2], path[3], path[4]));
	                        break;

	                    case 'H':
	                        path = ['L'].concat(path[1], d.y);
	                        break;

	                    case 'V':
	                        path = ['L'].concat(d.x, path[1]);
	                        break;

	                    case 'L':
	                        break;

	                    case 'Z':
	                        break;
	                }

	                return path;
	            }

	            function fixArc(pp, i) {

	                if (pp[i].length > 7) {

	                    pp[i].shift();
	                    var pi = pp[i];

	                    while (pi.length) {
	                        pcoms[i] = 'A'; // if created multiple 'C's, their original seg is saved
	                        pp.splice(i++, 0, ['C'].concat(pi.splice(0, 6)));
	                    }

	                    pp.splice(i, 1);
	                    ii = p.length;
	                }
	            }

	            var pcoms = []; // path commands of original path p
	            var pfirst = ''; // temporary holder for original path command
	            var pcom = ''; // holder for previous path command of original path

	            var ii = p.length;
	            for (var i = 0; i < ii; i++) {
	                if (p[i]) { pfirst = p[i][0]; } // save current path command

	                if (pfirst !== 'C') { // C is not saved yet, because it may be result of conversion
	                    pcoms[i] = pfirst; // Save current path command
	                    if (i > 0) { pcom = pcoms[i - 1]; } // Get previous path command pcom
	                }

	                p[i] = processPath(p[i], attrs, pcom); // Previous path command is inputted to processPath

	                if (pcoms[i] !== 'A' && pfirst === 'C') { pcoms[i] = 'C'; } // 'A' is the only command
	                // which may produce multiple 'C's
	                // so we have to make sure that 'C' is also 'C' in original path

	                fixArc(p, i); // fixArc adds also the right amount of 'A's to pcoms

	                var seg = p[i];
	                var seglen = seg.length;

	                attrs.x = seg[seglen - 2];
	                attrs.y = seg[seglen - 1];

	                attrs.bx = parseFloat(seg[seglen - 4]) || attrs.x;
	                attrs.by = parseFloat(seg[seglen - 3]) || attrs.y;
	            }

	            // make sure normalized path data string starts with an M segment
	            if (!p[0][0] || p[0][0] !== 'M') {
	                p.unshift(['M', 0, 0]);
	            }

	            return p;
	        }

	        return function(pathData) {
	            return normalize(pathData).join(',').split(',').join(' ');
	        };
	    })();

	    V.namespace = ns;

	    V.g = g;

	    return V;

	})();

	// Manipulation

	function cleanNodesData(nodes) {
	    var i = nodes.length;
	    while (i--) { cleanNodeData(nodes[i]); }
	}

	function cleanNodeData(node) {
	    $.event.remove(node);
	    dataPriv.remove(node);
	    dataUser.remove(node);
	}

	function removeNodes(nodes) {
	    for (var i = 0; i < nodes.length; i++) {
	        var node = nodes[i];
	        if (node.parentNode) {
	            node.parentNode.removeChild(node);
	        }
	    }
	}

	function remove() {
	    for (var i = 0; i < this.length; i++) {
	        var node = this[i];
	        cleanNodeData(node);
	        cleanNodesData(node.getElementsByTagName('*'));
	    }
	    removeNodes(this);
	    return this;
	}

	function detach() {
	    removeNodes(this);
	    return this;
	}

	function empty() {
	    for (var i = 0; i < this.length; i++) {
	        var node = this[i];
	        if (node.nodeType === 1) {
	            cleanNodesData(node.getElementsByTagName('*'));
	            // Remove any remaining nodes
	            node.textContent = '';
	        }
	    }
	    return this;
	}

	function clone$1() {
	    var clones = [];
	    for (var i = 0; i < this.length; i++) {
	        clones.push(this[i].cloneNode(true));
	    }
	    return this.pushStack(clones);
	}

	function html$1(html) {
	    var ref = this;
	    var el = ref[0];
	    if (!el) { return null; }
	    if (arguments.length === 0) { return el.innerHTML; }
	    if (html === undefined) { return this; } // do nothing
	    cleanNodesData(dataPriv, el.getElementsByTagName('*'));
	    if (typeof html === 'string' || typeof html === 'number') {
	        el.innerHTML = html;
	    } else {
	        el.innerHTML = '';
	        return this.append(html);
	    }
	    return this;
	}

	function append() {
	    var this$1 = this;
	    var nodes = [], len = arguments.length;
	    while ( len-- ) nodes[ len ] = arguments[ len ];

	    var ref = this;
	    var parent = ref[0];
	    if (!parent) { return this; }
	    nodes.forEach(function (node) {
	        var ref, ref$1;

	        if (!node) { return; }
	        if (typeof node === 'string') {
	            parent.append.apply(parent, $.parseHTML(node));
	        } else if (node.toString() === '[object Object]') {
	            // $ object
	            (ref = this$1).append.apply(ref, Array.from(node));
	        } else if (Array.isArray(node)) {
	            (ref$1 = this$1).append.apply(ref$1, node);
	        } else {
	            // DOM node
	            parent.appendChild(node);
	        }
	    });
	    return this;
	}

	function prepend() {
	    var this$1 = this;
	    var nodes = [], len = arguments.length;
	    while ( len-- ) nodes[ len ] = arguments[ len ];

	    var ref = this;
	    var parent = ref[0];
	    if (!parent) { return this; }
	    nodes.forEach(function (node) {
	        var ref, ref$1;

	        if (!node) { return; }
	        if (typeof node === 'string') {
	            parent.prepend.apply(parent, $.parseHTML(node));
	        } else if (node.toString() === '[object Object]') {
	            // $ object
	            (ref = this$1).prepend.apply(ref, Array.from(node));
	        } else if (Array.isArray(node)) {
	            (ref$1 = this$1).prepend.apply(ref$1, node);
	        } else {
	            // DOM node
	            parent.insertBefore(node, parent.firstChild);
	        }
	    });
	    return this;
	}

	function appendTo(parent) {
	    $(parent).append(this);
	    return this;
	}

	function prependTo(parent) {
	    $(parent).prepend(this);
	    return this;
	}

	// Styles and attributes

	var requireUnits = {};
	[
	    'width', 'height', 'top', 'bottom', 'left', 'right',
	    'padding', 'paddingTop', 'paddingBottom', 'paddingLeft', 'paddingRight',
	    'margin', 'marginTop', 'marginBottom', 'marginLeft', 'marginRight' ].forEach(function (cssProp) {
	    requireUnits[cssProp] = true;
	});

	function setCSSProperty(el, name, value) {
	    if (typeof value === 'number' && requireUnits[camelCase(name)]) {
	        value += 'px';
	    }
	    el.style[name] = value;
	}

	function css(name, value) {
	    var styles;
	    if (typeof name === 'string') {
	        if (value === undefined) {
	            var ref = this;
	            var el = ref[0];
	            if (!el) { return null; }
	            return el.style[name];
	        } else {
	            styles = {};
	            styles[name] = value;
	        }
	    } else if (!name) {
	        throw new Error('no styles provided');
	    } else {
	        styles = name;
	    }
	    for (var style in styles) {
	        if (styles.hasOwnProperty(style)) {
	            for (var i = 0; i < this.length; i++) {
	                setCSSProperty(this[i], style, styles[style]);
	            }
	        }
	    }
	    return this;
	}

	function data$1(name, value) {
	    if (arguments.length < 2) {
	        var ref = this;
	        var el = ref[0];
	        if (!el) { return null; }
	        if (name === undefined) {
	            return el.dataset;
	        }
	        return el.dataset[name];
	    }
	    for (var i = 0; i < this.length; i++) {
	        this[i].dataset[name] = value;
	    }
	    return this;
	}

	// Classes

	function setNodesClass(method, nodes, args) {
	    for (var i = 0; i < nodes.length; i++) {
	        var node = nodes[i];
	        V.prototype[method].apply({ node: node }, args);
	    }
	}

	function removeClass() {
	    setNodesClass('removeClass', this, arguments);
	    return this;
	}

	function addClass() {
	    setNodesClass('addClass', this, arguments);
	    return this;
	}

	function toggleClass() {
	    setNodesClass('toggleClass', this, arguments);
	    return this;
	}

	function hasClass() {
	    var ref = this;
	    var node = ref[0];
	    if (!node) { return false; }
	    return V.prototype.hasClass.apply({ node: node }, arguments);
	}

	// Traversing

	function children(selector) {
	    var matches = [];
	    for(var i = 0; i < this.length; i++) {
	        var node = this[i];
	        var children = Array.from(node.children);
	        if (typeof selector === 'string') {
	            children = children.filter(function (child) { return child.matches(selector); });
	        }
	        matches.push.apply(matches, children);
	    }
	    return this.pushStack(matches);
	}

	function closest(selector) {
	    var closest = [];
	    for (var i = 0; i < this.length; i++) {
	        var el = this[i];
	        if (typeof selector === 'string') {
	            var closestEl = el.closest(selector);
	            if (closestEl) {
	                closest.push(closestEl);
	            }
	        } else {
	            var ref = $(selector);
	            var ancestorEl = ref[0];
	            if (ancestorEl && ancestorEl.contains(el)) {
	                closest.push(ancestorEl);
	            }
	        }
	    }
	    return this.pushStack(closest);
	}

	// Events

	function on(types, selector, data, fn) {
	    $.event.on(this, types, selector, data, fn);
	    return this;
	}

	function one(types, selector, data, fn) {
	    $.event.on(this, types, selector, data, fn, 1);
	    return this;
	}

	function off(types, selector, fn) {
	    if (types && types.preventDefault && types.handleObj) {
	        // ( event )  dispatched $.Event
	        var handleObj = types.handleObj;
	        $(types.delegateTarget).off(
	            handleObj.namespace
	                ? handleObj.origType + '.' + handleObj.namespace
	                : handleObj.origType,
	            handleObj.selector,
	            handleObj.handler
	        );
	        return this;
	    }
	    if (typeof types === 'object') {
	        // ( types-object [, selector] )
	        for (var type in types) {
	            this.off(type, selector, types[type]);
	        }
	        return this;
	    }
	    if (selector === false || typeof selector === 'function') {
	        // ( types [, fn] )
	        fn = selector;
	        selector = undefined;
	    }
	    for (var i = 0; i < this.length; i++) {
	        $.event.remove(this[i], types, fn, selector);
	    }
	    return this;
	}

	// Measurements

	function width() {
	    var ref = this;
	    var el = ref[0];
	    if (el === window) { return el.document.documentElement.clientWidth; }
	    else if (!el) { return undefined; }
	    var styles = window.getComputedStyle(el);
	    var height = el.offsetWidth;
	    var borderTopWidth = parseFloat(styles.borderTopWidth);
	    var borderBottomWidth = parseFloat(styles.borderBottomWidth);
	    var paddingTop = parseFloat(styles.paddingTop);
	    var paddingBottom = parseFloat(styles.paddingBottom);
	    return height - borderBottomWidth - borderTopWidth - paddingTop - paddingBottom;
	}

	function height() {
	    var ref = this;
	    var el = ref[0];
	    if (el === window) { return el.document.documentElement.clientHeight; }
	    if (!el) { return undefined; }
	    var styles = window.getComputedStyle(el);
	    var width = el.offsetHeight;
	    var borderLeftWidth = parseFloat(styles.borderLeftWidth);
	    var borderRightWidth = parseFloat(styles.borderRightWidth);
	    var paddingLeft = parseFloat(styles.paddingLeft);
	    var paddingRight = parseFloat(styles.paddingRight);
	    return width - borderLeftWidth - borderRightWidth - paddingLeft - paddingRight;
	}

	function position() {
	    var ref = this;
	    var el = ref[0];
	    if (!el) { return; }
	    var $el = $(el);
	    var offsetParent;
	    var offset;
	    var doc;
	    var parentOffset = { top: 0, left: 0 };
	    // position:fixed elements are offset from the viewport, which itself always has zero offset
	    if ($el.css('position') === 'fixed') {
	        // Assume position:fixed implies availability of getBoundingClientRect
	        offset = el.getBoundingClientRect();
	    } else {
	        offset = $el.offset();
	        // Account for the *real* offset parent, which can be the document or its root element
	        // when a statically positioned element is identified
	        doc = el.ownerDocument;
	        offsetParent = el.offsetParent || doc.documentElement;
	        var $parentOffset = $(offsetParent);
	        var parentOffsetElementPosition = $parentOffset.css('position') || 'static';
	        while ( offsetParent && (offsetParent === doc.body || offsetParent === doc.documentElement) && parentOffsetElementPosition === 'static') {
	            offsetParent = offsetParent.parentNode;
	        }
	        if (offsetParent && offsetParent !== el && offsetParent.nodeType === 1) {
	            // Incorporate borders into its offset, since they are outside its content origin
	            var offsetParentStyles = window.getComputedStyle(offsetParent);
	            var borderTopWidth = parseFloat(offsetParentStyles.borderTopWidth) || 0;
	            var borderLeftWidth = parseFloat(offsetParentStyles.borderLeftWidth) || 0;
	            parentOffset = $parentOffset.offset();
	            parentOffset.top += borderTopWidth;
	            parentOffset.left += borderLeftWidth;
	        }
	    }
	    var marginTop = parseFloat(window.getComputedStyle(el).marginTop) || 0;
	    var marginLeft = parseFloat(window.getComputedStyle(el).marginLeft) || 0;
	    // Subtract parent offsets and element margins
	    return {
	        top: offset.top - parentOffset.top - marginTop,
	        left: offset.left - parentOffset.left - marginLeft
	    };
	}

	function offset(coordinates) {
	    var ref = this;
	    var el = ref[0];
	    //  Getter
	    if (coordinates === undefined) {
	        if (!el) { return null; }
	        if (!el.getClientRects().length) {
	            return { top: 0, left: 0 };
	        }
	        var rect = el.getBoundingClientRect();
	        return {
	            top: rect.top + window.scrollY,
	            left: rect.left + window.scrollX
	        };
	    }
	    // Setter
	    if (!el) { return this; }
	    var currentStyle = window.getComputedStyle(el);
	    if (currentStyle.position === 'static') {
	        this.css('position', 'relative');
	    }
	    var currentOffset = this.offset();
	    var topDifference = coordinates.top - currentOffset.top;
	    var leftDifference = coordinates.left - currentOffset.left;
	    this.css({
	        top: (parseFloat(currentStyle.top) || 0) + topDifference + 'px',
	        left: (parseFloat(currentStyle.left) || 0) + leftDifference + 'px'
	    });
	    return this;
	}

	var methods = ({
		remove: remove,
		detach: detach,
		empty: empty,
		clone: clone$1,
		html: html$1,
		append: append,
		prepend: prepend,
		appendTo: appendTo,
		prependTo: prependTo,
		css: css,
		data: data$1,
		removeClass: removeClass,
		addClass: addClass,
		toggleClass: toggleClass,
		hasClass: hasClass,
		children: children,
		closest: closest,
		on: on,
		one: one,
		off: off,
		width: width,
		height: height,
		position: position,
		offset: offset
	});

	var animationKey = 'animationFrameId';
	var cssReset = {};

	cssReset['transition-property'] =
	cssReset['transition-duration'] =
	cssReset['transition-delay'] =
	cssReset['transition-timing-function'] =
	cssReset['animation-name'] =
	cssReset['animation-duration'] =
	cssReset['animation-delay'] =
	cssReset['animation-timing-function'] = '';

	function animate(properties, opt) {
	    if ( opt === void 0 ) opt = {};

	    this.stop();
	    for (var i = 0; i < this.length; i++) {
	        animateNode(this[i], properties, opt);
	    }
	    return this;
	}

	function animateNode(el, properties, opt) {
	    if ( opt === void 0 ) opt = {};


	    var duration = opt.duration; if ( duration === void 0 ) duration = 400;
	    var easing = opt.easing; if ( easing === void 0 ) easing = 'ease-in-out';
	    var delay = opt.delay; if ( delay === void 0 ) delay = 0;
	    var complete = opt.complete;

	    var delayId = setTimeout(function() {

	        var $el = $(el);
	        var fired = false;
	        var endEvent = 'transitionend';

	        // Convert milliseconds to seconds for CSS
	        duration = duration / 1000;
	        delay = delay / 1000;

	        // Set up CSS values for transition or keyframe animation
	        var cssValues = {};
	        if (typeof properties === 'string') {
	            // Keyframe animation
	            cssValues['animation-name'] = properties;
	            cssValues['animation-duration'] = duration + 's';
	            cssValues['animation-delay'] = delay + 's';
	            cssValues['animation-timing-function'] = easing;
	            endEvent = 'animationend';
	        } else {
	            // CSS transitions
	            var transitionProperties = [];
	            for (var key in properties) {
	                if (properties.hasOwnProperty(key)) {
	                    cssValues[key] = properties[key];
	                    transitionProperties.push(key);
	                }
	            }

	            if (duration > 0) {
	                cssValues['transition-property'] = transitionProperties.join(', ');
	                cssValues['transition-duration'] = duration + 's';
	                cssValues['transition-delay'] = delay + 's';
	                cssValues['transition-timing-function'] = easing;
	            }
	        }

	        var wrappedCallback = function(event){
	            if (event) {
	                if (event.target !== event.currentTarget) { return; } // makes sure the event didn't bubble from "below"
	                event.target.removeEventListener(endEvent, wrappedCallback);
	            } else {
	                el.removeEventListener(endEvent, wrappedCallback); // triggered by setTimeout
	            }
	            fired = true;
	            $el.css(cssReset);
	            complete && complete.call(el);
	        };

	        if (duration > 0){
	            el.addEventListener(endEvent, wrappedCallback);
	            // transitionEnd is not always firing on older Android phones
	            // so make sure it gets fired
	            var callbackId = setTimeout(function() {
	                if (fired) { return; }
	                wrappedCallback(null);
	            }, ((duration + delay) * 1000) + 25);

	            dataPriv.set(el, animationKey, {
	                id: callbackId,
	                stop: function () {
	                    clearTimeout(callbackId);
	                    el.removeEventListener(endEvent, wrappedCallback);
	                }
	            });
	        }

	        $el.css(cssValues);

	        if (duration <= 0) {
	            wrappedCallback(null);
	        }
	    });

	    dataPriv.set(el, animationKey, {
	        stop: function () { return clearTimeout(delayId); }
	    });
	}

	function stop() {
	    for (var i = 0; i < this.length; i++) {
	        var el = this[i];
	        var animation = dataPriv.get(el, animationKey);
	        if (!animation) { continue; }
	        animation.stop();
	        dataPriv.remove(el, animationKey);
	    }
	    this.css(cssReset);
	    return this;
	}

	var animations = ({
		animate: animate,
		stop: stop
	});

	var propertySetters = {
	    outerWidth: 'offsetWidth',
	    outerHeight: 'offsetHeight',
	    innerWidth: 'clientWidth',
	    innerHeight: 'clientHeight',
	    scrollLeft: 'scrollLeft',
	    scrollTop: 'scrollTop',
	    val: 'value',
	    text: 'textContent',
	};

	var propertiesMap = {
	    disabled: 'disabled',
	    value: 'value',
	    text: 'textContent',
	};

	function prop(name, value) {
	    if (!name) { throw new Error('no property provided'); }
	    if (arguments.length === 1) {
	        var ref = this;
	        var el = ref[0];
	        if (!el) { return null; }
	        return el[name];
	    }
	    if (value === undefined) { return this; }
	    for (var i = 0; i < this.length; i++) {
	        this[i][name] = value;
	    }
	    return this;
	}

	function attr(name, value) {
	    var attributes;
	    if (typeof name === 'string') {
	        if (value === undefined) {
	            var ref = this;
	            var el = ref[0];
	            if (!el) { return null; }
	            return el.getAttribute(name);
	        } else {
	            attributes = {};
	            attributes[name] = value;
	        }
	    } else if (!name) {
	        throw new Error('no attributes provided');
	    } else {
	        attributes = name;
	    }
	    for (var attr in attributes) {
	        if (attributes.hasOwnProperty(attr)) {
	            var value$1 = attributes[attr];
	            if (propertiesMap[attr]) {
	                this.prop(propertiesMap[attr], value$1);
	                continue;
	            }
	            for (var i = 0; i < this.length; i++) {
	                if (value$1 === null) {
	                    this[i].removeAttribute(attr);
	                } else {
	                    this[i].setAttribute(attr, value$1);
	                }
	            }
	        }
	    }
	    return this;
	}

	var methods$1 = {
	    prop: prop,
	    attr: attr
	};

	Object.keys(propertySetters).forEach(function (methodName) {
	    methods$1[methodName] = function() {
	        var ref;

	        var args = [], len = arguments.length;
	        while ( len-- ) args[ len ] = arguments[ len ];
	        return (ref = this).prop.apply(ref, [ propertySetters[methodName] ].concat( args ));
	    };
	});

	var config = {
	    // When set to `true` the cell selectors could be defined as CSS selectors.
	    // If not, only JSON Markup selectors are taken into account.
	    useCSSSelectors: false,
	    // The class name prefix config is for advanced use only.
	    // Be aware that if you change the prefix, the JointJS CSS will no longer function properly.
	    classNamePrefix: 'joint-',
	    defaultTheme: 'default',
	    // The maximum delay required for two consecutive touchend events to be interpreted
	    // as a double-tap.
	    doubleTapInterval: 300
	};

	// TODO: should not read config outside the mvc package


	// Special events

	var special = Object.create(null);

	special.load = {
	    // Prevent triggered image.load events from bubbling to window.load
	    noBubble: true,
	};

	// Create mouseenter/leave events using mouseover/out and event-time checks
	// so that event delegation works in $.
	// Do the same for pointerenter/pointerleave and pointerover/pointerout
	[
	    ['mouseenter', 'mouseover'],
	    ['mouseleave', 'mouseout'],
	    ['pointerenter', 'pointerover'],
	    ['pointerleave', 'pointerout'] ].forEach(function (ref) {
	    var orig = ref[0];
	    var fix = ref[1];

	    special[orig] = {
	        delegateType: fix,
	        bindType: fix,
	        handle: function(event) {
	            var target = this;
	            var related = event.relatedTarget;
	            var handleObj = event.handleObj;
	            var ret;
	            // For mouseenter/leave call the handler if related is outside the target.
	            // NB: No relatedTarget if the mouse left/entered the browser window
	            if (!related || !target.contains(related)) {
	                event.type = handleObj.origType;
	                ret = handleObj.handler.apply(target, arguments);
	                event.type = fix;
	            }
	            return ret;
	        },
	    };
	});


	// Gestures

	var maxDelay = config.doubleTapInterval;
	var minDelay = 30;

	special.dbltap = {
	    bindType: 'touchend',
	    delegateType: 'touchend',
	    handle: function(event) {
	        var ref;

	        var args = [], len = arguments.length - 1;
	        while ( len-- > 0 ) args[ len ] = arguments[ len + 1 ];
	        var handleObj = event.handleObj;
	        var target = event.target;
	        var targetData = $.data.create(target);
	        var now = new Date().getTime();
	        var delta = 'lastTouch' in targetData ? now - targetData.lastTouch : 0;
	        if (delta < maxDelay && delta > minDelay) {
	            targetData.lastTouch = null;
	            event.type = handleObj.origType;
	            // let $ handle the triggering of "dbltap" event handlers
	            (ref = handleObj.handler).call.apply(ref, [ this, event ].concat( args ));
	        } else {
	            targetData.lastTouch = now;
	        }
	    }
	};

	Object.assign($.fn, methods);
	Object.assign($.fn, animations);
	Object.assign($.fn, methods$1);
	Object.assign($.event.special, special);

	var addClassNamePrefix = function(className) {

	    if (!className) { return className; }

	    return className.toString().split(' ').map(function(_className) {

	        if (_className.substr(0, config.classNamePrefix.length) !== config.classNamePrefix) {
	            _className = config.classNamePrefix + _className;
	        }

	        return _className;

	    }).join(' ');
	};

	var removeClassNamePrefix = function(className) {

	    if (!className) { return className; }

	    return className.toString().split(' ').map(function(_className) {

	        if (_className.substr(0, config.classNamePrefix.length) === config.classNamePrefix) {
	            _className = _className.substr(config.classNamePrefix.length);
	        }

	        return _className;

	    }).join(' ');
	};

	var parseDOMJSON = function(json, namespace) {

	    var selectors = {};
	    var groupSelectors = {};
	    var svgNamespace = V.namespace.svg;

	    var ns = namespace || svgNamespace;
	    var fragment = document.createDocumentFragment();

	    var parseNode = function(siblingsDef, parentNode, ns) {
	        for (var i = 0; i < siblingsDef.length; i++) {
	            var nodeDef = siblingsDef[i];

	            // Text node
	            if (typeof nodeDef === 'string') {
	                var textNode = document.createTextNode(nodeDef);
	                parentNode.appendChild(textNode);
	                continue;
	            }

	            // TagName
	            if (!nodeDef.hasOwnProperty('tagName')) { throw new Error('json-dom-parser: missing tagName'); }
	            var tagName = nodeDef.tagName;

	            var node = (void 0);

	            // Namespace URI
	            if (nodeDef.hasOwnProperty('namespaceURI')) { ns = nodeDef.namespaceURI; }
	            node = document.createElementNS(ns, tagName);
	            var svg = (ns === svgNamespace);

	            var wrapperNode = (svg) ? V(node) : $(node);
	            // Attributes
	            var attributes = nodeDef.attributes;
	            if (attributes) { wrapperNode.attr(attributes); }
	            // Style
	            var style = nodeDef.style;
	            if (style) { $(node).css(style); }
	            // ClassName
	            if (nodeDef.hasOwnProperty('className')) {
	                var className = nodeDef.className;
	                if (svg) {
	                    node.className.baseVal = className;
	                } else {
	                    node.className = className;
	                }
	            }
	            // TextContent
	            if (nodeDef.hasOwnProperty('textContent')) {
	                node.textContent = nodeDef.textContent;
	            }
	            // Selector
	            if (nodeDef.hasOwnProperty('selector')) {
	                var nodeSelector = nodeDef.selector;
	                if (selectors[nodeSelector]) { throw new Error('json-dom-parser: selector must be unique'); }
	                selectors[nodeSelector] = node;
	                wrapperNode.attr('joint-selector', nodeSelector);
	            }
	            // Groups
	            if (nodeDef.hasOwnProperty('groupSelector')) {
	                var nodeGroups = nodeDef.groupSelector;
	                if (!Array.isArray(nodeGroups)) { nodeGroups = [nodeGroups]; }
	                for (var j = 0; j < nodeGroups.length; j++) {
	                    var nodeGroup = nodeGroups[j];
	                    var group = groupSelectors[nodeGroup];
	                    if (!group) { group = groupSelectors[nodeGroup] = []; }
	                    group.push(node);
	                }
	            }

	            parentNode.appendChild(node);

	            // Children
	            var childrenDef = nodeDef.children;
	            if (Array.isArray(childrenDef)) {
	                parseNode(childrenDef, node, ns);
	            }
	        }
	    };
	    parseNode(json, fragment, ns);
	    return {
	        fragment: fragment,
	        selectors: selectors,
	        groupSelectors: groupSelectors
	    };
	};

	// Return a simple hash code from a string. See http://werxltd.com/wp/2010/05/13/javascript-implementation-of-javas-string-hashcode-method/.
	var hashCode = function(str) {

	    var hash = 0;
	    if (str.length === 0) { return hash; }
	    for (var i = 0; i < str.length; i++) {
	        var c = str.charCodeAt(i);
	        hash = ((hash << 5) - hash) + c;
	        hash = hash & hash; // Convert to 32bit integer
	    }
	    return hash;
	};

	var getByPath = function(obj, path, delimiter) {

	    var keys = Array.isArray(path) ? path : path.split(delimiter || '/');
	    var key;
	    var i = 0;
	    var length = keys.length;
	    while (i < length) {
	        key = keys[i++];
	        if (Object(obj) === obj && key in obj) {
	            obj = obj[key];
	        } else {
	            return undefined;
	        }
	    }
	    return obj;
	};

	var isGetSafe = function(obj, key) {
	    // Prevent prototype pollution
	    // https://snyk.io/vuln/SNYK-JS-JSON8MERGEPATCH-1038399
	    if (typeof key !== 'string' && typeof key !== 'number') {
	        key = String(key);
	    }
	    if (key === 'constructor' && typeof obj[key] === 'function') {
	        return false;
	    }
	    if (key === '__proto__') {
	        return false;
	    }
	    return true;
	};

	var setByPath = function(obj, path, value, delimiter) {

	    var keys = Array.isArray(path) ? path : path.split(delimiter || '/');
	    var last = keys.length - 1;
	    var diver = obj;
	    var i = 0;

	    for (; i < last; i++) {
	        var key = keys[i];
	        if (!isGetSafe(diver, key)) { return obj; }
	        var value$1 = diver[key];
	        // diver creates an empty object if there is no nested object under such a key.
	        // This means that one can populate an empty nested object with setByPath().
	        diver = value$1 || (diver[key] = {});
	    }

	    diver[keys[last]] = value;

	    return obj;
	};

	var unsetByPath = function(obj, path, delimiter) {

	    var keys = Array.isArray(path) ? path : path.split(delimiter || '/');
	    var last = keys.length - 1;
	    var diver = obj;
	    var i = 0;

	    for (; i < last; i++) {
	        var key = keys[i];
	        if (!isGetSafe(diver, key)) { return obj; }
	        var value = diver[key];
	        if (!value) { return obj; }
	        diver = value;
	    }

	    delete diver[keys[last]];

	    return obj;
	};

	var flattenObject = function(obj, delim, stop) {

	    delim = delim || '/';
	    var ret = {};

	    for (var key in obj) {

	        if (!obj.hasOwnProperty(key)) { continue; }

	        var shouldGoDeeper = typeof obj[key] === 'object';
	        if (shouldGoDeeper && stop && stop(obj[key])) {
	            shouldGoDeeper = false;
	        }

	        if (shouldGoDeeper) {

	            var flatObject = flattenObject(obj[key], delim, stop);

	            for (var flatKey in flatObject) {
	                if (!flatObject.hasOwnProperty(flatKey)) { continue; }
	                ret[key + delim + flatKey] = flatObject[flatKey];
	            }

	        } else {

	            ret[key] = obj[key];
	        }
	    }

	    return ret;
	};

	var uuid = function() {

	    // credit: http://stackoverflow.com/posts/2117523/revisions

	    return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
	        var r = (Math.random() * 16) | 0;
	        var v = (c === 'x') ? r : (r & 0x3 | 0x8);
	        return v.toString(16);
	    });
	};

	// Generates global unique id and stores it as a property of the object, if provided.
	var guid = function(obj) {

	    guid.id = guid.id || 1;

	    if (obj === undefined) {
	        return 'j_' + guid.id++;
	    }

	    obj.id = (obj.id === undefined ? 'j_' + guid.id++ : obj.id);
	    return obj.id;
	};

	var toKebabCase = function(string) {

	    return string.replace(/[A-Z]/g, '-$&').toLowerCase();
	};

	var normalizeEvent = function(evt) {

	    if (evt.normalized) { return evt; }

	    var originalEvent = evt.originalEvent;
	    var target = evt.target;

	    // If the event is a touch event, normalize it to a mouse event.
	    var touch = originalEvent && originalEvent.changedTouches && originalEvent.changedTouches[0];
	    if (touch) {
	        for (var property in touch) {
	            // copy all the properties from the first touch that are not
	            // defined on TouchEvent (clientX, clientY, pageX, pageY, screenX, screenY, identifier, ...)
	            if (evt[property] === undefined) {
	                evt[property] = touch[property];
	            }
	        }
	    }
	    // IE: evt.target could be set to SVGElementInstance for SVGUseElement
	    if (target) {
	        var useElement = target.correspondingUseElement;
	        if (useElement) { evt.target = useElement; }
	    }

	    evt.normalized = true;

	    return evt;
	};

	var normalizeWheel = function(evt) {
	    // Sane values derived empirically
	    var PIXEL_STEP  = 10;
	    var LINE_HEIGHT = 40;
	    var PAGE_HEIGHT = 800;

	    var sX = 0, sY = 0, pX = 0, pY = 0;

	    // Legacy
	    if ('detail'      in evt) { sY = evt.detail; }
	    if ('wheelDelta'  in evt) { sY = -evt.wheelDelta / 120; }
	    if ('wheelDeltaY' in evt) { sY = -evt.wheelDeltaY / 120; }
	    if ('wheelDeltaX' in evt) { sX = -evt.wheelDeltaX / 120; }

	    // side scrolling on FF with DOMMouseScroll
	    if ( 'axis' in evt && evt.axis === evt.HORIZONTAL_AXIS ) {
	        sX = sY;
	        sY = 0;
	    }

	    pX = 'deltaX' in evt ? evt.deltaX : sX * PIXEL_STEP;
	    pY = 'deltaY' in evt ? evt.deltaY : sY * PIXEL_STEP;

	    if ((pX || pY) && evt.deltaMode) {
	        if (evt.deltaMode == 1) {
	            pX *= LINE_HEIGHT;
	            pY *= LINE_HEIGHT;
	        } else {
	            pX *= PAGE_HEIGHT;
	            pY *= PAGE_HEIGHT;
	        }
	    }

	    // macOS switches deltaX and deltaY automatically when scrolling with shift key, so this is needed in other cases
	    if (evt.deltaX === 0 && evt.deltaY !== 0 && evt.shiftKey) {
	        pX = pY;
	        pY = 0;
	        sX = sY;
	        sY = 0;
	    }

	    // Fall-back if spin cannot be determined
	    if (pX && !sX) { sX = (pX < 1) ? -1 : 1; }
	    if (pY && !sY) { sY = (pY < 1) ? -1 : 1; }

	    return {
	        spinX  : sX,
	        spinY  : sY,
	        deltaX : pX,
	        deltaY : pY,
	    };
	};

	var cap = function(val, max) {
	    return val > max ? max : val < -max ? -max : val;
	};

	var nextFrame = (function() {

	    var raf;

	    if (typeof window !== 'undefined') {

	        raf = window.requestAnimationFrame ||
	            window.webkitRequestAnimationFrame ||
	            window.mozRequestAnimationFrame ||
	            window.oRequestAnimationFrame ||
	            window.msRequestAnimationFrame;
	    }

	    if (!raf) {

	        var lastTime = 0;

	        raf = function(callback) {

	            var currTime = new Date().getTime();
	            var timeToCall = Math.max(0, 16 - (currTime - lastTime));
	            var id = setTimeout(function() {
	                callback(currTime + timeToCall);
	            }, timeToCall);

	            lastTime = currTime + timeToCall;

	            return id;
	        };
	    }

	    return function(callback, context) {
	        var rest = [], len = arguments.length - 2;
	        while ( len-- > 0 ) rest[ len ] = arguments[ len + 2 ];

	        return (context !== undefined)
	            ? raf(callback.bind.apply(callback, [ context ].concat( rest )))
	            : raf(callback);
	    };

	})();

	var cancelFrame = (function() {

	    var caf;
	    var client = typeof window != 'undefined';

	    if (client) {

	        caf = window.cancelAnimationFrame ||
	            window.webkitCancelAnimationFrame ||
	            window.webkitCancelRequestAnimationFrame ||
	            window.msCancelAnimationFrame ||
	            window.msCancelRequestAnimationFrame ||
	            window.oCancelAnimationFrame ||
	            window.oCancelRequestAnimationFrame ||
	            window.mozCancelAnimationFrame ||
	            window.mozCancelRequestAnimationFrame;
	    }

	    caf = caf || clearTimeout;

	    return client ? caf.bind(window) : caf;

	})();

	var isPercentage = function(val) {

	    return isString(val) && val.slice(-1) === '%';
	};

	var parseCssNumeric = function(val, restrictUnits) {

	    function getUnit(validUnitExp) {

	        // one or more numbers, followed by
	        // any number of (
	        //  `.`, followed by
	        //  one or more numbers
	        // ), followed by
	        // `validUnitExp`, followed by
	        // end of string
	        var matches = new RegExp('(?:\\d+(?:\\.\\d+)*)(' + validUnitExp + ')$').exec(val);

	        if (!matches) { return null; }
	        return matches[1];
	    }

	    var number = parseFloat(val);

	    // if `val` cannot be parsed as a number, return `null`
	    if (Number.isNaN(number)) { return null; }

	    // else: we know `output.value`
	    var output = {};
	    output.value = number;

	    // determine the unit
	    var validUnitExp;
	    if (restrictUnits == null) {
	        // no restriction
	        // accept any unit, as well as no unit
	        validUnitExp = '[A-Za-z]*';

	    } else if (Array.isArray(restrictUnits)) {
	        // if this is an empty array, top restriction - return `null`
	        if (restrictUnits.length === 0) { return null; }

	        // else: restriction - an array of valid unit strings
	        validUnitExp = restrictUnits.join('|');

	    } else if (isString(restrictUnits)) {
	        // restriction - a single valid unit string
	        validUnitExp = restrictUnits;
	    }
	    var unit = getUnit(validUnitExp);

	    // if we found no matches for `restrictUnits`, return `null`
	    if (unit === null) { return null; }

	    // else: we know the unit
	    output.unit = unit;
	    return output;
	};

	var NO_SPACE = 0;

	function splitWordWithEOL(word, eol) {
	    var eolWords = word.split(eol);
	    var n = 1;
	    for (var j = 0, jl = eolWords.length - 1; j < jl; j++) {
	        var replacement = [];
	        if (j > 0 || eolWords[0] !== '') { replacement.push(NO_SPACE); }
	        replacement.push(eol);
	        if (j < jl - 1 || eolWords[jl] !== '') { replacement.push(NO_SPACE); }
	        eolWords.splice.apply(eolWords, [ n, 0 ].concat( replacement ));
	        n += replacement.length + 1;
	    }
	    return eolWords.filter(function (word) { return word !== ''; });
	}


	function getLineHeight(heightValue, textElement) {
	    if (heightValue === null) {
	        // Default 1em lineHeight
	        return textElement.getBBox().height;
	    }

	    switch (heightValue.unit) {
	        case 'em':
	            return textElement.getBBox().height * heightValue.value;
	        case 'px':
	        case '':
	            return heightValue.value;
	    }
	}

	var breakText = function(text, size, styles, opt) {
	    if ( styles === void 0 ) styles = {};
	    if ( opt === void 0 ) opt = {};


	    var width = size.width;
	    var height = size.height;

	    var svgDocument = opt.svgDocument || V('svg').node;
	    var textSpan = V('tspan').node;
	    var textElement = V('text').attr(styles).append(textSpan).node;
	    var textNode = document.createTextNode('');

	    // Prevent flickering
	    textElement.style.opacity = 0;
	    // Prevent FF from throwing an uncaught exception when `getBBox()`
	    // called on element that is not in the render tree (is not measurable).
	    // <tspan>.getComputedTextLength() returns always 0 in this case.
	    // Note that the `textElement` resp. `textSpan` can become hidden
	    // when it's appended to the DOM and a `display: none` CSS stylesheet
	    // rule gets applied.
	    textElement.style.display = 'block';
	    textSpan.style.display = 'block';

	    textSpan.appendChild(textNode);
	    svgDocument.appendChild(textElement); // lgtm [js/xss-through-dom]

	    if (!opt.svgDocument) {

	        document.body.appendChild(svgDocument);
	    }

	    var preserveSpaces = opt.preserveSpaces;
	    var space = ' ';
	    var separator = (opt.separator || opt.separator === '') ? opt.separator : space;
	    // If separator is a RegExp, we use the space character to join words together again (not ideal)
	    var separatorChar = (typeof separator === 'string') ? separator : space;
	    var eol = opt.eol || '\n';
	    var hyphen = opt.hyphen ? new RegExp(opt.hyphen) : /[^\w\d\u00C0-\u1FFF\u2800-\uFFFD]/;
	    var maxLineCount = opt.maxLineCount;
	    if (!isNumber(maxLineCount)) { maxLineCount = Infinity; }

	    var words = text.split(separator);
	    var full = [];
	    var lines = [];
	    var p, h;
	    var lineHeight;

	    if (preserveSpaces) {
	        V(textSpan).attr('xml:space', 'preserve');
	    }

	    for (var i = 0, l = 0, len = words.length; i < len; i++) {

	        var word = words[i];

	        if (!word && !preserveSpaces) { continue; }
	        if (typeof word !== 'string') { continue; }

	        var isEol = false;
	        if (eol && word.indexOf(eol) >= 0) {
	            // word contains end-of-line character
	            if (word.length > 1) {
	                // separate word and continue cycle
	                var eolWords = splitWordWithEOL(words[i], eol);
	                words.splice.apply(words, [ i, 1 ].concat( eolWords ));
	                i--;
	                len = words.length;
	                continue;
	            } else {
	                // creates a new line
	                if (preserveSpaces && typeof words[i - 1] === 'string' ) {
	                    words.splice(i, NO_SPACE, '', NO_SPACE);
	                    len += 2;
	                    i--;
	                    continue;
	                }
	                lines[++l] = (!preserveSpaces || typeof words[i + 1] === 'string') ? '' : undefined;
	                isEol = true;
	            }
	        }

	        if (!isEol) {

	            var data = (void 0);
	            if (preserveSpaces) {
	                data = lines[l] !== undefined ? lines[l] + separatorChar + word : word;
	            } else {
	                data = lines[l] ? lines[l] + separatorChar + word : word;
	            }

	            textNode.data = data;

	            if (textSpan.getComputedTextLength() <= width) {

	                // the current line fits
	                lines[l] = data;

	                if (p || h) {
	                    // We were partitioning. Put rest of the word onto next line
	                    full[l++] = true;

	                    // cancel partitioning and splitting by hyphens
	                    p = 0;
	                    h = 0;
	                }

	            } else {

	                if (!lines[l] || p) {

	                    var partition = !!p;

	                    p = word.length - 1;

	                    if (partition || !p) {

	                        // word has only one character.
	                        if (!p) {

	                            if (!lines[l]) {

	                                // we won't fit this text within our rect
	                                lines = [];

	                                break;
	                            }

	                            // partitioning didn't help on the non-empty line
	                            // try again, but this time start with a new line

	                            // cancel partitions created
	                            words.splice(i, 2, word + words[i + 1]);

	                            // adjust word length
	                            len--;

	                            full[l++] = true;
	                            i--;

	                            continue;
	                        }

	                        // move last letter to the beginning of the next word
	                        words[i] = word.substring(0, p);
	                        var nextWord = words[i + 1];
	                        words[i + 1] = word.substring(p) + (nextWord === undefined || nextWord === NO_SPACE ? '' : nextWord);

	                    } else {

	                        if (h) {
	                        // cancel splitting and put the words together again
	                            words.splice(i, 2, words[i] + words[i + 1]);
	                            h = 0;
	                        } else {
	                            var hyphenIndex = word.search(hyphen);
	                            if (hyphenIndex > -1 && hyphenIndex !== word.length - 1 && hyphenIndex !== 0) {
	                                h = hyphenIndex + 1;
	                                p = 0;
	                            }

	                            // We initiate partitioning or splitting
	                            // split the long word into two words
	                            words.splice(i, 1, word.substring(0, h || p), word.substring(h|| p));
	                            // adjust words length
	                            len++;

	                        }

	                        if (l && !full[l - 1]) {
	                        // if the previous line is not full, try to fit max part of
	                        // the current word there
	                            l--;
	                        }
	                    }

	                    if (!preserveSpaces || lines[l] !== '') {
	                        i--;
	                    }

	                    continue;
	                }

	                l++;
	                i--;
	            }
	        }
	        var lastL = null;

	        if (lines.length > maxLineCount) {

	            lastL = maxLineCount - 1;

	        } else if (height !== undefined) {

	            // if size.height is defined we have to check whether the height of the entire
	            // text exceeds the rect height

	            if (lineHeight === undefined && textNode.data !== '') {

	                // use the same defaults as in V.prototype.text
	                if (styles.lineHeight === 'auto') {
	                    lineHeight = getLineHeight({ value: 1.5, unit: 'em' }, textElement);
	                } else {
	                    var parsed = parseCssNumeric(styles.lineHeight, ['em', 'px', '']);

	                    lineHeight = getLineHeight(parsed, textElement);
	                }
	            }

	            if (lineHeight * lines.length > height) {
	                // remove overflowing lines
	                lastL = Math.floor(height / lineHeight) - 1;
	            }
	        }

	        if (lastL !== null) {

	            lines.splice(lastL + 1);

	            // add ellipsis
	            var ellipsis = opt.ellipsis;
	            if (!ellipsis || lastL < 0) { break; }
	            if (typeof ellipsis !== 'string') { ellipsis = '\u2026'; }

	            var lastLine = lines[lastL];
	            if (!lastLine && !isEol) { break; }
	            var k = lastLine.length;
	            var lastLineWithOmission, lastChar;
	            do {
	                lastChar = lastLine[k];
	                lastLineWithOmission = lastLine.substring(0, k);
	                if (!lastChar) {
	                    lastLineWithOmission += separatorChar;
	                } else if (lastChar.match(separator)) {
	                    lastLineWithOmission += lastChar;
	                }
	                lastLineWithOmission += ellipsis;
	                textNode.data = lastLineWithOmission;
	                if (textSpan.getComputedTextLength() <= width) {
	                    lines[lastL] = lastLineWithOmission;
	                    break;
	                }
	                k--;
	            } while (k >= 0);
	            break;
	        }
	    }

	    if (opt.svgDocument) {

	        // svg document was provided, remove the text element only
	        svgDocument.removeChild(textElement);

	    } else {

	        // clean svg document
	        document.body.removeChild(svgDocument);
	    }

	    return lines.join(eol);
	};

	// Sanitize HTML
	// Based on https://gist.github.com/ufologist/5a0da51b2b9ef1b861c30254172ac3c9
	// Parses a string into an array of DOM nodes.
	// Then outputs it back as a string.
	var sanitizeHTML = function(html) {

	    // Ignores tags that are invalid inside a <div> tag (e.g. <body>, <head>)
	    var ref = $.parseHTML('<div>' + html + '</div>');
	    var outputEl = ref[0];

	    Array.from(outputEl.getElementsByTagName('*')).forEach(function(node) { // for all nodes
	        var names = node.getAttributeNames();
	        names.forEach(function(name) {
	            var value = node.getAttribute(name);
	            // Remove attribute names that start with "on" (e.g. onload, onerror...).
	            // Remove attribute values that start with "javascript:" pseudo protocol (e.g. `href="javascript:alert(1)"`).
	            if (name.startsWith('on') || value.startsWith('javascript:' || value.startsWith('data:') || value.startsWith('vbscript:'))) {
	                node.removeAttribute(name);
	            }
	        });
	    });

	    return outputEl.innerHTML;
	};

	// Download `blob` as file with `fileName`.
	// Does not work in IE9.
	var downloadBlob = function(blob, fileName) {

	    if (window.navigator.msSaveBlob) { // requires IE 10+
	        // pulls up a save dialog
	        window.navigator.msSaveBlob(blob, fileName);

	    } else { // other browsers
	        // downloads directly in Chrome and Safari

	        // presents a save/open dialog in Firefox
	        // Firefox bug: `from` field in save dialog always shows `from:blob:`
	        // https://bugzilla.mozilla.org/show_bug.cgi?id=1053327

	        var url = window.URL.createObjectURL(blob);
	        var link = document.createElement('a');

	        link.href = url;
	        link.download = fileName;
	        document.body.appendChild(link);

	        link.click();

	        document.body.removeChild(link);
	        window.URL.revokeObjectURL(url); // mark the url for garbage collection
	    }
	};

	// Download `dataUri` as file with `fileName`.
	// Does not work in IE9.
	var downloadDataUri = function(dataUri, fileName) {

	    var blob = dataUriToBlob(dataUri);
	    downloadBlob(blob, fileName);
	};

	// Convert an uri-encoded data component (possibly also base64-encoded) to a blob.
	var dataUriToBlob = function(dataUri) {

	    // first, make sure there are no newlines in the data uri
	    dataUri = dataUri.replace(/\s/g, '');
	    dataUri = decodeURIComponent(dataUri);

	    var firstCommaIndex = dataUri.indexOf(','); // split dataUri as `dataTypeString`,`data`

	    var dataTypeString = dataUri.slice(0, firstCommaIndex); // e.g. 'data:image/jpeg;base64'
	    var mimeString = dataTypeString.split(':')[1].split(';')[0]; // e.g. 'image/jpeg'

	    var data = dataUri.slice(firstCommaIndex + 1);
	    var decodedString;
	    if (dataTypeString.indexOf('base64') >= 0) { // data may be encoded in base64
	        decodedString = atob(data); // decode data
	    } else {
	        // convert the decoded string to UTF-8
	        decodedString = unescape(encodeURIComponent(data));
	    }
	    // write the bytes of the string to a typed array
	    var ia = new Uint8Array(decodedString.length);
	    for (var i = 0; i < decodedString.length; i++) {
	        ia[i] = decodedString.charCodeAt(i);
	    }

	    return new Blob([ia], { type: mimeString }); // return the typed array as Blob
	};

	// Read an image at `url` and return it as base64-encoded data uri.
	// The mime type of the image is inferred from the `url` file extension.
	// If data uri is provided as `url`, it is returned back unchanged.
	// `callback` is a method with `err` as first argument and `dataUri` as second argument.
	// Works with IE9.
	var imageToDataUri = function(url, callback) {

	    if (!url || url.substr(0, 'data:'.length) === 'data:') {
	        // No need to convert to data uri if it is already in data uri.

	        // This not only convenient but desired. For example,
	        // IE throws a security error if data:image/svg+xml is used to render
	        // an image to the canvas and an attempt is made to read out data uri.
	        // Now if our image is already in data uri, there is no need to render it to the canvas
	        // and so we can bypass this error.

	        // Keep the async nature of the function.
	        return setTimeout(function() {
	            callback(null, url);
	        }, 0);
	    }

	    // chrome, IE10+
	    var modernHandler = function(xhr, callback) {

	        if (xhr.status === 200) {

	            var reader = new FileReader();

	            reader.onload = function(evt) {
	                var dataUri = evt.target.result;
	                callback(null, dataUri);
	            };

	            reader.onerror = function() {
	                callback(new Error('Failed to load image ' + url));
	            };

	            reader.readAsDataURL(xhr.response);
	        } else {
	            callback(new Error('Failed to load image ' + url));
	        }
	    };

	    var legacyHandler = function(xhr, callback) {

	        var Uint8ToString = function(u8a) {
	            var CHUNK_SZ = 0x8000;
	            var c = [];
	            for (var i = 0; i < u8a.length; i += CHUNK_SZ) {
	                c.push(String.fromCharCode.apply(null, u8a.subarray(i, i + CHUNK_SZ)));
	            }
	            return c.join('');
	        };

	        if (xhr.status === 200) {

	            var bytes = new Uint8Array(xhr.response);

	            var suffix = (url.split('.').pop()) || 'png';
	            var map = {
	                'svg': 'svg+xml'
	            };
	            var meta = 'data:image/' + (map[suffix] || suffix) + ';base64,';
	            var b64encoded = meta + btoa(Uint8ToString(bytes));
	            callback(null, b64encoded);
	        } else {
	            callback(new Error('Failed to load image ' + url));
	        }
	    };

	    var xhr = new XMLHttpRequest();

	    xhr.open('GET', url, true);
	    xhr.addEventListener('error', function() {
	        callback(new Error('Failed to load image ' + url));
	    });

	    xhr.responseType = window.FileReader ? 'blob' : 'arraybuffer';

	    xhr.addEventListener('load', function() {
	        if (window.FileReader) {
	            modernHandler(xhr, callback);
	        } else {
	            legacyHandler(xhr, callback);
	        }
	    });

	    xhr.send();
	};

	var getElementBBox = function(el) {

	    var $el = $(el);
	    if ($el.length === 0) {
	        throw new Error('Element not found');
	    }

	    var element = $el[0];
	    var doc = element.ownerDocument;
	    var clientBBox = element.getBoundingClientRect();

	    var strokeWidthX = 0;
	    var strokeWidthY = 0;

	    // Firefox correction
	    if (element.ownerSVGElement) {

	        var vel = V(element);
	        var bbox = vel.getBBox({ target: vel.svg() });

	        // if FF getBoundingClientRect includes stroke-width, getBBox doesn't.
	        // To unify this across all browsers we need to adjust the final bBox with `stroke-width` value.
	        strokeWidthX = (clientBBox.width - bbox.width);
	        strokeWidthY = (clientBBox.height - bbox.height);
	    }

	    return {
	        x: clientBBox.left + window.pageXOffset - doc.documentElement.offsetLeft + strokeWidthX / 2,
	        y: clientBBox.top + window.pageYOffset - doc.documentElement.offsetTop + strokeWidthY / 2,
	        width: clientBBox.width - strokeWidthX,
	        height: clientBBox.height - strokeWidthY
	    };
	};


	// Highly inspired by the jquery.sortElements plugin by Padolsey.
	// See http://james.padolsey.com/javascript/sorting-elements-with-jquery/.
	var sortElements = function(elements, comparator) {

	    elements = $(elements).toArray();
	    var placements = elements.map(function(sortElement) {

	        var parentNode = sortElement.parentNode;
	        // Since the element itself will change position, we have
	        // to have some way of storing it's original position in
	        // the DOM. The easiest way is to have a 'flag' node:
	        var nextSibling = parentNode.insertBefore(document.createTextNode(''), sortElement.nextSibling);

	        return function() {

	            if (parentNode === this) {
	                throw new Error('You can\'t sort elements if any one is a descendant of another.');
	            }

	            // Insert before flag:
	            parentNode.insertBefore(this, nextSibling);
	            // Remove flag:
	            parentNode.removeChild(nextSibling);
	        };
	    });

	    elements.sort(comparator);
	    for (var i = 0; i < placements.length; i++) {
	        placements[i].call(elements[i]);
	    }
	    return elements;
	};

	// Sets attributes on the given element and its descendants based on the selector.
	// `attrs` object: { [SELECTOR1]: { attrs1 }, [SELECTOR2]: { attrs2}, ... } e.g. { 'input': { color : 'red' }}
	var setAttributesBySelector = function(element, attrs) {

	    var $element = $(element);

	    forIn(attrs, function(attrs, selector) {
	        var $elements = $element.find(selector).addBack().filter(selector);
	        // Make a special case for setting classes.
	        // We do not want to overwrite any existing class.
	        if (has$2(attrs, 'class')) {
	            $elements.addClass(attrs['class']);
	            attrs = omit(attrs, 'class');
	        }
	        $elements.attr(attrs);
	    });
	};

	// Return a new object with all four sides (top, right, bottom, left) in it.
	// Value of each side is taken from the given argument (either number or object).
	// Default value for a side is 0.
	// Examples:
	// normalizeSides(5) --> { top: 5, right: 5, bottom: 5, left: 5 }
	// normalizeSides({ horizontal: 5 }) --> { top: 0, right: 5, bottom: 0, left: 5 }
	// normalizeSides({ left: 5 }) --> { top: 0, right: 0, bottom: 0, left: 5 }
	// normalizeSides({ horizontal: 10, left: 5 }) --> { top: 0, right: 10, bottom: 0, left: 5 }
	// normalizeSides({ horizontal: 0, left: 5 }) --> { top: 0, right: 0, bottom: 0, left: 5 }
	var normalizeSides = function(box) {

	    if (Object(box) !== box) { // `box` is not an object
	        var val = 0; // `val` left as 0 if `box` cannot be understood as finite number
	        if (isFinite(box)) { val = +box; } // actually also accepts string numbers (e.g. '100')

	        return { top: val, right: val, bottom: val, left: val };
	    }

	    // `box` is an object
	    var top, right, bottom, left;
	    top = right = bottom = left = 0;

	    if (isFinite(box.vertical)) { top = bottom = +box.vertical; }
	    if (isFinite(box.horizontal)) { right = left = +box.horizontal; }

	    if (isFinite(box.top)) { top = +box.top; } // overwrite vertical
	    if (isFinite(box.right)) { right = +box.right; } // overwrite horizontal
	    if (isFinite(box.bottom)) { bottom = +box.bottom; } // overwrite vertical
	    if (isFinite(box.left)) { left = +box.left; } // overwrite horizontal

	    return { top: top, right: right, bottom: bottom, left: left };
	};

	var timing = {

	    linear: function(t) {
	        return t;
	    },

	    quad: function(t) {
	        return t * t;
	    },

	    cubic: function(t) {
	        return t * t * t;
	    },

	    inout: function(t) {
	        if (t <= 0) { return 0; }
	        if (t >= 1) { return 1; }
	        var t2 = t * t;
	        var t3 = t2 * t;
	        return 4 * (t < .5 ? t3 : 3 * (t - t2) + t3 - .75);
	    },

	    exponential: function(t) {
	        return Math.pow(2, 10 * (t - 1));
	    },

	    bounce: function(t) {
	        for (var a = 0, b = 1; 1; a += b, b /= 2) {
	            if (t >= (7 - 4 * a) / 11) {
	                var q = (11 - 6 * a - 11 * t) / 4;
	                return -q * q + b * b;
	            }
	        }
	    },

	    reverse: function(f) {
	        return function(t) {
	            return 1 - f(1 - t);
	        };
	    },

	    reflect: function(f) {
	        return function(t) {
	            return .5 * (t < .5 ? f(2 * t) : (2 - f(2 - 2 * t)));
	        };
	    },

	    clamp: function(f, n, x) {
	        n = n || 0;
	        x = x || 1;
	        return function(t) {
	            var r = f(t);
	            return r < n ? n : r > x ? x : r;
	        };
	    },

	    back: function(s) {
	        if (!s) { s = 1.70158; }
	        return function(t) {
	            return t * t * ((s + 1) * t - s);
	        };
	    },

	    elastic: function(x) {
	        if (!x) { x = 1.5; }
	        return function(t) {
	            return Math.pow(2, 10 * (t - 1)) * Math.cos(20 * Math.PI * x / 3 * t);
	        };
	    }
	};

	var interpolate = {

	    number: function(a, b) {
	        var d = b - a;
	        return function(t) {
	            return a + d * t;
	        };
	    },

	    object: function(a, b) {
	        var s = Object.keys(a);
	        return function(t) {
	            var i, p;
	            var r = {};
	            for (i = s.length - 1; i != -1; i--) {
	                p = s[i];
	                r[p] = a[p] + (b[p] - a[p]) * t;
	            }
	            return r;
	        };
	    },

	    hexColor: function(a, b) {

	        var ca = parseInt(a.slice(1), 16);
	        var cb = parseInt(b.slice(1), 16);
	        var ra = ca & 0x0000ff;
	        var rd = (cb & 0x0000ff) - ra;
	        var ga = ca & 0x00ff00;
	        var gd = (cb & 0x00ff00) - ga;
	        var ba = ca & 0xff0000;
	        var bd = (cb & 0xff0000) - ba;

	        return function(t) {

	            var r = (ra + rd * t) & 0x000000ff;
	            var g = (ga + gd * t) & 0x0000ff00;
	            var b = (ba + bd * t) & 0x00ff0000;

	            return '#' + (1 << 24 | r | g | b).toString(16).slice(1);
	        };
	    },

	    unit: function(a, b) {

	        var r = /(-?[0-9]*.[0-9]*)(px|em|cm|mm|in|pt|pc|%)/;
	        var ma = r.exec(a);
	        var mb = r.exec(b);
	        var p = mb[1].indexOf('.');
	        var f = p > 0 ? mb[1].length - p - 1 : 0;
	        a = +ma[1];
	        var d = +mb[1] - a;
	        var u = ma[2];

	        return function(t) {
	            return (a + d * t).toFixed(f) + u;
	        };
	    }
	};

	// SVG filters.
	// (values in parentheses are default values)
	var filter = {

	    // `color` ... outline color ('blue')
	    // `width`... outline width (1)
	    // `opacity` ... outline opacity (1)
	    // `margin` ... gap between outline and the element (2)
	    outline: function(args) {

	        var tpl = '<filter><feFlood flood-color="${color}" flood-opacity="${opacity}" result="colored"/><feMorphology in="SourceAlpha" result="morphedOuter" operator="dilate" radius="${outerRadius}" /><feMorphology in="SourceAlpha" result="morphedInner" operator="dilate" radius="${innerRadius}" /><feComposite result="morphedOuterColored" in="colored" in2="morphedOuter" operator="in"/><feComposite operator="xor" in="morphedOuterColored" in2="morphedInner" result="outline"/><feMerge><feMergeNode in="outline"/><feMergeNode in="SourceGraphic"/></feMerge></filter>';

	        var margin = Number.isFinite(args.margin) ? args.margin : 2;
	        var width = Number.isFinite(args.width) ? args.width : 1;

	        return template(tpl)({
	            color: args.color || 'blue',
	            opacity: Number.isFinite(args.opacity) ? args.opacity : 1,
	            outerRadius: margin + width,
	            innerRadius: margin
	        });
	    },

	    // `color` ... color ('red')
	    // `width`... width (1)
	    // `blur` ... blur (0)
	    // `opacity` ... opacity (1)
	    highlight: function(args) {

	        var tpl = '<filter><feFlood flood-color="${color}" flood-opacity="${opacity}" result="colored"/><feMorphology result="morphed" in="SourceGraphic" operator="dilate" radius="${width}"/><feComposite result="composed" in="colored" in2="morphed" operator="in"/><feGaussianBlur result="blured" in="composed" stdDeviation="${blur}"/><feBlend in="SourceGraphic" in2="blured" mode="normal"/></filter>';

	        return template(tpl)({
	            color: args.color || 'red',
	            width: Number.isFinite(args.width) ? args.width : 1,
	            blur: Number.isFinite(args.blur) ? args.blur : 0,
	            opacity: Number.isFinite(args.opacity) ? args.opacity : 1
	        });
	    },

	    // `x` ... horizontal blur (2)
	    // `y` ... vertical blur (optional)
	    blur: function(args) {

	        var x = Number.isFinite(args.x) ? args.x : 2;

	        return template('<filter><feGaussianBlur stdDeviation="${stdDeviation}"/></filter>')({
	            stdDeviation: Number.isFinite(args.y) ? [x, args.y] : x
	        });
	    },

	    // `dx` ... horizontal shift (0)
	    // `dy` ... vertical shift (0)
	    // `blur` ... blur (4)
	    // `color` ... color ('black')
	    // `opacity` ... opacity (1)
	    dropShadow: function(args) {

	        var tpl = 'SVGFEDropShadowElement' in window
	            ? '<filter><feDropShadow stdDeviation="${blur}" dx="${dx}" dy="${dy}" flood-color="${color}" flood-opacity="${opacity}"/></filter>'
	            : '<filter><feGaussianBlur in="SourceAlpha" stdDeviation="${blur}"/><feOffset dx="${dx}" dy="${dy}" result="offsetblur"/><feFlood flood-color="${color}"/><feComposite in2="offsetblur" operator="in"/><feComponentTransfer><feFuncA type="linear" slope="${opacity}"/></feComponentTransfer><feMerge><feMergeNode/><feMergeNode in="SourceGraphic"/></feMerge></filter>';

	        return template(tpl)({
	            dx: args.dx || 0,
	            dy: args.dy || 0,
	            opacity: Number.isFinite(args.opacity) ? args.opacity : 1,
	            color: args.color || 'black',
	            blur: Number.isFinite(args.blur) ? args.blur : 4
	        });
	    },

	    // `amount` ... the proportion of the conversion (1). A value of 1 (default) is completely grayscale. A value of 0 leaves the input unchanged.
	    grayscale: function(args) {

	        var amount = Number.isFinite(args.amount) ? args.amount : 1;

	        return template('<filter><feColorMatrix type="matrix" values="${a} ${b} ${c} 0 0 ${d} ${e} ${f} 0 0 ${g} ${b} ${h} 0 0 0 0 0 1 0"/></filter>')({
	            a: 0.2126 + 0.7874 * (1 - amount),
	            b: 0.7152 - 0.7152 * (1 - amount),
	            c: 0.0722 - 0.0722 * (1 - amount),
	            d: 0.2126 - 0.2126 * (1 - amount),
	            e: 0.7152 + 0.2848 * (1 - amount),
	            f: 0.0722 - 0.0722 * (1 - amount),
	            g: 0.2126 - 0.2126 * (1 - amount),
	            h: 0.0722 + 0.9278 * (1 - amount)
	        });
	    },

	    // `amount` ... the proportion of the conversion (1). A value of 1 (default) is completely sepia. A value of 0 leaves the input unchanged.
	    sepia: function(args) {

	        var amount = Number.isFinite(args.amount) ? args.amount : 1;

	        return template('<filter><feColorMatrix type="matrix" values="${a} ${b} ${c} 0 0 ${d} ${e} ${f} 0 0 ${g} ${h} ${i} 0 0 0 0 0 1 0"/></filter>')({
	            a: 0.393 + 0.607 * (1 - amount),
	            b: 0.769 - 0.769 * (1 - amount),
	            c: 0.189 - 0.189 * (1 - amount),
	            d: 0.349 - 0.349 * (1 - amount),
	            e: 0.686 + 0.314 * (1 - amount),
	            f: 0.168 - 0.168 * (1 - amount),
	            g: 0.272 - 0.272 * (1 - amount),
	            h: 0.534 - 0.534 * (1 - amount),
	            i: 0.131 + 0.869 * (1 - amount)
	        });
	    },

	    // `amount` ... the proportion of the conversion (1). A value of 0 is completely un-saturated. A value of 1 (default) leaves the input unchanged.
	    saturate: function(args) {

	        var amount = Number.isFinite(args.amount) ? args.amount : 1;

	        return template('<filter><feColorMatrix type="saturate" values="${amount}"/></filter>')({
	            amount: 1 - amount
	        });
	    },

	    // `angle` ...  the number of degrees around the color circle the input samples will be adjusted (0).
	    hueRotate: function(args) {

	        return template('<filter><feColorMatrix type="hueRotate" values="${angle}"/></filter>')({
	            angle: args.angle || 0
	        });
	    },

	    // `amount` ... the proportion of the conversion (1). A value of 1 (default) is completely inverted. A value of 0 leaves the input unchanged.
	    invert: function(args) {

	        var amount = Number.isFinite(args.amount) ? args.amount : 1;

	        return template('<filter><feComponentTransfer><feFuncR type="table" tableValues="${amount} ${amount2}"/><feFuncG type="table" tableValues="${amount} ${amount2}"/><feFuncB type="table" tableValues="${amount} ${amount2}"/></feComponentTransfer></filter>')({
	            amount: amount,
	            amount2: 1 - amount
	        });
	    },

	    // `amount` ... proportion of the conversion (1). A value of 0 will create an image that is completely black. A value of 1 (default) leaves the input unchanged.
	    brightness: function(args) {

	        return template('<filter><feComponentTransfer><feFuncR type="linear" slope="${amount}"/><feFuncG type="linear" slope="${amount}"/><feFuncB type="linear" slope="${amount}"/></feComponentTransfer></filter>')({
	            amount: Number.isFinite(args.amount) ? args.amount : 1
	        });
	    },

	    // `amount` ... proportion of the conversion (1). A value of 0 will create an image that is completely black. A value of 1 (default) leaves the input unchanged.
	    contrast: function(args) {

	        var amount = Number.isFinite(args.amount) ? args.amount : 1;

	        return template('<filter><feComponentTransfer><feFuncR type="linear" slope="${amount}" intercept="${amount2}"/><feFuncG type="linear" slope="${amount}" intercept="${amount2}"/><feFuncB type="linear" slope="${amount}" intercept="${amount2}"/></feComponentTransfer></filter>')({
	            amount: amount,
	            amount2: .5 - amount / 2
	        });
	    }
	};

	var format = {

	    // Formatting numbers via the Python Format Specification Mini-language.
	    // See http://docs.python.org/release/3.1.3/library/string.html#format-specification-mini-language.
	    // Heavilly inspired by the D3.js library implementation.
	    number: function(specifier, value, locale) {

	        locale = locale || {

	            currency: ['$', ''],
	            decimal: '.',
	            thousands: ',',
	            grouping: [3]
	        };

	        // See Python format specification mini-language: http://docs.python.org/release/3.1.3/library/string.html#format-specification-mini-language.
	        // [[fill]align][sign][symbol][0][width][,][.precision][type]
	        var re = /(?:([^{])?([<>=^]))?([+\- ])?([$#])?(0)?(\d+)?(,)?(\.-?\d+)?([a-z%])?/i;

	        var match = re.exec(specifier);
	        var fill = match[1] || ' ';
	        var align = match[2] || '>';
	        var sign = match[3] || '';
	        var symbol = match[4] || '';
	        var zfill = match[5];
	        var width = +match[6];
	        var comma = match[7];
	        var precision = match[8];
	        var type = match[9];
	        var scale = 1;
	        var prefix = '';
	        var suffix = '';
	        var integer = false;

	        if (precision) { precision = +precision.substring(1); }

	        if (zfill || fill === '0' && align === '=') {
	            zfill = fill = '0';
	            align = '=';
	            if (comma) { width -= Math.floor((width - 1) / 4); }
	        }

	        switch (type) {
	            case 'n':
	                comma = true;
	                type = 'g';
	                break;
	            case '%':
	                scale = 100;
	                suffix = '%';
	                type = 'f';
	                break;
	            case 'p':
	                scale = 100;
	                suffix = '%';
	                type = 'r';
	                break;
	            case 'b':
	            case 'o':
	            case 'x':
	            case 'X':
	                if (symbol === '#') { prefix = '0' + type.toLowerCase(); }
	                break;
	            case 'c':
	            case 'd':
	                integer = true;
	                precision = 0;
	                break;
	            case 's':
	                scale = -1;
	                type = 'r';
	                break;
	        }

	        if (symbol === '$') {
	            prefix = locale.currency[0];
	            suffix = locale.currency[1];
	        }

	        // If no precision is specified for `'r'`, fallback to general notation.
	        if (type == 'r' && !precision) { type = 'g'; }

	        // Ensure that the requested precision is in the supported range.
	        if (precision != null) {
	            if (type == 'g') { precision = Math.max(1, Math.min(21, precision)); }
	            else if (type == 'e' || type == 'f') { precision = Math.max(0, Math.min(20, precision)); }
	        }

	        var zcomma = zfill && comma;

	        // Return the empty string for floats formatted as ints.
	        if (integer && (value % 1)) { return ''; }

	        // Convert negative to positive, and record the sign prefix.
	        var negative = value < 0 || value === 0 && 1 / value < 0 ? (value = -value, '-') : sign;

	        var fullSuffix = suffix;

	        // Apply the scale, computing it from the value's exponent for si format.
	        // Preserve the existing suffix, if any, such as the currency symbol.
	        if (scale < 0) {
	            var unit = this.prefix(value, precision);
	            value = unit.scale(value);
	            fullSuffix = unit.symbol + suffix;
	        } else {
	            value *= scale;
	        }

	        // Convert to the desired precision.
	        value = this.convert(type, value, precision);

	        // Break the value into the integer part (before) and decimal part (after).
	        var i = value.lastIndexOf('.');
	        var before = i < 0 ? value : value.substring(0, i);
	        var after = i < 0 ? '' : locale.decimal + value.substring(i + 1);

	        function formatGroup(value) {

	            var i = value.length;
	            var t = [];
	            var j = 0;
	            var g = locale.grouping[0];
	            while (i > 0 && g > 0) {
	                t.push(value.substring(i -= g, i + g));
	                g = locale.grouping[j = (j + 1) % locale.grouping.length];
	            }
	            return t.reverse().join(locale.thousands);
	        }

	        // If the fill character is not `'0'`, grouping is applied before padding.
	        if (!zfill && comma && locale.grouping) {

	            before = formatGroup(before);
	        }

	        var length = prefix.length + before.length + after.length + (zcomma ? 0 : negative.length);
	        var padding = length < width ? new Array(length = width - length + 1).join(fill) : '';

	        // If the fill character is `'0'`, grouping is applied after padding.
	        if (zcomma) { before = formatGroup(padding + before); }

	        // Apply prefix.
	        negative += prefix;

	        // Rejoin integer and decimal parts.
	        value = before + after;

	        return (align === '<' ? negative + value + padding
	            : align === '>' ? padding + negative + value
	                : align === '^' ? padding.substring(0, length >>= 1) + negative + value + padding.substring(length)
	                    : negative + (zcomma ? value : padding + value)) + fullSuffix;
	    },

	    // Formatting string via the Python Format string.
	    // See https://docs.python.org/2/library/string.html#format-string-syntax)
	    string: function(formatString, value) {

	        var fieldDelimiterIndex;
	        var fieldDelimiter = '{';
	        var endPlaceholder = false;
	        var formattedStringArray = [];

	        while ((fieldDelimiterIndex = formatString.indexOf(fieldDelimiter)) !== -1) {

	            var pieceFormattedString, formatSpec, fieldName;

	            pieceFormattedString = formatString.slice(0, fieldDelimiterIndex);

	            if (endPlaceholder) {
	                formatSpec = pieceFormattedString.split(':');
	                fieldName = formatSpec.shift().split('.');
	                pieceFormattedString = value;

	                for (var i = 0; i < fieldName.length; i++)
	                    { pieceFormattedString = pieceFormattedString[fieldName[i]]; }

	                if (formatSpec.length)
	                    { pieceFormattedString = this.number(formatSpec, pieceFormattedString); }
	            }

	            formattedStringArray.push(pieceFormattedString);

	            formatString = formatString.slice(fieldDelimiterIndex + 1);
	            endPlaceholder = !endPlaceholder;
	            fieldDelimiter = (endPlaceholder) ? '}' : '{';
	        }
	        formattedStringArray.push(formatString);

	        return formattedStringArray.join('');
	    },

	    convert: function(type, value, precision) {

	        switch (type) {
	            case 'b':
	                return value.toString(2);
	            case 'c':
	                return String.fromCharCode(value);
	            case 'o':
	                return value.toString(8);
	            case 'x':
	                return value.toString(16);
	            case 'X':
	                return value.toString(16).toUpperCase();
	            case 'g':
	                return value.toPrecision(precision);
	            case 'e':
	                return value.toExponential(precision);
	            case 'f':
	                return value.toFixed(precision);
	            case 'r':
	                return (value = this.round(value, this.precision(value, precision))).toFixed(Math.max(0, Math.min(20, this.precision(value * (1 + 1e-15), precision))));
	            default:
	                return value + '';
	        }
	    },

	    round: function(value, precision) {

	        return precision
	            ? Math.round(value * (precision = Math.pow(10, precision))) / precision
	            : Math.round(value);
	    },

	    precision: function(value, precision) {

	        return precision - (value ? Math.ceil(Math.log(value) / Math.LN10) : 1);
	    },

	    prefix: function(value, precision) {

	        var prefixes = ['y', 'z', 'a', 'f', 'p', 'n', 'µ', 'm', '', 'k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'].map(function(d, i) {
	            var k = Math.pow(10, Math.abs(8 - i) * 3);
	            return {
	                scale: i > 8 ? function(d) {
	                    return d / k;
	                } : function(d) {
	                    return d * k;
	                },
	                symbol: d
	            };
	        });

	        var i = 0;
	        if (value) {
	            if (value < 0) { value *= -1; }
	            if (precision) { value = this.round(value, this.precision(value, precision)); }
	            i = 1 + Math.floor(1e-12 + Math.log(value) / Math.LN10);
	            i = Math.max(-24, Math.min(24, Math.floor((i <= 0 ? i + 1 : i - 1) / 3) * 3));
	        }
	        return prefixes[8 + i / 3];
	    }
	};

	/*
	    Pre-compile the HTML to be used as a template.
	*/
	var template = function(html) {

	    /*
	        Must support the variation in templating syntax found here:
	        https://lodash.com/docs#template
	    */
	    var regex = /<%= ([^ ]+) %>|\$\{ ?([^{} ]+) ?\}|\{\{([^{} ]+)\}\}/g;

	    return function(data) {

	        data = data || {};

	        return html.replace(regex, function(match) {

	            var args = Array.from(arguments);
	            var attr = args.slice(1, 4).find(function(_attr) {
	                return !!_attr;
	            });

	            var attrArray = attr.split('.');
	            var value = data[attrArray.shift()];

	            while (value !== undefined && attrArray.length) {
	                value = value[attrArray.shift()];
	            }

	            return value !== undefined ? value : '';
	        });
	    };
	};

	/**
	 * @param {Element} el Element, which content is intent to display in full-screen mode, 'window.top.document.body' is default.
	 */
	var toggleFullScreen = function(el) {

	    var topDocument = window.top.document;
	    el = el || topDocument.body;

	    function prefixedResult(el, prop) {

	        var prefixes = ['webkit', 'moz', 'ms', 'o', ''];
	        for (var i = 0; i < prefixes.length; i++) {
	            var prefix = prefixes[i];
	            var propName = prefix ? (prefix + prop) : (prop.substr(0, 1).toLowerCase() + prop.substr(1));
	            if (el[propName] !== undefined) {
	                return isFunction(el[propName]) ? el[propName]() : el[propName];
	            }
	        }
	    }

	    if (prefixedResult(topDocument, 'FullscreenElement') || prefixedResult(topDocument, 'FullScreenElement')) {
	        prefixedResult(topDocument, 'ExitFullscreen') || // Spec.
	        prefixedResult(topDocument, 'CancelFullScreen'); // Firefox
	    } else {
	        prefixedResult(el, 'RequestFullscreen') || // Spec.
	        prefixedResult(el, 'RequestFullScreen'); // Firefox
	    }
	};

	var noop = function() {
	};

	// Events
	// ---------------

	// A module that can be mixed in to *any object* in order to provide it with
	// a custom event channel. You may bind a callback to an event with `on` or
	// remove with `off`; `trigger`-ing an event fires all callbacks in
	// succession.
	//
	//     const object = {};
	//     assign(object, Events);
	//     object.on('expand', function(){ alert('expanded'); });
	//     object.trigger('expand');
	//
	var Events = {};

	// Regular expression used to split event strings.
	var eventSplitter = /\s+/;

	// A private global variable to share between listeners and listenees.
	var _listening;

	// Iterates over the standard `event, callback` (as well as the fancy multiple
	// space-separated events `"change blur", callback` and jQuery-style event
	// maps `{event: callback}`).
	var eventsApi = function(iteratee, events, name, callback, opts) {
	    var i = 0, names;
	    if (name && typeof name === 'object') {
	    // Handle event maps.
	        if (callback !== void 0 && 'context' in opts && opts.context === void 0) { opts.context = callback; }
	        for (names = Object.keys(name); i < names.length ; i++) {
	            events = eventsApi(iteratee, events, names[i], name[names[i]], opts);
	        }
	    } else if (name && eventSplitter.test(name)) {
	    // Handle space-separated event names by delegating them individually.
	        for (names = name.split(eventSplitter); i < names.length; i++) {
	            events = iteratee(events, names[i], callback, opts);
	        }
	    } else {
	    // Finally, standard events.
	        events = iteratee(events, name, callback, opts);
	    }
	    return events;
	};

	// Bind an event to a `callback` function. Passing `"all"` will bind
	// the callback to all events fired.
	Events.on = function(name, callback, context) {
	    this._events = eventsApi(onApi, this._events || {}, name, callback, {
	        context: context,
	        ctx: this,
	        listening: _listening
	    });

	    if (_listening) {
	        var listeners = this._listeners || (this._listeners = {});
	        listeners[_listening.id] = _listening;
	        // Allow the listening to use a counter, instead of tracking
	        // callbacks for library interop
	        _listening.interop = false;
	    }

	    return this;
	};

	// Inversion-of-control versions of `on`. Tell *this* object to listen to
	// an event in another object... keeping track of what it's listening to
	// for easier unbinding later.
	Events.listenTo = function(obj, name, callback) {
	    if (!obj) { return this; }
	    var id = obj._listenId || (obj._listenId = uniqueId('l'));
	    var listeningTo = this._listeningTo || (this._listeningTo = {});
	    var listening = _listening = listeningTo[id];

	    // This object is not listening to any other events on `obj` yet.
	    // Setup the necessary references to track the listening callbacks.
	    if (!listening) {
	        this._listenId || (this._listenId = uniqueId('l'));
	        listening = _listening = listeningTo[id] = new Listening(this, obj);
	    }

	    // Bind callbacks on obj.
	    var error = tryCatchOn(obj, name, callback, this);
	    _listening = void 0;

	    if (error) { throw error; }
	    // If the target obj is not Events, track events manually.
	    if (listening.interop) { listening.on(name, callback); }

	    return this;
	};

	// The reducing API that adds a callback to the `events` object.
	var onApi = function(events, name, callback, options) {
	    if (callback) {
	        var handlers = events[name] || (events[name] = []);
	        var context = options.context, ctx = options.ctx, listening = options.listening;
	        if (listening) { listening.count++; }

	        handlers.push({ callback: callback, context: context, ctx: context || ctx, listening: listening });
	    }
	    return events;
	};

	// An try-catch guarded #on function, to prevent poisoning the global
	// `_listening` variable.
	var tryCatchOn = function(obj, name, callback, context) {
	    try {
	        obj.on(name, callback, context);
	    } catch (e) {
	        return e;
	    }
	};

	// Remove one or many callbacks. If `context` is null, removes all
	// callbacks with that function. If `callback` is null, removes all
	// callbacks for the event. If `name` is null, removes all bound
	// callbacks for all events.
	Events.off = function(name, callback, context) {
	    if (!this._events) { return this; }
	    this._events = eventsApi(offApi, this._events, name, callback, {
	        context: context,
	        listeners: this._listeners
	    });

	    return this;
	};

	// Tell this object to stop listening to either specific events ... or
	// to every object it's currently listening to.
	Events.stopListening = function(obj, name, callback) {
	    var listeningTo = this._listeningTo;
	    if (!listeningTo) { return this; }

	    var ids = obj ? [obj._listenId] : Object.keys(listeningTo);
	    for (var i = 0; i < ids.length; i++) {
	        var listening = listeningTo[ids[i]];

	        // If listening doesn't exist, this object is not currently
	        // listening to obj. Break out early.
	        if (!listening) { break; }

	        listening.obj.off(name, callback, this);
	        if (listening.interop) { listening.off(name, callback); }
	    }
	    if (isEmpty(listeningTo)) { this._listeningTo = void 0; }

	    return this;
	};

	// The reducing API that removes a callback from the `events` object.
	var offApi = function(events, name, callback, options) {
	    if (!events) { return; }

	    var context = options.context, listeners = options.listeners;
	    var i = 0, names;

	    // Delete all event listeners and "drop" events.
	    if (!name && !context && !callback) {
	        if(listeners != null) {
	            for (names = Object.keys(listeners); i < names.length; i++) {
	                listeners[names[i]].cleanup();
	            }
	        }
	        return;
	    }
	    names = name ? [name] : Object.keys(events);
	    for (; i < names.length; i++) {
	        name = names[i];
	        var handlers = events[name];

	        // Bail out if there are no events stored.
	        if (!handlers) { break; }

	        // Find any remaining events.
	        var remaining = [];
	        for (var j = 0; j < handlers.length; j++) {
	            var handler = handlers[j];
	            if (
	                callback && callback !== handler.callback &&
	        callback !== handler.callback._callback ||
	          context && context !== handler.context
	            ) {
	                remaining.push(handler);
	            } else {
	                var listening = handler.listening;
	                if (listening) { listening.off(name, callback); }
	            }
	        }

	        // Replace events if there are any remaining.  Otherwise, clean up.
	        if (remaining.length) {
	            events[name] = remaining;
	        } else {
	            delete events[name];
	        }
	    }

	    return events;
	};

	// Bind an event to only be triggered a single time. After the first time
	// the callback is invoked, its listener will be removed. If multiple events
	// are passed in using the space-separated syntax, the handler will fire
	// once for each event, not once for a combination of all events.
	Events.once = function(name, callback, context) {
	// Map the event into a `{event: once}` object.
	    var events = eventsApi(onceMap, {}, name, callback, this.off.bind(this));
	    if (typeof name === 'string' && context == null) { callback = void 0; }
	    return this.on(events, callback, context);
	};

	// Inversion-of-control versions of `once`.
	Events.listenToOnce = function(obj, name, callback) {
	// Map the event into a `{event: once}` object.
	    var events = eventsApi(onceMap, {}, name, callback, this.stopListening.bind(this, obj));
	    return this.listenTo(obj, events);
	};

	// Reduces the event callbacks into a map of `{event: onceWrapper}`.
	// `offer` unbinds the `onceWrapper` after it has been called.
	var onceMap = function(map, name, callback, offer) {
	    if (callback) {
	        var once = map[name] = onceInvoke(function() {
	            offer(name, once);
	            callback.apply(this, arguments);
	        });
	        once._callback = callback;
	    }
	    return map;
	};

	// Creates a function that is restricted to invoking 'func' once.
	// Repeat calls to the function return the value of the first invocation.
	var onceInvoke = function(func) {
	    var result;
	    if (typeof func != 'function') {
	        throw new TypeError('Expected a function');
	    }
	    var n = 2;
	    return function() {
	        if (--n > 0) {
	            result = func.apply(this, arguments);
	        }
	        if (n <= 1) {
	            func = undefined;
	        }
	        return result;
	    };
	};

	// Trigger one or many events, firing all bound callbacks. Callbacks are
	// passed the same arguments as `trigger` is, apart from the event name
	// (unless you're listening on `"all"`, which will cause your callback to
	// receive the true name of the event as the first argument).
	Events.trigger = function(name) {
	    var arguments$1 = arguments;

	    if (!this._events) { return this; }

	    var length = Math.max(0, arguments.length - 1);
	    var args = Array(length);
	    for (var i = 0; i < length; i++) { args[i] = arguments$1[i + 1]; }

	    eventsApi(triggerApi, this._events, name, void 0, args);
	    return this;
	};

	// Handles triggering the appropriate event callbacks.
	var triggerApi = function(objEvents, name, callback, args) {
	    if (objEvents) {
	        var events = objEvents[name];
	        var allEvents = objEvents.all;
	        if (events && allEvents) { allEvents = allEvents.slice(); }
	        if (events) { triggerEvents(events, args); }
	        if (allEvents) { triggerEvents(allEvents, [name].concat(args)); }
	    }
	    return objEvents;
	};

	// A difficult-to-believe, but optimized internal dispatch function for
	// triggering events. Tries to keep the usual cases speedy (most internal
	// events have 3 arguments).
	var triggerEvents = function(events, args) {
	    var ev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2];
	    switch (args.length) {
	        case 0: while (++i < l) { (ev = events[i]).callback.call(ev.ctx); } return;
	        case 1: while (++i < l) { (ev = events[i]).callback.call(ev.ctx, a1); } return;
	        case 2: while (++i < l) { (ev = events[i]).callback.call(ev.ctx, a1, a2); } return;
	        case 3: while (++i < l) { (ev = events[i]).callback.call(ev.ctx, a1, a2, a3); } return;
	        default: while (++i < l) { (ev = events[i]).callback.apply(ev.ctx, args); } return;
	    }
	};

	// A listening class that tracks and cleans up memory bindings
	// when all callbacks have been offed.
	var Listening = function(listener, obj) {
	    this.id = listener._listenId;
	    this.listener = listener;
	    this.obj = obj;
	    this.interop = true;
	    this.count = 0;
	    this._events = void 0;
	};

	Listening.prototype.on = Events.on;

	// Offs a callback (or several).
	// Uses an optimized counter if the listenee uses Events.
	// Otherwise, falls back to manual tracking to support events
	// library interop.
	Listening.prototype.off = function(name, callback) {
	    var cleanup;
	    if (this.interop) {
	        this._events = eventsApi(offApi, this._events, name, callback, {
	            context: void 0,
	            listeners: void 0
	        });
	        cleanup = !this._events;
	    } else {
	        this.count--;
	        cleanup = this.count === 0;
	    }
	    if (cleanup) { this.cleanup(); }
	};

	// Cleans up memory bindings between the listener and the listenee.
	Listening.prototype.cleanup = function() {
	    delete this.listener._listeningTo[this.obj._listenId];
	    if (!this.interop) { delete this.obj._listeners[this.id]; }
	};

	// Aliases for backwards compatibility.
	Events.bind   = Events.on;
	Events.unbind = Events.off;

	// Helpers
	// -------

	// Helper function to correctly set up the prototype chain for subclasses.
	// Similar to `goog.inherits`, but uses a hash of prototype properties and
	// class properties to be extended.
	var extend$1 = function(protoProps, staticProps) {
	    var parent = this;
	    var child;

	    // The constructor function for the new subclass is either defined by you
	    // (the "constructor" property in your `extend` definition), or defaulted
	    // by us to simply call the parent constructor.
	    if (protoProps && has$2(protoProps, 'constructor')) {
	        child = protoProps.constructor;
	    } else {
	        child = function(){ return parent.apply(this, arguments); };
	    }

	    // Add static properties to the constructor function, if supplied.
	    assign(child, parent, staticProps);

	    // Set the prototype chain to inherit from `parent`, without calling
	    // `parent`'s constructor function and add the prototype properties.
	    child.prototype = Object.assign(Object.create(parent.prototype), protoProps);
	    child.prototype.constructor = child;

	    // Set a convenience property in case the parent's prototype is needed
	    // later.
	    child.__super__ = parent.prototype;

	    return child;
	};

	// Proxy class methods to functions, wrapping the model's
	// `attributes` object or collection's `models` array behind the scenes.
	//
	// `Function#apply` can be slow so we use the method's arg count, if we know it.
	var addMethod = function(base, length, method, attribute) {
	    switch (length) {
	        case 1: return function() {
	            return base[method](this[attribute]);
	        };
	        case 2: return function(value) {
	            return base[method](this[attribute], value);
	        };
	        case 3: return function(iteratee, context) {
	            return base[method](this[attribute], cb(iteratee, this), context);
	        };
	        case 4: return function(iteratee, defaultVal, context) {
	            return base[method](this[attribute], cb(iteratee, this), defaultVal, context);
	        };
	        default: return function() {
	            var args = Array.prototype.slice.call(arguments);
	            args.unshift(this[attribute]);
	            return base[method].apply(base, args);
	        };
	    }
	};

	var addMethodsUtil = function(Class, base, methods, attribute) {
	    forIn(methods, function(length, method) {
	        if (base[method]) { Class.prototype[method] = addMethod(base, length, method, attribute); }
	    });
	};

	// Support `collection.sortBy('attr')`.
	var cb = function(iteratee, instance) {
	    if (isFunction(iteratee)) { return iteratee; }
	    if (isObject$1(iteratee) && !instance._isModel(iteratee)) { return modelMatcher(iteratee); }
	    if (isString(iteratee)) { return function(model) { return model.get(iteratee); }; }
	    return iteratee;
	};

	var modelMatcher = function(attrs) {
	    var matcher = matches(attrs);
	    return function(model) {
	        return matcher(model.attributes);
	    };
	};

	// Model
	// --------------

	// **Models** are the basic data object in the framework --
	// frequently representing a row in a table in a database on your server.
	// A discrete chunk of data and a bunch of useful, related methods for
	// performing computations and transformations on that data.

	// Create a new model with the specified attributes. A client id (`cid`)
	// is automatically generated and assigned for you.

	var Model = function(attributes, options) {
	    var attrs = attributes || {};
	    options || (options = {});
	    this.preinitialize.apply(this, arguments);
	    this.cid = uniqueId(this.cidPrefix);
	    this.attributes = {};
	    if (options.collection) { this.collection = options.collection; }
	    var attributeDefaults = result(this, 'defaults');

	    // Just _.defaults would work fine, but the additional _.extends
	    // is in there for historical reasons. See #3843.
	    attrs = defaults(assign({}, attributeDefaults, attrs), attributeDefaults);

	    this.set(attrs, options);
	    this.changed = {};
	    this.initialize.apply(this, arguments);
	};

	// Attach all inheritable methods to the Model prototype.
	assign(Model.prototype, Events, {

	    // A hash of attributes whose current and previous value differ.
	    changed: null,

	    // The value returned during the last failed validation.
	    validationError: null,

	    // The default name for the JSON `id` attribute is `"id"`. MongoDB and
	    // CouchDB users may want to set this to `"_id"`.
	    idAttribute: 'id',

	    // The prefix is used to create the client id which is used to identify models locally.
	    // You may want to override this if you're experiencing name clashes with model ids.
	    cidPrefix: 'c',

	    // preinitialize is an empty function by default. You can override it with a function
	    // or object.  preinitialize will run before any instantiation logic is run in the Model.
	    preinitialize: function(){},

	    // Initialize is an empty function by default. Override it with your own
	    // initialization logic.
	    initialize: function(){},

	    // Return a copy of the model's `attributes` object.
	    toJSON: function(options) {
	        return clone(this.attributes);
	    },

	    // Get the value of an attribute.
	    get: function(attr) {
	        return this.attributes[attr];
	    },

	    // Returns `true` if the attribute contains a value that is not null
	    // or undefined.
	    has: function(attr) {
	        return this.get(attr) != null;
	    },

	    // Set a hash of model attributes on the object, firing `"change"`. This is
	    // the core primitive operation of a model, updating the data and notifying
	    // anyone who needs to know about the change in state. The heart of the beast.
	    set: function(key, val, options) {
	        if (key == null) { return this; }

	        // Handle both `"key", value` and `{key: value}` -style arguments.
	        var attrs;
	        if (typeof key === 'object') {
	            attrs = key;
	            options = val;
	        } else {
	            (attrs = {})[key] = val;
	        }

	        options || (options = {});

	        // Run validation.
	        if (!this._validate(attrs, options)) { return false; }

	        // Extract attributes and options.
	        var unset      = options.unset;
	        var silent     = options.silent;
	        var changes    = [];
	        var changing   = this._changing;
	        this._changing = true;

	        if (!changing) {
	            this._previousAttributes = clone(this.attributes);
	            this.changed = {};
	        }

	        var current = this.attributes;
	        var changed = this.changed;
	        var prev    = this._previousAttributes;

	        // For each `set` attribute, update or delete the current value.
	        for (var attr in attrs) {
	            val = attrs[attr];
	            if (!isEqual(current[attr], val)) { changes.push(attr); }
	            if (!isEqual(prev[attr], val)) {
	                changed[attr] = val;
	            } else {
	                delete changed[attr];
	            }
	            unset ? delete current[attr] : current[attr] = val;
	        }

	        // Update the `id`.
	        if (this.idAttribute in attrs) {
	            var prevId = this.id;
	            this.id = this.get(this.idAttribute);
	            this.trigger('changeId', this, prevId, options);
	        }

	        // Trigger all relevant attribute changes.
	        if (!silent) {
	            if (changes.length) { this._pending = options; }
	            for (var i = 0; i < changes.length; i++) {
	                this.trigger('change:' + changes[i], this, current[changes[i]], options);
	            }
	        }

	        // You might be wondering why there's a `while` loop here. Changes can
	        // be recursively nested within `"change"` events.
	        if (changing) { return this; }
	        if (!silent) {
	            while (this._pending) {
	                options = this._pending;
	                this._pending = false;
	                this.trigger('change', this, options);
	            }
	        }
	        this._pending = false;
	        this._changing = false;
	        return this;
	    },

	    // Remove an attribute from the model, firing `"change"`. `unset` is a noop
	    // if the attribute doesn't exist.
	    unset: function(attr, options) {
	        return this.set(attr, void 0, assign({}, options, { unset: true }));
	    },

	    // Clear all attributes on the model, firing `"change"`.
	    clear: function(options) {
	        var attrs = {};
	        for (var key in this.attributes) { attrs[key] = void 0; }
	        return this.set(attrs, assign({}, options, { unset: true }));
	    },

	    // Determine if the model has changed since the last `"change"` event.
	    // If you specify an attribute name, determine if that attribute has changed.
	    hasChanged: function(attr) {
	        if (attr == null) { return !isEmpty(this.changed); }
	        return has$2(this.changed, attr);
	    },

	    // Return an object containing all the attributes that have changed, or
	    // false if there are no changed attributes. Useful for determining what
	    // parts of a view need to be updated and/or what attributes need to be
	    // persisted to the server. Unset attributes will be set to undefined.
	    // You can also pass an attributes object to diff against the model,
	    // determining if there *would be* a change.
	    changedAttributes: function(diff) {
	        if (!diff) { return this.hasChanged() ? clone(this.changed) : false; }
	        var old = this._changing ? this._previousAttributes : this.attributes;
	        var changed = {};
	        var hasChanged;
	        for (var attr in diff) {
	            var val = diff[attr];
	            if (isEqual(old[attr], val)) { continue; }
	            changed[attr] = val;
	            hasChanged = true;
	        }
	        return hasChanged ? changed : false;
	    },

	    // Get the previous value of an attribute, recorded at the time the last
	    // `"change"` event was fired.
	    previous: function(attr) {
	        if (attr == null || !this._previousAttributes) { return null; }
	        return this._previousAttributes[attr];
	    },

	    // Get all of the attributes of the model at the time of the previous
	    // `"change"` event.
	    previousAttributes: function() {
	        return clone(this._previousAttributes);
	    },

	    // Create a new model with identical attributes to this one.
	    clone: function() {
	        return new this.constructor(this.attributes);
	    },

	    // Check if the model is currently in a valid state.
	    isValid: function(options) {
	        return this._validate({}, assign({}, options, { validate: true }));
	    },

	    // Run validation against the next complete set of model attributes,
	    // returning `true` if all is well. Otherwise, fire an `"invalid"` event.
	    _validate: function(attrs, options) {
	        if (!options.validate || !this.validate) { return true; }
	        attrs = assign({}, this.attributes, attrs);
	        var error = this.validationError = this.validate(attrs, options) || null;
	        if (!error) { return true; }
	        this.trigger('invalid', this, error, assign(options, { validationError: error }));
	        return false;
	    }

	});

	// Set up inheritance for the model.
	Model.extend = extend$1;

	// Clone `cells` returning an object that maps the original cell ID to the clone. The number
	// of clones is exactly the same as the `cells.length`.
	// This function simply clones all the `cells`. However, it also reconstructs
	// all the `source/target` and `parent/embed` references within the `cells`.
	// This is the main difference from the `cell.clone()` method. The
	// `cell.clone()` method works on one single cell only.
	// For example, for a graph: `A --- L ---> B`, `cloneCells([A, L, B])`
	// returns `[A2, L2, B2]` resulting to a graph: `A2 --- L2 ---> B2`, i.e.
	// the source and target of the link `L2` is changed to point to `A2` and `B2`.
	function cloneCells(cells) {

	    cells = uniq(cells);

	    // A map of the form [original cell ID] -> [clone] helping
	    // us to reconstruct references for source/target and parent/embeds.
	    // This is also the returned value.
	    var cloneMap = toArray(cells).reduce(function(map, cell) {
	        map[cell.id] = cell.clone();
	        return map;
	    }, {});

	    toArray(cells).forEach(function(cell) {

	        var clone = cloneMap[cell.id];
	        // assert(clone exists)

	        if (clone.isLink()) {
	            var source = clone.source();
	            var target = clone.target();
	            if (source.id && cloneMap[source.id]) {
	                // Source points to an element and the element is among the clones.
	                // => Update the source of the cloned link.
	                clone.prop('source/id', cloneMap[source.id].id);
	            }
	            if (target.id && cloneMap[target.id]) {
	                // Target points to an element and the element is among the clones.
	                // => Update the target of the cloned link.
	                clone.prop('target/id', cloneMap[target.id].id);
	            }
	        }

	        // Find the parent of the original cell
	        var parent = cell.get('parent');
	        if (parent && cloneMap[parent]) {
	            clone.set('parent', cloneMap[parent].id);
	        }

	        // Find the embeds of the original cell
	        var embeds = toArray(cell.get('embeds')).reduce(function(newEmbeds, embed) {
	            // Embedded cells that are not being cloned can not be carried
	            // over with other embedded cells.
	            if (cloneMap[embed]) {
	                newEmbeds.push(cloneMap[embed].id);
	            }
	            return newEmbeds;
	        }, []);

	        if (!isEmpty(embeds)) {
	            clone.set('embeds', embeds);
	        }
	    });

	    return cloneMap;
	}

	var validPropertiesList = ['checked', 'selected', 'disabled', 'readOnly', 'contentEditable', 'value', 'indeterminate'];

	var validProperties = validPropertiesList.reduce(function (acc, key) {
	    acc[key] = true;
	    return acc;
	}, {});

	var props$1 = {
	    qualify: function(properties) {
	        return isPlainObject(properties);
	    },
	    set: function(properties, _, node) {
	        Object.keys(properties).forEach(function(key) {
	            if (validProperties[key] && key in node) {
	                var value = properties[key];
	                if (node.tagName === 'SELECT' && Array.isArray(value)) {
	                    Array.from(node.options).forEach(function(option, index) {
	                        option.selected = value.includes(option.value);
	                    });
	                } else {
	                    node[key] = value;
	                }
	            }
	        });
	    }
	};

	function positionWrapper(axis, dimension, origin) {
	    return function(value, refBBox) {
	        var valuePercentage = isPercentage(value);
	        value = parseFloat(value);
	        if (valuePercentage) {
	            value /= 100;
	        }

	        var delta;
	        if (isFinite(value)) {
	            var refOrigin = refBBox[origin]();
	            if (valuePercentage || value > 0 && value < 1) {
	                delta = refOrigin[axis] + refBBox[dimension] * value;
	            } else {
	                delta = refOrigin[axis] + value;
	            }
	        }

	        var point = Point();
	        point[axis] = delta || 0;
	        return point;
	    };
	}

	function setWrapper(attrName, dimension) {
	    return function(value, refBBox) {
	        var isValuePercentage = isPercentage(value);
	        value = parseFloat(value);
	        if (isValuePercentage) {
	            value /= 100;
	        }

	        var attrs = {};
	        if (isFinite(value)) {
	            var attrValue = (isValuePercentage || value >= 0 && value <= 1)
	                ? value * refBBox[dimension]
	                : Math.max(value + refBBox[dimension], 0);
	            attrs[attrName] = attrValue;
	        }

	        return attrs;
	    };
	}

	var legacyAttributesNS = {

	    // if `refX` is in [0, 1] then `refX` is a fraction of bounding box width
	    // if `refX` is < 0 then `refX`'s absolute values is the right coordinate of the bounding box
	    // otherwise, `refX` is the left coordinate of the bounding box
	    'ref-x': {
	        position: positionWrapper('x', 'width', 'origin')
	    },

	    'ref-y': {
	        position: positionWrapper('y', 'height', 'origin')
	    },

	    // `ref-dx` and `ref-dy` define the offset of the sub-element relative to the right and/or bottom
	    // coordinate of the reference element.

	    'ref-dx': {
	        position: positionWrapper('x', 'width', 'corner')
	    },

	    'ref-dy': {
	        position: positionWrapper('y', 'height', 'corner')
	    },

	    // 'ref-width'/'ref-height' defines the width/height of the sub-element relatively to
	    // the reference element size
	    // val in 0..1         ref-width = 0.75 sets the width to 75% of the ref. el. width
	    // val < 0 || val > 1  ref-height = -20 sets the height to the ref. el. height shorter by 20

	    'ref-width': {
	        set: setWrapper('width', 'width')
	    },

	    'ref-height': {
	        set: setWrapper('height', 'height')
	    },

	    'ref-rx': {
	        set: setWrapper('rx', 'width')
	    },

	    'ref-ry': {
	        set: setWrapper('ry', 'height')
	    },

	    'ref-cx': {
	        set: setWrapper('cx', 'width')
	    },

	    'ref-cy': {
	        set: setWrapper('cy', 'height')
	    },

	    'ref-r-inscribed': {
	        set: (function(attrName) {
	            var widthFn = setWrapper(attrName, 'width');
	            var heightFn = setWrapper(attrName, 'height');
	            return function(value, refBBox) {
	                var fn = (refBBox.height > refBBox.width) ? widthFn : heightFn;
	                return fn(value, refBBox);
	            };
	        })('r')
	    },

	    'ref-r-circumscribed': {
	        set: function(value, refBBox) {
	            var isValuePercentage = isPercentage(value);
	            value = parseFloat(value);
	            if (isValuePercentage) {
	                value /= 100;
	            }

	            var diagonalLength = Math.sqrt((refBBox.height * refBBox.height) + (refBBox.width * refBBox.width));

	            var rValue;
	            if (isFinite(value)) {
	                if (isValuePercentage || value >= 0 && value <= 1) { rValue = value * diagonalLength; }
	                else { rValue = Math.max(value + diagonalLength, 0); }
	            }

	            return { r: rValue };
	        }
	    },
	};

	// NOTE: refX & refY are SVG attributes that define the reference point of the marker.
	// That's why we need to define both variants: `refX` and `ref-x` (and `refY` and `ref-y`).
	legacyAttributesNS['refX'] = legacyAttributesNS['ref-x'];
	legacyAttributesNS['refY'] = legacyAttributesNS['ref-y'];

	// This allows to combine both absolute and relative positioning
	// refX: 50%, refX2: 20
	legacyAttributesNS['ref-x2'] = legacyAttributesNS['ref-x'];
	legacyAttributesNS['ref-y2'] = legacyAttributesNS['ref-y'];
	legacyAttributesNS['ref-width2'] = legacyAttributesNS['ref-width'];
	legacyAttributesNS['ref-height2'] = legacyAttributesNS['ref-height'];

	// Aliases
	legacyAttributesNS['ref-r'] = legacyAttributesNS['ref-r-inscribed'];

	function isTextInUse(_value, _node, attrs) {
	    return (attrs.text !== undefined);
	}

	var textAttributesNS = {

	    'line-height': {
	        qualify: isTextInUse
	    },

	    'text-vertical-anchor': {
	        qualify: isTextInUse
	    },

	    'text-path': {
	        qualify: isTextInUse
	    },

	    'annotations': {
	        qualify: isTextInUse
	    },

	    'eol': {
	        qualify: isTextInUse
	    },

	    'display-empty': {
	        qualify: isTextInUse
	    },

	    'text': {
	        qualify: function(_text, _node, attrs) {
	            var textWrap = attrs['text-wrap'];
	            return !textWrap || !isPlainObject(textWrap);
	        },
	        set: function(text, refBBox, node, attrs) {
	            var cacheName = 'joint-text';
	            var cache = $.data.get(node, cacheName);
	            var lineHeight = attrs['line-height'];
	            var textVerticalAnchor = attrs['text-vertical-anchor'];
	            var displayEmpty = attrs['display-empty'];
	            var fontSize = attrs['font-size'];
	            var annotations = attrs.annotations;
	            var eol = attrs.eol;
	            var x = attrs.x;
	            var textPath = attrs['text-path'];
	            // Update the text only if there was a change in the string
	            // or any of its attributes.
	            var textHash = JSON.stringify([text, lineHeight, annotations, textVerticalAnchor, eol, displayEmpty, textPath, x, fontSize]);
	            if (cache === undefined || cache !== textHash) {
	                // Chrome bug:
	                // <tspan> positions defined as `em` are not updated
	                // when container `font-size` change.
	                if (fontSize) { node.setAttribute('font-size', fontSize); }
	                // Text Along Path Selector
	                if (isObject$1(textPath)) {
	                    var pathSelector = textPath.selector;
	                    if (typeof pathSelector === 'string') {
	                        var pathNode = this.findNode(pathSelector);
	                        if (pathNode instanceof SVGPathElement) {
	                            textPath = assign({ 'xlink:href': '#' + pathNode.id }, textPath);
	                        }
	                    }
	                }
	                V(node).text('' + text, {
	                    lineHeight: lineHeight,
	                    annotations: annotations,
	                    textPath: textPath,
	                    x: x,
	                    textVerticalAnchor: textVerticalAnchor,
	                    eol: eol,
	                    displayEmpty: displayEmpty
	                });
	                $.data.set(node, cacheName, textHash);
	            }
	        }
	    },

	    'text-wrap': {
	        qualify: isPlainObject,
	        set: function(value, refBBox, node, attrs) {
	            var size = {};
	            // option `width`
	            var width = value.width || 0;
	            if (isPercentage(width)) {
	                size.width = refBBox.width * parseFloat(width) / 100;
	            } else if (isCalcAttribute(width)) {
	                size.width = Number(evalCalcAttribute(width, refBBox));
	            } else {
	                if (value.width === null) {
	                    // breakText() requires width to be specified.
	                    size.width = Infinity;
	                } else if (width <= 0) {
	                    size.width = refBBox.width + width;
	                } else {
	                    size.width = width;
	                }
	            }
	            // option `height`
	            var height = value.height || 0;
	            if (isPercentage(height)) {
	                size.height = refBBox.height * parseFloat(height) / 100;
	            } else if (isCalcAttribute(height)) {
	                size.height = Number(evalCalcAttribute(height, refBBox));
	            } else {
	                if (value.height === null) {
	                    // if height is not specified breakText() does not
	                    // restrict the height of the text.
	                } else if (height <= 0) {
	                    size.height = refBBox.height + height;
	                } else {
	                    size.height = height;
	                }
	            }
	            // option `text`
	            var wrappedText;
	            var text = value.text;
	            if (text === undefined) { text = attrs.text; }
	            if (text !== undefined) {
	                var breakTextFn = value.breakText || breakText;
	                wrappedText = breakTextFn('' + text, size, {
	                    'font-weight': attrs['font-weight'],
	                    'font-size': attrs['font-size'],
	                    'font-family': attrs['font-family'],
	                    'lineHeight': attrs['line-height'],
	                    'letter-spacing': attrs['letter-spacing']
	                }, {
	                    // Provide an existing SVG Document here
	                    // instead of creating a temporary one over again.
	                    svgDocument: this.paper.svg,
	                    ellipsis: value.ellipsis,
	                    hyphen: value.hyphen,
	                    separator: value.separator,
	                    maxLineCount: value.maxLineCount,
	                    preserveSpaces: value.preserveSpaces
	                });
	            } else {
	                wrappedText = '';
	            }
	            textAttributesNS.text.set.call(this, wrappedText, refBBox, node, attrs);
	        }
	    },

	    'title': {
	        qualify: function(title, node) {
	            // HTMLElement title is specified via an attribute (i.e. not an element)
	            return node instanceof SVGElement;
	        },
	        set: function(title, refBBox, node) {
	            var cacheName = 'joint-title';
	            var cache = $.data.get(node, cacheName);
	            if (cache === undefined || cache !== title) {
	                $.data.set(node, cacheName, title);
	                if (node.tagName === 'title') {
	                    // The target node is a <title> element.
	                    node.textContent = title;
	                    return;
	                }
	                // Generally <title> element should be the first child element of its parent.
	                var firstChild = node.firstElementChild;
	                if (firstChild && firstChild.tagName === 'title') {
	                    // Update an existing title
	                    firstChild.textContent = title;
	                } else {
	                    // Create a new title
	                    var titleNode = document.createElementNS(node.namespaceURI, 'title');
	                    titleNode.textContent = title;
	                    node.insertBefore(titleNode, firstChild);
	                }
	            }
	        }
	    },
	};

	function atConnectionWrapper(method, opt) {
	    var zeroVector = new Point(1, 0);
	    return function(value) {
	        var p, angle;
	        var tangent = this[method](value);
	        if (tangent) {
	            angle = (opt.rotate) ? tangent.vector().vectorAngle(zeroVector) : 0;
	            p = tangent.start;
	        } else {
	            p = this.path.start;
	            angle = 0;
	        }
	        if (angle === 0) { return { transform: 'translate(' + p.x + ',' + p.y + ')' }; }
	        return { transform: 'translate(' + p.x + ',' + p.y + ') rotate(' + angle + ')' };
	    };
	}

	function isLinkView() {
	    return this.model.isLink();
	}

	var connectionAttributesNS = {

	    'connection': {
	        qualify: isLinkView,
	        set: function(ref) {
	            var stubs = ref.stubs; if ( stubs === void 0 ) stubs = 0;

	            var d;
	            if (isFinite(stubs) && stubs !== 0) {
	                var offset;
	                if (stubs < 0) {
	                    offset = (this.getConnectionLength() + stubs) / 2;
	                } else {
	                    offset = stubs;
	                }
	                var path = this.getConnection();
	                var segmentSubdivisions = this.getConnectionSubdivisions();
	                var sourceParts = path.divideAtLength(offset, { segmentSubdivisions: segmentSubdivisions });
	                var targetParts = path.divideAtLength(-offset, { segmentSubdivisions: segmentSubdivisions });
	                if (sourceParts && targetParts) {
	                    d = (sourceParts[0].serialize()) + " " + (targetParts[1].serialize());
	                }
	            }

	            return { d: d || this.getSerializedConnection() };
	        }
	    },

	    'at-connection-length-keep-gradient': {
	        qualify: isLinkView,
	        set: atConnectionWrapper('getTangentAtLength', { rotate: true })
	    },

	    'at-connection-length-ignore-gradient': {
	        qualify: isLinkView,
	        set: atConnectionWrapper('getTangentAtLength', { rotate: false })
	    },

	    'at-connection-ratio-keep-gradient': {
	        qualify: isLinkView,
	        set: atConnectionWrapper('getTangentAtRatio', { rotate: true })
	    },

	    'at-connection-ratio-ignore-gradient': {
	        qualify: isLinkView,
	        set: atConnectionWrapper('getTangentAtRatio', { rotate: false })
	    }

	};

	connectionAttributesNS['at-connection-length'] = connectionAttributesNS['at-connection-length-keep-gradient'];
	connectionAttributesNS['at-connection-ratio'] = connectionAttributesNS['at-connection-ratio-keep-gradient'];

	function shapeWrapper(shapeConstructor, opt) {
	    var cacheName = 'joint-shape';
	    var resetOffset = opt && opt.resetOffset;
	    return function(value, refBBox, node) {
	        var cache = $.data.get(node, cacheName);
	        if (!cache || cache.value !== value) {
	            // only recalculate if value has changed
	            var cachedShape = shapeConstructor(value);
	            cache = {
	                value: value,
	                shape: cachedShape,
	                shapeBBox: cachedShape.bbox()
	            };
	            $.data.set(node, cacheName, cache);
	        }

	        var shape = cache.shape.clone();
	        var shapeBBox = cache.shapeBBox.clone();
	        var shapeOrigin = shapeBBox.origin();
	        var refOrigin = refBBox.origin();

	        shapeBBox.x = refOrigin.x;
	        shapeBBox.y = refOrigin.y;

	        var fitScale = refBBox.maxRectScaleToFit(shapeBBox, refOrigin);
	        // `maxRectScaleToFit` can give Infinity if width or height is 0
	        var sx = (shapeBBox.width === 0 || refBBox.width === 0) ? 1 : fitScale.sx;
	        var sy = (shapeBBox.height === 0 || refBBox.height === 0) ? 1 : fitScale.sy;

	        shape.scale(sx, sy, shapeOrigin);
	        if (resetOffset) {
	            shape.translate(-shapeOrigin.x, -shapeOrigin.y);
	        }

	        return shape;
	    };
	}

	// `d` attribute for SVGPaths
	function dWrapper(opt) {
	    function pathConstructor(value) {
	        return new Path(V.normalizePathData(value));
	    }

	    var shape = shapeWrapper(pathConstructor, opt);
	    return function(value, refBBox, node) {
	        var path = shape(value, refBBox, node);
	        return {
	            d: path.serialize()
	        };
	    };
	}

	// `points` attribute for SVGPolylines and SVGPolygons
	function pointsWrapper(opt) {
	    var shape = shapeWrapper(Polyline, opt);
	    return function(value, refBBox, node) {
	        var polyline = shape(value, refBBox, node);
	        return {
	            points: polyline.serialize()
	        };
	    };
	}

	var shapeAttributesNS = {

	    'ref-d-reset-offset': {
	        set: dWrapper({ resetOffset: true })
	    },

	    'ref-d-keep-offset': {
	        set: dWrapper({ resetOffset: false })
	    },

	    'ref-points-reset-offset': {
	        set: pointsWrapper({ resetOffset: true })
	    },

	    'ref-points-keep-offset': {
	        set: pointsWrapper({ resetOffset: false })
	    },
	};

	// Aliases
	shapeAttributesNS['ref-d'] = shapeAttributesNS['ref-d-reset-offset'];
	shapeAttributesNS['ref-points'] = shapeAttributesNS['ref-points-reset-offset'];

	function contextMarker(context) {
	    var marker = {};
	    // Stroke
	    // The context 'fill' is disregarded here. The usual case is to use the marker with a connection
	    // (for which 'fill' attribute is set to 'none').
	    var stroke = context.stroke;
	    if (typeof stroke === 'string') {
	        marker['stroke'] = stroke;
	        marker['fill'] = stroke;
	    }
	    // Opacity
	    // Again the context 'fill-opacity' is ignored.
	    var strokeOpacity = context['stroke-opacity'];
	    if (strokeOpacity === undefined) { strokeOpacity = context.opacity; }
	    if (strokeOpacity !== undefined) {
	        marker['stroke-opacity'] = strokeOpacity;
	        marker['fill-opacity'] = strokeOpacity;
	    }
	    return marker;
	}

	function setPaintURL(def) {
	    var ref = this;
	    var paper = ref.paper;
	    var url = (def.type === 'pattern')
	        ? paper.definePattern(def)
	        : paper.defineGradient(def);
	    return ("url(#" + url + ")");
	}

	var defsAttributesNS = {

	    'source-marker': {
	        qualify: isPlainObject,
	        set: function(marker, refBBox, node, attrs) {
	            marker = assign(contextMarker(attrs), marker);
	            return { 'marker-start': 'url(#' + this.paper.defineMarker(marker) + ')' };
	        }
	    },

	    'target-marker': {
	        qualify: isPlainObject,
	        set: function(marker, refBBox, node, attrs) {
	            marker = assign(contextMarker(attrs), { 'transform': 'rotate(180)' }, marker);
	            return { 'marker-end': 'url(#' + this.paper.defineMarker(marker) + ')' };
	        }
	    },

	    'vertex-marker': {
	        qualify: isPlainObject,
	        set: function(marker, refBBox, node, attrs) {
	            marker = assign(contextMarker(attrs), marker);
	            return { 'marker-mid': 'url(#' + this.paper.defineMarker(marker) + ')' };
	        }
	    },

	    'fill': {
	        qualify: isPlainObject,
	        set: setPaintURL
	    },

	    'stroke': {
	        qualify: isPlainObject,
	        set: setPaintURL
	    },

	    'filter': {
	        qualify: isPlainObject,
	        set: function(filter) {
	            return 'url(#' + this.paper.defineFilter(filter) + ')';
	        }
	    },
	};

	function offsetWrapper(axis, dimension, corner) {
	    return function(value, nodeBBox) {
	        var delta;
	        if (value === 'middle') {
	            delta = nodeBBox[dimension] / 2;
	        } else if (value === corner) {
	            delta = nodeBBox[dimension];
	        } else if (isFinite(value)) {
	            // TODO: or not to do a breaking change?
	            delta = (value > -1 && value < 1) ? (-nodeBBox[dimension] * value) : -value;
	        } else if (isPercentage(value)) {
	            delta = nodeBBox[dimension] * parseFloat(value) / 100;
	        } else {
	            delta = 0;
	        }

	        var point = new Point();
	        point[axis] = -(nodeBBox[axis] + delta);
	        return point;
	    };
	}

	var offsetAttributesNS = {

	    // `x-alignment` when set to `middle` causes centering of the sub-element around its new x coordinate.
	    // `x-alignment` when set to `right` uses the x coordinate as referenced to the right of the bbox.
	    'x-alignment': {
	        offset: offsetWrapper('x', 'width', 'right')
	    },

	    // `y-alignment` when set to `middle` causes centering of the sub-element around its new y coordinate.
	    // `y-alignment` when set to `bottom` uses the y coordinate as referenced to the bottom of the bbox.
	    'y-alignment': {
	        offset: offsetWrapper('y', 'height', 'bottom')
	    },

	    'reset-offset': {
	        offset: function(val, nodeBBox) {
	            return (val)
	                ? { x: -nodeBBox.x, y: -nodeBBox.y }
	                : { x: 0, y: 0 };
	        }
	    },
	};

	function setIfChangedWrapper(attribute) {
	    return function setIfChanged(value, _, node) {
	        var vel = V(node);
	        if (vel.attr(attribute) === value) { return; }
	        vel.attr(attribute, value);
	    };
	}

	var attributesNS = {

	    'ref': {
	        // We do not set `ref` attribute directly on an element.
	        // The attribute itself does not qualify for relative positioning.
	    },

	    'href': {
	        set: setIfChangedWrapper('href')
	    },

	    'xlink:href': {
	        set: setIfChangedWrapper('xlink:href')
	    },

	    // `port` attribute contains the `id` of the port that the underlying magnet represents.
	    'port': {
	        set: function(port) {
	            return (port === null || port.id === undefined) ? port : port.id;
	        }
	    },

	    // `style` attribute is special in the sense that it sets the CSS style of the sub-element.
	    'style': {
	        qualify: isPlainObject,
	        set: function(styles, refBBox, node) {
	            $(node).css(styles);
	        }
	    },

	    'html': {
	        set: function(html, refBBox, node) {
	            $(node).html(html + '');
	        }
	    },

	    // Properties setter (set various properties on the node)
	    props: props$1,
	};

	assign(attributesNS, legacyAttributesNS);
	assign(attributesNS, textAttributesNS);
	assign(attributesNS, connectionAttributesNS);
	assign(attributesNS, shapeAttributesNS);
	assign(attributesNS, defsAttributesNS);
	assign(attributesNS, offsetAttributesNS);

	var attributes = attributesNS;

	// Cell base model.
	// --------------------------

	var attributesMerger = function(a, b) {
	    if (Array.isArray(a)) {
	        return b;
	    }
	};

	var Cell = Model.extend({

	    // This is the same as mvc.Model with the only difference that is uses util.merge
	    // instead of just _.extend. The reason is that we want to mixin attributes set in upper classes.
	    constructor: function(attributes, options) {

	        var defaults;
	        var attrs = attributes || {};
	        if (typeof this.preinitialize === 'function') {
	            // Check to support an older version
	            this.preinitialize.apply(this, arguments);
	        }
	        this.cid = uniqueId('c');
	        this.attributes = {};
	        if (options && options.collection) { this.collection = options.collection; }
	        if (options && options.parse) { attrs = this.parse(attrs, options) || {}; }
	        if ((defaults = result(this, 'defaults'))) {
	            //<custom code>
	            // Replaced the call to _.defaults with util.merge.
	            var customizer = (options && options.mergeArrays === true) ? false : attributesMerger;
	            attrs = merge({}, defaults, attrs, customizer);
	            //</custom code>
	        }
	        this.set(attrs, options);
	        this.changed = {};
	        this.initialize.apply(this, arguments);
	    },

	    translate: function(dx, dy, opt) {

	        throw new Error('Must define a translate() method.');
	    },

	    toJSON: function() {

	        var defaults = result(this.constructor.prototype, 'defaults');
	        var defaultAttrs = defaults.attrs || {};
	        var attrs = this.attributes.attrs;
	        var finalAttrs = {};

	        // Loop through all the attributes and
	        // omit the default attributes as they are implicitly reconstructible by the cell 'type'.
	        forIn(attrs, function(attr, selector) {

	            var defaultAttr = defaultAttrs[selector];

	            forIn(attr, function(value, name) {

	                // attr is mainly flat though it might have one more level (consider the `style` attribute).
	                // Check if the `value` is object and if yes, go one level deep.
	                if (isObject$1(value) && !Array.isArray(value)) {

	                    forIn(value, function(value2, name2) {

	                        if (!defaultAttr || !defaultAttr[name] || !isEqual(defaultAttr[name][name2], value2)) {

	                            finalAttrs[selector] = finalAttrs[selector] || {};
	                            (finalAttrs[selector][name] || (finalAttrs[selector][name] = {}))[name2] = value2;
	                        }
	                    });

	                } else if (!defaultAttr || !isEqual(defaultAttr[name], value)) {
	                    // `value` is not an object, default attribute for such a selector does not exist
	                    // or it is different than the attribute value set on the model.

	                    finalAttrs[selector] = finalAttrs[selector] || {};
	                    finalAttrs[selector][name] = value;
	                }
	            });
	        });

	        var attributes = cloneDeep(omit(this.attributes, 'attrs'));
	        attributes.attrs = finalAttrs;

	        return attributes;
	    },

	    initialize: function(options) {

	        var idAttribute = this.getIdAttribute();
	        if (!options || options[idAttribute] === undefined) {
	            this.set(idAttribute, this.generateId(), { silent: true });
	        }

	        this._transitionIds = {};
	        this._scheduledTransitionIds = {};

	        // Collect ports defined in `attrs` and keep collecting whenever `attrs` object changes.
	        this.processPorts();
	        this.on('change:attrs', this.processPorts, this);
	    },

	    getIdAttribute: function() {
	        return this.idAttribute || 'id';
	    },

	    generateId: function() {
	        return uuid();
	    },

	    /**
	     * @deprecated
	     */
	    processPorts: function() {

	        // Whenever `attrs` changes, we extract ports from the `attrs` object and store it
	        // in a more accessible way. Also, if any port got removed and there were links that had `target`/`source`
	        // set to that port, we remove those links as well (to follow the same behaviour as
	        // with a removed element).

	        var previousPorts = this.ports;

	        // Collect ports from the `attrs` object.
	        var ports = {};
	        forIn(this.get('attrs'), function(attrs, selector) {

	            if (attrs && attrs.port) {

	                // `port` can either be directly an `id` or an object containing an `id` (and potentially other data).
	                if (attrs.port.id !== undefined) {
	                    ports[attrs.port.id] = attrs.port;
	                } else {
	                    ports[attrs.port] = { id: attrs.port };
	                }
	            }
	        });

	        // Collect ports that have been removed (compared to the previous ports) - if any.
	        // Use hash table for quick lookup.
	        var removedPorts = {};
	        forIn(previousPorts, function(port, id) {

	            if (!ports[id]) { removedPorts[id] = true; }
	        });

	        // Remove all the incoming/outgoing links that have source/target port set to any of the removed ports.
	        if (this.graph && !isEmpty(removedPorts)) {

	            var inboundLinks = this.graph.getConnectedLinks(this, { inbound: true });
	            inboundLinks.forEach(function(link) {

	                if (removedPorts[link.get('target').port]) { link.remove(); }
	            });

	            var outboundLinks = this.graph.getConnectedLinks(this, { outbound: true });
	            outboundLinks.forEach(function(link) {

	                if (removedPorts[link.get('source').port]) { link.remove(); }
	            });
	        }

	        // Update the `ports` object.
	        this.ports = ports;
	    },

	    remove: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        // Store the graph in a variable because `this.graph` won't be accessible
	        // after `this.trigger('remove', ...)` down below.
	        var ref = this;
	        var graph = ref.graph;
	        var collection = ref.collection;
	        if (!graph) {
	            // The collection is a common mvc collection (not the graph collection).
	            if (collection) { collection.remove(this, opt); }
	            return this;
	        }

	        graph.startBatch('remove');

	        // First, unembed this cell from its parent cell if there is one.
	        var parentCell = this.getParentCell();
	        if (parentCell) {
	            parentCell.unembed(this, opt);
	        }

	        // Remove also all the cells, which were embedded into this cell
	        var embeddedCells = this.getEmbeddedCells();
	        for (var i = 0, n = embeddedCells.length; i < n; i++) {
	            var embed = embeddedCells[i];
	            if (embed) {
	                embed.remove(opt);
	            }
	        }

	        this.trigger('remove', this, graph.attributes.cells, opt);

	        graph.stopBatch('remove');

	        return this;
	    },

	    toFront: function(opt) {
	        var graph = this.graph;
	        if (graph) {
	            opt = defaults(opt || {}, { foregroundEmbeds: true });

	            var cells;
	            if (opt.deep) {
	                cells = this.getEmbeddedCells({ deep: true, breadthFirst: opt.breadthFirst !== false, sortSiblings: opt.foregroundEmbeds });
	                cells.unshift(this);
	            } else {
	                cells = [this];
	            }

	            var sortedCells = opt.foregroundEmbeds ? cells : sortBy(cells, function (cell) { return cell.z(); });

	            var maxZ = graph.maxZIndex();
	            var z = maxZ - cells.length + 1;

	            var collection = graph.get('cells');

	            var shouldUpdate = (collection.toArray().indexOf(sortedCells[0]) !== (collection.length - cells.length));
	            if (!shouldUpdate) {
	                shouldUpdate = sortedCells.some(function(cell, index) {
	                    return cell.z() !== z + index;
	                });
	            }

	            if (shouldUpdate) {
	                this.startBatch('to-front');

	                z = z + cells.length;

	                sortedCells.forEach(function(cell, index) {
	                    cell.set('z', z + index, opt);
	                });

	                this.stopBatch('to-front');
	            }
	        }

	        return this;
	    },

	    toBack: function(opt) {
	        var graph = this.graph;
	        if (graph) {
	            opt = defaults(opt || {}, { foregroundEmbeds: true });

	            var cells;
	            if (opt.deep) {
	                cells = this.getEmbeddedCells({ deep: true, breadthFirst: opt.breadthFirst !== false, sortSiblings: opt.foregroundEmbeds });
	                cells.unshift(this);
	            } else {
	                cells = [this];
	            }

	            var sortedCells = opt.foregroundEmbeds ? cells : sortBy(cells, function (cell) { return cell.z(); });

	            var z = graph.minZIndex();

	            var collection = graph.get('cells');

	            var shouldUpdate = (collection.toArray().indexOf(sortedCells[0]) !== 0);
	            if (!shouldUpdate) {
	                shouldUpdate = sortedCells.some(function(cell, index) {
	                    return cell.z() !== z + index;
	                });
	            }

	            if (shouldUpdate) {
	                this.startBatch('to-back');

	                z -= cells.length;

	                sortedCells.forEach(function(cell, index) {
	                    cell.set('z', z + index, opt);
	                });

	                this.stopBatch('to-back');
	            }
	        }

	        return this;
	    },

	    parent: function(parent, opt) {

	        // getter
	        if (parent === undefined) { return this.get('parent'); }
	        // setter
	        return this.set('parent', parent, opt);
	    },

	    embed: function(cell, opt) {
	        var this$1 = this;

	        var cells = Array.isArray(cell) ? cell : [cell];
	        if (!this.canEmbed(cells)) {
	            throw new Error('Recursive embedding not allowed.');
	        }
	        if (cells.some(function (c) { return c.isEmbedded() && this$1.id !== c.parent(); })) {
	            throw new Error('Embedding of already embedded cells is not allowed.');
	        }
	        this._embedCells(cells, opt);
	        return this;
	    },

	    unembed: function(cell, opt) {
	        var cells = Array.isArray(cell) ? cell : [cell];
	        this._unembedCells(cells, opt);
	        return this;
	    },

	    canEmbed: function(cell) {
	        var this$1 = this;

	        var cells = Array.isArray(cell) ? cell : [cell];
	        return cells.every(function (c) { return this$1 !== c && !this$1.isEmbeddedIn(c); });
	    },

	    _embedCells: function(cells, opt) {
	        var this$1 = this;

	        var batchName = 'embed';
	        this.startBatch(batchName);
	        var embeds = assign([], this.get('embeds'));
	        cells.forEach(function (cell) {
	            // We keep all element ids after link ids.
	            embeds[cell.isLink() ? 'unshift' : 'push'](cell.id);
	            cell.parent(this$1.id, opt);
	        });
	        this.set('embeds', uniq(embeds), opt);
	        this.stopBatch(batchName);
	    },

	    _unembedCells: function(cells, opt) {
	        var batchName = 'unembed';
	        this.startBatch(batchName);
	        cells.forEach(function (cell) { return cell.unset('parent', opt); });
	        this.set('embeds', without.apply(void 0, [ this.get('embeds') ].concat( cells.map(function (cell) { return cell.id; }) )), opt);
	        this.stopBatch(batchName);
	    },

	    getParentCell: function() {

	        // unlike link.source/target, cell.parent stores id directly as a string
	        var parentId = this.parent();
	        var graph = this.graph;

	        return (parentId && graph && graph.getCell(parentId)) || null;
	    },

	    // Return an array of ancestor cells.
	    // The array is ordered from the parent of the cell
	    // to the most distant ancestor.
	    getAncestors: function() {

	        var ancestors = [];

	        if (!this.graph) {
	            return ancestors;
	        }

	        var parentCell = this.getParentCell();
	        while (parentCell) {
	            ancestors.push(parentCell);
	            parentCell = parentCell.getParentCell();
	        }

	        return ancestors;
	    },

	    getEmbeddedCells: function(opt) {

	        opt = opt || {};

	        // Cell models can only be retrieved when this element is part of a collection.
	        // There is no way this element knows about other cells otherwise.
	        // This also means that calling e.g. `translate()` on an element with embeds before
	        // adding it to a graph does not translate its embeds.
	        if (!this.graph) {
	            return [];
	        }

	        if (opt.deep) {
	            if (opt.breadthFirst) {
	                return this._getEmbeddedCellsBfs(opt.sortSiblings);
	            } else {
	                return this._getEmbeddedCellsDfs(opt.sortSiblings);
	            }
	        }

	        var embeddedIds = this.get('embeds');
	        if (isEmpty(embeddedIds)) {
	            return [];
	        }

	        var cells = embeddedIds.map(this.graph.getCell, this.graph);
	        if (opt.sortSiblings) {
	            cells = sortBy(cells, function (cell) { return cell.z(); });
	        }

	        return cells;
	    },

	    _getEmbeddedCellsBfs: function(sortSiblings) {
	        var cells = [];

	        var queue = [];
	        queue.push(this);

	        while (queue.length > 0) {
	            var current = queue.shift();
	            cells.push(current);

	            var embeddedCells = current.getEmbeddedCells({ sortSiblings: sortSiblings });

	            queue.push.apply(queue, embeddedCells);
	        }
	        cells.shift();

	        return cells;
	    },

	    _getEmbeddedCellsDfs: function(sortSiblings) {
	        var cells = [];

	        var stack = [];
	        stack.push(this);

	        while (stack.length > 0) {
	            var current = stack.pop();
	            cells.push(current);

	            var embeddedCells = current.getEmbeddedCells({ sortSiblings: sortSiblings });

	            // When using the stack, cells that are embedded last are processed first.
	            // To maintain the original order, we need to push the cells in reverse order
	            for (var i = embeddedCells.length - 1; i >= 0; --i) {
	                stack.push(embeddedCells[i]);
	            }
	        }
	        cells.shift();

	        return cells;
	    },

	    isEmbeddedIn: function(cell, opt) {

	        var cellId = isString(cell) ? cell : cell.id;
	        var parentId = this.parent();

	        opt = assign({ deep: true }, opt);

	        // See getEmbeddedCells().
	        if (this.graph && opt.deep) {

	            while (parentId) {
	                if (parentId === cellId) {
	                    return true;
	                }
	                parentId = this.graph.getCell(parentId).parent();
	            }

	            return false;

	        } else {

	            // When this cell is not part of a collection check
	            // at least whether it's a direct child of given cell.
	            return parentId === cellId;
	        }
	    },

	    // Whether or not the cell is embedded in any other cell.
	    isEmbedded: function() {

	        return !!this.parent();
	    },

	    // Isolated cloning. Isolated cloning has two versions: shallow and deep (pass `{ deep: true }` in `opt`).
	    // Shallow cloning simply clones the cell and returns a new cell with different ID.
	    // Deep cloning clones the cell and all its embedded cells recursively.
	    clone: function(opt) {

	        opt = opt || {};

	        if (!opt.deep) {
	            // Shallow cloning.

	            var clone = Model.prototype.clone.apply(this, arguments);
	            // We don't want the clone to have the same ID as the original.
	            clone.set(this.getIdAttribute(), this.generateId());
	            // A shallow cloned element does not carry over the original embeds.
	            clone.unset('embeds');
	            // And can not be embedded in any cell
	            // as the clone is not part of the graph.
	            clone.unset('parent');

	            return clone;

	        } else {
	            // Deep cloning.

	            // For a deep clone, simply call `graph.cloneCells()` with the cell and all its embedded cells.
	            return toArray(cloneCells([this].concat(this.getEmbeddedCells({ deep: true }))));
	        }
	    },

	    // A convenient way to set nested properties.
	    // This method merges the properties you'd like to set with the ones
	    // stored in the cell and makes sure change events are properly triggered.
	    // You can either set a nested property with one object
	    // or use a property path.
	    // The most simple use case is:
	    // `cell.prop('name/first', 'John')` or
	    // `cell.prop({ name: { first: 'John' } })`.
	    // Nested arrays are supported too:
	    // `cell.prop('series/0/data/0/degree', 50)` or
	    // `cell.prop({ series: [ { data: [ { degree: 50 } ] } ] })`.
	    prop: function(props, value, opt) {

	        var delim = '/';
	        var _isString = isString(props);

	        if (_isString || Array.isArray(props)) {
	            // Get/set an attribute by a special path syntax that delimits
	            // nested objects by the colon character.

	            if (arguments.length > 1) {

	                var path;
	                var pathArray;

	                if (_isString) {
	                    path = props;
	                    pathArray = path.split('/');
	                } else {
	                    path = props.join(delim);
	                    pathArray = props.slice();
	                }

	                var property = pathArray[0];
	                var pathArrayLength = pathArray.length;

	                var options$1 = opt || {};
	                options$1.propertyPath = path;
	                options$1.propertyValue = value;
	                options$1.propertyPathArray = pathArray;
	                if (!('rewrite' in options$1)) {
	                    options$1.rewrite = false;
	                }

	                var update = {};
	                // Initialize the nested object. Sub-objects are either arrays or objects.
	                // An empty array is created if the sub-key is an integer. Otherwise, an empty object is created.
	                // Note that this imposes a limitation on object keys one can use with Inspector.
	                // Pure integer keys will cause issues and are therefore not allowed.
	                var initializer = update;
	                var prevProperty = property;

	                for (var i = 1; i < pathArrayLength; i++) {
	                    var pathItem = pathArray[i];
	                    var isArrayIndex = Number.isFinite(_isString ? Number(pathItem) : pathItem);
	                    initializer = initializer[prevProperty] = isArrayIndex ? [] : {};
	                    prevProperty = pathItem;
	                }

	                // Fill update with the `value` on `path`.
	                update = setByPath(update, pathArray, value, '/');

	                var baseAttributes = merge({}, this.attributes);
	                // if rewrite mode enabled, we replace value referenced by path with
	                // the new one (we don't merge).
	                options$1.rewrite && unsetByPath(baseAttributes, path, '/');

	                // Merge update with the model attributes.
	                var attributes = merge(baseAttributes, update);
	                // Finally, set the property to the updated attributes.
	                return this.set(property, attributes[property], options$1);

	            } else {

	                return getByPath(this.attributes, props, delim);
	            }
	        }

	        var options = value || {};
	        // Note: '' is not the path to the root. It's a path with an empty string i.e. { '': {}}.
	        options.propertyPath = null;
	        options.propertyValue = props;
	        options.propertyPathArray = [];
	        if (!('rewrite' in options)) {
	            options.rewrite = false;
	        }

	        // Create a new object containing only the changed attributes.
	        var changedAttributes = {};
	        for (var key in props) {
	            // Merging the values of changed attributes with the current ones.
	            var ref = merge({}, { changedValue: this.attributes[key] }, { changedValue: props[key] });
	            var changedValue = ref.changedValue;
	            changedAttributes[key] = changedValue;
	        }

	        return this.set(changedAttributes, options);
	    },

	    // A convenient way to unset nested properties
	    removeProp: function(path, opt) {

	        opt = opt || {};

	        var pathArray = Array.isArray(path) ? path : path.split('/');

	        // Once a property is removed from the `attrs` attribute
	        // the cellView will recognize a `dirty` flag and re-render itself
	        // in order to remove the attribute from SVG element.
	        var property = pathArray[0];
	        if (property === 'attrs') { opt.dirty = true; }

	        if (pathArray.length === 1) {
	            // A top level property
	            return this.unset(path, opt);
	        }

	        // A nested property
	        var nestedPath = pathArray.slice(1);
	        var propertyValue = this.get(property);
	        if (propertyValue === undefined || propertyValue === null) { return this; }
	        propertyValue = cloneDeep(propertyValue);

	        unsetByPath(propertyValue, nestedPath, '/');

	        return this.set(property, propertyValue, opt);
	    },

	    // A convenient way to set nested attributes.
	    attr: function(attrs, value, opt) {

	        var args = Array.from(arguments);
	        if (args.length === 0) {
	            return this.get('attrs');
	        }

	        if (Array.isArray(attrs)) {
	            args[0] = ['attrs'].concat(attrs);
	        } else if (isString(attrs)) {
	            // Get/set an attribute by a special path syntax that delimits
	            // nested objects by the colon character.
	            args[0] = 'attrs/' + attrs;

	        } else {

	            args[0] = { 'attrs' : attrs };
	        }

	        return this.prop.apply(this, args);
	    },

	    // A convenient way to unset nested attributes
	    removeAttr: function(path, opt) {

	        if (Array.isArray(path)) {

	            return this.removeProp(['attrs'].concat(path));
	        }

	        return this.removeProp('attrs/' + path, opt);
	    },

	    transition: function(path, value, opt, delim) {
	        var this$1 = this;


	        delim = delim || '/';

	        var defaults = {
	            duration: 100,
	            delay: 10,
	            timingFunction: timing.linear,
	            valueFunction: interpolate.number
	        };

	        opt = assign(defaults, opt);

	        var firstFrameTime = 0;
	        var interpolatingFunction;

	        var setter = function(runtime) {

	            var id, progress, propertyValue;

	            firstFrameTime = firstFrameTime || runtime;
	            runtime -= firstFrameTime;
	            progress = runtime / opt.duration;

	            if (progress < 1) {
	                this._transitionIds[path] = id = nextFrame(setter);
	            } else {
	                progress = 1;
	                delete this._transitionIds[path];
	            }

	            propertyValue = interpolatingFunction(opt.timingFunction(progress));

	            opt.transitionId = id;

	            this.prop(path, propertyValue, opt);

	            if (!id) { this.trigger('transition:end', this, path); }

	        }.bind(this);

	        var ref = this;
	        var _scheduledTransitionIds = ref._scheduledTransitionIds;
	        var initialId;

	        var initiator = function (callback) {

	            if (_scheduledTransitionIds[path]) {
	                _scheduledTransitionIds[path] = without(_scheduledTransitionIds[path], initialId);
	                if (_scheduledTransitionIds[path].length === 0) {
	                    delete _scheduledTransitionIds[path];
	                }
	            }

	            this$1.stopPendingTransitions(path, delim);

	            interpolatingFunction = opt.valueFunction(getByPath(this$1.attributes, path, delim), value);

	            this$1._transitionIds[path] = nextFrame(callback);

	            this$1.trigger('transition:start', this$1, path);

	        };

	        initialId = setTimeout(initiator, opt.delay, setter);

	        _scheduledTransitionIds[path] || (_scheduledTransitionIds[path] = []);
	        _scheduledTransitionIds[path].push(initialId);

	        return initialId;
	    },

	    getTransitions: function() {
	        return union(
	            Object.keys(this._transitionIds),
	            Object.keys(this._scheduledTransitionIds)
	        );
	    },

	    stopScheduledTransitions: function(path, delim) {
	        if ( delim === void 0 ) delim = '/';

	        var ref = this;
	        var _scheduledTransitionIds = ref._scheduledTransitionIds; if ( _scheduledTransitionIds === void 0 ) _scheduledTransitionIds = {};
	        var transitions = Object.keys(_scheduledTransitionIds);
	        if (path) {
	            var pathArray = path.split(delim);
	            transitions = transitions.filter(function (key) {
	                return isEqual(pathArray, key.split(delim).slice(0, pathArray.length));
	            });
	        }
	        transitions.forEach(function (key) {
	            var transitionIds = _scheduledTransitionIds[key];
	            // stop the initiator
	            transitionIds.forEach(function (transitionId) { return clearTimeout(transitionId); });
	            delete _scheduledTransitionIds[key];
	            // Note: we could trigger transition:cancel` event here
	        });
	        return this;
	    },

	    stopPendingTransitions: function stopPendingTransitions(path, delim) {
	        var this$1 = this;
	        if ( delim === void 0 ) delim = '/';

	        var ref = this;
	        var _transitionIds = ref._transitionIds; if ( _transitionIds === void 0 ) _transitionIds = {};
	        var transitions = Object.keys(_transitionIds);
	        if (path) {
	            var pathArray = path.split(delim);
	            transitions = transitions.filter(function (key) {
	                return isEqual(pathArray, key.split(delim).slice(0, pathArray.length));
	            });
	        }
	        transitions.forEach(function (key) {
	            var transitionId = _transitionIds[key];
	            // stop the setter
	            cancelFrame(transitionId);
	            delete _transitionIds[key];
	            this$1.trigger('transition:end', this$1, key);
	        });
	    },

	    stopTransitions: function(path, delim) {
	        if ( delim === void 0 ) delim = '/';

	        this.stopScheduledTransitions(path, delim);
	        this.stopPendingTransitions(path, delim);
	        return this;
	    },

	    // A shorcut making it easy to create constructs like the following:
	    // `var el = (new joint.shapes.standard.Rectangle()).addTo(graph)`.
	    addTo: function(graph, opt) {

	        graph.addCell(this, opt);
	        return this;
	    },

	    // A shortcut for an equivalent call: `paper.findViewByModel(cell)`
	    // making it easy to create constructs like the following:
	    // `cell.findView(paper).highlight()`
	    findView: function(paper) {

	        return paper.findViewByModel(this);
	    },

	    isElement: function() {

	        return false;
	    },

	    isLink: function() {

	        return false;
	    },

	    startBatch: function(name, opt) {

	        if (this.graph) { this.graph.startBatch(name, assign({}, opt, { cell: this })); }
	        return this;
	    },

	    stopBatch: function(name, opt) {

	        if (this.graph) { this.graph.stopBatch(name, assign({}, opt, { cell: this })); }
	        return this;
	    },

	    getChangeFlag: function(attributes) {

	        var flag = 0;
	        if (!attributes) { return flag; }
	        for (var key in attributes) {
	            if (!attributes.hasOwnProperty(key) || !this.hasChanged(key)) { continue; }
	            flag |= attributes[key];
	        }
	        return flag;
	    },

	    angle: function() {

	        // To be overridden.
	        return 0;
	    },

	    position: function() {

	        // To be overridden.
	        return new Point(0, 0);
	    },

	    z: function() {
	        return this.get('z') || 0;
	    },

	    getPointFromConnectedLink: function() {

	        // To be overridden
	        return new Point();
	    },

	    getBBox: function() {

	        // To be overridden
	        return new Rect(0, 0, 0, 0);
	    },

	    getPointRotatedAroundCenter: function getPointRotatedAroundCenter(angle, x, y) {
	        var point = new Point(x, y);
	        if (angle) { point.rotate(this.getBBox().center(), angle); }
	        return point;
	    },

	    getAbsolutePointFromRelative: function getAbsolutePointFromRelative(x, y) {
	        // Rotate the position to take the model angle into account
	        return this.getPointRotatedAroundCenter(
	            -this.angle(),
	            // Transform the relative position to absolute
	            this.position().offset(x, y)
	        );
	    },

	    getRelativePointFromAbsolute: function getRelativePointFromAbsolute(x, y) {
	        return this
	            // Rotate the coordinates to mitigate the element's rotation.
	            .getPointRotatedAroundCenter(this.angle(), x, y)
	            // Transform the absolute position into relative
	            .difference(this.position());
	    }

	}, {

	    getAttributeDefinition: function(attrName) {

	        var defNS = this.attributes;
	        var globalDefNS = attributes;
	        return (defNS && defNS[attrName]) || globalDefNS[attrName];
	    },

	    define: function(type, defaults, protoProps, staticProps) {

	        protoProps = assign({
	            defaults: defaultsDeep({ type: type }, defaults, this.prototype.defaults)
	        }, protoProps);

	        var Cell = this.extend(protoProps, staticProps);
	        // es5 backward compatibility
	        /* eslint-disable no-undef */
	        if (typeof joint !== 'undefined' && has$2(joint, 'shapes')) {
	            setByPath(joint.shapes, type, Cell, '.');
	        }
	        /* eslint-enable no-undef */
	        return Cell;
	    }
	});

	var wrapWith = function(object, methods, wrapper) {

	    if (isString(wrapper)) {

	        if (!wrappers[wrapper]) {
	            throw new Error('Unknown wrapper: "' + wrapper + '"');
	        }

	        wrapper = wrappers[wrapper];
	    }

	    if (!isFunction(wrapper)) {
	        throw new Error('Wrapper must be a function.');
	    }

	    toArray(methods).forEach(function(method) {
	        object[method] = wrapper(object[method]);
	    });
	};

	var wrappers = {

	    cells: function(fn) {

	        return function() {

	            var args = Array.from(arguments);
	            var n = args.length;
	            var cells = n > 0 && args[0] || [];
	            var opt = n > 1 && args[n - 1] || {};

	            if (!Array.isArray(cells)) {

	                if (opt instanceof Cell) {
	                    cells = args;
	                } else if (cells instanceof Cell) {
	                    if (args.length > 1) {
	                        args.pop();
	                    }
	                    cells = args;
	                }
	            }

	            if (opt instanceof Cell) {
	                opt = {};
	            }

	            return fn.call(this, cells, opt);
	        };
	    }

	};

	function svg(strings) {
	    var expressions = [], len = arguments.length - 1;
	    while ( len-- > 0 ) expressions[ len ] = arguments[ len + 1 ];

	    var svgParts = [];
	    strings.forEach(function (part, index) {
	        svgParts.push(part);
	        if (index in expressions) {
	            svgParts.push(expressions[index]);
	        }
	    });
	    var markup = parseFromSVGString(svgParts.join(''));
	    return markup;
	}

	function parseFromSVGString(str) {
	    var parser = new DOMParser();
	    var markupString = "<svg>" + (str.trim()) + "</svg>";
	    var xmldocument = parser.parseFromString(markupString.replace(/@/g, ''), 'application/xml');
	    if (xmldocument.getElementsByTagName('parsererror')[0]) {
	        throw new Error('Invalid SVG markup');
	    }
	    var document = parser.parseFromString(markupString, 'text/html');
	    var svg = document.querySelector('svg');
	    return build(svg);
	}

	function buildNode(node) {
	    var markupNode = {};
	    var tagName = node.tagName;
	    var attributes = node.attributes;
	    var namespaceURI = node.namespaceURI;
	    var style = node.style;
	    var childNodes = node.childNodes;

	    markupNode.namespaceURI = namespaceURI;
	    markupNode.tagName = (namespaceURI === V.namespace.xhtml)
	        // XHTML documents must use lower case for all HTML element and attribute names.
	        // The tagName property returns upper case value for HTML elements.
	        // e.g. <DIV> vs.<div/>
	        ? tagName.toLowerCase()
	        : tagName;

	    var stylesObject = {};
	    for (var i = style.length; i--;) {
	        var nameString = style[i];
	        stylesObject[nameString] = style.getPropertyValue(nameString);
	    }
	    markupNode.style = stylesObject;

	    // selector fallbacks to tagName
	    var selectorAttribute = attributes.getNamedItem('@selector');
	    if (selectorAttribute) {
	        markupNode.selector = selectorAttribute.value;
	        attributes.removeNamedItem('@selector');
	    }

	    var groupSelectorAttribute = attributes.getNamedItem('@group-selector');
	    if (groupSelectorAttribute) {
	        var groupSelectors = groupSelectorAttribute.value.split(',');
	        markupNode.groupSelector = groupSelectors.map(function (s) { return s.trim(); });

	        attributes.removeNamedItem('@group-selector');
	    }

	    var className = attributes.getNamedItem('class');
	    if (className) {
	        markupNode.className = className.value;
	    }

	    var children = [];
	    childNodes.forEach(function (node) {
	        switch (node.nodeType) {
	            case Node.TEXT_NODE: {
	                var trimmedText = node.data.replace(/\s\s+/g, ' ');
	                if (trimmedText.trim()) {
	                    children.push(trimmedText);
	                }
	                break;
	            }
	            case Node.ELEMENT_NODE: {
	                children.push(buildNode(node));
	                break;
	            }
	            default:
	                break;
	        }
	    });
	    if (children.length) {
	        markupNode.children = children;
	    }

	    var nodeAttrs = {};

	    Array.from(attributes).forEach(function (nodeAttribute) {
	        var name = nodeAttribute.name;
	        var value = nodeAttribute.value;
	        nodeAttrs[name] = value;
	    });

	    if (Object.keys(nodeAttrs).length > 0) {
	        markupNode.attributes = nodeAttrs;
	    }

	    return markupNode;
	}

	function build(root) {
	    var markup = [];

	    Array.from(root.children).forEach(function (node) {
	        markup.push(buildNode(node));
	    });

	    return markup;
	}

	var Positions = {
	    TOP: 'top',
	    RIGHT: 'right',
	    BOTTOM: 'bottom',
	    LEFT: 'left',
	    TOP_LEFT: 'top-left',
	    TOP_RIGHT: 'top-right',
	    BOTTOM_LEFT: 'bottom-left',
	    BOTTOM_RIGHT: 'bottom-right',
	    CENTER: 'center',
	};

	function getRectPoint(rect, position) {
	    var r = new Rect(rect);
	    switch (position) {
	        case undefined:
	            throw new Error('Position required');

	        // Middle Points
	        case Positions.LEFT:
	        case 'leftMiddle':
	            return r.leftMiddle();

	        case Positions.RIGHT:
	        case 'rightMiddle':
	            return r.rightMiddle();

	        case Positions.TOP:
	        case 'topMiddle':
	            return r.topMiddle();

	        case Positions.BOTTOM:
	        case 'bottomMiddle':
	            return r.bottomMiddle();

	        // Corners
	        case Positions.TOP_LEFT:
	        case 'topLeft':
	        case 'origin':
	            return r.topLeft();

	        case Positions.TOP_RIGHT:
	        case 'topRight':
	            return r.topRight();

	        case Positions.BOTTOM_LEFT:
	        case 'bottomLeft':
	            return r.bottomLeft();

	        case Positions.BOTTOM_RIGHT:
	        case 'bottomRight':
	        case 'corner':
	            return r.bottomRight();

	        // Center
	        case Positions.CENTER:
	            return r.center();

	        // TODO: calc(), percentage etc.
	        default:
	            throw new Error(("Unknown position: " + position));
	    }
	}



	var index = ({
		getRectPoint: getRectPoint,
		wrapWith: wrapWith,
		wrappers: wrappers,
		addClassNamePrefix: addClassNamePrefix,
		removeClassNamePrefix: removeClassNamePrefix,
		parseDOMJSON: parseDOMJSON,
		hashCode: hashCode,
		getByPath: getByPath,
		setByPath: setByPath,
		unsetByPath: unsetByPath,
		flattenObject: flattenObject,
		uuid: uuid,
		guid: guid,
		toKebabCase: toKebabCase,
		normalizeEvent: normalizeEvent,
		normalizeWheel: normalizeWheel,
		cap: cap,
		nextFrame: nextFrame,
		cancelFrame: cancelFrame,
		isPercentage: isPercentage,
		parseCssNumeric: parseCssNumeric,
		breakText: breakText,
		sanitizeHTML: sanitizeHTML,
		downloadBlob: downloadBlob,
		downloadDataUri: downloadDataUri,
		dataUriToBlob: dataUriToBlob,
		imageToDataUri: imageToDataUri,
		getElementBBox: getElementBBox,
		sortElements: sortElements,
		setAttributesBySelector: setAttributesBySelector,
		normalizeSides: normalizeSides,
		timing: timing,
		interpolate: interpolate,
		filter: filter,
		format: format,
		template: template,
		toggleFullScreen: toggleFullScreen,
		isBoolean: isBoolean,
		isObject: isObject$1,
		isNumber: isNumber,
		isString: isString,
		mixin: mixin,
		deepMixin: deepMixin,
		supplement: supplement,
		defaults: defaults,
		deepSupplement: deepSupplement,
		defaultsDeep: defaultsDeep,
		assign: assign,
		invoke: invoke,
		invokeProperty: invokeProperty,
		sortedIndex: sortedIndex,
		uniq: uniq,
		clone: clone,
		cloneDeep: cloneDeep,
		isEmpty: isEmpty,
		isEqual: isEqual,
		isFunction: isFunction,
		isPlainObject: isPlainObject,
		toArray: toArray,
		debounce: debounce,
		groupBy: groupBy,
		sortBy: sortBy,
		flattenDeep: flattenDeep,
		without: without,
		difference: difference,
		intersection: intersection$1,
		union: union,
		has: has$2,
		result: result,
		omit: omit,
		pick: pick,
		bindAll: bindAll,
		forIn: forIn,
		camelCase: camelCase,
		uniqueId: uniqueId,
		merge: merge,
		noop: noop,
		cloneCells: cloneCells,
		svg: svg
	});

	function portTransformAttrs(point, angle, opt) {

	    var trans = point.toJSON();

	    trans.angle = angle || 0;

	    return defaults({}, opt, trans);
	}

	function lineLayout(ports, p1, p2, elBBox) {
	    return ports.map(function(port, index, ports) {
	        var p = this.pointAt(((index + 0.5) / ports.length));
	        // `dx`,`dy` per port offset option
	        if (port.dx || port.dy) {
	            p.offset(port.dx || 0, port.dy || 0);
	        }
	        return portTransformAttrs(p.round(), 0, argTransform(elBBox, port));
	    }, line(p1, p2));
	}

	function ellipseLayout(ports, elBBox, startAngle, stepFn) {

	    var center = elBBox.center();
	    var ratio = elBBox.width / elBBox.height;
	    var p1 = elBBox.topMiddle();

	    var ellipse = Ellipse.fromRect(elBBox);

	    return ports.map(function(port, index, ports) {

	        var angle = startAngle + stepFn(index, ports.length);
	        var p2 = p1.clone()
	            .rotate(center, -angle)
	            .scale(ratio, 1, center);

	        var theta = port.compensateRotation ? -ellipse.tangentTheta(p2) : 0;

	        // `dx`,`dy` per port offset option
	        if (port.dx || port.dy) {
	            p2.offset(port.dx || 0, port.dy || 0);
	        }

	        // `dr` delta radius option
	        if (port.dr) {
	            p2.move(center, port.dr);
	        }

	        return portTransformAttrs(p2.round(), theta, argTransform(elBBox, port));
	    });
	}


	function argTransform(bbox, args) {
	    var x = args.x;
	    var y = args.y;
	    var angle = args.angle;
	    if (isPercentage(x)) {
	        x = parseFloat(x) / 100 * bbox.width;
	    } else if (isCalcAttribute(x)) {
	        x = Number(evalCalcAttribute(x, bbox));
	    }
	    if (isPercentage(y)) {
	        y = parseFloat(y) / 100 * bbox.height;
	    } else if (isCalcAttribute(y)) {
	        y = Number(evalCalcAttribute(y, bbox));
	    }
	    return { x: x, y: y, angle: angle };
	}

	// Creates a point stored in arguments
	function argPoint(bbox, args) {
	    var ref = argTransform(bbox, args);
	    var x = ref.x;
	    var y = ref.y;
	    return new Point(x || 0, y || 0);
	}


	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var absolute = function(ports, elBBox) {
	    return ports.map(function (port) {
	        var transformation = argPoint(elBBox, port).round().toJSON();
	        transformation.angle = port.angle || 0;
	        return transformation;
	    });
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var fn = function(ports, elBBox, opt) {
	    return opt.fn(ports, elBBox, opt);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var line$1 = function(ports, elBBox, opt) {

	    var start = argPoint(elBBox, opt.start || elBBox.origin());
	    var end = argPoint(elBBox, opt.end || elBBox.corner());

	    return lineLayout(ports, start, end, elBBox);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var left = function(ports, elBBox, opt) {
	    return lineLayout(ports, elBBox.origin(), elBBox.bottomLeft(), elBBox);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var right = function(ports, elBBox, opt) {
	    return lineLayout(ports, elBBox.topRight(), elBBox.corner(), elBBox);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var top = function(ports, elBBox, opt) {
	    return lineLayout(ports, elBBox.origin(), elBBox.topRight(), elBBox);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt opt Group options
	 * @returns {Array<g.Point>}
	 */
	var bottom = function(ports, elBBox, opt) {
	    return lineLayout(ports, elBBox.bottomLeft(), elBBox.corner(), elBBox);
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt Group options
	 * @returns {Array<g.Point>}
	 */
	var ellipseSpread = function(ports, elBBox, opt) {

	    var startAngle = opt.startAngle || 0;
	    var stepAngle = opt.step || 360 / ports.length;

	    return ellipseLayout(ports, elBBox, startAngle, function(index) {
	        return index * stepAngle;
	    });
	};

	/**
	 * @param {Array<Object>} ports
	 * @param {g.Rect} elBBox
	 * @param {Object=} opt Group options
	 * @returns {Array<g.Point>}
	 */
	var ellipse$1 = function(ports, elBBox, opt) {

	    var startAngle = opt.startAngle || 0;
	    var stepAngle = opt.step || 20;

	    return ellipseLayout(ports, elBBox, startAngle, function(index, count) {
	        return (index + 0.5 - count / 2) * stepAngle;
	    });
	};

	var Port = ({
		absolute: absolute,
		fn: fn,
		line: line$1,
		left: left,
		right: right,
		top: top,
		bottom: bottom,
		ellipseSpread: ellipseSpread,
		ellipse: ellipse$1
	});

	function labelAttributes(opt1, opt2) {

	    // use value from `opt2` if it is missing in `opt1`
	    // use value from this object if it is missing in `opt2` as well
	    return defaultsDeep({}, opt1, opt2, {
	        x: 0,
	        y: 0,
	        angle: 0,
	        attrs: {}
	    });
	}

	function getBBoxAngles(elBBox) {

	    var center = elBBox.center();

	    var tl = center.theta(elBBox.origin());
	    var bl = center.theta(elBBox.bottomLeft());
	    var br = center.theta(elBBox.corner());
	    var tr = center.theta(elBBox.topRight());

	    return [tl, tr, br, bl];
	}

	function outsideLayout(portPosition, elBBox, autoOrient, opt) {

	    opt = defaults({}, opt, { offset: 15 });
	    var angle = elBBox.center().theta(portPosition);

	    var tx, ty, y, textAnchor;
	    var offset = opt.offset;
	    var orientAngle = 0;

	    var ref = getBBoxAngles(elBBox);
	    var topLeftAngle = ref[0];
	    var bottomLeftAngle = ref[1];
	    var bottomRightAngle = ref[2];
	    var topRightAngle = ref[3];
	    if ((angle < bottomLeftAngle) || (angle > bottomRightAngle)) {
	        y = '.3em';
	        tx = offset;
	        ty = 0;
	        textAnchor = 'start';
	    } else if (angle < topLeftAngle) {
	        tx = 0;
	        ty = -offset;
	        if (autoOrient) {
	            orientAngle = -90;
	            textAnchor = 'start';
	            y = '.3em';
	        } else {
	            textAnchor = 'middle';
	            y = '0';
	        }
	    } else if (angle < topRightAngle) {
	        y = '.3em';
	        tx = -offset;
	        ty = 0;
	        textAnchor = 'end';
	    } else {
	        tx = 0;
	        ty = offset;
	        if (autoOrient) {
	            orientAngle = 90;
	            textAnchor = 'start';
	            y = '.3em';
	        } else {
	            textAnchor = 'middle';
	            y = '.6em';
	        }
	    }

	    var round = Math.round;
	    return labelAttributes(opt, {
	        x: round(tx),
	        y: round(ty),
	        angle: orientAngle,
	        attrs: { labelText: { y: y, textAnchor: textAnchor }}
	    });
	}

	function insideLayout(portPosition, elBBox, autoOrient, opt) {

	    opt = defaults({}, opt, { offset: 15 });
	    var angle = elBBox.center().theta(portPosition);

	    var tx, ty, y, textAnchor;
	    var offset = opt.offset;
	    var orientAngle = 0;

	    var ref = getBBoxAngles(elBBox);
	    var topLeftAngle = ref[0];
	    var bottomLeftAngle = ref[1];
	    var bottomRightAngle = ref[2];
	    var topRightAngle = ref[3];
	    if ((angle < bottomLeftAngle) || (angle > bottomRightAngle)) {
	        y = '.3em';
	        tx = -offset;
	        ty = 0;
	        textAnchor = 'end';
	    } else if (angle < topLeftAngle) {
	        tx = 0;
	        ty = offset;
	        if (autoOrient) {
	            orientAngle = 90;
	            textAnchor = 'start';
	            y = '.3em';
	        } else {
	            textAnchor = 'middle';
	            y = '.6em';
	        }
	    } else if (angle < topRightAngle) {
	        y = '.3em';
	        tx = offset;
	        ty = 0;
	        textAnchor = 'start';
	    } else {
	        tx = 0;
	        ty = -offset;
	        if (autoOrient) {
	            orientAngle = -90;
	            textAnchor = 'start';
	            y = '.3em';
	        } else {
	            textAnchor = 'middle';
	            y = '0';
	        }
	    }

	    var round = Math.round;
	    return labelAttributes(opt, {
	        x: round(tx),
	        y: round(ty),
	        angle: orientAngle,
	        attrs: { labelText: { y: y, textAnchor: textAnchor }}
	    });
	}

	function radialLayout(portCenterOffset, autoOrient, opt) {

	    opt = defaults({}, opt, { offset: 20 });

	    var origin = point(0, 0);
	    var angle = -portCenterOffset.theta(origin);
	    var orientAngle = angle;
	    var offset = portCenterOffset.clone()
	        .move(origin, opt.offset)
	        .difference(portCenterOffset)
	        .round();

	    var y = '.3em';
	    var textAnchor;

	    if ((angle + 90) % 180 === 0) {
	        textAnchor = autoOrient ? 'end' : 'middle';
	        if (!autoOrient && angle === -270) {
	            y = '0em';
	        }
	    } else if (angle > -270 && angle < -90) {
	        textAnchor = 'start';
	        orientAngle = angle - 180;
	    } else {
	        textAnchor = 'end';
	    }

	    var round = Math.round;
	    return labelAttributes(opt, {
	        x: round(offset.x),
	        y: round(offset.y),
	        angle: ((autoOrient) ? orientAngle : 0),
	        attrs: { labelText: { y: y, textAnchor: textAnchor }}
	    });
	}

	var manual = function(_portPosition, _elBBox, opt) {
	    return labelAttributes(opt);
	};

	var left$1 = function(portPosition, elBBox, opt) {
	    return labelAttributes(opt, {
	        x: -15,
	        attrs: { labelText: { y: '.3em', textAnchor: 'end' }},
	    });
	};

	var right$1 = function(portPosition, elBBox, opt) {
	    return labelAttributes(opt, {
	        x: 15,
	        attrs: { labelText: { y: '.3em', textAnchor: 'start' }},
	    });
	};

	var top$1 = function(portPosition, elBBox, opt) {
	    return labelAttributes(opt, {
	        y: -15,
	        attrs: { labelText: { y: '0', textAnchor: 'middle' }},
	    });
	};

	var bottom$1 = function(portPosition, elBBox, opt) {
	    return labelAttributes(opt, {
	        y: 15,
	        attrs: { labelText: { y: '.6em', textAnchor: 'middle' }},
	    });
	};

	var outsideOriented = function(portPosition, elBBox, opt) {
	    return outsideLayout(portPosition, elBBox, true, opt);
	};

	var outside = function(portPosition, elBBox, opt) {
	    return outsideLayout(portPosition, elBBox, false, opt);
	};

	var insideOriented = function(portPosition, elBBox, opt) {
	    return insideLayout(portPosition, elBBox, true, opt);
	};

	var inside = function(portPosition, elBBox, opt) {
	    return insideLayout(portPosition, elBBox, false, opt);
	};

	var radial = function(portPosition, elBBox, opt) {
	    return radialLayout(portPosition.difference(elBBox.center()), false, opt);
	};

	var radialOriented = function(portPosition, elBBox, opt) {
	    return radialLayout(portPosition.difference(elBBox.center()), true, opt);
	};

	var PortLabel = ({
		manual: manual,
		left: left$1,
		right: right$1,
		top: top$1,
		bottom: bottom$1,
		outsideOriented: outsideOriented,
		outside: outside,
		insideOriented: insideOriented,
		inside: inside,
		radial: radial,
		radialOriented: radialOriented
	});

	var PortData = function(data) {

	    var clonedData = cloneDeep(data) || {};
	    this.ports = [];
	    this.groups = {};
	    this.portLayoutNamespace = Port;
	    this.portLabelLayoutNamespace = PortLabel;

	    this._init(clonedData);
	};

	PortData.prototype = {

	    getPorts: function() {
	        return this.ports;
	    },

	    getGroup: function(name) {
	        return this.groups[name] || {};
	    },

	    getPortsByGroup: function(groupName) {

	        return this.ports.filter(function(port) {
	            return port.group === groupName;
	        });
	    },

	    getGroupPortsMetrics: function(groupName, elBBox) {

	        var group = this.getGroup(groupName);
	        var ports = this.getPortsByGroup(groupName);

	        var groupPosition = group.position || {};
	        var groupPositionName = groupPosition.name;
	        var namespace = this.portLayoutNamespace;
	        if (!namespace[groupPositionName]) {
	            groupPositionName = 'left';
	        }

	        var groupArgs = groupPosition.args || {};
	        var portsArgs = ports.map(function(port) {
	            return port && port.position && port.position.args;
	        });
	        var groupPortTransformations = namespace[groupPositionName](portsArgs, elBBox, groupArgs);

	        var accumulator = {
	            ports: ports,
	            result: []
	        };

	        toArray(groupPortTransformations).reduce(function(res, portTransformation, index) {
	            var port = res.ports[index];
	            res.result.push({
	                portId: port.id,
	                portTransformation: portTransformation,
	                labelTransformation: this._getPortLabelLayout(port, Point(portTransformation), elBBox),
	                portAttrs: port.attrs,
	                portSize: port.size,
	                labelSize: port.label.size
	            });
	            return res;
	        }.bind(this), accumulator);

	        return accumulator.result;
	    },

	    _getPortLabelLayout: function(port, portPosition, elBBox) {

	        var namespace = this.portLabelLayoutNamespace;
	        var labelPosition = port.label.position.name || 'left';

	        if (namespace[labelPosition]) {
	            return namespace[labelPosition](portPosition, elBBox, port.label.position.args);
	        }

	        return null;
	    },

	    _init: function(data) {

	        // prepare groups
	        if (isObject$1(data.groups)) {
	            var groups = Object.keys(data.groups);
	            for (var i = 0, n = groups.length; i < n; i++) {
	                var key = groups[i];
	                this.groups[key] = this._evaluateGroup(data.groups[key]);
	            }
	        }

	        // prepare ports
	        var ports = toArray(data.items);
	        for (var j = 0, m = ports.length; j < m; j++) {
	            this.ports.push(this._evaluatePort(ports[j]));
	        }
	    },

	    _evaluateGroup: function(group) {

	        return merge(group, {
	            position: this._getPosition(group.position, true),
	            label: this._getLabel(group, true)
	        });
	    },

	    _evaluatePort: function(port) {

	        var evaluated = assign({}, port);

	        var group = this.getGroup(port.group);

	        evaluated.markup = evaluated.markup || group.markup;
	        evaluated.attrs = merge({}, group.attrs, evaluated.attrs);
	        evaluated.position = this._createPositionNode(group, evaluated);
	        evaluated.label = merge({}, group.label, this._getLabel(evaluated));
	        evaluated.z = this._getZIndex(group, evaluated);
	        evaluated.size = assign({}, group.size, evaluated.size);

	        return evaluated;
	    },

	    _getZIndex: function(group, port) {

	        if (isNumber(port.z)) {
	            return port.z;
	        }
	        if (isNumber(group.z) || group.z === 'auto') {
	            return group.z;
	        }
	        return 'auto';
	    },

	    _createPositionNode: function(group, port) {

	        return merge({
	            name: 'left',
	            args: {}
	        }, group.position, { args: port.args });
	    },

	    _getPosition: function(position, setDefault) {

	        var args = {};
	        var positionName;

	        if (isFunction(position)) {
	            positionName = 'fn';
	            args.fn = position;
	        } else if (isString(position)) {
	            positionName = position;
	        } else if (position === undefined) {
	            positionName = setDefault ? 'left' : null;
	        } else if (Array.isArray(position)) {
	            positionName = 'absolute';
	            args.x = position[0];
	            args.y = position[1];
	        } else if (isObject$1(position)) {
	            positionName = position.name;
	            assign(args, position.args);
	        }

	        var result = { args: args };

	        if (positionName) {
	            result.name = positionName;
	        }
	        return result;
	    },

	    _getLabel: function(item, setDefaults) {

	        var label = item.label || {};

	        var ret = label;
	        ret.position = this._getPosition(label.position, setDefaults);

	        return ret;
	    }
	};

	var elementPortPrototype = {

	    _initializePorts: function() {

	        this._createPortData();
	        this.on('change:ports', function() {

	            this._processRemovedPort();
	            this._createPortData();
	        }, this);
	    },

	    /**
	     * remove links tied wiht just removed element
	     * @private
	     */
	    _processRemovedPort: function() {

	        var current = this.get('ports') || {};
	        var currentItemsMap = {};

	        toArray(current.items).forEach(function(item) {
	            currentItemsMap[item.id] = true;
	        });

	        var previous = this.previous('ports') || {};
	        var removed = {};

	        toArray(previous.items).forEach(function(item) {
	            if (!currentItemsMap[item.id]) {
	                removed[item.id] = true;
	            }
	        });

	        var graph = this.graph;
	        if (graph && !isEmpty(removed)) {

	            var inboundLinks = graph.getConnectedLinks(this, { inbound: true });
	            inboundLinks.forEach(function(link) {

	                if (removed[link.get('target').port]) { link.remove(); }
	            });

	            var outboundLinks = graph.getConnectedLinks(this, { outbound: true });
	            outboundLinks.forEach(function(link) {

	                if (removed[link.get('source').port]) { link.remove(); }
	            });
	        }
	    },

	    /**
	     * @returns {boolean}
	     */
	    hasPorts: function() {

	        var ports = this.prop('ports/items');
	        return Array.isArray(ports) && ports.length > 0;
	    },

	    /**
	     * @param {string} id
	     * @returns {boolean}
	     */
	    hasPort: function(id) {

	        return this.getPortIndex(id) !== -1;
	    },

	    /**
	     * @returns {Array<object>}
	     */
	    getPorts: function() {

	        return cloneDeep(this.prop('ports/items')) || [];
	    },

	    /**
	     * @returns {Array<object>}
	     */
	    getGroupPorts: function(groupName) {
	        var groupPorts = toArray(this.prop(['ports','items'])).filter(function (port) { return port.group === groupName; });
	        return cloneDeep(groupPorts);
	    },

	    /**
	     * @param {string} id
	     * @returns {object}
	     */
	    getPort: function(id) {

	        return cloneDeep(toArray(this.prop('ports/items')).find(function(port) {
	            return port.id && port.id === id;
	        }));
	    },

	    /**
	     * @param {string} groupName
	     * @returns {Object<portId, {x: number, y: number, angle: number}>}
	     */
	    getPortsPositions: function(groupName) {

	        var portsMetrics = this._portSettingsData.getGroupPortsMetrics(groupName, Rect(this.size()));

	        return portsMetrics.reduce(function(positions, metrics) {
	            var transformation = metrics.portTransformation;
	            positions[metrics.portId] = {
	                x: transformation.x,
	                y: transformation.y,
	                angle: transformation.angle
	            };
	            return positions;
	        }, {});
	    },

	    /**
	     * @param {string|Port} port port id or port
	     * @returns {number} port index
	     */
	    getPortIndex: function(port) {

	        var id = isObject$1(port) ? port.id : port;

	        if (!this._isValidPortId(id)) {
	            return -1;
	        }

	        return toArray(this.prop('ports/items')).findIndex(function(item) {
	            return item.id === id;
	        });
	    },

	    /**
	     * @param {object} port
	     * @param {object} [opt]
	     * @returns {joint.dia.Element}
	     */
	    addPort: function(port, opt) {

	        if (!isObject$1(port) || Array.isArray(port)) {
	            throw new Error('Element: addPort requires an object.');
	        }

	        var ports = assign([], this.prop('ports/items'));
	        ports.push(port);
	        this.prop('ports/items', ports, opt);

	        return this;
	    },

	    /**
	     * @param {string|Port|number} before
	     * @param {object} port
	     * @param {object} [opt]
	     * @returns {joint.dia.Element}
	     */
	    insertPort: function(before, port, opt) {
	        var index$1 = (typeof before === 'number') ? before : this.getPortIndex(before);

	        if (!isObject$1(port) || Array.isArray(port)) {
	            throw new Error('dia.Element: insertPort requires an object.');
	        }

	        var ports = assign([], this.prop('ports/items'));
	        ports.splice(index$1, 0, port);
	        this.prop('ports/items', ports, opt);

	        return this;
	    },

	    /**
	     * @param {string} portId
	     * @param {string|object=} path
	     * @param {*=} value
	     * @param {object=} opt
	     * @returns {joint.dia.Element}
	     */
	    portProp: function(portId, path, value, opt) {

	        var index$1 = this.getPortIndex(portId);

	        if (index$1 === -1) {
	            throw new Error('Element: unable to find port with id ' + portId);
	        }

	        var args = Array.prototype.slice.call(arguments, 1);
	        if (Array.isArray(path)) {
	            args[0] = ['ports', 'items', index$1].concat(path);
	        } else if (isString(path)) {

	            // Get/set an attribute by a special path syntax that delimits
	            // nested objects by the colon character.
	            args[0] = ['ports/items/', index$1, '/', path].join('');

	        } else {

	            args = ['ports/items/' + index$1];
	            if (isPlainObject(path)) {
	                args.push(path);
	                args.push(value);
	            }
	        }

	        return this.prop.apply(this, args);
	    },

	    _validatePorts: function() {

	        var portsAttr = this.get('ports') || {};

	        var errorMessages = [];
	        portsAttr = portsAttr || {};
	        var ports = toArray(portsAttr.items);

	        ports.forEach(function(p) {

	            if (typeof p !== 'object') {
	                errorMessages.push('Element: invalid port ', p);
	            }

	            if (!this._isValidPortId(p.id)) {
	                p.id = this.generatePortId();
	            }
	        }, this);

	        if (uniq(ports, 'id').length !== ports.length) {
	            errorMessages.push('Element: found id duplicities in ports.');
	        }

	        return errorMessages;
	    },

	    generatePortId: function() {
	        return this.generateId();
	    },

	    /**
	     * @param {string} id port id
	     * @returns {boolean}
	     * @private
	     */
	    _isValidPortId: function(id) {

	        return id !== null && id !== undefined && !isObject$1(id);
	    },

	    addPorts: function(ports, opt) {

	        if (ports.length) {
	            this.prop('ports/items', assign([], this.prop('ports/items')).concat(ports), opt);
	        }

	        return this;
	    },

	    removePort: function(port, opt) {
	        var options = opt || {};
	        var index$1 = this.getPortIndex(port);
	        if (index$1 !== -1) {
	            var ports = assign([], this.prop(['ports', 'items']));
	            ports.splice(index$1, 1);
	            options.rewrite = true;
	            this.startBatch('port-remove');
	            this.prop(['ports', 'items'], ports, options);
	            this.stopBatch('port-remove');
	        }
	        return this;
	    },

	    removePorts: function(portsForRemoval, opt) {
	        var options, newPorts;
	        if (Array.isArray(portsForRemoval)) {
	            options = opt || {};
	            if (portsForRemoval.length === 0) { return this.this; }
	            var currentPorts = assign([], this.prop(['ports', 'items']));
	            newPorts = currentPorts.filter(function(cp) {
	                return !portsForRemoval.some(function(rp) {
	                    var rpId = isObject$1(rp) ? rp.id : rp;
	                    return cp.id === rpId;
	                });
	            });
	        } else {
	            options = portsForRemoval || {};
	            newPorts = [];
	        }
	        this.startBatch('port-remove');
	        options.rewrite = true;
	        this.prop(['ports', 'items'], newPorts, options);
	        this.stopBatch('port-remove');
	        return this;
	    },

	    /**
	     * @private
	     */
	    _createPortData: function() {

	        var err = this._validatePorts();

	        if (err.length > 0) {
	            this.set('ports', this.previous('ports'));
	            throw new Error(err.join(' '));
	        }

	        var prevPortData;

	        if (this._portSettingsData) {

	            prevPortData = this._portSettingsData.getPorts();
	        }

	        this._portSettingsData = new PortData(this.get('ports'));

	        var curPortData = this._portSettingsData.getPorts();

	        if (prevPortData) {

	            var added = curPortData.filter(function(item) {
	                if (!prevPortData.find(function(prevPort) {
	                    return prevPort.id === item.id;
	                })) {
	                    return item;
	                }
	            });

	            var removed = prevPortData.filter(function(item) {
	                if (!curPortData.find(function(curPort) {
	                    return curPort.id === item.id;
	                })) {
	                    return item;
	                }
	            });

	            if (removed.length > 0) {
	                this.trigger('ports:remove', this, removed);
	            }

	            if (added.length > 0) {
	                this.trigger('ports:add', this, added);
	            }
	        }
	    }
	};

	var elementViewPortPrototype = {

	    portContainerMarkup: 'g',
	    portMarkup: [{
	        tagName: 'circle',
	        selector: 'circle',
	        attributes: {
	            'r': 10,
	            'fill': '#FFFFFF',
	            'stroke': '#000000'
	        }
	    }],
	    portLabelMarkup: [{
	        tagName: 'text',
	        selector: 'text',
	        attributes: {
	            'fill': '#000000'
	        }
	    }],
	    /** @type {Object<string, {portElement: Vectorizer, portLabelElement: Vectorizer}>} */
	    _portElementsCache: null,

	    /**
	     * @private
	     */
	    _initializePorts: function() {
	        this._cleanPortsCache();
	    },

	    /**
	     * @typedef {Object} Port
	     *
	     * @property {string} id
	     * @property {Object} position
	     * @property {Object} label
	     * @property {Object} attrs
	     * @property {string} markup
	     * @property {string} group
	     */

	    /**
	     * @private
	     */
	    _refreshPorts: function() {

	        this._removePorts();
	        this._cleanPortsCache();
	        this._renderPorts();
	    },

	    _cleanPortsCache: function() {
	        this._portElementsCache = {};
	    },

	    /**
	     * @private
	     */
	    _renderPorts: function() {

	        // references to rendered elements without z-index
	        var elementReferences = [];
	        var elem = this._getContainerElement();

	        for (var i = 0, count = elem.node.childNodes.length; i < count; i++) {
	            elementReferences.push(elem.node.childNodes[i]);
	        }

	        var portsGropsByZ = groupBy(this.model._portSettingsData.getPorts(), 'z');
	        var withoutZKey = 'auto';

	        // render non-z first
	        toArray(portsGropsByZ[withoutZKey]).forEach(function(port) {
	            var portElement = this._getPortElement(port);
	            elem.append(portElement);
	            elementReferences.push(portElement);
	        }, this);

	        var groupNames = Object.keys(portsGropsByZ);
	        for (var k = 0; k < groupNames.length; k++) {
	            var groupName = groupNames[k];
	            if (groupName !== withoutZKey) {
	                var z = parseInt(groupName, 10);
	                this._appendPorts(portsGropsByZ[groupName], z, elementReferences);
	            }
	        }

	        this._updatePorts();
	    },

	    /**
	     * @returns {V}
	     * @private
	     */
	    _getContainerElement: function() {

	        return this.rotatableNode || this.vel;
	    },

	    /**
	     * @param {Array<Port>}ports
	     * @param {number} z
	     * @param refs
	     * @private
	     */
	    _appendPorts: function(ports, z, refs) {

	        var containerElement = this._getContainerElement();
	        var portElements = toArray(ports).map(this._getPortElement, this);

	        if (refs[z] || z < 0) {
	            V(refs[Math.max(z, 0)]).before(portElements);
	        } else {
	            containerElement.append(portElements);
	        }
	    },

	    /**
	     * Try to get element from cache,
	     * @param port
	     * @returns {*}
	     * @private
	     */
	    _getPortElement: function(port) {

	        if (this._portElementsCache[port.id]) {
	            return this._portElementsCache[port.id].portElement;
	        }
	        return this._createPortElement(port);
	    },

	    findPortNodes: function(portId, selector) {
	        var portCache = this._portElementsCache[portId];
	        if (!portCache) { return []; }
	        if (!selector) { return [portCache.portContentElement.node]; }
	        var portRoot = portCache.portElement.node;
	        var portSelectors = portCache.portSelectors;
	        return this.findBySelector(selector, portRoot, portSelectors);
	    },

	    findPortNode: function(portId, selector) {
	        var ref = this.findPortNodes(portId, selector);
	        var node = ref[0]; if ( node === void 0 ) node = null;
	        return node;
	    },

	    /**
	     * @private
	     */
	    _updatePorts: function() {

	        // layout ports without group
	        this._updatePortGroup(undefined);
	        // layout ports with explicit group
	        var groupsNames = Object.keys(this.model._portSettingsData.groups);
	        groupsNames.forEach(this._updatePortGroup, this);
	    },

	    /**
	     * @private
	     */
	    _removePorts: function() {
	        invoke(this._portElementsCache, 'portElement.remove');
	    },

	    /**
	     * @param {Port} port
	     * @returns {V}
	     * @private
	     */
	    _createPortElement: function(port) {

	        var portElement;
	        var labelElement;
	        var labelSelectors;
	        var portSelectors;

	        var portContainerElement = V(this.portContainerMarkup).addClass('joint-port');

	        var portMarkup = this._getPortMarkup(port);
	        if (Array.isArray(portMarkup)) {
	            var portDoc = this.parseDOMJSON(portMarkup, portContainerElement.node);
	            var portFragment = portDoc.fragment;
	            if (portFragment.childNodes.length > 1) {
	                portElement = V('g').append(portFragment);
	            } else {
	                portElement = V(portFragment.firstChild);
	            }
	            portSelectors = portDoc.selectors;
	        } else {
	            portElement = V(portMarkup);
	            if (Array.isArray(portElement)) {
	                portElement = V('g').append(portElement);
	            }
	        }

	        if (!portElement) {
	            throw new Error('ElementView: Invalid port markup.');
	        }

	        portElement.attr({
	            'port': port.id,
	            'port-group': port.group
	        });

	        var labelMarkupDef = this._getPortLabelMarkup(port.label);
	        if (Array.isArray(labelMarkupDef)) {
	            // JSON Markup
	            var ref = this.parseDOMJSON(labelMarkupDef, portContainerElement.node);
	            var fragment = ref.fragment;
	            var selectors = ref.selectors;
	            var childCount = fragment.childNodes.length;
	            if (childCount > 0) {
	                labelSelectors = selectors;
	                labelElement = (childCount === 1) ? V(fragment.firstChild) : V('g').append(fragment);
	            }
	        } else {
	            // String Markup
	            labelElement = V(labelMarkupDef);
	            if (Array.isArray(labelElement)) {
	                labelElement = V('g').append(labelElement);
	            }
	        }

	        var portContainerSelectors;
	        if (portSelectors && labelSelectors) {
	            for (var key in labelSelectors) {
	                if (portSelectors[key] && key !== this.selector) { throw new Error('ElementView: selectors within port must be unique.'); }
	            }
	            portContainerSelectors = assign({}, portSelectors, labelSelectors);
	        } else {
	            portContainerSelectors = portSelectors || labelSelectors || {};
	        }

	        // The `portRootSelector` points to the root SVGNode of the port.
	        // Either the implicit wrapping group <g/> in case the port consist of multiple SVGNodes.
	        // Or the single SVGNode of the port.
	        var portRootSelector = 'portRoot';
	        // The `labelRootSelector` points to the root SVGNode of the label.
	        var labelRootSelector = 'labelRoot';
	        // The `labelTextSelector` points to all text SVGNodes of the label.
	        var labelTextSelector = 'labelText';

	        if (!(portRootSelector in portContainerSelectors)) {
	            portContainerSelectors[portRootSelector] = portElement.node;
	        }

	        if (labelElement) {
	            var labelNode = labelElement.node;
	            if (!(labelRootSelector in portContainerSelectors)) {
	                portContainerSelectors[labelRootSelector] = labelNode;
	            }
	            if (!(labelTextSelector in portContainerSelectors)) {
	                // If the label is a <text> element, we can use it directly.
	                // Otherwise, we need to find the <text> element within the label.
	                var labelTextNode = (labelElement.tagName() === 'TEXT')
	                    ? labelNode
	                    : Array.from(labelNode.querySelectorAll('text'));
	                portContainerSelectors[labelTextSelector] = labelTextNode;
	                if (!labelSelectors) { labelSelectors = {}; }
	                labelSelectors[labelTextSelector] = labelTextNode;
	            }
	        }

	        portContainerElement.append(portElement.addClass('joint-port-body'));
	        if (labelElement) {
	            portContainerElement.append(labelElement.addClass('joint-port-label'));
	        }

	        this._portElementsCache[port.id] = {
	            portElement: portContainerElement,
	            portLabelElement: labelElement,
	            portSelectors: portContainerSelectors,
	            portLabelSelectors: labelSelectors,
	            portContentElement: portElement,
	            portContentSelectors: portSelectors
	        };

	        return portContainerElement;
	    },

	    /**
	     * @param {string=} groupName
	     * @private
	     */
	    _updatePortGroup: function(groupName) {

	        var elementBBox = Rect(this.model.size());
	        var portsMetrics = this.model._portSettingsData.getGroupPortsMetrics(groupName, elementBBox);

	        for (var i = 0, n = portsMetrics.length; i < n; i++) {
	            var metrics = portsMetrics[i];
	            var portId = metrics.portId;
	            var cached = this._portElementsCache[portId] || {};
	            var portTransformation = metrics.portTransformation;
	            var labelTransformation = metrics.labelTransformation;
	            if (labelTransformation && cached.portLabelElement) {
	                this.updateDOMSubtreeAttributes(cached.portLabelElement.node, labelTransformation.attrs, {
	                    rootBBox: new Rect(metrics.labelSize),
	                    selectors: cached.portLabelSelectors
	                });
	                this.applyPortTransform(cached.portLabelElement, labelTransformation, (-portTransformation.angle || 0));
	            }
	            this.updateDOMSubtreeAttributes(cached.portElement.node, metrics.portAttrs, {
	                rootBBox: new Rect(metrics.portSize),
	                selectors: cached.portSelectors
	            });
	            this.applyPortTransform(cached.portElement, portTransformation);
	        }
	    },

	    /**
	     * @param {Vectorizer} element
	     * @param {{dx:number, dy:number, angle: number, attrs: Object, x:number: y:number}} transformData
	     * @param {number=} initialAngle
	     * @constructor
	     */
	    applyPortTransform: function(element, transformData, initialAngle) {

	        var matrix = V.createSVGMatrix()
	            .rotate(initialAngle || 0)
	            .translate(transformData.x || 0, transformData.y || 0)
	            .rotate(transformData.angle || 0);

	        element.transform(matrix, { absolute: true });
	    },

	    /**
	     * @param {Port} port
	     * @returns {string}
	     * @private
	     */
	    _getPortMarkup: function(port) {

	        return port.markup || this.model.get('portMarkup') || this.model.portMarkup || this.portMarkup;
	    },

	    /**
	     * @param {Object} label
	     * @returns {string}
	     * @private
	     */
	    _getPortLabelMarkup: function(label) {

	        return label.markup || this.model.get('portLabelMarkup') || this.model.portLabelMarkup || this.portLabelMarkup;
	    }
	};

	// Element base model.
	// -----------------------------

	var Element$1 = Cell.extend({

	    defaults: {
	        position: { x: 0, y: 0 },
	        size: { width: 1, height: 1 },
	        angle: 0
	    },

	    initialize: function() {

	        this._initializePorts();
	        Cell.prototype.initialize.apply(this, arguments);
	    },

	    /**
	     * @abstract
	     */
	    _initializePorts: function() {
	        // implemented in ports.js
	    },

	    _refreshPorts: function() {
	        // implemented in ports.js
	    },

	    isElement: function() {

	        return true;
	    },

	    position: function(x, y, opt) {

	        var isSetter = isNumber(y);
	        opt = (isSetter ? opt : x) || {};
	        var parentRelative = opt.parentRelative;
	        var deep = opt.deep;
	        var restrictedArea = opt.restrictedArea;


	        // option `parentRelative` for setting the position relative to the element's parent.
	        var parentPosition;
	        if (parentRelative) {

	            // Getting the parent's position requires the collection.
	            // Cell.parent() holds cell id only.
	            if (!this.graph) { throw new Error('Element must be part of a graph.'); }

	            var parent = this.getParentCell();
	            if (parent && !parent.isLink()) {
	                parentPosition = parent.get('position');
	            }
	        }

	        if (isSetter) {

	            if (parentPosition) {
	                x += parentPosition.x;
	                y += parentPosition.y;
	            }

	            if (deep || restrictedArea) {
	                var ref = this.get('position');
	                var x0 = ref.x;
	                var y0 = ref.y;
	                this.translate(x - x0, y - y0, opt);
	            } else {
	                this.set('position', { x: x, y: y }, opt);
	            }

	            return this;

	        } else { // Getter returns a geometry point.

	            var elementPosition = Point(this.get('position'));
	            return parentRelative
	                ? elementPosition.difference(parentPosition)
	                : elementPosition;
	        }
	    },

	    translate: function(tx, ty, opt) {

	        tx = tx || 0;
	        ty = ty || 0;

	        if (tx === 0 && ty === 0) {
	            // Like nothing has happened.
	            return this;
	        }

	        opt = opt || {};
	        // Pass the initiator of the translation.
	        opt.translateBy = opt.translateBy || this.id;

	        var position = this.get('position') || { x: 0, y: 0 };
	        var ra = opt.restrictedArea;
	        if (ra && opt.translateBy === this.id) {

	            if (typeof ra === 'function') {

	                var newPosition = ra.call(this, position.x + tx, position.y + ty, opt);

	                tx = newPosition.x - position.x;
	                ty = newPosition.y - position.y;

	            } else  {
	                // We are restricting the translation for the element itself only. We get
	                // the bounding box of the element including all its embeds.
	                // All embeds have to be translated the exact same way as the element.
	                var bbox = this.getBBox({ deep: true });
	                //- - - - - - - - - - - - -> ra.x + ra.width
	                // - - - -> position.x      |
	                // -> bbox.x
	                //                ▓▓▓▓▓▓▓   |
	                //         ░░░░░░░▓▓▓▓▓▓▓
	                //         ░░░░░░░░░        |
	                //   ▓▓▓▓▓▓▓▓░░░░░░░
	                //   ▓▓▓▓▓▓▓▓               |
	                //   <-dx->                     | restricted area right border
	                //         <-width->        |   ░ translated element
	                //   <- - bbox.width - ->       ▓ embedded element
	                var dx = position.x - bbox.x;
	                var dy = position.y - bbox.y;
	                // Find the maximal/minimal coordinates that the element can be translated
	                // while complies the restrictions.
	                var x = Math.max(ra.x + dx, Math.min(ra.x + ra.width + dx - bbox.width, position.x + tx));
	                var y = Math.max(ra.y + dy, Math.min(ra.y + ra.height + dy - bbox.height, position.y + ty));
	                // recalculate the translation taking the restrictions into account.
	                tx = x - position.x;
	                ty = y - position.y;
	            }
	        }

	        var translatedPosition = {
	            x: position.x + tx,
	            y: position.y + ty
	        };

	        // To find out by how much an element was translated in event 'change:position' handlers.
	        opt.tx = tx;
	        opt.ty = ty;

	        if (opt.transition) {

	            if (!isObject$1(opt.transition)) { opt.transition = {}; }

	            this.transition('position', translatedPosition, assign({}, opt.transition, {
	                valueFunction: interpolate.object
	            }));

	            // Recursively call `translate()` on all the embeds cells.
	            invoke(this.getEmbeddedCells(), 'translate', tx, ty, opt);

	        } else {

	            this.startBatch('translate', opt);
	            this.set('position', translatedPosition, opt);
	            invoke(this.getEmbeddedCells(), 'translate', tx, ty, opt);
	            this.stopBatch('translate', opt);
	        }

	        return this;
	    },

	    size: function(width, height, opt) {

	        var currentSize = this.get('size');
	        // Getter
	        // () signature
	        if (width === undefined) {
	            return {
	                width: currentSize.width,
	                height: currentSize.height
	            };
	        }
	        // Setter
	        // (size, opt) signature
	        if (isObject$1(width)) {
	            opt = height;
	            height = isNumber(width.height) ? width.height : currentSize.height;
	            width = isNumber(width.width) ? width.width : currentSize.width;
	        }

	        return this.resize(width, height, opt);
	    },

	    resize: function(width, height, opt) {

	        opt = opt || {};

	        this.startBatch('resize', opt);

	        if (opt.direction) {

	            var currentSize = this.get('size');

	            switch (opt.direction) {

	                case 'left':
	                case 'right':
	                    // Don't change height when resizing horizontally.
	                    height = currentSize.height;
	                    break;

	                case 'top':
	                case 'bottom':
	                    // Don't change width when resizing vertically.
	                    width = currentSize.width;
	                    break;
	            }

	            // Get the angle and clamp its value between 0 and 360 degrees.
	            var angle = normalizeAngle(this.get('angle') || 0);

	            // This is a rectangle in size of the un-rotated element.
	            var bbox = this.getBBox();

	            var origin;

	            if (angle) {

	                var quadrant = {
	                    'top-right': 0,
	                    'right': 0,
	                    'top-left': 1,
	                    'top': 1,
	                    'bottom-left': 2,
	                    'left': 2,
	                    'bottom-right': 3,
	                    'bottom': 3
	                }[opt.direction];

	                if (opt.absolute) {

	                    // We are taking the element's rotation into account
	                    quadrant += Math.floor((angle + 45) / 90);
	                    quadrant %= 4;
	                }

	                // Pick the corner point on the element, which meant to stay on its place before and
	                // after the rotation.
	                var fixedPoint = bbox[['bottomLeft', 'corner', 'topRight', 'origin'][quadrant]]();

	                // Find  an image of the previous indent point. This is the position, where is the
	                // point actually located on the screen.
	                var imageFixedPoint = Point(fixedPoint).rotate(bbox.center(), -angle);

	                // Every point on the element rotates around a circle with the centre of rotation
	                // in the middle of the element while the whole element is being rotated. That means
	                // that the distance from a point in the corner of the element (supposed its always rect) to
	                // the center of the element doesn't change during the rotation and therefore it equals
	                // to a distance on un-rotated element.
	                // We can find the distance as DISTANCE = (ELEMENTWIDTH/2)^2 + (ELEMENTHEIGHT/2)^2)^0.5.
	                var radius = Math.sqrt((width * width) + (height * height)) / 2;

	                // Now we are looking for an angle between x-axis and the line starting at image of fixed point
	                // and ending at the center of the element. We call this angle `alpha`.

	                // The image of a fixed point is located in n-th quadrant. For each quadrant passed
	                // going anti-clockwise we have to add 90 degrees. Note that the first quadrant has index 0.
	                //
	                // 3 | 2
	                // --c-- Quadrant positions around the element's center `c`
	                // 0 | 1
	                //
	                var alpha = quadrant * Math.PI / 2;

	                // Add an angle between the beginning of the current quadrant (line parallel with x-axis or y-axis
	                // going through the center of the element) and line crossing the indent of the fixed point and the center
	                // of the element. This is the angle we need but on the un-rotated element.
	                alpha += Math.atan(quadrant % 2 == 0 ? height / width : width / height);

	                // Lastly we have to deduct the original angle the element was rotated by and that's it.
	                alpha -= toRad(angle);

	                // With this angle and distance we can easily calculate the centre of the un-rotated element.
	                // Note that fromPolar constructor accepts an angle in radians.
	                var center = Point.fromPolar(radius, alpha, imageFixedPoint);

	                // The top left corner on the un-rotated element has to be half a width on the left
	                // and half a height to the top from the center. This will be the origin of rectangle
	                // we were looking for.
	                origin = Point(center).offset(width / -2, height / -2);

	            } else {
	                // calculation for the origin Point when there is no rotation of the element
	                origin = bbox.topLeft();

	                switch (opt.direction) {
	                    case 'top':
	                    case 'top-right':
	                        origin.offset(0, bbox.height - height);
	                        break;
	                    case 'left':
	                    case 'bottom-left':
	                        origin.offset(bbox.width -width, 0);
	                        break;
	                    case 'top-left':
	                        origin.offset(bbox.width - width, bbox.height - height);
	                        break;
	                }
	            }

	            // Resize the element (before re-positioning it).
	            this.set('size', { width: width, height: height }, opt);

	            // Finally, re-position the element.
	            this.position(origin.x, origin.y, opt);

	        } else {

	            // Resize the element.
	            this.set('size', { width: width, height: height }, opt);
	        }

	        this.stopBatch('resize', opt);

	        return this;
	    },

	    scale: function(sx, sy, origin, opt) {

	        var scaledBBox = this.getBBox().scale(sx, sy, origin);
	        this.startBatch('scale', opt);
	        this.position(scaledBBox.x, scaledBBox.y, opt);
	        this.resize(scaledBBox.width, scaledBBox.height, opt);
	        this.stopBatch('scale');
	        return this;
	    },

	    fitEmbeds: function(opt) {

	        return this.fitToChildren(opt);
	    },

	    fitToChildren: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        // Getting the children's size and position requires the collection.
	        // Cell.get('embeds') holds an array of cell ids only.
	        var ref = this;
	        var graph = ref.graph;
	        if (!graph) { throw new Error('Element must be part of a graph.'); }

	        var childElements = this.getEmbeddedCells().filter(function (cell) { return cell.isElement(); });
	        if (childElements.length === 0) { return this; }

	        this.startBatch('fit-embeds', opt);

	        if (opt.deep) {
	            // `opt.deep = true` means "fit to all descendants".
	            // As the first action of the fitting algorithm, recursively apply `fitToChildren()` on all descendants.
	            // - i.e. the algorithm is applied in reverse-depth order - start from deepest descendant, then go up (= this element).
	            invoke(childElements, 'fitToChildren', opt);
	        }

	        // Set new size and position of this element, based on:
	        // - union of bboxes of all children
	        // - inflated by given `opt.padding`
	        this._fitToElements(Object.assign({ elements: childElements }, opt));

	        this.stopBatch('fit-embeds');

	        return this;
	    },

	    fitParent: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var ref = this;
	        var graph = ref.graph;
	        if (!graph) { throw new Error('Element must be part of a graph.'); }

	        // When `opt.deep = true`, we want `opt.terminator` to be the last ancestor processed.
	        // If the current element is `opt.terminator`, it means that this element has already been processed as parent so we can exit now.
	        if (opt.deep && opt.terminator && ((opt.terminator === this) || (opt.terminator === this.id))) { return this; }

	        var parentElement = this.getParentCell();
	        if (!parentElement || !parentElement.isElement()) { return this; }

	        // Get all children of parent element (i.e. this element + any sibling elements).
	        var siblingElements = parentElement.getEmbeddedCells().filter(function (cell) { return cell.isElement(); });
	        if (siblingElements.length === 0) { return this; }

	        this.startBatch('fit-parent', opt);

	        // Set new size and position of parent element, based on:
	        // - union of bboxes of all children of parent element (i.e. this element + any sibling elements)
	        // - inflated by given `opt.padding`
	        parentElement._fitToElements(Object.assign({ elements: siblingElements }, opt));

	        if (opt.deep) {
	            // `opt.deep = true` means "fit all ancestors to their respective children".
	            // As the last action of the fitting algorithm, recursively apply `fitParent()` on all ancestors.
	            // - i.e. the algorithm is applied in reverse-depth order - start from deepest descendant (= this element), then go up.
	            parentElement.fitParent(opt);
	        }

	        this.stopBatch('fit-parent');

	        return this;
	    },

	    // Assumption: This element is part of a graph.
	    _fitToElements: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var elementsBBox = this.graph.getCellsBBox(opt.elements);
	        // If no `opt.elements` were provided, do nothing.
	        if (!elementsBBox) { return; }

	        var expandOnly = opt.expandOnly;
	        var shrinkOnly = opt.shrinkOnly;
	        // This combination is meaningless, do nothing.
	        if (expandOnly && shrinkOnly) { return; }

	        // Calculate new size and position of this element based on:
	        // - union of bboxes of `opt.elements`
	        // - inflated by `opt.padding` (if not provided, all four properties = 0)
	        var x = elementsBBox.x;
	        var y = elementsBBox.y;
	        var width = elementsBBox.width;
	        var height = elementsBBox.height;
	        var ref = normalizeSides(opt.padding);
	        var left = ref.left;
	        var right = ref.right;
	        var top = ref.top;
	        var bottom = ref.bottom;
	        x -= left;
	        y -= top;
	        width += left + right;
	        height += bottom + top;
	        var resultBBox = new Rect(x, y, width, height);

	        if (expandOnly) {
	            // Non-shrinking is enforced by taking union of this element's current bbox with bbox calculated from `opt.elements`.
	            resultBBox = this.getBBox().union(resultBBox);

	        } else if (shrinkOnly) {
	            // Non-expansion is enforced by taking intersection of this element's current bbox with bbox calculated from `opt.elements`.
	            var intersectionBBox = this.getBBox().intersect(resultBBox);
	            // If all children are outside this element's current bbox, then `intersectionBBox` is `null` - does not make sense, do nothing.
	            if (!intersectionBBox) { return; }

	            resultBBox =  intersectionBBox;
	        }

	        // Set the new size and position of this element.
	        this.set({
	            position: { x: resultBBox.x, y: resultBBox.y },
	            size: { width: resultBBox.width, height: resultBBox.height }
	        }, opt);
	    },

	    // Rotate element by `angle` degrees, optionally around `origin` point.
	    // If `origin` is not provided, it is considered to be the center of the element.
	    // If `absolute` is `true`, the `angle` is considered is absolute, i.e. it is not
	    // the difference from the previous angle.
	    rotate: function(angle, absolute, origin, opt) {

	        if (origin) {

	            var center = this.getBBox().center();
	            var size = this.get('size');
	            var position = this.get('position');
	            center.rotate(origin, this.get('angle') - angle);
	            var dx = center.x - size.width / 2 - position.x;
	            var dy = center.y - size.height / 2 - position.y;
	            this.startBatch('rotate', { angle: angle, absolute: absolute, origin: origin });
	            this.position(position.x + dx, position.y + dy, opt);
	            this.rotate(angle, absolute, null, opt);
	            this.stopBatch('rotate');

	        } else {

	            this.set('angle', absolute ? angle : (this.get('angle') + angle) % 360, opt);
	        }

	        return this;
	    },

	    angle: function() {
	        return normalizeAngle(this.get('angle') || 0);
	    },

	    getBBox: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var ref = this;
	        var graph = ref.graph;
	        var attributes = ref.attributes;
	        var deep = opt.deep;
	        var rotate = opt.rotate;

	        if (deep && graph) {
	            // Get all the embedded elements using breadth first algorithm.
	            var elements = this.getEmbeddedCells({ deep: true, breadthFirst: true });
	            // Add the model itself.
	            elements.push(this);
	            // Note: the default of getCellsBBox() is rotate=true and can't be
	            // changed without a breaking change
	            return graph.getCellsBBox(elements, opt);
	        }

	        var angle = attributes.angle; if ( angle === void 0 ) angle = 0;
	        var attributes_position = attributes.position;
	        var x = attributes_position.x;
	        var y = attributes_position.y;
	        var attributes_size = attributes.size;
	        var width = attributes_size.width;
	        var height = attributes_size.height;
	        var bbox = new Rect(x, y, width, height);
	        if (rotate) {
	            bbox.rotateAroundCenter(angle);
	        }
	        return bbox;
	    },

	    getPointFromConnectedLink: function(link, endType) {
	        // Center of the model
	        var bbox = this.getBBox();
	        var center = bbox.center();
	        // Center of a port
	        var endDef = link.get(endType);
	        if (!endDef) { return center; }
	        var portId = endDef.port;
	        if (!portId || !this.hasPort(portId)) { return center; }
	        var portGroup = this.portProp(portId, ['group']);
	        var portsPositions = this.getPortsPositions(portGroup);
	        var portCenter = new Point(portsPositions[portId]).offset(bbox.origin());
	        var angle = this.angle();
	        if (angle) { portCenter.rotate(center, -angle); }
	        return portCenter;
	    }
	});

	assign(Element$1.prototype, elementPortPrototype);

	// Link base model.
	// --------------------------

	var Link = Cell.extend({

	    // may be overwritten by user to change default label (its markup, size, attrs, position)
	    defaultLabel: undefined,

	    // deprecated
	    // may be overwritten by user to change default label markup
	    // lower priority than defaultLabel.markup
	    labelMarkup: undefined,

	    // private
	    _builtins: {
	        defaultLabel: {
	            // builtin default markup:
	            // used if neither defaultLabel.markup
	            // nor label.markup is set
	            markup: [
	                {
	                    tagName: 'rect',
	                    selector: 'rect' // faster than tagName CSS selector
	                }, {
	                    tagName: 'text',
	                    selector: 'text' // faster than tagName CSS selector
	                }
	            ],
	            // builtin default attributes:
	            // applied only if builtin default markup is used
	            attrs: {
	                text: {
	                    fill: '#000000',
	                    fontSize: 14,
	                    textAnchor: 'middle',
	                    textVerticalAnchor: 'middle',
	                    pointerEvents: 'none'
	                },
	                rect: {
	                    ref: 'text',
	                    fill: '#ffffff',
	                    rx: 3,
	                    ry: 3,
	                    x: 'calc(x)',
	                    y: 'calc(y)',
	                    width: 'calc(w)',
	                    height: 'calc(h)'
	                }
	            },
	            // builtin default position:
	            // used if neither defaultLabel.position
	            // nor label.position is set
	            position: {
	                distance: 0.5
	            }
	        }
	    },

	    defaults: {
	        source: {},
	        target: {}
	    },

	    isLink: function() {

	        return true;
	    },

	    disconnect: function(opt) {

	        return this.set({
	            source: { x: 0, y: 0 },
	            target: { x: 0, y: 0 }
	        }, opt);
	    },

	    source: function(source, args, opt) {

	        // getter
	        if (source === undefined) {
	            return clone(this.get('source'));
	        }

	        // setter
	        var setSource;
	        var setOpt;

	        // `source` is a cell
	        // take only its `id` and combine with `args`
	        var isCellProvided = source instanceof Cell;
	        if (isCellProvided) { // three arguments
	            setSource = clone(args) || {};
	            setSource.id = source.id;
	            setOpt = opt;
	            return this.set('source', setSource, setOpt);
	        }

	        // `source` is a point-like object
	        // for example, a g.Point
	        // take only its `x` and `y` and combine with `args`
	        var isPointProvided = !isPlainObject(source);
	        if (isPointProvided) { // three arguments
	            setSource = clone(args) || {};
	            setSource.x = source.x;
	            setSource.y = source.y;
	            setOpt = opt;
	            return this.set('source', setSource, setOpt);
	        }

	        // `source` is an object
	        // no checking
	        // two arguments
	        setSource = source;
	        setOpt = args;
	        return this.set('source', setSource, setOpt);
	    },

	    target: function(target, args, opt) {

	        // getter
	        if (target === undefined) {
	            return clone(this.get('target'));
	        }

	        // setter
	        var setTarget;
	        var setOpt;

	        // `target` is a cell
	        // take only its `id` argument and combine with `args`
	        var isCellProvided = target instanceof Cell;
	        if (isCellProvided) { // three arguments
	            setTarget = clone(args) || {};
	            setTarget.id = target.id;
	            setOpt = opt;
	            return this.set('target', setTarget, setOpt);
	        }

	        // `target` is a point-like object
	        // for example, a g.Point
	        // take only its `x` and `y` and combine with `args`
	        var isPointProvided = !isPlainObject(target);
	        if (isPointProvided) { // three arguments
	            setTarget = clone(args) || {};
	            setTarget.x = target.x;
	            setTarget.y = target.y;
	            setOpt = opt;
	            return this.set('target', setTarget, setOpt);
	        }

	        // `target` is an object
	        // no checking
	        // two arguments
	        setTarget = target;
	        setOpt = args;
	        return this.set('target', setTarget, setOpt);
	    },

	    router: function(name, args, opt) {

	        // getter
	        if (name === undefined) {
	            var router = this.get('router');
	            if (!router) {
	                return null;
	            }
	            if (typeof router === 'object') { return clone(router); }
	            return router; // e.g. a function
	        }

	        // setter
	        var isRouterProvided = ((typeof name === 'object') || (typeof name === 'function'));
	        var localRouter = isRouterProvided ? name : { name: name, args: args };
	        var localOpt = isRouterProvided ? args : opt;

	        return this.set('router', localRouter, localOpt);
	    },

	    connector: function(name, args, opt) {

	        // getter
	        if (name === undefined) {
	            var connector = this.get('connector');
	            if (!connector) {
	                return null;
	            }
	            if (typeof connector === 'object') { return clone(connector); }
	            return connector; // e.g. a function
	        }

	        // setter
	        var isConnectorProvided = ((typeof name === 'object' || typeof name === 'function'));
	        var localConnector = isConnectorProvided ? name : { name: name, args: args };
	        var localOpt = isConnectorProvided ? args : opt;

	        return this.set('connector', localConnector, localOpt);
	    },

	    // Labels API

	    // A convenient way to set labels. Currently set values will be mixined with `value` if used as a setter.
	    label: function(idx, label, opt) {

	        var labels = this.labels();

	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : 0;
	        if (idx < 0) { idx = labels.length + idx; }

	        // getter
	        if (arguments.length <= 1) { return this.prop(['labels', idx]); }
	        // setter
	        return this.prop(['labels', idx], label, opt);
	    },

	    labels: function(labels, opt) {

	        // getter
	        if (arguments.length === 0) {
	            labels = this.get('labels');
	            if (!Array.isArray(labels)) { return []; }
	            return labels.slice();
	        }
	        // setter
	        if (!Array.isArray(labels)) { labels = []; }
	        return this.set('labels', labels, opt);
	    },

	    hasLabels: function() {
	        var ref = this.attributes;
	        var labels = ref.labels;
	        return Array.isArray(labels) && labels.length > 0;
	    },

	    insertLabel: function(idx, label, opt) {

	        if (!label) { throw new Error('dia.Link: no label provided'); }

	        var labels = this.labels();
	        var n = labels.length;
	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : n;
	        if (idx < 0) { idx = n + idx + 1; }

	        labels.splice(idx, 0, label);
	        return this.labels(labels, opt);
	    },

	    // convenience function
	    // add label to end of labels array
	    appendLabel: function(label, opt) {

	        return this.insertLabel(-1, label, opt);
	    },

	    removeLabel: function(idx, opt) {

	        var labels = this.labels();
	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : -1;

	        labels.splice(idx, 1);
	        return this.labels(labels, opt);
	    },

	    // Vertices API

	    vertex: function(idx, vertex, opt) {

	        var vertices = this.vertices();

	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : 0;
	        if (idx < 0) { idx = vertices.length + idx; }

	        // getter
	        if (arguments.length <= 1) { return this.prop(['vertices', idx]); }

	        // setter
	        var setVertex = this._normalizeVertex(vertex);
	        return this.prop(['vertices', idx], setVertex, opt);
	    },

	    vertices: function(vertices, opt) {

	        // getter
	        if (arguments.length === 0) {
	            vertices = this.get('vertices');
	            if (!Array.isArray(vertices)) { return []; }
	            return vertices.slice();
	        }

	        // setter
	        if (!Array.isArray(vertices)) { vertices = []; }
	        var setVertices = [];
	        for (var i = 0; i < vertices.length; i++) {
	            var vertex = vertices[i];
	            var setVertex = this._normalizeVertex(vertex);
	            setVertices.push(setVertex);
	        }
	        return this.set('vertices', setVertices, opt);
	    },

	    insertVertex: function(idx, vertex, opt) {

	        if (!vertex) { throw new Error('dia.Link: no vertex provided'); }

	        var vertices = this.vertices();
	        var n = vertices.length;
	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : n;
	        if (idx < 0) { idx = n + idx + 1; }

	        var setVertex = this._normalizeVertex(vertex);
	        vertices.splice(idx, 0, setVertex);
	        return this.vertices(vertices, opt);
	    },

	    removeVertex: function(idx, opt) {

	        var vertices = this.vertices();
	        idx = (isFinite(idx) && idx !== null) ? (idx | 0) : -1;

	        vertices.splice(idx, 1);
	        return this.vertices(vertices, opt);
	    },

	    _normalizeVertex: function(vertex) {

	        // is vertex a point-like object?
	        // for example, a g.Point
	        var isPointProvided = !isPlainObject(vertex);
	        if (isPointProvided) { return { x: vertex.x, y: vertex.y }; }

	        // else: return vertex unchanged
	        return vertex;
	    },

	    // Transformations

	    translate: function(tx, ty, opt) {

	        // enrich the option object
	        opt = opt || {};
	        opt.translateBy = opt.translateBy || this.id;
	        opt.tx = tx;
	        opt.ty = ty;

	        return this.applyToPoints(function(p) {
	            return { x: (p.x || 0) + tx, y: (p.y || 0) + ty };
	        }, opt);
	    },

	    scale: function(sx, sy, origin, opt) {

	        return this.applyToPoints(function(p) {
	            return Point(p).scale(sx, sy, origin).toJSON();
	        }, opt);
	    },

	    applyToPoints: function(fn, opt) {

	        if (!isFunction(fn)) {
	            throw new TypeError('dia.Link: applyToPoints expects its first parameter to be a function.');
	        }

	        var attrs = {};

	        var ref = this.attributes;
	        var source = ref.source;
	        var target = ref.target;
	        if (!source.id) {
	            attrs.source = fn(source);
	        }
	        if (!target.id) {
	            attrs.target = fn(target);
	        }

	        var vertices = this.vertices();
	        if (vertices.length > 0) {
	            attrs.vertices = vertices.map(fn);
	        }

	        return this.set(attrs, opt);
	    },

	    getSourcePoint: function() {
	        var sourceCell = this.getSourceCell();
	        if (!sourceCell) { return new Point(this.source()); }
	        return sourceCell.getPointFromConnectedLink(this, 'source');
	    },

	    getTargetPoint: function() {
	        var targetCell = this.getTargetCell();
	        if (!targetCell) { return new Point(this.target()); }
	        return targetCell.getPointFromConnectedLink(this, 'target');
	    },

	    getPointFromConnectedLink: function(/* link, endType */) {
	        return this.getPolyline().pointAt(0.5);
	    },

	    getPolyline: function() {
	        var points = [
	            this.getSourcePoint() ].concat( this.vertices().map(Point),
	            [this.getTargetPoint()]
	        );
	        return new Polyline(points);
	    },

	    getBBox: function() {
	        return this.getPolyline().bbox();
	    },

	    reparent: function(opt) {

	        var newParent;

	        if (this.graph) {

	            var source = this.getSourceElement();
	            var target = this.getTargetElement();
	            var prevParent = this.getParentCell();

	            if (source && target) {
	                if (source === target || source.isEmbeddedIn(target)) {
	                    newParent = target;
	                } else if (target.isEmbeddedIn(source)) {
	                    newParent = source;
	                } else {
	                    newParent = this.graph.getCommonAncestor(source, target);
	                }
	            }

	            if (prevParent && (!newParent || newParent.id !== prevParent.id)) {
	                // Unembed the link if source and target has no common ancestor
	                // or common ancestor changed
	                prevParent.unembed(this, opt);
	            }

	            if (newParent) {
	                newParent.embed(this, opt);
	            }
	        }

	        return newParent;
	    },

	    hasLoop: function(opt) {

	        opt = opt || {};

	        var ref = this.attributes;
	        var source = ref.source;
	        var target = ref.target;
	        var sourceId = source.id;
	        var targetId = target.id;

	        if (!sourceId || !targetId) {
	            // Link "pinned" to the paper does not have a loop.
	            return false;
	        }

	        var loop = sourceId === targetId;

	        // Note that there in the deep mode a link can have a loop,
	        // even if it connects only a parent and its embed.
	        // A loop "target equals source" is valid in both shallow and deep mode.
	        if (!loop && opt.deep && this.graph) {

	            var sourceElement = this.getSourceCell();
	            var targetElement = this.getTargetCell();

	            loop = sourceElement.isEmbeddedIn(targetElement) || targetElement.isEmbeddedIn(sourceElement);
	        }

	        return loop;
	    },

	    // unlike source(), this method returns null if source is a point
	    getSourceCell: function() {

	        var ref = this;
	        var graph = ref.graph;
	        var attributes = ref.attributes;
	        var source = attributes.source;
	        return (source && source.id && graph && graph.getCell(source.id)) || null;
	    },

	    getSourceElement: function() {
	        var cell = this;
	        var visited = {};
	        do {
	            if (visited[cell.id]) { return null; }
	            visited[cell.id] = true;
	            cell = cell.getSourceCell();
	        } while (cell && cell.isLink());
	        return cell;
	    },

	    // unlike target(), this method returns null if target is a point
	    getTargetCell: function() {

	        var ref = this;
	        var graph = ref.graph;
	        var attributes = ref.attributes;
	        var target = attributes.target;
	        return (target && target.id && graph && graph.getCell(target.id)) || null;
	    },

	    getTargetElement: function() {
	        var cell = this;
	        var visited = {};
	        do {
	            if (visited[cell.id]) { return null; }
	            visited[cell.id] = true;
	            cell = cell.getTargetCell();
	        } while (cell && cell.isLink());
	        return cell;
	    },

	    // Returns the common ancestor for the source element,
	    // target element and the link itself.
	    getRelationshipAncestor: function() {

	        var connectionAncestor;

	        if (this.graph) {

	            var cells = [
	                this,
	                this.getSourceElement(), // null if source is a point
	                this.getTargetElement() // null if target is a point
	            ].filter(function(item) {
	                return !!item;
	            });

	            connectionAncestor = this.graph.getCommonAncestor.apply(this.graph, cells);
	        }

	        return connectionAncestor || null;
	    },

	    // Is source, target and the link itself embedded in a given cell?
	    isRelationshipEmbeddedIn: function(cell) {

	        var cellId = (isString(cell) || isNumber(cell)) ? cell : cell.id;
	        var ancestor = this.getRelationshipAncestor();

	        return !!ancestor && (ancestor.id === cellId || ancestor.isEmbeddedIn(cellId));
	    },

	    // Get resolved default label.
	    _getDefaultLabel: function() {

	        var defaultLabel = this.get('defaultLabel') || this.defaultLabel || {};

	        var label = {};
	        label.markup = defaultLabel.markup || this.get('labelMarkup') || this.labelMarkup;
	        label.position = defaultLabel.position;
	        label.attrs = defaultLabel.attrs;
	        label.size = defaultLabel.size;

	        return label;
	    }
	}, {

	    endsEqual: function(a, b) {

	        var portsEqual = a.port === b.port || !a.port && !b.port;
	        return a.id === b.id && portsEqual;
	    }
	});

	var env = {

	    _results: {},

	    _tests: {

	        svgforeignobject: function() {
	            return !!document.createElementNS &&
	                /SVGForeignObject/.test(({}).toString.call(document.createElementNS('http://www.w3.org/2000/svg', 'foreignObject')));
	        }
	    },

	    addTest: function(name, fn) {

	        return this._tests[name] = fn;
	    },

	    test: function(name) {

	        var fn = this._tests[name];

	        if (!fn) {
	            throw new Error('Test not defined ("' + name + '"). Use `joint.env.addTest(name, fn) to add a new test.`');
	        }

	        var result = this._results[name];

	        if (typeof result !== 'undefined') {
	            return result;
	        }

	        try {
	            result = fn();
	        } catch (error) {
	            result = false;
	        }

	        // Cache the test result.
	        this._results[name] = result;

	        return result;
	    }
	};

	// ELEMENTS

	var Rectangle = Element$1.define('standard.Rectangle', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            strokeWidth: 2,
	            stroke: '#000000',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'rect',
	        selector: 'body',
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Circle = Element$1.define('standard.Circle', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            cx: 'calc(s/2)',
	            cy: 'calc(s/2)',
	            r: 'calc(s/2)',
	            strokeWidth: 2,
	            stroke: '#333333',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'circle',
	        selector: 'body'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Ellipse$1 = Element$1.define('standard.Ellipse', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            cx: 'calc(w/2)',
	            cy: 'calc(h/2)',
	            rx: 'calc(w/2)',
	            ry: 'calc(h/2)',
	            strokeWidth: 2,
	            stroke: '#333333',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'ellipse',
	        selector: 'body'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Path$1 = Element$1.define('standard.Path', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            d: 'M 0 0 H calc(w) V calc(h) H 0 Z',
	            strokeWidth: 2,
	            stroke: '#333333',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'path',
	        selector: 'body'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Polygon$1 = Element$1.define('standard.Polygon', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            points: '0 0 calc(w) 0 calc(w) calc(h) 0 calc(h)',
	            strokeWidth: 2,
	            stroke: '#333333',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'polygon',
	        selector: 'body'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Polyline$1 = Element$1.define('standard.Polyline', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            points: '0 0 calc(w) 0 calc(w) calc(h) 0 calc(h)',
	            strokeWidth: 2,
	            stroke: '#333333',
	            fill: '#FFFFFF'
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'polyline',
	        selector: 'body'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var Image = Element$1.define('standard.Image', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        image: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            // xlinkHref: '[URL]'
	        },
	        label: {
	            textVerticalAnchor: 'top',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h+10)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'image',
	        selector: 'image'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var BorderedImage = Element$1.define('standard.BorderedImage', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        border: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            stroke: '#333333',
	            strokeWidth: 2
	        },
	        background: {
	            width: 'calc(w-1)',
	            height: 'calc(h-1)',
	            x: 0.5,
	            y: 0.5,
	            fill: '#FFFFFF'
	        },
	        image: {
	            // xlinkHref: '[URL]'
	            width: 'calc(w-1)',
	            height: 'calc(h-1)',
	            x: 0.5,
	            y: 0.5
	        },
	        label: {
	            textVerticalAnchor: 'top',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h+10)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'rect',
	        selector: 'background',
	        attributes: {
	            'stroke': 'none'
	        }
	    }, {
	        tagName: 'image',
	        selector: 'image'
	    }, {
	        tagName: 'rect',
	        selector: 'border',
	        attributes: {
	            'fill': 'none'
	        }
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var EmbeddedImage = Element$1.define('standard.EmbeddedImage', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            stroke: '#333333',
	            fill: '#FFFFFF',
	            strokeWidth: 2
	        },
	        image: {
	            // xlinkHref: '[URL]'
	            width: 'calc(0.3*w)',
	            height: 'calc(h-20)',
	            x: 10,
	            y: 10,
	            preserveAspectRatio: 'xMidYMin'
	        },
	        label: {
	            textVerticalAnchor: 'top',
	            textAnchor: 'left',
	            x: 'calc(0.3*w+20)', // 10 + 10
	            y: 10,
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'rect',
	        selector: 'body'
	    }, {
	        tagName: 'image',
	        selector: 'image'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var InscribedImage = Element$1.define('standard.InscribedImage', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        border: {
	            rx: 'calc(w/2)',
	            ry: 'calc(h/2)',
	            cx: 'calc(w/2)',
	            cy: 'calc(h/2)',
	            stroke: '#333333',
	            strokeWidth: 2
	        },
	        background: {
	            rx: 'calc(w/2)',
	            ry: 'calc(h/2)',
	            cx: 'calc(w/2)',
	            cy: 'calc(h/2)',
	            fill: '#FFFFFF'
	        },
	        image: {
	            // The image corners touch the border when its size is Math.sqrt(2) / 2 = 0.707.. ~= 70%
	            width: 'calc(0.68*w)',
	            height: 'calc(0.68*h)',
	            // The image offset is calculated as (100% - 68%) / 2
	            x: 'calc(0.16*w)',
	            y: 'calc(0.16*h)',
	            preserveAspectRatio: 'xMidYMid'
	            // xlinkHref: '[URL]'
	        },
	        label: {
	            textVerticalAnchor: 'top',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h+10)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'ellipse',
	        selector: 'background'
	    }, {
	        tagName: 'image',
	        selector: 'image'
	    }, {
	        tagName: 'ellipse',
	        selector: 'border',
	        attributes: {
	            'fill': 'none'
	        }
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }]
	});

	var HeaderedRectangle = Element$1.define('standard.HeaderedRectangle', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            strokeWidth: 2,
	            stroke: '#000000',
	            fill: '#FFFFFF'
	        },
	        header: {
	            width: 'calc(w)',
	            height: 30,
	            strokeWidth: 2,
	            stroke: '#000000',
	            fill: '#FFFFFF'
	        },
	        headerText: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 15,
	            fontSize: 16,
	            fill: '#333333'
	        },
	        bodyText: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h/2+15)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'rect',
	        selector: 'body'
	    }, {
	        tagName: 'rect',
	        selector: 'header'
	    }, {
	        tagName: 'text',
	        selector: 'headerText'
	    }, {
	        tagName: 'text',
	        selector: 'bodyText'
	    }]
	});

	var CYLINDER_TILT = 10;

	var Cylinder = Element$1.define('standard.Cylinder', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            lateralArea: CYLINDER_TILT,
	            fill: '#FFFFFF',
	            stroke: '#333333',
	            strokeWidth: 2
	        },
	        top: {
	            cx: 'calc(w/2)',
	            cy: CYLINDER_TILT,
	            rx: 'calc(w/2)',
	            ry: CYLINDER_TILT,
	            fill: '#FFFFFF',
	            stroke: '#333333',
	            strokeWidth: 2
	        },
	        label: {
	            textVerticalAnchor: 'middle',
	            textAnchor: 'middle',
	            x: 'calc(w/2)',
	            y: 'calc(h+15)',
	            fontSize: 14,
	            fill: '#333333'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'path',
	        selector: 'body'
	    }, {
	        tagName: 'ellipse',
	        selector: 'top'
	    }, {
	        tagName: 'text',
	        selector: 'label'
	    }],

	    topRy: function(t, opt) {
	        // getter
	        if (t === undefined) { return this.attr('body/lateralArea'); }

	        // setter
	        var bodyAttrs = { lateralArea: t };

	        var isPercentageSetter = isPercentage(t);
	        var ty = (isPercentageSetter) ? ("calc(" + (parseFloat(t) / 100) + "*h)") : t;
	        var topAttrs = { cy: ty, ry: ty };

	        return this.attr({ body: bodyAttrs, top: topAttrs }, opt);
	    }

	}, {
	    attributes: {
	        'lateral-area': {
	            set: function(t, refBBox) {
	                var isPercentageSetter = isPercentage(t);
	                if (isPercentageSetter) { t = parseFloat(t) / 100; }

	                var x = refBBox.x;
	                var y = refBBox.y;
	                var w = refBBox.width;
	                var h = refBBox.height;

	                // curve control point variables
	                var rx = w / 2;
	                var ry = isPercentageSetter ? (h * t) : t;

	                var kappa = V.KAPPA;
	                var cx = kappa * rx;
	                var cy = kappa * (isPercentageSetter ? (h * t) : t);

	                // shape variables
	                var xLeft = x;
	                var xCenter = x + (w / 2);
	                var xRight = x + w;

	                var ySideTop = y + ry;
	                var yCurveTop = ySideTop - ry;
	                var ySideBottom = y + h - ry;
	                var yCurveBottom = y + h;

	                // return calculated shape
	                var data = [
	                    'M', xLeft, ySideTop,
	                    'L', xLeft, ySideBottom,
	                    'C', x, (ySideBottom + cy), (xCenter - cx), yCurveBottom, xCenter, yCurveBottom,
	                    'C', (xCenter + cx), yCurveBottom, xRight, (ySideBottom + cy), xRight, ySideBottom,
	                    'L', xRight, ySideTop,
	                    'C', xRight, (ySideTop - cy), (xCenter + cx), yCurveTop, xCenter, yCurveTop,
	                    'C', (xCenter - cx), yCurveTop, xLeft, (ySideTop - cy), xLeft, ySideTop,
	                    'Z'
	                ];
	                return { d: data.join(' ') };
	            }
	        }
	    }
	});

	var foLabelMarkup = {
	    tagName: 'foreignObject',
	    selector: 'foreignObject',
	    attributes: {
	        'overflow': 'hidden'
	    },
	    children: [{
	        tagName: 'div',
	        namespaceURI: 'http://www.w3.org/1999/xhtml',
	        selector: 'label',
	        style: {
	            width: '100%',
	            height: '100%',
	            position: 'static',
	            backgroundColor: 'transparent',
	            textAlign: 'center',
	            margin: 0,
	            padding: '0px 5px',
	            boxSizing: 'border-box',
	            display: 'flex',
	            alignItems: 'center',
	            justifyContent: 'center'
	        }
	    }]
	};

	var svgLabelMarkup = {
	    tagName: 'text',
	    selector: 'label',
	    attributes: {
	        'text-anchor': 'middle'
	    }
	};

	var labelMarkup = (env.test('svgforeignobject')) ? foLabelMarkup : svgLabelMarkup;

	var TextBlock = Element$1.define('standard.TextBlock', {
	    attrs: {
	        root: {
	            cursor: 'move'
	        },
	        body: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	            stroke: '#333333',
	            fill: '#ffffff',
	            strokeWidth: 2
	        },
	        foreignObject: {
	            width: 'calc(w)',
	            height: 'calc(h)',
	        },
	        label: {
	            style: {
	                fontSize: 14
	            }
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'rect',
	        selector: 'body'
	    }, labelMarkup]
	}, {
	    attributes: {
	        text: {
	            set: function(text, refBBox, node, attrs) {
	                if (node instanceof HTMLElement) {
	                    node.textContent = text;
	                } else {
	                    // No foreign object
	                    var style = attrs['style'] || {};
	                    var wrapValue = { text: text, width: -5, height: '100%' };
	                    var wrapAttrs = assign({ 'text-vertical-anchor': 'middle' }, style);
	                    attributes['text-wrap'].set.call(this, wrapValue, refBBox, node, wrapAttrs);
	                    return { fill: style.color || null };
	                }
	            },
	            position: function(text, refBBox, node) {
	                // No foreign object
	                if (node instanceof SVGElement) { return refBBox.center(); }
	            }
	        }
	    }
	});

	// LINKS

	var Link$1 = Link.define('standard.Link', {
	    attrs: {
	        line: {
	            connection: true,
	            stroke: '#333333',
	            strokeWidth: 2,
	            strokeLinejoin: 'round',
	            targetMarker: {
	                'type': 'path',
	                'd': 'M 10 -5 0 0 10 5 z'
	            }
	        },
	        wrapper: {
	            connection: true,
	            strokeWidth: 10,
	            strokeLinejoin: 'round'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'path',
	        selector: 'wrapper',
	        attributes: {
	            'fill': 'none',
	            'cursor': 'pointer',
	            'stroke': 'transparent',
	            'stroke-linecap': 'round'
	        }
	    }, {
	        tagName: 'path',
	        selector: 'line',
	        attributes: {
	            'fill': 'none',
	            'pointer-events': 'none'
	        }
	    }]
	});

	var DoubleLink = Link.define('standard.DoubleLink', {
	    attrs: {
	        line: {
	            connection: true,
	            stroke: '#DDDDDD',
	            strokeWidth: 4,
	            strokeLinejoin: 'round',
	            targetMarker: {
	                type: 'path',
	                stroke: '#000000',
	                d: 'M 10 -3 10 -10 -2 0 10 10 10 3'
	            }
	        },
	        outline: {
	            connection: true,
	            stroke: '#000000',
	            strokeWidth: 6,
	            strokeLinejoin: 'round'
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'path',
	        selector: 'outline',
	        attributes: {
	            'fill': 'none',
	            'cursor': 'pointer'
	        }
	    }, {
	        tagName: 'path',
	        selector: 'line',
	        attributes: {
	            'fill': 'none',
	            'pointer-events': 'none'
	        }
	    }]
	});

	var ShadowLink = Link.define('standard.ShadowLink', {
	    attrs: {
	        line: {
	            connection: true,
	            stroke: '#FF0000',
	            strokeWidth: 20,
	            strokeLinejoin: 'round',
	            targetMarker: {
	                'type': 'path',
	                'stroke': 'none',
	                'd': 'M 0 -10 -10 0 0 10 z'
	            },
	            sourceMarker: {
	                'type': 'path',
	                'stroke': 'none',
	                'd': 'M -10 -10 0 0 -10 10 0 10 0 -10 z'
	            }
	        },
	        shadow: {
	            connection: true,
	            transform: 'translate(3,6)',
	            stroke: '#000000',
	            strokeOpacity: 0.2,
	            strokeWidth: 20,
	            strokeLinejoin: 'round',
	            targetMarker: {
	                'type': 'path',
	                'd': 'M 0 -10 -10 0 0 10 z',
	                'stroke': 'none'
	            },
	            sourceMarker: {
	                'type': 'path',
	                'stroke': 'none',
	                'd': 'M -10 -10 0 0 -10 10 0 10 0 -10 z'
	            }
	        }
	    }
	}, {
	    markup: [{
	        tagName: 'path',
	        selector: 'shadow',
	        attributes: {
	            'fill': 'none',
	            'pointer-events': 'none'
	        }
	    }, {
	        tagName: 'path',
	        selector: 'line',
	        attributes: {
	            'fill': 'none',
	            'cursor': 'pointer'
	        }
	    }]
	});

	var standard = ({
		Rectangle: Rectangle,
		Circle: Circle,
		Ellipse: Ellipse$1,
		Path: Path$1,
		Polygon: Polygon$1,
		Polyline: Polyline$1,
		Image: Image,
		BorderedImage: BorderedImage,
		EmbeddedImage: EmbeddedImage,
		InscribedImage: InscribedImage,
		HeaderedRectangle: HeaderedRectangle,
		Cylinder: Cylinder,
		TextBlock: TextBlock,
		Link: Link$1,
		DoubleLink: DoubleLink,
		ShadowLink: ShadowLink
	});



	var index$1 = ({
		standard: standard
	});

	var CornerTypes = {
	    POINT: 'point',
	    CUBIC: 'cubic',
	    LINE: 'line',
	    GAP: 'gap'
	};

	var DEFINED_CORNER_TYPES = Object.values(CornerTypes);

	var CORNER_RADIUS = 10;
	var PRECISION = 1;

	var straight = function(sourcePoint, targetPoint, routePoints, opt) {
	    if ( routePoints === void 0 ) routePoints = [];
	    if ( opt === void 0 ) opt = {};


	    var cornerType = opt.cornerType; if ( cornerType === void 0 ) cornerType = CornerTypes.POINT;
	    var cornerRadius = opt.cornerRadius; if ( cornerRadius === void 0 ) cornerRadius = CORNER_RADIUS;
	    var cornerPreserveAspectRatio = opt.cornerPreserveAspectRatio; if ( cornerPreserveAspectRatio === void 0 ) cornerPreserveAspectRatio = false;
	    var precision = opt.precision; if ( precision === void 0 ) precision = PRECISION;
	    var raw = opt.raw; if ( raw === void 0 ) raw = false;

	    if (DEFINED_CORNER_TYPES.indexOf(cornerType) === -1) {
	        // unknown `cornerType` provided => error
	        throw new Error('Invalid `cornerType` provided to `straight` connector.');
	    }

	    var path;

	    if ((cornerType === CornerTypes.POINT) || !cornerRadius) {
	        // default option => normal connector
	        // simply connect all points with straight lines
	        var points = [sourcePoint].concat(routePoints).concat([targetPoint]);
	        var polyline = new Polyline(points);
	        path = new Path(polyline);

	    } else {
	        // `cornerType` is not unknown and not 'point' (default) => must be one of other valid types
	        path = new Path();

	        // add initial gap segment = to source point
	        path.appendSegment(Path.createSegment('M', sourcePoint));

	        var nextDistance;
	        var routePointsLength = routePoints.length;
	        for (var i = 0; i < routePointsLength; i++) {

	            var curr = new Point(routePoints[i]);
	            var prev = (routePoints[i - 1] || sourcePoint);
	            var next = (routePoints[i + 1] || targetPoint);
	            var prevDistance = (nextDistance || (curr.distance(prev) / 2)); // try to re-use previously-computed `nextDistance`
	            nextDistance = (curr.distance(next) / 2);

	            var startMove = (void 0), endMove = (void 0);
	            if (!cornerPreserveAspectRatio) {
	                // `startMove` and `endMove` may be different
	                // (this happens when next or previous path point is closer than `2 * cornerRadius`)
	                startMove = -Math.min(cornerRadius, prevDistance);
	                endMove = -Math.min(cornerRadius, nextDistance);
	            } else {
	                // force `startMove` and `endMove` to be the same
	                startMove = endMove = -Math.min(cornerRadius, prevDistance, nextDistance);
	            }

	            // to find `cornerStart` and `cornerEnd`, the logic is as follows (using `cornerStart` as example):
	            // - find a point lying on the line `prev - startMove` such that...
	            // - ...the point lies `abs(startMove)` distance away from `curr`...
	            // - ...and its coordinates are rounded to whole numbers
	            var cornerStart = curr.clone().move(prev, startMove).round(precision);
	            var cornerEnd = curr.clone().move(next, endMove).round(precision);

	            // add in-between straight segment = from previous route point to corner start point
	            // (may have zero length)
	            path.appendSegment(Path.createSegment('L', cornerStart));

	            // add corner segment = from corner start point to corner end point
	            switch (cornerType) {
	                case CornerTypes.CUBIC: {
	                    // corner is rounded
	                    var _13 = (1 / 3);
	                    var _23 = (2 / 3);
	                    var control1 = new Point((_13 * cornerStart.x) + (_23 * curr.x), (_23 * curr.y) + (_13 * cornerStart.y));
	                    var control2 = new Point((_13 * cornerEnd.x) + (_23 * curr.x), (_23 * curr.y) + (_13 * cornerEnd.y));
	                    path.appendSegment(Path.createSegment('C', control1, control2, cornerEnd));
	                    break;
	                }
	                case CornerTypes.LINE: {
	                    // corner has bevel
	                    path.appendSegment(Path.createSegment('L', cornerEnd));
	                    break;
	                }
	                case CornerTypes.GAP: {
	                    // corner has empty space
	                    path.appendSegment(Path.createSegment('M', cornerEnd));
	                    break;
	                }
	                // default: no segment is created
	            }
	        }

	        // add final straight segment = from last corner end point to target point
	        // (= or from start point to end point, if there are no route points)
	        // (may have zero length)
	        path.appendSegment(Path.createSegment('L', targetPoint));
	    }

	    return ((raw) ? path : path.serialize());
	};

	// default size of jump if not specified in options
	var JUMP_SIZE = 5;

	// available jump types
	// first one taken as default
	var JUMP_TYPES = ['arc', 'gap', 'cubic'];

	// default radius
	var RADIUS = 0;

	// takes care of math. error for case when jump is too close to end of line
	var CLOSE_PROXIMITY_PADDING = 1;

	// list of connector types not to jump over.
	var IGNORED_CONNECTORS = ['smooth'];

	// internal constants for round segment
	var _13 = 1 / 3;
	var _23 = 2 / 3;

	function sortPointsAscending(p1, p2) {

	    var x1 = p1.x;
	    var y1 = p1.y;
	    var x2 = p2.x;
	    var y2 = p2.y;

	    if (x1 > x2) {

	        var swap = x1;
	        x1 = x2;
	        x2 = swap;

	        swap = y1;
	        y1 = y2;
	        y2 = swap;
	    }

	    if (y1 > y2) {
	        var swap$1 = x1;
	        x1 = x2;
	        x2 = swap$1;

	        swap$1 = y1;
	        y1 = y2;
	        y2 = swap$1;
	    }

	    return [new Point(x1, y1), new Point(x2, y2)];
	}

	function overlapExists(line1, line2) {

	    var ref = sortPointsAscending(line1.start, line1.end);
	    var ref_0 = ref[0];
	    var x1 = ref_0.x;
	    var y1 = ref_0.y;
	    var ref_1 = ref[1];
	    var x2 = ref_1.x;
	    var y2 = ref_1.y;
	    var ref$1 = sortPointsAscending(line2.start, line2.end);
	    var ref$1_0 = ref$1[0];
	    var x3 = ref$1_0.x;
	    var y3 = ref$1_0.y;
	    var ref$1_1 = ref$1[1];
	    var x4 = ref$1_1.x;
	    var y4 = ref$1_1.y;

	    var xMatch = x1 <= x4 && x3 <= x2;
	    var yMatch = y1 <= y4 && y3 <= y2;

	    return xMatch && yMatch;
	}

	/**
	 * Transform start/end and route into series of lines
	 * @param {g.point} sourcePoint start point
	 * @param {g.point} targetPoint end point
	 * @param {g.point[]} route optional list of route
	 * @return {g.line[]} [description]
	 */
	function createLines(sourcePoint, targetPoint, route) {
	    // make a flattened array of all points
	    var points = [].concat(sourcePoint, route, targetPoint);
	    return points.reduce(function(resultLines, point, idx) {
	        // if there is a next point, make a line with it
	        var nextPoint = points[idx + 1];
	        if (nextPoint != null) {
	            resultLines[idx] = line(point, nextPoint);
	        }
	        return resultLines;
	    }, []);
	}

	function setupUpdating(jumpOverLinkView) {
	    var paper = jumpOverLinkView.paper;
	    var updateList = paper._jumpOverUpdateList;

	    // first time setup for this paper
	    if (updateList == null) {
	        updateList = paper._jumpOverUpdateList = [];
	        var graph = paper.model;
	        graph.on('batch:stop', function() {
	            if (this.hasActiveBatch()) { return; }
	            updateJumpOver(paper);
	        });
	        graph.on('reset', function() {
	            updateList = paper._jumpOverUpdateList = [];
	        });
	    }

	    // add this link to a list so it can be updated when some other link is updated
	    if (updateList.indexOf(jumpOverLinkView) < 0) {
	        updateList.push(jumpOverLinkView);

	        // watch for change of connector type or removal of link itself
	        // to remove the link from a list of jump over connectors
	        jumpOverLinkView.listenToOnce(jumpOverLinkView.model, 'change:connector remove', function() {
	            updateList.splice(updateList.indexOf(jumpOverLinkView), 1);
	        });
	    }
	}

	/**
	 * Handler for a batch:stop event to force
	 * update of all registered links with jump over connector
	 * @param {object} batchEvent optional object with info about batch
	 */
	function updateJumpOver(paper) {
	    var updateList = paper._jumpOverUpdateList;
	    for (var i = 0; i < updateList.length; i++) {
	        var linkView = updateList[i];
	        var updateFlag = linkView.getFlag(linkView.constructor.Flags.CONNECTOR);
	        linkView.requestUpdate(updateFlag);
	    }
	}

	/**
	 * Utility function to collect all intersection points of a single
	 * line against group of other lines.
	 * @param {g.line} line where to find points
	 * @param {g.line[]} crossCheckLines lines to cross
	 * @return {g.point[]} list of intersection points
	 */
	function findLineIntersections(line, crossCheckLines) {
	    return toArray(crossCheckLines).reduce(function(res, crossCheckLine) {
	        var intersection = line.intersection(crossCheckLine);
	        if (intersection) {
	            res.push(intersection);
	        }
	        return res;
	    }, []);
	}

	/**
	 * Sorting function for list of points by their distance.
	 * @param {g.point} p1 first point
	 * @param {g.point} p2 second point
	 * @return {number} squared distance between points
	 */
	function sortPoints(p1, p2) {
	    return line(p1, p2).squaredLength();
	}

	/**
	 * Split input line into multiple based on intersection points.
	 * @param {g.line} line input line to split
	 * @param {g.point[]} intersections points where to split the line
	 * @param {number} jumpSize the size of jump arc (length empty spot on a line)
	 * @return {g.line[]} list of lines being split
	 */
	function createJumps(line$1, intersections, jumpSize) {
	    return intersections.reduce(function(resultLines, point$1, idx) {
	        // skipping points that were merged with the previous line
	        // to make bigger arc over multiple lines that are close to each other
	        if (point$1.skip === true) {
	            return resultLines;
	        }

	        // always grab the last line from buffer and modify it
	        var lastLine = resultLines.pop() || line$1;

	        // calculate start and end of jump by moving by a given size of jump
	        var jumpStart = point(point$1).move(lastLine.start, -(jumpSize));
	        var jumpEnd = point(point$1).move(lastLine.start, +(jumpSize));

	        // now try to look at the next intersection point
	        var nextPoint = intersections[idx + 1];
	        if (nextPoint != null) {
	            var distance = jumpEnd.distance(nextPoint);
	            if (distance <= jumpSize) {
	                // next point is close enough, move the jump end by this
	                // difference and mark the next point to be skipped
	                jumpEnd = nextPoint.move(lastLine.start, distance);
	                nextPoint.skip = true;
	            }
	        } else {
	            // this block is inside of `else` as an optimization so the distance is
	            // not calculated when we know there are no other intersection points
	            var endDistance = jumpStart.distance(lastLine.end);
	            // if the end is too close to possible jump, draw remaining line instead of a jump
	            if (endDistance < jumpSize * 2 + CLOSE_PROXIMITY_PADDING) {
	                resultLines.push(lastLine);
	                return resultLines;
	            }
	        }

	        var startDistance = jumpEnd.distance(lastLine.start);
	        if (startDistance < jumpSize * 2 + CLOSE_PROXIMITY_PADDING) {
	            // if the start of line is too close to jump, draw that line instead of a jump
	            resultLines.push(lastLine);
	            return resultLines;
	        }

	        // finally create a jump line
	        var jumpLine = line(jumpStart, jumpEnd);
	        // it's just simple line but with a `isJump` property
	        jumpLine.isJump = true;

	        resultLines.push(
	            line(lastLine.start, jumpStart),
	            jumpLine,
	            line(jumpEnd, lastLine.end)
	        );
	        return resultLines;
	    }, []);
	}

	/**
	 * Assemble `D` attribute of a SVG path by iterating given lines.
	 * @param {g.line[]} lines source lines to use
	 * @param {number} jumpSize the size of jump arc (length empty spot on a line)
	 * @param {number} radius the radius
	 * @return {string}
	 */
	function buildPath(lines, jumpSize, jumpType, radius) {

	    var path = new Path();
	    var segment;

	    // first move to the start of a first line
	    segment = Path.createSegment('M', lines[0].start);
	    path.appendSegment(segment);

	    // make a paths from lines
	    toArray(lines).forEach(function(line, index) {

	        if (line.isJump) {
	            var angle, diff;

	            var control1, control2;

	            if (jumpType === 'arc') { // approximates semicircle with 2 curves
	                angle = -90;
	                // determine rotation of arc based on difference between points
	                diff = line.start.difference(line.end);
	                // make sure the arc always points up (or right)
	                var xAxisRotate = Number((diff.x < 0) || (diff.x === 0 && diff.y < 0));
	                if (xAxisRotate) { angle += 180; }

	                var midpoint = line.midpoint();
	                var centerLine = new Line(midpoint, line.end).rotate(midpoint, angle);

	                var halfLine;

	                // first half
	                halfLine = new Line(line.start, midpoint);

	                control1 = halfLine.pointAt(2 / 3).rotate(line.start, angle);
	                control2 = centerLine.pointAt(1 / 3).rotate(centerLine.end, -angle);

	                segment = Path.createSegment('C', control1, control2, centerLine.end);
	                path.appendSegment(segment);

	                // second half
	                halfLine = new Line(midpoint, line.end);

	                control1 = centerLine.pointAt(1 / 3).rotate(centerLine.end, angle);
	                control2 = halfLine.pointAt(1 / 3).rotate(line.end, -angle);

	                segment = Path.createSegment('C', control1, control2, line.end);
	                path.appendSegment(segment);

	            } else if (jumpType === 'gap') {
	                segment = Path.createSegment('M', line.end);
	                path.appendSegment(segment);

	            } else if (jumpType === 'cubic') { // approximates semicircle with 1 curve
	                angle = line.start.theta(line.end);

	                var xOffset = jumpSize * 0.6;
	                var yOffset = jumpSize * 1.35;

	                // determine rotation of arc based on difference between points
	                diff = line.start.difference(line.end);
	                // make sure the arc always points up (or right)
	                xAxisRotate = Number((diff.x < 0) || (diff.x === 0 && diff.y < 0));
	                if (xAxisRotate) { yOffset *= -1; }

	                control1 = Point(line.start.x + xOffset, line.start.y + yOffset).rotate(line.start, angle);
	                control2 = Point(line.end.x - xOffset, line.end.y + yOffset).rotate(line.end, angle);

	                segment = Path.createSegment('C', control1, control2, line.end);
	                path.appendSegment(segment);
	            }

	        } else {
	            var nextLine = lines[index + 1];
	            if (radius == 0 || !nextLine || nextLine.isJump) {
	                segment = Path.createSegment('L', line.end);
	                path.appendSegment(segment);
	            } else {
	                buildRoundedSegment(radius, path, line.end, line.start, nextLine.end);
	            }
	        }
	    });

	    return path;
	}

	function buildRoundedSegment(offset, path, curr, prev, next) {
	    var prevDistance = curr.distance(prev) / 2;
	    var nextDistance = curr.distance(next) / 2;

	    var startMove = -Math.min(offset, prevDistance);
	    var endMove = -Math.min(offset, nextDistance);

	    var roundedStart = curr.clone().move(prev, startMove).round();
	    var roundedEnd = curr.clone().move(next, endMove).round();

	    var control1 = new Point((_13 * roundedStart.x) + (_23 * curr.x), (_23 * curr.y) + (_13 * roundedStart.y));
	    var control2 = new Point((_13 * roundedEnd.x) + (_23 * curr.x), (_23 * curr.y) + (_13 * roundedEnd.y));

	    var segment;
	    segment = Path.createSegment('L', roundedStart);
	    path.appendSegment(segment);

	    segment = Path.createSegment('C', control1, control2, roundedEnd);
	    path.appendSegment(segment);
	}

	/**
	 * Actual connector function that will be run on every update.
	 * @param {g.point} sourcePoint start point of this link
	 * @param {g.point} targetPoint end point of this link
	 * @param {g.point[]} route of this link
	 * @param {object} opt options
	 * @property {number} size optional size of a jump arc
	 * @return {string} created `D` attribute of SVG path
	 */
	var jumpover = function(sourcePoint, targetPoint, route, opt) { // eslint-disable-line max-params

	    setupUpdating(this);

	    var raw = opt.raw;
	    var jumpSize = opt.size || JUMP_SIZE;
	    var jumpType = opt.jump && ('' + opt.jump).toLowerCase();
	    var radius = opt.radius || RADIUS;
	    var ignoreConnectors = opt.ignoreConnectors || IGNORED_CONNECTORS;

	    // grab the first jump type as a default if specified one is invalid
	    if (JUMP_TYPES.indexOf(jumpType) === -1) {
	        jumpType = JUMP_TYPES[0];
	    }

	    var paper = this.paper;
	    var graph = paper.model;
	    var allLinks = graph.getLinks();

	    // there is just one link, draw it directly
	    if (allLinks.length === 1) {
	        return buildPath(
	            createLines(sourcePoint, targetPoint, route),
	            jumpSize, jumpType, radius
	        );
	    }

	    var thisModel = this.model;
	    var thisIndex = allLinks.indexOf(thisModel);
	    var defaultConnector = paper.options.defaultConnector || {};

	    // not all links are meant to be jumped over.
	    var links = allLinks.filter(function(link, idx) {

	        var connector = link.get('connector') || defaultConnector;

	        // avoid jumping over links with connector type listed in `ignored connectors`.
	        if (toArray(ignoreConnectors).includes(connector.name)) {
	            return false;
	        }
	        // filter out links that are above this one and  have the same connector type
	        // otherwise there would double hoops for each intersection
	        if (idx > thisIndex) {
	            return connector.name !== 'jumpover';
	        }
	        return true;
	    });

	    // find views for all links
	    var linkViews = links.map(function(link) {
	        return paper.findViewByModel(link);
	    });

	    // create lines for this link
	    var thisLines = createLines(
	        sourcePoint,
	        targetPoint,
	        route
	    );

	    // create lines for all other links
	    var linkLines = linkViews.map(function(linkView) {
	        if (linkView == null) {
	            return [];
	        }
	        if (linkView === this) {
	            return thisLines;
	        }
	        return createLines(
	            linkView.sourcePoint,
	            linkView.targetPoint,
	            linkView.route
	        );
	    }, this);

	    // transform lines for this link by splitting with jump lines at
	    // points of intersection with other links
	    var jumpingLines = thisLines.reduce(function(resultLines, thisLine) {
	        // iterate all links and grab the intersections with this line
	        // these are then sorted by distance so the line can be split more easily
	        var intersections = links.reduce(function(res, link, i) {
	            // don't intersection with itself
	            if (link !== thisModel) {

	                var linkLinesToTest = linkLines[i].slice();
	                var overlapIndex = linkLinesToTest.findIndex(function (line) { return overlapExists(thisLine, line); });

	                // Overlap occurs and the end point of one segment lies on thisLine
	                if (overlapIndex > -1 && thisLine.containsPoint(linkLinesToTest[overlapIndex].end)) {
	                    // Remove the next segment because there will never be a jump
	                    linkLinesToTest.splice(overlapIndex + 1, 1);
	                }
	                var lineIntersections = findLineIntersections(thisLine, linkLinesToTest);
	                res.push.apply(res, lineIntersections);
	            }
	            return res;
	        }, []).sort(function(a, b) {
	            return sortPoints(thisLine.start, a) - sortPoints(thisLine.start, b);
	        });

	        if (intersections.length > 0) {
	            // split the line based on found intersection points
	            resultLines.push.apply(resultLines, createJumps(thisLine, intersections, jumpSize));
	        } else {
	            // without any intersection the line goes uninterrupted
	            resultLines.push(thisLine);
	        }
	        return resultLines;
	    }, []);

	    var path = buildPath(jumpingLines, jumpSize, jumpType, radius);
	    return (raw) ? path : path.serialize();
	};

	var normal = function(sourcePoint, targetPoint, route, opt) {
	    if ( route === void 0 ) route = [];
	    if ( opt === void 0 ) opt = {};


	    var raw = opt.raw;
	    var localOpt = {
	        cornerType: 'point',
	        raw: raw
	    };

	    return straight(sourcePoint, targetPoint, route, localOpt);
	};

	var CORNER_RADIUS$1 = 10;
	var PRECISION$1 = 0;

	var rounded = function(sourcePoint, targetPoint, route, opt) {
	    if ( route === void 0 ) route = [];
	    if ( opt === void 0 ) opt = {};


	    var radius = opt.radius; if ( radius === void 0 ) radius = CORNER_RADIUS$1;
	    var raw = opt.raw;
	    var localOpt = {
	        cornerType: 'cubic',
	        cornerRadius: radius,
	        precision: PRECISION$1,
	        raw: raw
	    };

	    return straight(sourcePoint, targetPoint, route, localOpt);
	};

	var smooth = function(sourcePoint, targetPoint, route, opt) {

	    var raw = opt && opt.raw;
	    var path;

	    if (route && route.length !== 0) {

	        var points = [sourcePoint].concat(route).concat([targetPoint]);
	        var curves = Curve.throughPoints(points);

	        path = new Path(curves);

	    } else {
	        // if we have no route, use a default cubic bezier curve
	        // cubic bezier requires two control points
	        // the control points have `x` midway between source and target
	        // this produces an S-like curve

	        path = new Path();

	        var segment;

	        segment = Path.createSegment('M', sourcePoint);
	        path.appendSegment(segment);

	        if ((Math.abs(sourcePoint.x - targetPoint.x)) >= (Math.abs(sourcePoint.y - targetPoint.y))) {
	            var controlPointX = (sourcePoint.x + targetPoint.x) / 2;

	            segment = Path.createSegment('C', controlPointX, sourcePoint.y, controlPointX, targetPoint.y, targetPoint.x, targetPoint.y);
	            path.appendSegment(segment);

	        } else {
	            var controlPointY = (sourcePoint.y + targetPoint.y) / 2;

	            segment = Path.createSegment('C', sourcePoint.x, controlPointY, targetPoint.x, controlPointY, targetPoint.x, targetPoint.y);
	            path.appendSegment(segment);

	        }
	    }

	    return (raw) ? path : path.serialize();
	};

	var Directions = {
	    AUTO: 'auto',
	    HORIZONTAL: 'horizontal',
	    VERTICAL: 'vertical',
	    CLOSEST_POINT: 'closest-point',
	    OUTWARDS: 'outwards'
	};

	var TangentDirections = {
	    UP: 'up',
	    DOWN: 'down',
	    LEFT: 'left',
	    RIGHT: 'right',
	    AUTO: 'auto',
	    CLOSEST_POINT: 'closest-point',
	    OUTWARDS: 'outwards'
	};

	var curve = function(sourcePoint, targetPoint, route, opt, linkView) {
	    if ( route === void 0 ) route = [];
	    if ( opt === void 0 ) opt = {};

	    var raw = Boolean(opt.raw);
	    // distanceCoefficient - a coefficient of the tangent vector length relative to the distance between points.
	    // angleTangentCoefficient - a coefficient of the end tangents length in the case of angles larger than 45 degrees.
	    // tension - a Catmull-Rom curve tension parameter.
	    // sourceTangent - a tangent vector along the curve at the sourcePoint.
	    // sourceDirection - a unit direction vector along the curve at the sourcePoint.
	    // targetTangent - a tangent vector along the curve at the targetPoint.
	    // targetDirection - a unit direction vector along the curve at the targetPoint.
	    // precision - a rounding precision for path values.
	    var direction = opt.direction; if ( direction === void 0 ) direction = Directions.AUTO;
	    var precision = opt.precision; if ( precision === void 0 ) precision = 3;
	    var options = {
	        coeff: opt.distanceCoefficient || 0.6,
	        angleTangentCoefficient: opt.angleTangentCoefficient || 80,
	        tau: opt.tension || 0.5,
	        sourceTangent: opt.sourceTangent ? new Point(opt.sourceTangent) : null,
	        targetTangent: opt.targetTangent ? new Point(opt.targetTangent) : null,
	        rotate: Boolean(opt.rotate)
	    };
	    if (typeof opt.sourceDirection === 'string')
	        { options.sourceDirection = opt.sourceDirection; }
	    else if (typeof opt.sourceDirection === 'number')
	        { options.sourceDirection = new Point(1, 0).rotate(null, opt.sourceDirection); }
	    else
	        { options.sourceDirection = opt.sourceDirection ? new Point(opt.sourceDirection).normalize() : null; }

	    if (typeof opt.targetDirection === 'string')
	        { options.targetDirection = opt.targetDirection; }
	    else if (typeof opt.targetDirection === 'number')
	        { options.targetDirection = new Point(1, 0).rotate(null, opt.targetDirection); }
	    else
	        { options.targetDirection = opt.targetDirection ? new Point(opt.targetDirection).normalize() : null; }

	    var completeRoute = [sourcePoint ].concat( route, [targetPoint]).map(function (p) { return new Point(p); });

	    // The calculation of a sourceTangent
	    var sourceTangent;
	    if (options.sourceTangent) {
	        sourceTangent = options.sourceTangent;
	    } else {
	        var sourceDirection = getSourceTangentDirection(linkView, completeRoute, direction, options);
	        var tangentLength = completeRoute[0].distance(completeRoute[1]) * options.coeff;
	        var pointsVector = completeRoute[1].difference(completeRoute[0]).normalize();
	        var angle = angleBetweenVectors(sourceDirection, pointsVector);
	        if (angle > Math.PI / 4) {
	            var updatedLength = tangentLength + (angle - Math.PI / 4) * options.angleTangentCoefficient;
	            sourceTangent = sourceDirection.clone().scale(updatedLength, updatedLength);
	        } else {
	            sourceTangent = sourceDirection.clone().scale(tangentLength, tangentLength);
	        }
	    }

	    // The calculation of a targetTangent
	    var targetTangent;
	    if (options.targetTangent) {
	        targetTangent = options.targetTangent;
	    } else {
	        var targetDirection = getTargetTangentDirection(linkView, completeRoute, direction, options);
	        var last = completeRoute.length - 1;
	        var tangentLength$1 = completeRoute[last - 1].distance(completeRoute[last]) * options.coeff;
	        var pointsVector$1 = completeRoute[last - 1].difference(completeRoute[last]).normalize();
	        var angle$1 = angleBetweenVectors(targetDirection, pointsVector$1);
	        if (angle$1 > Math.PI / 4) {
	            var updatedLength$1 = tangentLength$1 + (angle$1 - Math.PI / 4) * options.angleTangentCoefficient;
	            targetTangent = targetDirection.clone().scale(updatedLength$1, updatedLength$1);
	        } else {
	            targetTangent = targetDirection.clone().scale(tangentLength$1, tangentLength$1);
	        }
	    }

	    var catmullRomCurves = createCatmullRomCurves(completeRoute, sourceTangent, targetTangent, options);
	    var bezierCurves = catmullRomCurves.map(function (curve) { return catmullRomToBezier(curve, options); });
	    var path = new Path(bezierCurves).round(precision);

	    return (raw) ? path : path.serialize();
	};
	curve.Directions = Directions;
	curve.TangentDirections = TangentDirections;

	function getHorizontalSourceDirection(linkView, route, options) {
	    var sourceBBox = linkView.sourceBBox;

	    var sourceSide;
	    var rotation;
	    if (!linkView.sourceView) {
	        if (sourceBBox.x > route[1].x)
	            { sourceSide = 'right'; }
	        else
	            { sourceSide = 'left'; }
	    } else {
	        rotation = linkView.sourceView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.sourceView.getNodeUnrotatedBBox(linkView.sourceView.el);
	            var sourcePoint = route[0].clone();
	            sourcePoint.rotate(sourceBBox.center(), rotation);
	            sourceSide = unrotatedBBox.sideNearestToPoint(sourcePoint);
	        } else {
	            sourceSide = sourceBBox.sideNearestToPoint(route[0]);
	        }
	    }

	    var direction;
	    switch (sourceSide) {
	        case 'left':
	            direction = new Point(-1, 0);
	            break;
	        case 'right':
	        default:
	            direction = new Point(1, 0);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getHorizontalTargetDirection(linkView, route, options) {
	    var targetBBox = linkView.targetBBox;

	    var targetSide;
	    var rotation;
	    if (!linkView.targetView) {
	        if (targetBBox.x > route[route.length - 2].x)
	            { targetSide = 'left'; }
	        else
	            { targetSide = 'right'; }
	    } else {
	        rotation = linkView.targetView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.targetView.getNodeUnrotatedBBox(linkView.targetView.el);
	            var targetPoint = route[route.length - 1].clone();
	            targetPoint.rotate(targetBBox.center(), rotation);
	            targetSide = unrotatedBBox.sideNearestToPoint(targetPoint);
	        } else {
	            targetSide = targetBBox.sideNearestToPoint(route[route.length - 1]);
	        }
	    }

	    var direction;
	    switch (targetSide) {
	        case 'left':
	            direction = new Point(-1, 0);
	            break;
	        case 'right':
	        default:
	            direction = new Point(1, 0);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getVerticalSourceDirection(linkView, route, options) {
	    var sourceBBox = linkView.sourceBBox;

	    var sourceSide;
	    var rotation;
	    if (!linkView.sourceView) {
	        if (sourceBBox.y > route[1].y)
	            { sourceSide = 'bottom'; }
	        else
	            { sourceSide = 'top'; }
	    } else {
	        rotation = linkView.sourceView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.sourceView.getNodeUnrotatedBBox(linkView.sourceView.el);
	            var sourcePoint = route[0].clone();
	            sourcePoint.rotate(sourceBBox.center(), rotation);
	            sourceSide = unrotatedBBox.sideNearestToPoint(sourcePoint);
	        } else {
	            sourceSide = sourceBBox.sideNearestToPoint(route[0]);
	        }
	    }

	    var direction;
	    switch (sourceSide) {
	        case 'top':
	            direction = new Point(0, -1);
	            break;
	        case 'bottom':
	        default:
	            direction = new Point(0, 1);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getVerticalTargetDirection(linkView, route, options) {
	    var targetBBox = linkView.targetBBox;

	    var targetSide;
	    var rotation;
	    if (!linkView.targetView) {
	        if (targetBBox.y > route[route.length - 2].y)
	            { targetSide = 'top'; }
	        else
	            { targetSide = 'bottom'; }
	    } else {
	        rotation = linkView.targetView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.targetView.getNodeUnrotatedBBox(linkView.targetView.el);
	            var targetPoint = route[route.length - 1].clone();
	            targetPoint.rotate(targetBBox.center(), rotation);
	            targetSide = unrotatedBBox.sideNearestToPoint(targetPoint);
	        } else {
	            targetSide = targetBBox.sideNearestToPoint(route[route.length - 1]);
	        }
	    }


	    var direction;
	    switch (targetSide) {
	        case 'top':
	            direction = new Point(0, -1);
	            break;
	        case 'bottom':
	        default:
	            direction = new Point(0, 1);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getAutoSourceDirection(linkView, route, options) {
	    var sourceBBox = linkView.sourceBBox;

	    var sourceSide;
	    var rotation;
	    if (!linkView.sourceView) {
	        sourceSide = sourceBBox.sideNearestToPoint(route[1]);
	    } else {
	        rotation = linkView.sourceView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.sourceView.getNodeUnrotatedBBox(linkView.sourceView.el);
	            var sourcePoint = route[0].clone();
	            sourcePoint.rotate(sourceBBox.center(), rotation);
	            sourceSide = unrotatedBBox.sideNearestToPoint(sourcePoint);
	        } else {
	            sourceSide = sourceBBox.sideNearestToPoint(route[0]);
	        }
	    }

	    var direction;
	    switch (sourceSide) {
	        case 'top':
	            direction = new Point(0, -1);
	            break;
	        case 'bottom':
	            direction = new Point(0, 1);
	            break;
	        case 'right':
	            direction = new Point(1, 0);
	            break;
	        case 'left':
	            direction = new Point(-1, 0);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getAutoTargetDirection(linkView, route, options) {
	    var targetBBox = linkView.targetBBox;

	    var targetSide;
	    var rotation;
	    if (!linkView.targetView) {
	        targetSide = targetBBox.sideNearestToPoint(route[route.length - 2]);
	    } else {
	        rotation = linkView.targetView.model.angle();
	        if (options.rotate && rotation) {
	            var unrotatedBBox = linkView.targetView.getNodeUnrotatedBBox(linkView.targetView.el);
	            var targetPoint = route[route.length - 1].clone();
	            targetPoint.rotate(targetBBox.center(), rotation);
	            targetSide = unrotatedBBox.sideNearestToPoint(targetPoint);
	        } else {
	            targetSide = targetBBox.sideNearestToPoint(route[route.length - 1]);
	        }
	    }

	    var direction;
	    switch (targetSide) {
	        case 'top':
	            direction = new Point(0, -1);
	            break;
	        case 'bottom':
	            direction = new Point(0, 1);
	            break;
	        case 'right':
	            direction = new Point(1, 0);
	            break;
	        case 'left':
	            direction = new Point(-1, 0);
	            break;
	    }

	    if (options.rotate && rotation) {
	        direction.rotate(null, -rotation);
	    }

	    return direction;
	}

	function getClosestPointSourceDirection(linkView, route, options) {
	    return route[1].difference(route[0]).normalize();
	}

	function getClosestPointTargetDirection(linkView, route, options) {
	    var last = route.length - 1;
	    return route[last - 1].difference(route[last]).normalize();
	}

	function getOutwardsSourceDirection(linkView, route, options) {
	    var sourceBBox = linkView.sourceBBox;
	    var sourceCenter = sourceBBox.center();
	    return route[0].difference(sourceCenter).normalize();
	}

	function getOutwardsTargetDirection(linkView, route, options) {
	    var targetBBox = linkView.targetBBox;
	    var targetCenter = targetBBox.center();
	    return route[route.length - 1].difference(targetCenter).normalize();
	}

	function getSourceTangentDirection(linkView, route, direction, options) {
	    if (options.sourceDirection) {
	        switch (options.sourceDirection) {
	            case TangentDirections.UP:
	                return new Point(0, -1);
	            case TangentDirections.DOWN:
	                return new Point(0, 1);
	            case TangentDirections.LEFT:
	                return new Point(-1, 0);
	            case TangentDirections.RIGHT:
	                return new Point(1, 0);
	            case TangentDirections.AUTO:
	                return getAutoSourceDirection(linkView, route, options);
	            case TangentDirections.CLOSEST_POINT:
	                return getClosestPointSourceDirection(linkView, route, options);
	            case TangentDirections.OUTWARDS:
	                return getOutwardsSourceDirection(linkView, route, options);
	            default:
	                return options.sourceDirection;
	        }
	    }

	    switch (direction) {
	        case Directions.HORIZONTAL:
	            return getHorizontalSourceDirection(linkView, route, options);
	        case Directions.VERTICAL:
	            return getVerticalSourceDirection(linkView, route, options);
	        case Directions.CLOSEST_POINT:
	            return getClosestPointSourceDirection(linkView, route, options);
	        case Directions.OUTWARDS:
	            return getOutwardsSourceDirection(linkView, route, options);
	        case Directions.AUTO:
	        default:
	            return getAutoSourceDirection(linkView, route, options);
	    }
	}

	function getTargetTangentDirection(linkView, route, direction, options) {
	    if (options.targetDirection) {
	        switch (options.targetDirection) {
	            case TangentDirections.UP:
	                return new Point(0, -1);
	            case TangentDirections.DOWN:
	                return new Point(0, 1);
	            case TangentDirections.LEFT:
	                return new Point(-1, 0);
	            case TangentDirections.RIGHT:
	                return new Point(1, 0);
	            case TangentDirections.AUTO:
	                return getAutoTargetDirection(linkView, route, options);
	            case TangentDirections.CLOSEST_POINT:
	                return getClosestPointTargetDirection(linkView, route, options);
	            case TangentDirections.OUTWARDS:
	                return getOutwardsTargetDirection(linkView, route, options);
	            default:
	                return options.targetDirection;
	        }
	    }

	    switch (direction) {
	        case Directions.HORIZONTAL:
	            return getHorizontalTargetDirection(linkView, route, options);
	        case Directions.VERTICAL:
	            return getVerticalTargetDirection(linkView, route, options);
	        case Directions.CLOSEST_POINT:
	            return getClosestPointTargetDirection(linkView, route, options);
	        case Directions.OUTWARDS:
	            return getOutwardsTargetDirection(linkView, route, options);
	        case Directions.AUTO:
	        default:
	            return getAutoTargetDirection(linkView, route, options);
	    }
	}

	function rotateVector(vector, angle) {
	    var cos = Math.cos(angle);
	    var sin = Math.sin(angle);
	    var x = cos * vector.x - sin * vector.y;
	    var y = sin * vector.x + cos * vector.y;
	    vector.x = x;
	    vector.y = y;
	}

	function angleBetweenVectors(v1, v2) {
	    var cos = v1.dot(v2) / (v1.magnitude() * v2.magnitude());
	    if (cos < -1) { cos = -1; }
	    if (cos > 1) { cos = 1; }
	    return Math.acos(cos);
	}

	function determinant(v1, v2) {
	    return v1.x * v2.y - v1.y * v2.x;
	}

	function createCatmullRomCurves(points, sourceTangent, targetTangent, options) {
	    var tau = options.tau;
	    var coeff = options.coeff;
	    var distances = [];
	    var tangents = [];
	    var catmullRomCurves = [];
	    var n = points.length - 1;

	    for (var i = 0; i < n; i++) {
	        distances[i] = points[i].distance(points[i + 1]);
	    }

	    tangents[0] = sourceTangent;
	    tangents[n] = targetTangent;

	    // The calculation of tangents of vertices
	    for (var i$1 = 1; i$1 < n; i$1++) {
	        var tpPrev = (void 0);
	        var tpNext = (void 0);
	        if (i$1 === 1) {
	            tpPrev = points[i$1 - 1].clone().offset(tangents[i$1 - 1].x, tangents[i$1 - 1].y);
	        } else {
	            tpPrev = points[i$1 - 1].clone();
	        }
	        if (i$1 === n - 1) {
	            tpNext = points[i$1 + 1].clone().offset(tangents[i$1 + 1].x, tangents[i$1 + 1].y);
	        } else {
	            tpNext = points[i$1 + 1].clone();
	        }
	        var v1 = tpPrev.difference(points[i$1]).normalize();
	        var v2 = tpNext.difference(points[i$1]).normalize();
	        var vAngle = angleBetweenVectors(v1, v2);

	        var rot = (Math.PI - vAngle) / 2;
	        var t = (void 0);
	        var vectorDeterminant = determinant(v1, v2);
	        var pointsDeterminant = (void 0);
	        pointsDeterminant = determinant(points[i$1].difference(points[i$1 + 1]), points[i$1].difference(points[i$1 - 1]));
	        if (vectorDeterminant < 0) {
	            rot = -rot;
	        }
	        if ((vAngle < Math.PI / 2) && ((rot < 0 && pointsDeterminant < 0) || (rot > 0 && pointsDeterminant > 0))) {
	            rot = rot - Math.PI;
	        }
	        t = v2.clone();
	        rotateVector(t, rot);

	        var t1 = t.clone();
	        var t2 = t.clone();
	        var scaleFactor1 = distances[i$1 - 1] * coeff;
	        var scaleFactor2 = distances[i$1] * coeff;
	        t1.scale(scaleFactor1, scaleFactor1);
	        t2.scale(scaleFactor2, scaleFactor2);

	        tangents[i$1] = [t1, t2];
	    }

	    // The building of a Catmull-Rom curve based of tangents of points
	    for (var i$2 = 0; i$2 < n; i$2++) {
	        var p0 = (void 0);
	        var p3 = (void 0);
	        if (i$2 === 0) {
	            p0 = points[i$2 + 1].difference(tangents[i$2].x / tau, tangents[i$2].y / tau);
	        } else {
	            p0 = points[i$2 + 1].difference(tangents[i$2][1].x / tau, tangents[i$2][1].y / tau);
	        }
	        if (i$2 === n - 1) {
	            p3 = points[i$2].clone().offset(tangents[i$2 + 1].x / tau, tangents[i$2 + 1].y / tau);
	        } else {
	            p3 = points[i$2].difference(tangents[i$2 + 1][0].x / tau, tangents[i$2 + 1][0].y / tau);
	        }

	        catmullRomCurves[i$2] = [p0, points[i$2], points[i$2 + 1], p3];
	    }
	    return catmullRomCurves;
	}

	// The function to convert Catmull-Rom curve to Bezier curve using the tension (tau)
	function catmullRomToBezier(points, options) {
	    var tau = options.tau;

	    var bcp1 = new Point();
	    bcp1.x = points[1].x + (points[2].x - points[0].x) / (6 * tau);
	    bcp1.y = points[1].y + (points[2].y - points[0].y) / (6 * tau);

	    var bcp2 = new Point();
	    bcp2.x = points[2].x + (points[3].x - points[1].x) / (6 * tau);
	    bcp2.y = points[2].y + (points[3].y - points[1].y) / (6 * tau);
	    return new Curve(
	        points[1],
	        bcp1,
	        bcp2,
	        points[2]
	    );
	}



	var connectors = ({
		straight: straight,
		jumpover: jumpover,
		normal: normal,
		rounded: rounded,
		smooth: smooth,
		curve: curve
	});

	// ViewBase
	// -------------

	// ViewBases are almost more convention than they are actual code. A View
	// is simply a JavaScript object that represents a logical chunk of UI in the
	// DOM. This might be a single item, an entire list, a sidebar or panel, or
	// even the surrounding frame which wraps your whole app. Defining a chunk of
	// UI as a **View** allows you to define your DOM events declaratively, without
	// having to worry about render order ... and makes it easy for the view to
	// react to specific changes in the state of your models.

	// Creating a ViewBase creates its initial element outside of the DOM,
	// if an existing element is not provided...
	var ViewBase = function(options) {
	    this.cid = uniqueId('view');
	    this.preinitialize.apply(this, arguments);
	    assign(this, pick(options, viewOptions));
	    this._ensureElement();
	    this.initialize.apply(this, arguments);
	};

	// Cached regex to split keys for `delegate`.
	var delegateEventSplitter = /^(\S+)\s*(.*)$/;

	// List of view options to be set as properties.
	var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName', 'events'];

	// Set up all inheritable **ViewBase** properties and methods.
	assign(ViewBase.prototype, Events, {

	    // The default `tagName` of a View's element is `"div"`.
	    tagName: 'div',

	    // mvc.$ delegate for element lookup, scoped to DOM elements within the
	    // current view. This should be preferred to global lookups where possible.
	    $: function(selector) {
	        return this.$el.find(selector);
	    },

	    // preinitialize is an empty function by default. You can override it with a function
	    // or object.  preinitialize will run before any instantiation logic is run in the View
	    preinitialize: function(){},

	    // Initialize is an empty function by default. Override it with your own
	    // initialization logic.
	    initialize: function(){},

	    // **render** is the core function that your view should override, in order
	    // to populate its element (`this.el`), with the appropriate HTML. The
	    // convention is for **render** to always return `this`.
	    render: function() {
	        return this;
	    },

	    // Remove this view by taking the element out of the DOM, and removing any
	    // applicable Events listeners.
	    remove: function() {
	        this._removeElement();
	        this.stopListening();
	        return this;
	    },

	    // Remove this view's element from the document and all event listeners
	    // attached to it. Exposed for subclasses using an alternative DOM
	    // manipulation API.
	    _removeElement: function() {
	        this.$el.remove();
	    },

	    // Change the view's element (`this.el` property) and re-delegate the
	    // view's events on the new element.
	    setElement: function(element) {
	        this.undelegateEvents();
	        this._setElement(element);
	        this.delegateEvents();
	        return this;
	    },

	    // Creates the `this.el` and `this.$el` references for this view using the
	    // given `el`. `el` can be a CSS selector or an HTML string, a mvc.$
	    // context or an element. Subclasses can override this to utilize an
	    // alternative DOM manipulation API and are only required to set the
	    // `this.el` property.
	    _setElement: function(el) {
	        this.$el = el instanceof $ ? el : $(el);
	        this.el = this.$el[0];
	    },

	    // Set callbacks, where `this.events` is a hash of
	    //
	    // *{"event selector": "callback"}*
	    //
	    //     {
	    //       'mousedown .title':  'edit',
	    //       'click .button':     'save',
	    //       'click .open':       function(e) { ... }
	    //     }
	    //
	    // pairs. Callbacks will be bound to the view, with `this` set properly.
	    // Uses event delegation for efficiency.
	    // Omitting the selector binds the event to `this.el`.
	    delegateEvents: function(events) {
	        events || (events = result(this, 'events'));
	        if (!events) { return this; }
	        this.undelegateEvents();
	        for (var key in events) {
	            var method = events[key];
	            if (!isFunction(method)) { method = this[method]; }
	            if (!method) { continue; }
	            var match = key.match(delegateEventSplitter);
	            this.delegate(match[1], match[2], method.bind(this));
	        }
	        return this;
	    },

	    // Add a single event listener to the view's element (or a child element
	    // using `selector`). This only works for delegate-able events: not `focus`,
	    // `blur`, and not `change`, `submit`, and `reset` in Internet Explorer.
	    delegate: function(eventName, selector, listener) {
	        this.$el.on(eventName + '.delegateEvents' + this.cid, selector, listener);
	        return this;
	    },

	    // Clears all callbacks previously bound to the view by `delegateEvents`.
	    // You usually don't need to use this, but may wish to if you have multiple
	    // viewbases attached to the same DOM element.
	    undelegateEvents: function() {
	        if (this.$el) { this.$el.off('.delegateEvents' + this.cid); }
	        return this;
	    },

	    // A finer-grained `undelegateEvents` for removing a single delegated event.
	    // `selector` and `listener` are both optional.
	    undelegate: function(eventName, selector, listener) {
	        this.$el.off(eventName + '.delegateEvents' + this.cid, selector, listener);
	        return this;
	    },

	    // Produces a DOM element to be assigned to your view. Exposed for
	    // subclasses using an alternative DOM manipulation API.
	    _createElement: function(tagName) {
	        return document.createElement(tagName);
	    },

	    // Ensure that the View has a DOM element to render into.
	    // If `this.el` is a string, pass it through `$()`, take the first
	    // matching element, and re-assign it to `el`. Otherwise, create
	    // an element from the `id`, `className` and `tagName` properties.
	    _ensureElement: function() {
	        if (!this.el) {
	            var attrs = assign({}, result(this, 'attributes'));
	            if (this.id) { attrs.id = result(this, 'id'); }
	            if (this.className) { attrs['class'] = result(this, 'className'); }
	            this.setElement(this._createElement(result(this, 'tagName')));
	            this._setAttributes(attrs);
	        } else {
	            this.setElement(result(this, 'el'));
	        }
	    },

	    // Set attributes from a hash on this view's element.  Exposed for
	    // subclasses using an alternative DOM manipulation API.
	    _setAttributes: function(attributes) {
	        this.$el.attr(attributes);
	    }

	});

	// Set up inheritance for the view.
	ViewBase.extend = extend$1;

	var views = {};

	var View = ViewBase.extend({

	    options: {},
	    theme: null,
	    themeClassNamePrefix: addClassNamePrefix('theme-'),
	    requireSetThemeOverride: false,
	    defaultTheme: config.defaultTheme,
	    children: null,
	    childNodes: null,

	    DETACHABLE: true,
	    UPDATE_PRIORITY: 2,
	    FLAG_INSERT: 1<<30,
	    FLAG_REMOVE: 1<<29,
	    FLAG_INIT: 1<<28,

	    constructor: function(options) {

	        this.requireSetThemeOverride = options && !!options.theme;
	        this.options = assign({}, this.options, options);

	        ViewBase.call(this, options);
	    },

	    initialize: function() {

	        views[this.cid] = this;

	        this.setTheme(this.options.theme || this.defaultTheme);
	        this.init();
	    },

	    unmount: function() {
	        if (this.svgElement) {
	            this.vel.remove();
	        } else {
	            this.$el.remove();
	        }
	    },

	    isMounted: function() {
	        return this.el.parentNode !== null;
	    },

	    renderChildren: function(children) {
	        children || (children = result(this, 'children'));
	        if (children) {
	            var isSVG = this.svgElement;
	            var namespace = V.namespace[isSVG ? 'svg' : 'xhtml'];
	            var doc = parseDOMJSON(children, namespace);
	            (isSVG ? this.vel : this.$el).empty().append(doc.fragment);
	            this.childNodes = doc.selectors;
	        }
	        return this;
	    },

	    findAttribute: function(attributeName, node) {

	        var currentNode = node;

	        while (currentNode && currentNode.nodeType === 1) {
	            var attributeValue = currentNode.getAttribute(attributeName);
	            // attribute found
	            if (attributeValue) { return attributeValue; }
	            // do not climb up the DOM
	            if (currentNode === this.el) { return null; }
	            // try parent node
	            currentNode = currentNode.parentNode;
	        }

	        return null;
	    },

	    // Override the mvc ViewBase `_ensureElement()` method in order to create an
	    // svg element (e.g., `<g>`) node that wraps all the nodes of the Cell view.
	    // Expose class name setter as a separate method.
	    _ensureElement: function() {
	        if (!this.el) {
	            var tagName = result(this, 'tagName');
	            var attrs = assign({}, result(this, 'attributes'));
	            var style = assign({}, result(this, 'style'));
	            if (this.id) { attrs.id = result(this, 'id'); }
	            this.setElement(this._createElement(tagName));
	            this._setAttributes(attrs);
	            this._setStyle(style);
	        } else {
	            this.setElement(result(this, 'el'));
	        }
	        this._ensureElClassName();
	    },

	    _setAttributes: function(attrs) {
	        if (this.svgElement) {
	            this.vel.attr(attrs);
	        } else {
	            this.$el.attr(attrs);
	        }
	    },

	    _setStyle: function(style) {
	        this.$el.css(style);
	    },

	    _createElement: function(tagName) {
	        if (this.svgElement) {
	            return document.createElementNS(V.namespace.svg, tagName);
	        } else {
	            return document.createElement(tagName);
	        }
	    },

	    // Utilize an alternative DOM manipulation API by
	    // adding an element reference wrapped in Vectorizer.
	    _setElement: function(el) {
	        this.$el = el instanceof $ ? el : $(el);
	        this.el = this.$el[0];
	        if (this.svgElement) { this.vel = V(this.el); }
	    },

	    _ensureElClassName: function() {
	        var className = result(this, 'className');
	        if (!className) { return; }
	        var prefixedClassName = addClassNamePrefix(className);
	        // Note: className removal here kept for backwards compatibility only
	        if (this.svgElement) {
	            this.vel.removeClass(className).addClass(prefixedClassName);
	        } else {
	            this.$el.removeClass(className).addClass(prefixedClassName);
	        }
	    },

	    init: function() {
	        // Intentionally empty.
	        // This method is meant to be overridden.
	    },

	    onRender: function() {
	        // Intentionally empty.
	        // This method is meant to be overridden.
	    },

	    confirmUpdate: function() {
	        // Intentionally empty.
	        // This method is meant to be overridden.
	        return 0;
	    },

	    setTheme: function(theme, opt) {

	        opt = opt || {};

	        // Theme is already set, override is required, and override has not been set.
	        // Don't set the theme.
	        if (this.theme && this.requireSetThemeOverride && !opt.override) {
	            return this;
	        }

	        this.removeThemeClassName();
	        this.addThemeClassName(theme);
	        this.onSetTheme(this.theme/* oldTheme */, theme/* newTheme */);
	        this.theme = theme;

	        return this;
	    },

	    addThemeClassName: function(theme) {

	        theme = theme || this.theme;
	        if (!theme) { return this; }

	        var className = this.themeClassNamePrefix + theme;

	        if (this.svgElement) {
	            this.vel.addClass(className);
	        } else {
	            this.$el.addClass(className);
	        }

	        return this;
	    },

	    removeThemeClassName: function(theme) {

	        theme = theme || this.theme;

	        var className = this.themeClassNamePrefix + theme;

	        if (this.svgElement) {
	            this.vel.removeClass(className);
	        } else {
	            this.$el.removeClass(className);
	        }

	        return this;
	    },

	    onSetTheme: function(oldTheme, newTheme) {
	        // Intentionally empty.
	        // This method is meant to be overridden.
	    },

	    remove: function() {

	        this.onRemove();
	        this.undelegateDocumentEvents();

	        views[this.cid] = null;

	        ViewBase.prototype.remove.apply(this, arguments);

	        return this;
	    },

	    onRemove: function() {
	        // Intentionally empty.
	        // This method is meant to be overridden.
	    },

	    getEventNamespace: function() {
	        // Returns a per-session unique namespace
	        return '.joint-event-ns-' + this.cid;
	    },

	    delegateElementEvents: function(element, events, data) {
	        if (!events) { return this; }
	        data || (data = {});
	        var eventNS = this.getEventNamespace();
	        for (var eventName in events) {
	            var method = events[eventName];
	            if (typeof method !== 'function') { method = this[method]; }
	            if (!method) { continue; }
	            $(element).on(eventName + eventNS, data, method.bind(this));
	        }
	        return this;
	    },

	    undelegateElementEvents: function(element) {
	        $(element).off(this.getEventNamespace());
	        return this;
	    },

	    delegateDocumentEvents: function(events, data) {
	        events || (events = result(this, 'documentEvents'));
	        return this.delegateElementEvents(document, events, data);
	    },

	    undelegateDocumentEvents: function() {
	        return this.undelegateElementEvents(document);
	    },

	    eventData: function(evt, data) {
	        if (!evt) { throw new Error('eventData(): event object required.'); }
	        var currentData = evt.data;
	        var key = '__' + this.cid + '__';
	        if (data === undefined) {
	            if (!currentData) { return {}; }
	            return currentData[key] || {};
	        }
	        currentData || (currentData = evt.data = {});
	        currentData[key] || (currentData[key] = {});
	        assign(currentData[key], data);
	        return this;
	    },

	    stopPropagation: function(evt) {
	        this.eventData(evt, { propagationStopped: true });
	        return this;
	    },

	    isPropagationStopped: function(evt) {
	        return !!this.eventData(evt).propagationStopped;
	    }

	}, {

	    extend: function() {

	        var args = Array.from(arguments);

	        // Deep clone the prototype and static properties objects.
	        // This prevents unexpected behavior where some properties are overwritten outside of this function.
	        var protoProps = args[0] && assign({}, args[0]) || {};
	        var staticProps = args[1] && assign({}, args[1]) || {};

	        // Need the real render method so that we can wrap it and call it later.
	        var renderFn = protoProps.render || (this.prototype && this.prototype.render) || null;

	        /*
	            Wrap the real render method so that:
	                .. `onRender` is always called.
	                .. `this` is always returned.
	        */
	        protoProps.render = function() {

	            if (typeof renderFn === 'function') {
	                // Call the original render method.
	                renderFn.apply(this, arguments);
	            }

	            if (this.render.__render__ === renderFn) {
	                // Should always call onRender() method.
	                // Should call it only once when renderFn is actual prototype method i.e. not the wrapper
	                this.onRender();
	            }

	            // Should always return itself.
	            return this;
	        };

	        protoProps.render.__render__ = renderFn;

	        return ViewBase.extend.call(this, protoProps, staticProps);
	    }
	});

	var Listener = function Listener() {
	    var callbackArguments = [], len = arguments.length;
	    while ( len-- ) callbackArguments[ len ] = arguments[ len ];

	    this.callbackArguments = callbackArguments;
	};

	Listener.prototype.listenTo = function listenTo (object, evt) {
	        var this$1 = this;
	        var args = [], len = arguments.length - 2;
	        while ( len-- > 0 ) args[ len ] = arguments[ len + 2 ];

	    var ref = this;
	        var callbackArguments = ref.callbackArguments;
	    // signature 1 - (object, eventHashMap, context)
	    if (V.isObject(evt)) {
	        var context = args[0]; if ( context === void 0 ) context = null;
	        Object.entries(evt).forEach(function (ref) {
	                var eventName = ref[0];
	                var cb = ref[1];

	            if (typeof cb !== 'function') { return; }
	            // Invoke the callback with callbackArguments passed first
	            if (context || callbackArguments.length > 0) { cb = cb.bind.apply(cb, [ context ].concat( callbackArguments )); }
	            Events.listenTo.call(this$1, object, eventName, cb);
	        });
	    }
	    // signature 2 - (object, event, callback, context)
	    else if (typeof evt === 'string' && typeof args[0] === 'function') {
	        var cb = args[0];
	            var context$1 = args[1]; if ( context$1 === void 0 ) context$1 = null;
	        // Invoke the callback with callbackArguments passed first
	        if (context$1 || callbackArguments.length > 0) { cb = cb.bind.apply(cb, [ context$1 ].concat( callbackArguments )); }
	        Events.listenTo.call(this, object, evt, cb);
	    }
	};

	Listener.prototype.stopListening = function stopListening () {
	    Events.stopListening.call(this);
	};

	// Collection
	// -------------------

	// If models tend to represent a single row of data, a Collection is
	// more analogous to a table full of data ... or a small slice or page of that
	// table, or a collection of rows that belong together for a particular reason
	// -- all of the messages in this particular folder, all of the documents
	// belonging to this particular author, and so on. Collections maintain
	// indexes of their models, both in order, and for lookup by `id`.

	// Create a new **Collection**, perhaps to contain a specific type of `model`.
	// If a `comparator` is specified, the Collection will maintain
	// its models in sort order, as they're added and removed.
	var Collection = function(models, options) {
	    options || (options = {});
	    this.preinitialize.apply(this, arguments);
	    if (options.model) { this.model = options.model; }
	    if (options.comparator !== void 0) { this.comparator = options.comparator; }
	    this._reset();
	    this.initialize.apply(this, arguments);
	    if (models) { this.reset(models, assign({ silent: true }, options)); }
	};

	// Default options for `Collection#set`.
	var setOptions = { add: true, remove: true, merge: true };
	var addOptions = { add: true, remove: false };

	// Splices `insert` into `array` at index `at`.
	var splice = function(array, insert, at) {
	    at = Math.min(Math.max(at, 0), array.length);
	    var tail = Array(array.length - at);
	    var length = insert.length;
	    var i;
	    for (i = 0; i < tail.length; i++) { tail[i] = array[i + at]; }
	    for (i = 0; i < length; i++) { array[i + at] = insert[i]; }
	    for (i = 0; i < tail.length; i++) { array[i + length + at] = tail[i]; }
	};

	// Define the Collection's inheritable methods.
	assign(Collection.prototype, Events, {

	    // The default model for a collection is just a **Model**.
	    // This should be overridden in most cases.
	    model: Model,


	    // preinitialize is an empty function by default. You can override it with a function
	    // or object.  preinitialize will run before any instantiation logic is run in the Collection.
	    preinitialize: function(){},

	    // Initialize is an empty function by default. Override it with your own
	    // initialization logic.
	    initialize: function(){},

	    // The JSON representation of a Collection is an array of the
	    // models' attributes.
	    toJSON: function(options) {
	        return this.map(function(model) { return model.toJSON(options); });
	    },

	    // Add a model, or list of models to the set. `models` may be
	    // Models or raw JavaScript objects to be converted to Models, or any
	    // combination of the two.
	    add: function(models, options) {
	        return this.set(models, assign({ merge: false }, options, addOptions));
	    },

	    // Remove a model, or a list of models from the set.
	    remove: function(models, options) {
	        options = assign({}, options);
	        var singular = !Array.isArray(models);
	        models = singular ? [models] : models.slice();
	        var removed = this._removeModels(models, options);
	        if (!options.silent && removed.length) {
	            options.changes = { added: [], merged: [], removed: removed };
	            this.trigger('update', this, options);
	        }
	        return singular ? removed[0] : removed;
	    },

	    // Update a collection by `set`-ing a new list of models, adding new ones,
	    // removing models that are no longer present, and merging models that
	    // already exist in the collection, as necessary. Similar to **Model#set**,
	    // the core operation for updating the data contained by the collection.
	    set: function(models, options) {
	        if (models == null) { return; }

	        options = assign({}, setOptions, options);

	        var singular = !Array.isArray(models);
	        models = singular ? [models] : models.slice();

	        var at = options.at;
	        if (at != null) { at = +at; }
	        if (at > this.length) { at = this.length; }
	        if (at < 0) { at += this.length + 1; }

	        var set = [];
	        var toAdd = [];
	        var toMerge = [];
	        var toRemove = [];
	        var modelMap = {};

	        var add = options.add;
	        var merge = options.merge;
	        var remove = options.remove;

	        var sort = false;
	        var sortable = this.comparator && at == null && options.sort !== false;
	        var sortAttr = isString(this.comparator) ? this.comparator : null;

	        // Turn bare objects into model references, and prevent invalid models
	        // from being added.
	        var model, i;
	        for (i = 0; i < models.length; i++) {
	            model = models[i];

	            // If a duplicate is found, prevent it from being added and
	            // optionally merge it into the existing model.
	            var existing = this.get(model);
	            if (existing) {
	                if (merge && model !== existing) {
	                    var attrs = this._isModel(model) ? model.attributes : model;
	                    existing.set(attrs, options);
	                    toMerge.push(existing);
	                    if (sortable && !sort) { sort = existing.hasChanged(sortAttr); }
	                }
	                if (!modelMap[existing.cid]) {
	                    modelMap[existing.cid] = true;
	                    set.push(existing);
	                }
	                models[i] = existing;

	                // If this is a new, valid model, push it to the `toAdd` list.
	            } else if (add) {
	                model = models[i] = this._prepareModel(model, options);
	                if (model) {
	                    toAdd.push(model);
	                    this._addReference(model, options);
	                    modelMap[model.cid] = true;
	                    set.push(model);
	                }
	            }
	        }

	        // Remove stale models.
	        if (remove) {
	            for (i = 0; i < this.length; i++) {
	                model = this.models[i];
	                if (!modelMap[model.cid]) { toRemove.push(model); }
	            }
	            if (toRemove.length) { this._removeModels(toRemove, options); }
	        }

	        // See if sorting is needed, update `length` and splice in new models.
	        var orderChanged = false;
	        var replace = !sortable && add && remove;
	        if (set.length && replace) {
	            orderChanged = this.length !== set.length || this.models.some(function(m, index) {
	                return m !== set[index];
	            });
	            this.models.length = 0;
	            splice(this.models, set, 0);
	            this.length = this.models.length;
	        } else if (toAdd.length) {
	            if (sortable) { sort = true; }
	            splice(this.models, toAdd, at == null ? this.length : at);
	            this.length = this.models.length;
	        }

	        // Silently sort the collection if appropriate.
	        if (sort) { this.sort({ silent: true }); }

	        // Unless silenced, it's time to fire all appropriate add/sort/update events.
	        if (!options.silent) {
	            for (i = 0; i < toAdd.length; i++) {
	                if (at != null) { options.index = at + i; }
	                model = toAdd[i];
	                model.trigger('add', model, this, options);
	            }
	            if (sort || orderChanged) { this.trigger('sort', this, options); }
	            if (toAdd.length || toRemove.length || toMerge.length) {
	                options.changes = {
	                    added: toAdd,
	                    removed: toRemove,
	                    merged: toMerge
	                };
	                this.trigger('update', this, options);
	            }
	        }

	        // Return the added (or merged) model (or models).
	        return singular ? models[0] : models;
	    },

	    // When you have more items than you want to add or remove individually,
	    // you can reset the entire set with a new list of models, without firing
	    // any granular `add` or `remove` events. Fires `reset` when finished.
	    // Useful for bulk operations and optimizations.
	    reset: function(models, options) {
	        options = options ? clone(options) : {};
	        for (var i = 0; i < this.models.length; i++) {
	            this._removeReference(this.models[i], options);
	        }
	        options.previousModels = this.models;
	        this._reset();
	        models = this.add(models, assign({ silent: true }, options));
	        if (!options.silent) { this.trigger('reset', this, options); }
	        return models;
	    },

	    // Add a model to the end of the collection.
	    push: function(model, options) {
	        return this.add(model, assign({ at: this.length }, options));
	    },

	    // Remove a model from the end of the collection.
	    pop: function(options) {
	        var model = this.at(this.length - 1);
	        return this.remove(model, options);
	    },

	    // Add a model to the beginning of the collection.
	    unshift: function(model, options) {
	        return this.add(model, assign({ at: 0 }, options));
	    },

	    // Remove a model from the beginning of the collection.
	    shift: function(options) {
	        var model = this.at(0);
	        return this.remove(model, options);
	    },

	    // Slice out a sub-array of models from the collection.
	    slice: function() {
	        return Array.prototype.slice.apply(this.models, arguments);
	    },

	    // Get a model from the set by id, cid, model object with id or cid
	    // properties, or an attributes object that is transformed through modelId.
	    get: function(obj) {
	        if (obj == null) { return void 0; }
	        return this._byId[obj] ||
	        this._byId[this.modelId(this._isModel(obj) ? obj.attributes : obj, obj.idAttribute)] ||
	        obj.cid && this._byId[obj.cid];
	    },

	    // Returns `true` if the model is in the collection.
	    has: function(obj) {
	        return this.get(obj) != null;
	    },

	    // Get the model at the given index.
	    at: function(index) {
	        if (index < 0) { index += this.length; }
	        return this.models[index];
	    },

	    // Force the collection to re-sort itself. You don't need to call this under
	    // normal circumstances, as the set will maintain sort order as each item
	    // is added.
	    sort: function(options) {
	        var comparator = this.comparator;
	        if (!comparator) { throw new Error('Cannot sort a set without a comparator'); }
	        options || (options = {});

	        var length = comparator.length;
	        if (isFunction(comparator)) { comparator = comparator.bind(this); }

	        // Run sort based on type of `comparator`.
	        if (length === 1 || isString(comparator)) {
	            this.models = this.sortBy(comparator);
	        } else {
	            this.models.sort(comparator);
	        }
	        if (!options.silent) { this.trigger('sort', this, options); }
	        return this;
	    },

	    // Create a new collection with an identical list of models as this one.
	    clone: function() {
	        return new this.constructor(this.models, {
	            model: this.model,
	            comparator: this.comparator
	        });
	    },

	    // Define how to uniquely identify models in the collection.
	    modelId: function(attrs, idAttribute) {
	        return attrs[idAttribute || this.model.prototype.idAttribute || 'id'];
	    },

	    // Get an iterator of all models in this collection.
	    values: function() {
	        return new CollectionIterator(this, ITERATOR_VALUES);
	    },

	    // Get an iterator of all model IDs in this collection.
	    keys: function() {
	        return new CollectionIterator(this, ITERATOR_KEYS);
	    },

	    // Get an iterator of all [ID, model] tuples in this collection.
	    entries: function() {
	        return new CollectionIterator(this, ITERATOR_KEYSVALUES);
	    },

	    // Iterate over elements of the collection, and invoke fn for each element
	    each: function(fn, context) {
	        this.models.forEach(fn, context);
	    },

	    // Iterate over elements of collection, and return an array of all elements fn returns truthy for
	    filter: function(fn, context) {
	        return this.models.filter(fn, context);
	    },

	    find: function(fn, context) {
	        return this.models.find(fn, context);
	    },

	    findIndex: function(fn, context) {
	        return this.models.findIndex(fn, context);
	    },

	    // Return the first model of the collection
	    first: function() {
	        return this.models[0];
	    },

	    // Return true if value is in the collection
	    includes: function(value) {
	        return this.models.includes(value);
	    },

	    // Return the last model of the collection
	    last: function() {
	        return this.models[this.models.length - 1];
	    },

	    // Return true if collection has no elements
	    isEmpty: function() {
	        return !this.models.length;
	    },

	    // Create an array of values by running each element in the collection through fn
	    map: function(fn, context) {
	        return this.models.map(fn, context);
	    },

	    // Runs "reducer" fn over all elements in the collection, in ascending-index order, and accumulates them into a single value
	    reduce: function(fn, initAcc) {
	        if ( initAcc === void 0 ) initAcc = this.first();

	        return this.models.reduce(fn, initAcc);
	    },

	    // Private method to reset all internal state. Called when the collection
	    // is first initialized or reset.
	    _reset: function() {
	        this.length = 0;
	        this.models = [];
	        this._byId  = {};
	    },

	    // Prepare a hash of attributes (or other model) to be added to this
	    // collection.
	    _prepareModel: function(attrs, options) {
	        if (this._isModel(attrs)) {
	            if (!attrs.collection) { attrs.collection = this; }
	            return attrs;
	        }
	        options = options ? clone(options) : {};
	        options.collection = this;

	        var model;
	        if (this.model.prototype) {
	            model = new this.model(attrs, options);
	        } else {
	        // ES class methods didn't have prototype
	            model = this.model(attrs, options);
	        }

	        if (!model.validationError) { return model; }
	        this.trigger('invalid', this, model.validationError, options);
	        return false;
	    },

	    // Internal method called by both remove and set.
	    _removeModels: function(models, options) {
	        var removed = [];
	        for (var i = 0; i < models.length; i++) {
	            var model = this.get(models[i]);
	            if (!model) { continue; }

	            var index = this.models.indexOf(model);
	            this.models.splice(index, 1);
	            this.length--;

	            // Remove references before triggering 'remove' event to prevent an
	            // infinite loop. #3693
	            delete this._byId[model.cid];
	            var id = this.modelId(model.attributes, model.idAttribute);
	            if (id != null) { delete this._byId[id]; }

	            if (!options.silent) {
	                options.index = index;
	                model.trigger('remove', model, this, options);
	            }

	            removed.push(model);
	            this._removeReference(model, options);
	        }
	        if (models.length > 0 && !options.silent) { delete options.index; }
	        return removed;
	    },

	    // Method for checking whether an object should be considered a model for
	    // the purposes of adding to the collection.
	    _isModel: function(model) {
	        return model instanceof Model;
	    },

	    // Internal method to create a model's ties to a collection.
	    _addReference: function(model, options) {
	        this._byId[model.cid] = model;
	        var id = this.modelId(model.attributes, model.idAttribute);
	        if (id != null) { this._byId[id] = model; }
	        model.on('all', this._onModelEvent, this);
	    },

	    // Internal method to sever a model's ties to a collection.
	    _removeReference: function(model, options) {
	        delete this._byId[model.cid];
	        var id = this.modelId(model.attributes, model.idAttribute);
	        if (id != null) { delete this._byId[id]; }
	        if (this === model.collection) { delete model.collection; }
	        model.off('all', this._onModelEvent, this);
	    },

	    // Internal method called every time a model in the set fires an event.
	    // Sets need to update their indexes when models change ids. All other
	    // events simply proxy through. "add" and "remove" events that originate
	    // in other collections are ignored.
	    _onModelEvent: function(event, model, collection, options) {
	        if (model) {
	            if ((event === 'add' || event === 'remove') && collection !== this) { return; }
	            if (event === 'changeId') {
	                var prevId = this.modelId(model.previousAttributes(), model.idAttribute);
	                var id = this.modelId(model.attributes, model.idAttribute);
	                if (prevId != null) { delete this._byId[prevId]; }
	                if (id != null) { this._byId[id] = model; }
	            }
	        }
	        this.trigger.apply(this, arguments);
	    }

	});

	// Defining an @@iterator method implements JavaScript's Iterable protocol.
	// In modern ES2015 browsers, this value is found at Symbol.iterator.
	var $$iterator = typeof Symbol === 'function' && Symbol.iterator;
	if ($$iterator) {
	    Collection.prototype[$$iterator] = Collection.prototype.values;
	}

	// CollectionIterator
	// ------------------

	// A CollectionIterator implements JavaScript's Iterator protocol, allowing the
	// use of `for of` loops in modern browsers and interoperation between
	// Collection and other JavaScript functions and third-party libraries
	// which can operate on Iterables.
	var CollectionIterator = function(collection, kind) {
	    this._collection = collection;
	    this._kind = kind;
	    this._index = 0;
	};

	// This "enum" defines the three possible kinds of values which can be emitted
	// by a CollectionIterator that correspond to the values(), keys() and entries()
	// methods on Collection, respectively.
	var ITERATOR_VALUES = 1;
	var ITERATOR_KEYS = 2;
	var ITERATOR_KEYSVALUES = 3;

	// All Iterators should themselves be Iterable.
	if ($$iterator) {
	    CollectionIterator.prototype[$$iterator] = function() {
	        return this;
	    };
	}

	CollectionIterator.prototype.next = function() {
	    if (this._collection) {

	        // Only continue iterating if the iterated collection is long enough.
	        if (this._index < this._collection.length) {
	            var model = this._collection.at(this._index);
	            this._index++;

	            // Construct a value depending on what kind of values should be iterated.
	            var value;
	            if (this._kind === ITERATOR_VALUES) {
	                value = model;
	            } else {
	                var id = this._collection.modelId(model.attributes, model.idAttribute);
	                if (this._kind === ITERATOR_KEYS) {
	                    value = id;
	                } else { // ITERATOR_KEYSVALUES
	                    value = [id, model];
	                }
	            }
	            return { value: value, done: false };
	        }

	        // Once exhausted, remove the reference to the collection so future
	        // calls to the next method always return done.
	        this._collection = void 0;
	    }

	    return { value: void 0, done: true };
	};

	//  Methods that we want to implement on the Collection.
	var collectionMethods = { toArray: 1, sortBy: 3 };


	// Mix in each method as a proxy to `Collection#models`.

	var config$1 = [ Collection, collectionMethods, 'models' ];

	function addMethods(config) {
	    var Base = config[0],
	        methods = config[1],
	        attribute = config[2];

	    var methodsToAdd = {
	        sortBy: sortBy,
	        toArray: toArray
	    };

	    addMethodsUtil(Base, methodsToAdd, methods, attribute);
	}

	addMethods(config$1);

	// Set up inheritance for the collection.
	Collection.extend = extend$1;



	var index$2 = ({
		Data: Data,
		$: $,
		views: views,
		View: View,
		Listener: Listener,
		Events: Events,
		Collection: Collection,
		Model: Model,
		ViewBase: ViewBase,
		Event: Event
	});

	function toArray$1(obj) {
	    if (!obj) { return []; }
	    if (Array.isArray(obj)) { return obj; }
	    return [obj];
	}

	var HighlighterView = View.extend({

	    tagName: 'g',
	    svgElement: true,
	    className: 'highlight',

	    HIGHLIGHT_FLAG: 1,
	    UPDATE_PRIORITY: 3,
	    DETACHABLE: false,
	    UPDATABLE: true,
	    MOUNTABLE: true,

	    cellView: null,
	    nodeSelector: null,
	    node: null,
	    updateRequested: false,
	    postponedUpdate: false,
	    transformGroup: null,
	    detachedTransformGroup: null,

	    requestUpdate: function requestUpdate(cellView, nodeSelector) {
	        var paper = cellView.paper;
	        this.cellView = cellView;
	        this.nodeSelector = nodeSelector;
	        if (paper) {
	            this.updateRequested = true;
	            paper.requestViewUpdate(this, this.HIGHLIGHT_FLAG, this.UPDATE_PRIORITY);
	        }
	    },

	    confirmUpdate: function confirmUpdate() {
	        // The cellView is now rendered/updated since it has a higher update priority.
	        this.updateRequested = false;
	        var ref = this;
	        var cellView = ref.cellView;
	        var nodeSelector = ref.nodeSelector;
	        if (!cellView.isMounted()) {
	            this.postponedUpdate = true;
	            return 0;
	        }
	        this.update(cellView, nodeSelector);
	        this.mount();
	        this.transform();
	        return 0;
	    },

	    findNode: function findNode(cellView, nodeSelector) {
	        if ( nodeSelector === void 0 ) nodeSelector = null;

	        var el;
	        if (typeof nodeSelector === 'string') {
	            el = cellView.findNode(nodeSelector);
	        } else if (isPlainObject(nodeSelector)) {
	            var isLink = cellView.model.isLink();
	            var label = nodeSelector.label; if ( label === void 0 ) label = null;
	            var port = nodeSelector.port;
	            var selector = nodeSelector.selector;
	            if (isLink && label !== null) {
	                // Link Label Selector
	                el = cellView.findLabelNode(label, selector);
	            } else if (!isLink && port) {
	                // Element Port Selector
	                el = cellView.findPortNode(port, selector);
	            } else {
	                // Cell Selector
	                el = cellView.findNode(selector);
	            }
	        } else if (nodeSelector) {
	            el = V.toNode(nodeSelector);
	            if (!(el instanceof SVGElement)) { el = null; }
	        }
	        return el ? el : null;
	    },

	    getNodeMatrix: function getNodeMatrix(cellView, node) {
	        var ref = this;
	        var options = ref.options;
	        var layer = options.layer;
	        var rotatableNode = cellView.rotatableNode;
	        var nodeMatrix = cellView.getNodeMatrix(node);
	        if (rotatableNode) {
	            if (layer) {
	                if (rotatableNode.contains(node)) {
	                    return nodeMatrix;
	                }
	                // The node is outside of the rotatable group.
	                // Compensate the rotation set by transformGroup.
	                return cellView.getRootRotateMatrix().inverse().multiply(nodeMatrix);
	            } else {
	                return cellView.getNodeRotateMatrix(node).multiply(nodeMatrix);
	            }
	        }
	        return nodeMatrix;
	    },

	    mount: function mount() {
	        var ref = this;
	        var MOUNTABLE = ref.MOUNTABLE;
	        var cellView = ref.cellView;
	        var el = ref.el;
	        var options = ref.options;
	        var transformGroup = ref.transformGroup;
	        var detachedTransformGroup = ref.detachedTransformGroup;
	        var postponedUpdate = ref.postponedUpdate;
	        var nodeSelector = ref.nodeSelector;
	        if (!MOUNTABLE || transformGroup) { return; }
	        if (postponedUpdate) {
	            // The cellView was not mounted when the update was requested.
	            // The update was postponed until the cellView is mounted.
	            this.update(cellView, nodeSelector);
	            this.transform();
	            return;
	        }
	        var cellViewRoot = cellView.vel;
	        var paper = cellView.paper;
	        var layerName = options.layer;
	        if (layerName) {
	            var vGroup;
	            if (detachedTransformGroup) {
	                vGroup = detachedTransformGroup;
	                this.detachedTransformGroup = null;
	            } else {
	                vGroup = V('g').addClass('highlight-transform').append(el);
	            }
	            this.transformGroup = vGroup;
	            paper.getLayerView(layerName).insertSortedNode(vGroup.node, options.z);
	        } else {
	            // TODO: prepend vs append
	            if (!el.parentNode || el.nextSibling) {
	                // Not appended yet or not the last child
	                cellViewRoot.append(el);
	            }
	        }
	    },

	    unmount: function unmount() {
	        var ref = this;
	        var MOUNTABLE = ref.MOUNTABLE;
	        var transformGroup = ref.transformGroup;
	        var vel = ref.vel;
	        if (!MOUNTABLE) { return; }
	        if (transformGroup) {
	            this.transformGroup = null;
	            this.detachedTransformGroup = transformGroup;
	            transformGroup.remove();
	        } else {
	            vel.remove();
	        }
	    },

	    transform: function transform() {
	        var ref = this;
	        var transformGroup = ref.transformGroup;
	        var cellView = ref.cellView;
	        var updateRequested = ref.updateRequested;
	        if (!transformGroup || cellView.model.isLink() || updateRequested) { return; }
	        var translateMatrix = cellView.getRootTranslateMatrix();
	        var rotateMatrix = cellView.getRootRotateMatrix();
	        var transformMatrix = translateMatrix.multiply(rotateMatrix);
	        transformGroup.attr('transform', V.matrixToTransformString(transformMatrix));
	    },

	    update: function update() {
	        var ref = this;
	        var prevNode = ref.node;
	        var cellView = ref.cellView;
	        var nodeSelector = ref.nodeSelector;
	        var updateRequested = ref.updateRequested;
	        var id = ref.id;
	        if (updateRequested) { return; }
	        this.postponedUpdate = false;
	        var node = this.node = this.findNode(cellView, nodeSelector);
	        if (prevNode) {
	            this.unhighlight(cellView, prevNode);
	        }
	        if (node) {
	            this.highlight(cellView, node);
	            this.mount();
	        } else {
	            this.unmount();
	            cellView.notify('cell:highlight:invalid', id, this);
	        }
	    },

	    onRemove: function onRemove() {
	        var ref = this;
	        var node = ref.node;
	        var cellView = ref.cellView;
	        var id = ref.id;
	        var constructor = ref.constructor;
	        if (node) {
	            this.unhighlight(cellView, node);
	        }
	        this.unmount();
	        constructor._removeRef(cellView, id);
	    },

	    highlight: function highlight(_cellView, _node) {
	        // to be overridden
	    },

	    unhighlight: function unhighlight(_cellView, _node) {
	        // to be overridden
	    },

	    // Update Attributes

	    listenToUpdateAttributes: function listenToUpdateAttributes(cellView) {
	        var attributes = result(this, 'UPDATE_ATTRIBUTES');
	        if (!Array.isArray(attributes) || attributes.length === 0) { return; }
	        this.listenTo(cellView.model, 'change', this.onCellAttributeChange);
	    },

	    onCellAttributeChange: function onCellAttributeChange() {
	        var ref = this;
	        var cellView = ref.cellView;
	        if (!cellView) { return; }
	        var model = cellView.model;
	        var paper = cellView.paper;
	        var attributes = result(this, 'UPDATE_ATTRIBUTES');
	        if (!attributes.some(function (attribute) { return model.hasChanged(attribute); })) { return; }
	        paper.requestViewUpdate(this, this.HIGHLIGHT_FLAG, this.UPDATE_PRIORITY);
	    }

	}, {

	    _views: {},

	    // Used internally by CellView highlight()
	    highlight: function(cellView, node, opt) {
	        var id = this.uniqueId(node, opt);
	        this.add(cellView, node, id, opt);
	    },

	    // Used internally by CellView unhighlight()
	    unhighlight: function(cellView, node, opt) {
	        var id = this.uniqueId(node, opt);
	        this.remove(cellView, id);
	    },

	    get: function get(cellView, id) {
	        if ( id === void 0 ) id = null;

	        var cid = cellView.cid;
	        var ref$2 = this;
	        var _views = ref$2._views;
	        var refs = _views[cid];
	        if (id === null) {
	            // all highlighters
	            var views = [];
	            if (!refs) { return views; }
	            for (var hid in refs) {
	                var ref = refs[hid];
	                if (ref instanceof this) {
	                    views.push(ref);
	                }
	            }
	            return views;
	        } else {
	            // single highlighter
	            if (!refs) { return null; }
	            if (id in refs) {
	                var ref$1 = refs[id];
	                if (ref$1 instanceof this) { return ref$1; }
	            }
	            return null;
	        }
	    },

	    add: function add(cellView, nodeSelector, id, opt) {
	        if ( opt === void 0 ) opt = {};

	        if (!id) { throw new Error('dia.HighlighterView: An ID required.'); }
	        // Search the existing view amongst all the highlighters
	        var previousView = HighlighterView.get(cellView, id);
	        if (previousView) { previousView.remove(); }
	        var view = new this(opt);
	        view.id = id;
	        this._addRef(cellView, id, view);
	        view.requestUpdate(cellView, nodeSelector);
	        view.listenToUpdateAttributes(cellView);
	        return view;
	    },

	    _addRef: function _addRef(cellView, id, view) {
	        var cid = cellView.cid;
	        var ref = this;
	        var _views = ref._views;
	        var refs = _views[cid];
	        if (!refs) { refs = _views[cid] = {}; }
	        refs[id] = view;
	    },

	    _removeRef: function _removeRef(cellView, id) {
	        var cid = cellView.cid;
	        var ref = this;
	        var _views = ref._views;
	        var refs = _views[cid];
	        if (!refs) { return; }
	        if (id) { delete refs[id]; }
	        for (var _ in refs) { return; }
	        delete _views[cid];
	    },

	    remove: function remove(cellView, id) {
	        if ( id === void 0 ) id = null;

	        toArray$1(this.get(cellView, id)).forEach(function (view) {
	            view.remove();
	        });
	    },

	    removeAll: function removeAll(paper, id) {
	        if ( id === void 0 ) id = null;

	        var ref = this;
	        var _views = ref._views;

	        for (var cid in _views) {
	            for (var hid in _views[cid]) {
	                var view = _views[cid][hid];

	                if (view.cellView.paper === paper && view instanceof this && (id === null || hid === id)) {
	                    view.remove();
	                }
	            }
	        }
	    },

	    update: function update(cellView, id, dirty) {
	        if ( id === void 0 ) id = null;
	        if ( dirty === void 0 ) dirty = false;

	        toArray$1(this.get(cellView, id)).forEach(function (view) {
	            if (dirty || view.UPDATABLE) { view.update(); }
	        });
	    },

	    transform: function transform(cellView, id) {
	        if ( id === void 0 ) id = null;

	        toArray$1(this.get(cellView, id)).forEach(function (view) {
	            if (view.UPDATABLE) { view.transform(); }
	        });
	    },

	    unmount: function unmount(cellView, id) {
	        if ( id === void 0 ) id = null;

	        toArray$1(this.get(cellView, id)).forEach(function (view) { return view.unmount(); });
	    },

	    mount: function mount(cellView, id) {
	        if ( id === void 0 ) id = null;

	        toArray$1(this.get(cellView, id)).forEach(function (view) { return view.mount(); });
	    },

	    uniqueId: function uniqueId(node, opt) {
	        if ( opt === void 0 ) opt = '';

	        return V.ensureId(node) + JSON.stringify(opt);
	    }

	});

	var stroke = HighlighterView.extend({

	    tagName: 'path',
	    className: 'highlight-stroke',
	    attributes: {
	        'pointer-events': 'none',
	        'fill': 'none'
	    },

	    options: {
	        padding: 3,
	        rx: 0,
	        ry: 0,
	        useFirstSubpath: false,
	        attrs: {
	            'stroke-width': 3,
	            'stroke': '#FEB663'
	        }
	    },

	    getPathData: function getPathData(cellView, node) {
	        var ref = this;
	        var options = ref.options;
	        var useFirstSubpath = options.useFirstSubpath;
	        var d;
	        try {
	            var vNode = V(node);
	            d = vNode.convertToPathData().trim();
	            if (vNode.tagName() === 'PATH' && useFirstSubpath) {
	                var secondSubpathIndex = d.search(/.M/i) + 1;
	                if (secondSubpathIndex > 0) {
	                    d = d.substr(0, secondSubpathIndex);
	                }
	            }
	        } catch (error) {
	            // Failed to get path data from magnet element.
	            // Draw a rectangle around the node instead.
	            var nodeBBox = cellView.getNodeBoundingRect(node);
	            d = V.rectToPath(assign({}, options, nodeBBox.toJSON()));
	        }
	        return d;
	    },

	    highlightConnection: function highlightConnection(cellView) {
	        this.vel.attr('d', cellView.getSerializedConnection());
	    },

	    highlightNode: function highlightNode(cellView, node) {
	        var ref = this;
	        var vel = ref.vel;
	        var options = ref.options;
	        var padding = options.padding;
	        var layer = options.layer;
	        var highlightMatrix = this.getNodeMatrix(cellView, node);
	        // Add padding to the highlight element.
	        if (padding) {
	            if (!layer && node === cellView.el) {
	                // If the highlighter is appended to the cellView
	                // and we measure the size of the cellView wrapping group
	                // it's necessary to remove the highlighter first
	                vel.remove();
	            }
	            var nodeBBox = cellView.getNodeBoundingRect(node);
	            var cx = nodeBBox.x + (nodeBBox.width / 2);
	            var cy = nodeBBox.y + (nodeBBox.height / 2);
	            nodeBBox = V.transformRect(nodeBBox, highlightMatrix);
	            var width = Math.max(nodeBBox.width, 1);
	            var height = Math.max(nodeBBox.height, 1);
	            var sx = (width + padding) / width;
	            var sy = (height + padding) / height;
	            var paddingMatrix = V.createSVGMatrix({
	                a: sx,
	                b: 0,
	                c: 0,
	                d: sy,
	                e: cx - sx * cx,
	                f: cy - sy * cy
	            });
	            highlightMatrix = highlightMatrix.multiply(paddingMatrix);
	        }
	        vel.attr({
	            'd': this.getPathData(cellView, node),
	            'transform': V.matrixToTransformString(highlightMatrix)
	        });
	    },

	    highlight: function highlight(cellView, node) {
	        var ref = this;
	        var vel = ref.vel;
	        var options = ref.options;
	        vel.attr(options.attrs);
	        if (options.nonScalingStroke) {
	            vel.attr('vector-effect', 'non-scaling-stroke');
	        }
	        if (cellView.isNodeConnection(node)) {
	            this.highlightConnection(cellView);
	        } else {
	            this.highlightNode(cellView, node);
	        }
	    }

	});

	var MASK_CLIP = 20;

	function forEachDescendant(vel, fn) {
	    var descendants = vel.children();
	    while (descendants.length > 0) {
	        var descendant = descendants.shift();
	        if (fn(descendant)) {
	            descendants.push.apply(descendants, descendant.children());
	        }
	    }
	}

	var mask = HighlighterView.extend({

	    tagName: 'rect',
	    className: 'highlight-mask',
	    attributes: {
	        'pointer-events': 'none'
	    },

	    options: {
	        padding: 3,
	        maskClip: MASK_CLIP,
	        deep: false,
	        attrs: {
	            'stroke': '#FEB663',
	            'stroke-width': 3,
	            'stroke-linecap': 'butt',
	            'stroke-linejoin': 'miter',
	        }
	    },

	    VISIBLE: 'white',
	    INVISIBLE: 'black',

	    MASK_ROOT_ATTRIBUTE_BLACKLIST: [
	        'marker-start',
	        'marker-end',
	        'marker-mid',
	        'transform',
	        'stroke-dasharray',
	        'class' ],

	    MASK_CHILD_ATTRIBUTE_BLACKLIST: [
	        'stroke',
	        'fill',
	        'stroke-width',
	        'stroke-opacity',
	        'stroke-dasharray',
	        'fill-opacity',
	        'marker-start',
	        'marker-end',
	        'marker-mid',
	        'class' ],

	    // TODO: change the list to a function callback
	    MASK_REPLACE_TAGS: [
	        'FOREIGNOBJECT',
	        'IMAGE',
	        'USE',
	        'TEXT',
	        'TSPAN',
	        'TEXTPATH'
	    ],

	    // TODO: change the list to a function callback
	    MASK_REMOVE_TAGS: [
	        'TEXT',
	        'TSPAN',
	        'TEXTPATH'
	    ],

	    transformMaskChild: function transformMaskChild(cellView, childEl) {
	        var ref = this;
	        var MASK_CHILD_ATTRIBUTE_BLACKLIST = ref.MASK_CHILD_ATTRIBUTE_BLACKLIST;
	        var MASK_REPLACE_TAGS = ref.MASK_REPLACE_TAGS;
	        var MASK_REMOVE_TAGS = ref.MASK_REMOVE_TAGS;
	        var childTagName = childEl.tagName();
	        // Do not include the element in the mask's image
	        if (!V.isSVGGraphicsElement(childEl) || MASK_REMOVE_TAGS.includes(childTagName)) {
	            childEl.remove();
	            return false;
	        }
	        // Replace the element with a rectangle
	        if (MASK_REPLACE_TAGS.includes(childTagName)) {
	            // Note: clone() method does not change the children ids
	            var originalChild = cellView.vel.findOne(("#" + (childEl.id)));
	            if (originalChild) {
	                var originalNode = originalChild.node;
	                var childBBox = cellView.getNodeBoundingRect(originalNode);
	                if (cellView.model.isElement()) {
	                    childBBox = V.transformRect(childBBox, cellView.getNodeMatrix(originalNode));
	                }
	                var replacement = V('rect', childBBox.toJSON());
	                var ref$1 = childBBox.center();
	                var ox = ref$1.x;
	                var oy = ref$1.y;
	                var ref$2 = originalChild.rotate();
	                var angle = ref$2.angle;
	                var cx = ref$2.cx; if ( cx === void 0 ) cx = ox;
	                var cy = ref$2.cy; if ( cy === void 0 ) cy = oy;
	                if (angle) { replacement.rotate(angle, cx, cy); }
	                // Note: it's not important to keep the same sibling index since all subnodes are filled
	                childEl.parent().append(replacement);
	            }
	            childEl.remove();
	            return false;
	        }
	        // Keep the element, but clean it from certain attributes
	        MASK_CHILD_ATTRIBUTE_BLACKLIST.forEach(function (attrName) {
	            if (attrName === 'fill' && childEl.attr('fill') === 'none') { return; }
	            childEl.removeAttr(attrName);
	        });
	        return true;
	    },

	    transformMaskRoot: function transformMaskRoot(_cellView, rootEl) {
	        var ref = this;
	        var MASK_ROOT_ATTRIBUTE_BLACKLIST = ref.MASK_ROOT_ATTRIBUTE_BLACKLIST;
	        MASK_ROOT_ATTRIBUTE_BLACKLIST.forEach(function (attrName) {
	            rootEl.removeAttr(attrName);
	        });
	    },

	    getMaskShape: function getMaskShape(cellView, vel) {
	        var this$1 = this;

	        var ref = this;
	        var options = ref.options;
	        var MASK_REPLACE_TAGS = ref.MASK_REPLACE_TAGS;
	        var deep = options.deep;
	        var tagName = vel.tagName();
	        var maskRoot;
	        if (tagName === 'G') {
	            if (!deep) { return null; }
	            maskRoot = vel.clone();
	            forEachDescendant(maskRoot, function (maskChild) { return this$1.transformMaskChild(cellView, maskChild); });
	        } else {
	            if (MASK_REPLACE_TAGS.includes(tagName)) { return null; }
	            maskRoot = vel.clone();
	        }
	        this.transformMaskRoot(cellView, maskRoot);
	        return maskRoot;
	    },

	    getMaskId: function getMaskId() {
	        return ("highlight-mask-" + (this.cid));
	    },

	    getMask: function getMask(cellView, vNode) {

	        var ref = this;
	        var VISIBLE = ref.VISIBLE;
	        var INVISIBLE = ref.INVISIBLE;
	        var options = ref.options;
	        var padding = options.padding;
	        var attrs = options.attrs;
	        // support both `strokeWidth` and `stroke-width` attribute names
	        var strokeWidth = parseFloat(V('g').attr(attrs).attr('stroke-width'));
	        var hasNodeFill = vNode.attr('fill') !== 'none';
	        var magnetStrokeWidth = parseFloat(vNode.attr('stroke-width'));
	        if (isNaN(magnetStrokeWidth)) { magnetStrokeWidth = 1; }
	        // stroke of the invisible shape
	        var minStrokeWidth = magnetStrokeWidth + padding * 2;
	        // stroke of the visible shape
	        var maxStrokeWidth = minStrokeWidth + strokeWidth * 2;
	        var maskEl = this.getMaskShape(cellView, vNode);
	        if (!maskEl) {
	            var nodeBBox = cellView.getNodeBoundingRect(vNode.node);
	            // Make sure the rect is visible
	            nodeBBox.inflate(nodeBBox.width ? 0 : 0.5, nodeBBox.height ? 0 : 0.5);
	            maskEl =  V('rect', nodeBBox.toJSON());
	        }
	        maskEl.attr(attrs);
	        return V('mask', {
	            'id': this.getMaskId()
	        }).append([
	            maskEl.clone().attr({
	                'fill': hasNodeFill ? VISIBLE : 'none',
	                'stroke': VISIBLE,
	                'stroke-width': maxStrokeWidth
	            }),
	            maskEl.clone().attr({
	                'fill': hasNodeFill ? INVISIBLE : 'none',
	                'stroke': INVISIBLE,
	                'stroke-width': minStrokeWidth
	            })
	        ]);
	    },

	    removeMask: function removeMask(paper) {
	        var maskNode = paper.svg.getElementById(this.getMaskId());
	        if (maskNode) {
	            paper.defs.removeChild(maskNode);
	        }
	    },

	    addMask: function addMask(paper, maskEl) {
	        paper.defs.appendChild(maskEl.node);
	    },

	    highlight: function highlight(cellView, node) {
	        var ref = this;
	        var options = ref.options;
	        var vel = ref.vel;
	        var padding = options.padding;
	        var attrs = options.attrs;
	        var maskClip = options.maskClip; if ( maskClip === void 0 ) maskClip = MASK_CLIP;
	        var layer = options.layer;
	        var color = ('stroke' in attrs) ? attrs['stroke'] : '#000000';
	        if (!layer && node === cellView.el) {
	            // If the highlighter is appended to the cellView
	            // and we measure the size of the cellView wrapping group
	            // it's necessary to remove the highlighter first
	            vel.remove();
	        }
	        var highlighterBBox = cellView.getNodeBoundingRect(node).inflate(padding + maskClip);
	        var highlightMatrix = this.getNodeMatrix(cellView, node);
	        var maskEl = this.getMask(cellView, V(node));
	        this.addMask(cellView.paper, maskEl);
	        vel.attr(highlighterBBox.toJSON());
	        vel.attr({
	            'transform': V.matrixToTransformString(highlightMatrix),
	            'mask': ("url(#" + (maskEl.id) + ")"),
	            'fill': color
	        });
	    },

	    unhighlight: function unhighlight(cellView) {
	        this.removeMask(cellView.paper);
	    }

	});

	var opacity = HighlighterView.extend({

	    UPDATABLE: false,
	    MOUNTABLE: false,

	    highlight: function(_cellView, node) {
	        var ref = this.options;
	        var alphaValue = ref.alphaValue; if ( alphaValue === void 0 ) alphaValue = 0.3;
	        node.style.opacity = alphaValue;
	    },

	    unhighlight: function(_cellView, node) {
	        node.style.opacity = '';
	    }

	});

	var className = addClassNamePrefix('highlighted');

	var addClass$1 = HighlighterView.extend({

	    UPDATABLE: false,
	    MOUNTABLE: false,

	    options: {
	        className: className
	    },

	    highlight: function(_cellView, node) {
	        V(node).addClass(this.options.className);
	    },

	    unhighlight: function(_cellView, node) {
	        V(node).removeClass(this.options.className);
	    }

	}, {
	    // Backwards Compatibility
	    className: className
	});

	var Directions$1 = {
	    ROW: 'row',
	    COLUMN: 'column'
	};

	var list = HighlighterView.extend({

	    tagName: 'g',
	    MOUNTABLE: true,
	    UPDATE_ATTRIBUTES: function() {
	        return [this.options.attribute];
	    },

	    _prevItems: null,

	    highlight: function highlight(elementView, node) {
	        var this$1 = this;

	        var element = elementView.model;
	        var ref = this.options;
	        var attribute = ref.attribute;
	        var size = ref.size; if ( size === void 0 ) size = 20;
	        var gap = ref.gap; if ( gap === void 0 ) gap = 5;
	        var direction = ref.direction; if ( direction === void 0 ) direction = Directions$1.ROW;
	        if (!attribute) { throw new Error('List: attribute is required'); }
	        var normalizedSize = (typeof size === 'number') ? { width: size, height: size } : size;
	        var isRowDirection = (direction === Directions$1.ROW);
	        var itemWidth = isRowDirection ? normalizedSize.width : normalizedSize.height;
	        var items = element.get(attribute);
	        if (!Array.isArray(items)) { items = []; }
	        var prevItems = this._prevItems || [];
	        var comparison = items.map(function (item, index) { return isEqual(prevItems[index], items[index]); });
	        if (prevItems.length !== items.length || comparison.some(function (unchanged) { return !unchanged; })) {
	            var prevEls = this.vel.children();
	            var itemsEls = items.map(function (item, index) {
	                var prevEl = (index in prevEls) ? prevEls[index].node : null;
	                if (comparison[index]) { return prevEl; }
	                var itemEl = this$1.createListItem(item, normalizedSize, prevEl);
	                if (!itemEl) { return null; }
	                if (!(itemEl instanceof SVGElement)) { throw new Error('List: item must be an SVGElement'); }
	                itemEl.dataset.index = index;
	                itemEl.dataset.attribute = attribute;
	                var offset = index * (itemWidth + gap);
	                itemEl.setAttribute('transform', (isRowDirection)
	                    ? ("translate(" + offset + ", 0)")
	                    : ("translate(0, " + offset + ")")
	                );
	                return itemEl;
	            });
	            this.vel.empty().append(itemsEls);
	            this._prevItems = items;
	        }
	        var itemsCount = items.length;
	        var length = (itemsCount === 0)
	            ? 0
	            : (itemsCount * itemWidth + (itemsCount - 1) * gap);
	        var listSize = (isRowDirection)
	            ? { width: length, height: normalizedSize.height }
	            : { width: normalizedSize.width, height: length };

	        this.position(element, listSize);
	    },

	    position: function position(element, listSize) {
	        var ref = this;
	        var vel = ref.vel;
	        var options = ref.options;
	        var margin = options.margin; if ( margin === void 0 ) margin = 5;
	        var position = options.position; if ( position === void 0 ) position = 'top-left';
	        var ref$1 = element.size();
	        var width = ref$1.width;
	        var height = ref$1.height;
	        var ref$2 = normalizeSides(margin);
	        var left = ref$2.left;
	        var right = ref$2.right;
	        var top = ref$2.top;
	        var bottom = ref$2.bottom;
	        var bbox = new Rect(left, top, width - (left + right), height - (top + bottom));
	        var ref$3 = getRectPoint(bbox, position);
	        var x = ref$3.x;
	        var y = ref$3.y;
	        // x
	        switch (position) {
	            case Positions.CENTER:
	            case Positions.TOP:
	            case Positions.BOTTOM: {
	                x -= listSize.width / 2;
	                break;
	            }
	            case Positions.RIGHT:
	            case Positions.BOTTOM_RIGHT:
	            case Positions.TOP_RIGHT: {
	                x -= listSize.width;
	                break;
	            }
	        }
	        // y
	        switch (position) {
	            case Positions.CENTER:
	            case Positions.RIGHT:
	            case Positions.LEFT: {
	                y -= listSize.height / 2;
	                break;
	            }
	            case Positions.BOTTOM:
	            case Positions.BOTTOM_RIGHT:
	            case Positions.BOTTOM_LEFT: {
	                y -= listSize.height;
	                break;
	            }
	        }
	        vel.attr('transform', ("translate(" + x + ", " + y + ")"));
	    }
	}, {
	    Directions: Directions$1,
	    Positions: Positions
	});



	var highlighters = ({
		stroke: stroke,
		mask: mask,
		opacity: opacity,
		addClass: addClass$1,
		list: list
	});

	function offsetPoint(p1, p2, offset) {
	    if (isPlainObject(offset)) {
	        var x = offset.x;
	        var y = offset.y;
	        if (isFinite(y)) {
	            var line =  new Line(p2, p1);
	            var ref = line.parallel(y);
	            var start = ref.start;
	            var end = ref.end;
	            p2 = start;
	            p1 = end;
	        }
	        offset = x;
	    }
	    if (!isFinite(offset)) { return p1; }
	    var length = p1.distance(p2);
	    if (offset === 0 && length > 0) { return p1; }
	    return p1.move(p2, -Math.min(offset, length - 1));
	}

	function stroke$1(magnet) {

	    var stroke = magnet.getAttribute('stroke-width');
	    if (stroke === null) { return 0; }
	    return parseFloat(stroke) || 0;
	}

	function alignLine(line, type, offset) {
	    if ( offset === void 0 ) offset = 0;

	    var coordinate, a, b, direction;
	    var start = line.start;
	    var end = line.end;
	    switch (type) {
	        case 'left':
	            coordinate = 'x';
	            a = end;
	            b = start;
	            direction = -1;
	            break;
	        case 'right':
	            coordinate = 'x';
	            a = start;
	            b = end;
	            direction = 1;
	            break;
	        case 'top':
	            coordinate = 'y';
	            a = end;
	            b = start;
	            direction = -1;
	            break;
	        case 'bottom':
	            coordinate = 'y';
	            a = start;
	            b = end;
	            direction = 1;
	            break;
	        default:
	            return;
	    }
	    if (start[coordinate] < end[coordinate]) {
	        a[coordinate] = b[coordinate];
	    } else {
	        b[coordinate] = a[coordinate];
	    }
	    if (isFinite(offset)) {
	        a[coordinate] += direction * offset;
	        b[coordinate] += direction * offset;
	    }
	}

	// Connection Points

	function anchorConnectionPoint(line, _view, _magnet, opt) {
	    var offset = opt.offset;
	    var alignOffset = opt.alignOffset;
	    var align = opt.align;
	    if (align) { alignLine(line, align, alignOffset); }
	    return offsetPoint(line.end, line.start, offset);
	}

	function bboxIntersection(line, view, magnet, opt) {

	    var bbox = view.getNodeBBox(magnet);
	    if (opt.stroke) { bbox.inflate(stroke$1(magnet) / 2); }
	    var intersections = line.intersect(bbox);
	    var cp = (intersections)
	        ? line.start.chooseClosest(intersections)
	        : line.end;
	    return offsetPoint(cp, line.start, opt.offset);
	}

	function rectangleIntersection(line, view, magnet, opt) {

	    var angle = view.model.angle();
	    if (angle === 0) {
	        return bboxIntersection(line, view, magnet, opt);
	    }

	    var bboxWORotation = view.getNodeUnrotatedBBox(magnet);
	    if (opt.stroke) { bboxWORotation.inflate(stroke$1(magnet) / 2); }
	    var center = bboxWORotation.center();
	    var lineWORotation = line.clone().rotate(center, angle);
	    var intersections = lineWORotation.setLength(1e6).intersect(bboxWORotation);
	    var cp = (intersections)
	        ? lineWORotation.start.chooseClosest(intersections).rotate(center, -angle)
	        : line.end;
	    return offsetPoint(cp, line.start, opt.offset);
	}

	function findShapeNode(magnet) {
	    if (!magnet) { return null; }
	    var node = magnet;
	    do {
	        var tagName = node.tagName;
	        if (typeof tagName !== 'string') { return null; }
	        tagName = tagName.toUpperCase();
	        if (tagName === 'G') {
	            node = node.firstElementChild;
	        } else if (tagName === 'TITLE') {
	            node = node.nextElementSibling;
	        } else { break; }
	    } while (node);
	    return node;
	}

	var BNDR_SUBDIVISIONS = 'segmentSubdivisons';
	var BNDR_SHAPE_BBOX = 'shapeBBox';

	function boundaryIntersection(line, view, magnet, opt) {

	    var node, intersection;
	    var selector = opt.selector;
	    var anchor = line.end;

	    if (typeof selector === 'string') {
	        node = view.findNode(selector);
	    } else if (selector === false) {
	        node = magnet;
	    } else if (Array.isArray(selector)) {
	        node = getByPath(magnet, selector);
	    } else {
	        node = findShapeNode(magnet);
	    }

	    if (!V.isSVGGraphicsElement(node)) {
	        if (node === magnet || !V.isSVGGraphicsElement(magnet)) { return anchor; }
	        node = magnet;
	    }

	    var localShape = view.getNodeShape(node);
	    var magnetMatrix = view.getNodeMatrix(node);
	    var translateMatrix = view.getRootTranslateMatrix();
	    var rotateMatrix = view.getRootRotateMatrix();
	    var targetMatrix = translateMatrix.multiply(rotateMatrix).multiply(magnetMatrix);
	    var localMatrix = targetMatrix.inverse();
	    var localLine = V.transformLine(line, localMatrix);
	    var localRef = localLine.start.clone();
	    var data = view.getNodeData(node);

	    if (opt.insideout === false) {
	        if (!data[BNDR_SHAPE_BBOX]) { data[BNDR_SHAPE_BBOX] = localShape.bbox(); }
	        var localBBox = data[BNDR_SHAPE_BBOX];
	        if (localBBox.containsPoint(localRef)) { return anchor; }
	    }

	    // Caching segment subdivisions for paths
	    var pathOpt;
	    if (localShape instanceof Path) {
	        var precision = opt.precision || 2;
	        if (!data[BNDR_SUBDIVISIONS]) { data[BNDR_SUBDIVISIONS] = localShape.getSegmentSubdivisions({ precision: precision }); }
	        pathOpt = {
	            precision: precision,
	            segmentSubdivisions: data[BNDR_SUBDIVISIONS]
	        };
	    }

	    if (opt.extrapolate === true) { localLine.setLength(1e6); }

	    intersection = localLine.intersect(localShape, pathOpt);
	    if (intersection) {
	        // More than one intersection
	        if (V.isArray(intersection)) { intersection = localRef.chooseClosest(intersection); }
	    } else if (opt.sticky === true) {
	        // No intersection, find the closest point instead
	        if (localShape instanceof Rect) {
	            intersection = localShape.pointNearestToPoint(localRef);
	        } else if (localShape instanceof Ellipse) {
	            intersection = localShape.intersectionWithLineFromCenterToPoint(localRef);
	        } else {
	            intersection = localShape.closestPoint(localRef, pathOpt);
	        }
	    }

	    var cp = (intersection) ? V.transformPoint(intersection, targetMatrix) : anchor;
	    var cpOffset = opt.offset || 0;
	    if (opt.stroke) { cpOffset += stroke$1(node) / 2; }

	    return offsetPoint(cp, line.start, cpOffset);
	}

	var anchor = anchorConnectionPoint;
	var bbox = bboxIntersection;
	var rectangle = rectangleIntersection;
	var boundary = boundaryIntersection;

	var connectionPoints = ({
		anchor: anchor,
		bbox: bbox,
		rectangle: rectangle,
		boundary: boundary
	});

	function abs2rel(absolute, max) {

	    if (max === 0) { return '0%'; }
	    // round to 3 decimal places
	    var dp = 1000;
	    var relative = Math.round(absolute / max * 100 * dp) / dp;
	    return (relative + "%");
	}

	function pin(relative) {

	    return function(end, view, magnet, coords) {
	        var fn = (view.isNodeConnection(magnet)) ? pinnedLinkEnd : pinnedElementEnd;
	        return fn(relative, end, view, magnet, coords);
	    };
	}

	function pinnedElementEnd(relative, end, view, magnet, coords) {

	    var angle = view.model.angle();
	    var bbox = view.getNodeUnrotatedBBox(magnet);
	    var origin = view.model.getBBox().center();
	    coords.rotate(origin, angle);
	    var dx = coords.x - bbox.x;
	    var dy = coords.y - bbox.y;

	    if (relative) {
	        dx = abs2rel(dx, bbox.width);
	        dy = abs2rel(dy, bbox.height);
	    }

	    end.anchor = {
	        name: 'topLeft',
	        args: {
	            dx: dx,
	            dy: dy,
	            rotate: true
	        }
	    };

	    return end;
	}

	function pinnedLinkEnd(relative, end, view, _magnet, coords) {

	    var connection = view.getConnection();
	    if (!connection) { return end; }
	    var length = connection.closestPointLength(coords);
	    if (relative) {
	        var totalLength = connection.length();
	        end.anchor = {
	            name: 'connectionRatio',
	            args: {
	                ratio: length / totalLength
	            }
	        };
	    } else {
	        end.anchor = {
	            name: 'connectionLength',
	            args: {
	                length: length
	            }
	        };
	    }
	    return end;
	}

	var useDefaults = noop;
	var pinAbsolute = pin(false);
	var pinRelative = pin(true);

	var index$3 = ({
		useDefaults: useDefaults,
		pinAbsolute: pinAbsolute,
		pinRelative: pinRelative
	});

	// Does not make any changes to vertices.
	// Returns the arguments that are passed to it, unchanged.
	var normal$1 = function(vertices, opt, linkView) {

	    return vertices;
	};

	// Routes the link always to/from a certain side
	//
	// Arguments:
	//   padding ... gap between the element and the first vertex. :: Default 40.
	//   side ... 'left' | 'right' | 'top' | 'bottom' :: Default 'bottom'.
	//
	var oneSide = function(vertices, opt, linkView) {

	    var side = opt.side || 'bottom';
	    var padding = normalizeSides(opt.padding || 40);

	    // LinkView contains cached source an target bboxes.
	    // Note that those are Geometry rectangle objects.
	    var sourceBBox = linkView.sourceBBox;
	    var targetBBox = linkView.targetBBox;
	    var sourcePoint = sourceBBox.center();
	    var targetPoint = targetBBox.center();

	    var coordinate, dimension, direction;

	    switch (side) {
	        case 'bottom':
	            direction = 1;
	            coordinate = 'y';
	            dimension = 'height';
	            break;
	        case 'top':
	            direction = -1;
	            coordinate = 'y';
	            dimension = 'height';
	            break;
	        case 'left':
	            direction = -1;
	            coordinate = 'x';
	            dimension = 'width';
	            break;
	        case 'right':
	            direction = 1;
	            coordinate = 'x';
	            dimension = 'width';
	            break;
	        default:
	            throw new Error('Router: invalid side');
	    }

	    // move the points from the center of the element to outside of it.
	    sourcePoint[coordinate] += direction * (sourceBBox[dimension] / 2 + padding[side]);
	    targetPoint[coordinate] += direction * (targetBBox[dimension] / 2 + padding[side]);

	    // make link orthogonal (at least the first and last vertex).
	    if ((direction * (sourcePoint[coordinate] - targetPoint[coordinate])) > 0) {
	        targetPoint[coordinate] = sourcePoint[coordinate];
	    } else {
	        sourcePoint[coordinate] = targetPoint[coordinate];
	    }

	    return [sourcePoint].concat(vertices, targetPoint);
	};

	// bearing -> opposite bearing
	var opposites = {
	    N: 'S',
	    S: 'N',
	    E: 'W',
	    W: 'E'
	};

	// bearing -> radians
	var radians = {
	    N: -Math.PI / 2 * 3,
	    S: -Math.PI / 2,
	    E: 0,
	    W: Math.PI
	};

	// HELPERS //

	// returns a point `p` where lines p,p1 and p,p2 are perpendicular and p is not contained
	// in the given box
	function freeJoin(p1, p2, bbox) {

	    var p = new Point(p1.x, p2.y);
	    if (bbox.containsPoint(p)) { p = new Point(p2.x, p1.y); }
	    // kept for reference
	    // if (bbox.containsPoint(p)) p = null;

	    return p;
	}

	// returns either width or height of a bbox based on the given bearing
	function getBBoxSize(bbox, bearing) {

	    return bbox[(bearing === 'W' || bearing === 'E') ? 'width' : 'height'];
	}

	// simple bearing method (calculates only orthogonal cardinals)
	function getBearing(from, to) {

	    if (from.x === to.x) { return (from.y > to.y) ? 'N' : 'S'; }
	    if (from.y === to.y) { return (from.x > to.x) ? 'W' : 'E'; }
	    return null;
	}

	// transform point to a rect
	function getPointBox(p) {

	    return new Rect(p.x, p.y, 0, 0);
	}

	function getPaddingBox(opt) {

	    // if both provided, opt.padding wins over opt.elementPadding
	    var sides = normalizeSides(opt.padding || opt.elementPadding || 20);

	    return {
	        x: -sides.left,
	        y: -sides.top,
	        width: sides.left + sides.right,
	        height: sides.top + sides.bottom
	    };
	}

	// return source bbox
	function getSourceBBox(linkView, opt) {

	    return linkView.sourceBBox.clone().moveAndExpand(getPaddingBox(opt));
	}

	// return target bbox
	function getTargetBBox(linkView, opt) {

	    return linkView.targetBBox.clone().moveAndExpand(getPaddingBox(opt));
	}

	// return source anchor
	function getSourceAnchor(linkView, opt) {

	    if (linkView.sourceAnchor) { return linkView.sourceAnchor; }

	    // fallback: center of bbox
	    var sourceBBox = getSourceBBox(linkView, opt);
	    return sourceBBox.center();
	}

	// return target anchor
	function getTargetAnchor(linkView, opt) {

	    if (linkView.targetAnchor) { return linkView.targetAnchor; }

	    // fallback: center of bbox
	    var targetBBox = getTargetBBox(linkView, opt);
	    return targetBBox.center(); // default
	}

	// PARTIAL ROUTERS //

	function vertexVertex(from, to, bearing) {

	    var p1 = new Point(from.x, to.y);
	    var p2 = new Point(to.x, from.y);
	    var d1 = getBearing(from, p1);
	    var d2 = getBearing(from, p2);
	    var opposite = opposites[bearing];

	    var p = (d1 === bearing || (d1 !== opposite && (d2 === opposite || d2 !== bearing))) ? p1 : p2;

	    return { points: [p], direction: getBearing(p, to) };
	}

	function elementVertex(from, to, fromBBox) {

	    var p = freeJoin(from, to, fromBBox);

	    return { points: [p], direction: getBearing(p, to) };
	}

	function vertexElement(from, to, toBBox, bearing) {

	    var route = {};

	    var points = [new Point(from.x, to.y), new Point(to.x, from.y)];
	    var freePoints = points.filter(function(pt) {
	        return !toBBox.containsPoint(pt);
	    });
	    var freeBearingPoints = freePoints.filter(function(pt) {
	        return getBearing(pt, from) !== bearing;
	    });

	    var p;

	    if (freeBearingPoints.length > 0) {
	        // Try to pick a point which bears the same direction as the previous segment.

	        p = freeBearingPoints.filter(function(pt) {
	            return getBearing(from, pt) === bearing;
	        }).pop();
	        p = p || freeBearingPoints[0];

	        route.points = [p];
	        route.direction = getBearing(p, to);

	    } else {
	        // Here we found only points which are either contained in the element or they would create
	        // a link segment going in opposite direction from the previous one.
	        // We take the point inside element and move it outside the element in the direction the
	        // route is going. Now we can join this point with the current end (using freeJoin).

	        p = difference(points, freePoints)[0];

	        var p2 = (new Point(to)).move(p, -getBBoxSize(toBBox, bearing) / 2);
	        var p1 = freeJoin(p2, from, toBBox);

	        route.points = [p1, p2];
	        route.direction = getBearing(p2, to);
	    }

	    return route;
	}

	function elementElement(from, to, fromBBox, toBBox) {

	    var route = elementVertex(to, from, toBBox);
	    var p1 = route.points[0];

	    if (fromBBox.containsPoint(p1)) {

	        route = elementVertex(from, to, fromBBox);
	        var p2 = route.points[0];

	        if (toBBox.containsPoint(p2)) {

	            var fromBorder = (new Point(from)).move(p2, -getBBoxSize(fromBBox, getBearing(from, p2)) / 2);
	            var toBorder = (new Point(to)).move(p1, -getBBoxSize(toBBox, getBearing(to, p1)) / 2);
	            var mid = (new Line(fromBorder, toBorder)).midpoint();

	            var startRoute = elementVertex(from, mid, fromBBox);
	            var endRoute = vertexVertex(mid, to, startRoute.direction);

	            route.points = [startRoute.points[0], endRoute.points[0]];
	            route.direction = endRoute.direction;
	        }
	    }

	    return route;
	}

	// Finds route for situations where one element is inside the other.
	// Typically the route is directed outside the outer element first and
	// then back towards the inner element.
	function insideElement(from, to, fromBBox, toBBox, bearing) {

	    var route = {};
	    var boundary = fromBBox.union(toBBox).inflate(1);

	    // start from the point which is closer to the boundary
	    var reversed = boundary.center().distance(to) > boundary.center().distance(from);
	    var start = reversed ? to : from;
	    var end = reversed ? from : to;

	    var p1, p2, p3;

	    if (bearing) {
	        // Points on circle with radius equals 'W + H` are always outside the rectangle
	        // with width W and height H if the center of that circle is the center of that rectangle.
	        p1 = Point.fromPolar(boundary.width + boundary.height, radians[bearing], start);
	        p1 = boundary.pointNearestToPoint(p1).move(p1, -1);

	    } else {
	        p1 = boundary.pointNearestToPoint(start).move(start, 1);
	    }

	    p2 = freeJoin(p1, end, boundary);

	    if (p1.round().equals(p2.round())) {
	        p2 = Point.fromPolar(boundary.width + boundary.height, toRad(p1.theta(start)) + Math.PI / 2, end);
	        p2 = boundary.pointNearestToPoint(p2).move(end, 1).round();
	        p3 = freeJoin(p1, p2, boundary);
	        route.points = reversed ? [p2, p3, p1] : [p1, p3, p2];

	    } else {
	        route.points = reversed ? [p2, p1] : [p1, p2];
	    }

	    route.direction = reversed ? getBearing(p1, to) : getBearing(p2, to);

	    return route;
	}

	// MAIN ROUTER //

	// Return points through which a connection needs to be drawn in order to obtain an orthogonal link
	// routing from source to target going through `vertices`.
	function orthogonal(vertices, opt, linkView) {

	    var sourceBBox = getSourceBBox(linkView, opt);
	    var targetBBox = getTargetBBox(linkView, opt);

	    var sourceAnchor = getSourceAnchor(linkView, opt);
	    var targetAnchor = getTargetAnchor(linkView, opt);

	    // if anchor lies outside of bbox, the bbox expands to include it
	    sourceBBox = sourceBBox.union(getPointBox(sourceAnchor));
	    targetBBox = targetBBox.union(getPointBox(targetAnchor));

	    vertices = toArray(vertices).map(Point);
	    vertices.unshift(sourceAnchor);
	    vertices.push(targetAnchor);

	    var bearing; // bearing of previous route segment

	    var orthogonalVertices = []; // the array of found orthogonal vertices to be returned
	    for (var i = 0, max = vertices.length - 1; i < max; i++) {

	        var route = null;

	        var from = vertices[i];
	        var to = vertices[i + 1];

	        var isOrthogonal = !!getBearing(from, to);

	        if (i === 0) { // source

	            if (i + 1 === max) { // route source -> target

	                // Expand one of the elements by 1px to detect situations when the two
	                // elements are positioned next to each other with no gap in between.
	                if (sourceBBox.intersect(targetBBox.clone().inflate(1))) {
	                    route = insideElement(from, to, sourceBBox, targetBBox);

	                } else if (!isOrthogonal) {
	                    route = elementElement(from, to, sourceBBox, targetBBox);
	                }

	            } else { // route source -> vertex

	                if (sourceBBox.containsPoint(to)) {
	                    route = insideElement(from, to, sourceBBox, getPointBox(to).moveAndExpand(getPaddingBox(opt)));

	                } else if (!isOrthogonal) {
	                    route = elementVertex(from, to, sourceBBox);
	                }
	            }

	        } else if (i + 1 === max) { // route vertex -> target

	            // prevent overlaps with previous line segment
	            var isOrthogonalLoop = isOrthogonal && getBearing(to, from) === bearing;

	            if (targetBBox.containsPoint(from) || isOrthogonalLoop) {
	                route = insideElement(from, to, getPointBox(from).moveAndExpand(getPaddingBox(opt)), targetBBox, bearing);

	            } else if (!isOrthogonal) {
	                route = vertexElement(from, to, targetBBox, bearing);
	            }

	        } else if (!isOrthogonal) { // route vertex -> vertex
	            route = vertexVertex(from, to, bearing);
	        }

	        // applicable to all routes:

	        // set bearing for next iteration
	        if (route) {
	            Array.prototype.push.apply(orthogonalVertices, route.points);
	            bearing = route.direction;

	        } else {
	            // orthogonal route and not looped
	            bearing = getBearing(from, to);
	        }

	        // push `to` point to identified orthogonal vertices array
	        if (i + 1 < max) {
	            orthogonalVertices.push(to);
	        }
	    }

	    return orthogonalVertices;
	}

	var config$2 = {

	    // size of the step to find a route (the grid of the manhattan pathfinder)
	    step: 10,

	    // the number of route finding loops that cause the router to abort
	    // returns fallback route instead
	    maximumLoops: 2000,

	    // the number of decimal places to round floating point coordinates
	    precision: 1,

	    // maximum change of direction
	    maxAllowedDirectionChange: 90,

	    // should the router use perpendicular linkView option?
	    // does not connect anchor of element but rather a point close-by that is orthogonal
	    // this looks much better
	    perpendicular: true,

	    // should the source and/or target not be considered as obstacles?
	    excludeEnds: [], // 'source', 'target'

	    // should certain types of elements not be considered as obstacles?
	    excludeTypes: [],

	    // possible starting directions from an element
	    startDirections: ['top', 'right', 'bottom', 'left'],

	    // possible ending directions to an element
	    endDirections: ['top', 'right', 'bottom', 'left'],

	    // specify the directions used above and what they mean
	    directionMap: {
	        top: { x: 0, y: -1 },
	        right: { x: 1, y: 0 },
	        bottom: { x: 0, y: 1 },
	        left: { x: -1, y: 0 }
	    },

	    // cost of an orthogonal step
	    cost: function() {

	        return this.step;
	    },

	    // an array of directions to find next points on the route
	    // different from start/end directions
	    directions: function() {

	        var step = this.step;
	        var cost = this.cost();

	        return [
	            { offsetX: step, offsetY: 0, cost: cost },
	            { offsetX: -step, offsetY: 0, cost: cost },
	            { offsetX: 0, offsetY: step, cost: cost },
	            { offsetX: 0, offsetY: -step, cost: cost }
	        ];
	    },

	    // a penalty received for direction change
	    penalties: function() {

	        return {
	            0: 0,
	            45: this.step / 2,
	            90: this.step / 2
	        };
	    },

	    // padding applied on the element bounding boxes
	    paddingBox: function() {

	        var step = this.step;

	        return {
	            x: -step,
	            y: -step,
	            width: 2 * step,
	            height: 2 * step
	        };
	    },

	    // A function that determines whether a given point is an obstacle or not.
	    // If used, the `padding`, `excludeEnds`and `excludeTypes` options are ignored.
	    // (point: dia.Point) => boolean;
	    isPointObstacle: null,

	    // a router to use when the manhattan router fails
	    // (one of the partial routes returns null)
	    fallbackRouter: function(vertices, opt, linkView) {

	        if (!isFunction(orthogonal)) {
	            throw new Error('Manhattan requires the orthogonal router as default fallback.');
	        }

	        return orthogonal(vertices, assign({}, config$2, opt), linkView);
	    },

	    /* Deprecated */
	    // a simple route used in situations when main routing method fails
	    // (exceed max number of loop iterations, inaccessible)
	    fallbackRoute: function(from, to, opt) {

	        return null; // null result will trigger the fallbackRouter

	        // left for reference:
	        /*// Find an orthogonal route ignoring obstacles.

	        var point = ((opt.previousDirAngle || 0) % 180 === 0)
	                ? new g.Point(from.x, to.y)
	                : new g.Point(to.x, from.y);

	        return [point];*/
	    },

	    // if a function is provided, it's used to route the link while dragging an end
	    // i.e. function(from, to, opt) { return []; }
	    draggingRoute: null
	};

	// HELPER CLASSES //

	// Map of obstacles
	// Helper structure to identify whether a point lies inside an obstacle.
	function ObstacleMap(opt) {

	    this.map = {};
	    this.options = opt;
	    // tells how to divide the paper when creating the elements map
	    this.mapGridSize = 100;
	}

	ObstacleMap.prototype.build = function(graph, link) {

	    var opt = this.options;

	    // source or target element could be excluded from set of obstacles
	    var excludedEnds = toArray(opt.excludeEnds).reduce(function(res, item) {

	        var end = link.get(item);
	        if (end) {
	            var cell = graph.getCell(end.id);
	            if (cell) {
	                res.push(cell);
	            }
	        }

	        return res;
	    }, []);

	    // Exclude any embedded elements from the source and the target element.
	    var excludedAncestors = [];

	    var source = graph.getCell(link.get('source').id);
	    if (source) {
	        excludedAncestors = union(excludedAncestors, source.getAncestors().map(function(cell) {
	            return cell.id;
	        }));
	    }

	    var target = graph.getCell(link.get('target').id);
	    if (target) {
	        excludedAncestors = union(excludedAncestors, target.getAncestors().map(function(cell) {
	            return cell.id;
	        }));
	    }

	    // Builds a map of all elements for quicker obstacle queries (i.e. is a point contained
	    // in any obstacle?) (a simplified grid search).
	    // The paper is divided into smaller cells, where each holds information about which
	    // elements belong to it. When we query whether a point lies inside an obstacle we
	    // don't need to go through all obstacles, we check only those in a particular cell.
	    var mapGridSize = this.mapGridSize;

	    graph.getElements().reduce(function(map, element) {

	        var isExcludedType = toArray(opt.excludeTypes).includes(element.get('type'));
	        var isExcludedEnd = excludedEnds.find(function(excluded) {
	            return excluded.id === element.id;
	        });
	        var isExcludedAncestor = excludedAncestors.includes(element.id);

	        var isExcluded = isExcludedType || isExcludedEnd || isExcludedAncestor;
	        if (!isExcluded) {
	            var bbox = element.getBBox().moveAndExpand(opt.paddingBox);

	            var origin = bbox.origin().snapToGrid(mapGridSize);
	            var corner = bbox.corner().snapToGrid(mapGridSize);

	            for (var x = origin.x; x <= corner.x; x += mapGridSize) {
	                for (var y = origin.y; y <= corner.y; y += mapGridSize) {
	                    var gridKey = x + '@' + y;
	                    map[gridKey] = map[gridKey] || [];
	                    map[gridKey].push(bbox);
	                }
	            }
	        }

	        return map;
	    }, this.map);

	    return this;
	};

	ObstacleMap.prototype.isPointAccessible = function(point) {

	    var mapKey = point.clone().snapToGrid(this.mapGridSize).toString();

	    return toArray(this.map[mapKey]).every(function(obstacle) {
	        return !obstacle.containsPoint(point);
	    });
	};

	// Sorted Set
	// Set of items sorted by given value.
	function SortedSet() {
	    this.items = [];
	    this.hash = {};
	    this.values = {};
	    this.OPEN = 1;
	    this.CLOSE = 2;
	}

	SortedSet.prototype.add = function(item, value) {

	    if (this.hash[item]) {
	        // item removal
	        this.items.splice(this.items.indexOf(item), 1);
	    } else {
	        this.hash[item] = this.OPEN;
	    }

	    this.values[item] = value;

	    var index$1 = sortedIndex(this.items, item, function(i) {
	        return this.values[i];
	    }.bind(this));

	    this.items.splice(index$1, 0, item);
	};

	SortedSet.prototype.remove = function(item) {

	    this.hash[item] = this.CLOSE;
	};

	SortedSet.prototype.isOpen = function(item) {

	    return this.hash[item] === this.OPEN;
	};

	SortedSet.prototype.isClose = function(item) {

	    return this.hash[item] === this.CLOSE;
	};

	SortedSet.prototype.isEmpty = function() {

	    return this.items.length === 0;
	};

	SortedSet.prototype.pop = function() {

	    var item = this.items.shift();
	    this.remove(item);
	    return item;
	};

	// HELPERS //

	// return source bbox
	function getSourceBBox$1(linkView, opt) {

	    // expand by padding box
	    if (opt && opt.paddingBox) { return linkView.sourceBBox.clone().moveAndExpand(opt.paddingBox); }

	    return linkView.sourceBBox.clone();
	}

	// return target bbox
	function getTargetBBox$1(linkView, opt) {

	    // expand by padding box
	    if (opt && opt.paddingBox) { return linkView.targetBBox.clone().moveAndExpand(opt.paddingBox); }

	    return linkView.targetBBox.clone();
	}

	// return source anchor
	function getSourceAnchor$1(linkView, opt) {

	    if (linkView.sourceAnchor) { return linkView.sourceAnchor; }

	    // fallback: center of bbox
	    var sourceBBox = getSourceBBox$1(linkView, opt);
	    return sourceBBox.center();
	}

	// return target anchor
	function getTargetAnchor$1(linkView, opt) {

	    if (linkView.targetAnchor) { return linkView.targetAnchor; }

	    // fallback: center of bbox
	    var targetBBox = getTargetBBox$1(linkView, opt);
	    return targetBBox.center(); // default
	}

	// returns a direction index from start point to end point
	// corrects for grid deformation between start and end
	function getDirectionAngle(start, end, numDirections, grid, opt) {

	    var quadrant = 360 / numDirections;
	    var angleTheta = start.theta(fixAngleEnd(start, end, grid, opt));
	    var normalizedAngle = normalizeAngle(angleTheta + (quadrant / 2));
	    return quadrant * Math.floor(normalizedAngle / quadrant);
	}

	// helper function for getDirectionAngle()
	// corrects for grid deformation
	// (if a point is one grid steps away from another in both dimensions,
	// it is considered to be 45 degrees away, even if the real angle is different)
	// this causes visible angle discrepancies if `opt.step` is much larger than `paper.gridSize`
	function fixAngleEnd(start, end, grid, opt) {

	    var step = opt.step;

	    var diffX = end.x - start.x;
	    var diffY = end.y - start.y;

	    var gridStepsX = diffX / grid.x;
	    var gridStepsY = diffY / grid.y;

	    var distanceX = gridStepsX * step;
	    var distanceY = gridStepsY * step;

	    return new Point(start.x + distanceX, start.y + distanceY);
	}

	// return the change in direction between two direction angles
	function getDirectionChange(angle1, angle2) {

	    var directionChange = Math.abs(angle1 - angle2);
	    return (directionChange > 180) ? (360 - directionChange) : directionChange;
	}

	// fix direction offsets according to current grid
	function getGridOffsets(directions, grid, opt) {

	    var step = opt.step;

	    toArray(opt.directions).forEach(function(direction) {

	        direction.gridOffsetX = (direction.offsetX / step) * grid.x;
	        direction.gridOffsetY = (direction.offsetY / step) * grid.y;
	    });
	}

	// get grid size in x and y dimensions, adapted to source and target positions
	function getGrid(step, source, target) {

	    return {
	        source: source.clone(),
	        x: getGridDimension(target.x - source.x, step),
	        y: getGridDimension(target.y - source.y, step)
	    };
	}

	// helper function for getGrid()
	function getGridDimension(diff, step) {

	    // return step if diff = 0
	    if (!diff) { return step; }

	    var absDiff = Math.abs(diff);
	    var numSteps = Math.round(absDiff / step);

	    // return absDiff if less than one step apart
	    if (!numSteps) { return absDiff; }

	    // otherwise, return corrected step
	    var roundedDiff = numSteps * step;
	    var remainder = absDiff - roundedDiff;
	    var stepCorrection = remainder / numSteps;

	    return step + stepCorrection;
	}

	// return a clone of point snapped to grid
	function snapToGrid$1(point, grid) {

	    var source = grid.source;

	    var snappedX = snapToGrid(point.x - source.x, grid.x) + source.x;
	    var snappedY = snapToGrid(point.y - source.y, grid.y) + source.y;

	    return new Point(snappedX, snappedY);
	}

	// round the point to opt.precision
	function round$4(point, precision) {

	    return point.round(precision);
	}

	// snap to grid and then round the point
	function align(point, grid, precision) {

	    return round$4(snapToGrid$1(point.clone(), grid), precision);
	}

	// return a string representing the point
	// string is rounded in both dimensions
	function getKey(point) {

	    return point.clone().toString();
	}

	// return a normalized vector from given point
	// used to determine the direction of a difference of two points
	function normalizePoint(point) {

	    return new Point(
	        point.x === 0 ? 0 : Math.abs(point.x) / point.x,
	        point.y === 0 ? 0 : Math.abs(point.y) / point.y
	    );
	}

	// PATHFINDING //

	// reconstructs a route by concatenating points with their parents
	function reconstructRoute(parents, points, tailPoint, from, to, grid, opt) {

	    var route = [];

	    var prevDiff = normalizePoint(to.difference(tailPoint));

	    // tailPoint is assumed to be aligned already
	    var currentKey = getKey(tailPoint);
	    var parent = parents[currentKey];

	    var point;
	    while (parent) {

	        // point is assumed to be aligned already
	        point = points[currentKey];

	        var diff = normalizePoint(point.difference(parent));
	        if (!diff.equals(prevDiff)) {
	            route.unshift(point);
	            prevDiff = diff;
	        }

	        // parent is assumed to be aligned already
	        currentKey = getKey(parent);
	        parent = parents[currentKey];
	    }

	    // leadPoint is assumed to be aligned already
	    var leadPoint = points[currentKey];

	    var fromDiff = normalizePoint(leadPoint.difference(from));
	    if (!fromDiff.equals(prevDiff)) {
	        route.unshift(leadPoint);
	    }

	    return route;
	}

	// heuristic method to determine the distance between two points
	function estimateCost(from, endPoints) {

	    var min = Infinity;

	    for (var i = 0, len = endPoints.length; i < len; i++) {
	        var cost = from.manhattanDistance(endPoints[i]);
	        if (cost < min) { min = cost; }
	    }

	    return min;
	}

	// find points around the bbox taking given directions into account
	// lines are drawn from anchor in given directions, intersections recorded
	// if anchor is outside bbox, only those directions that intersect get a rect point
	// the anchor itself is returned as rect point (representing some directions)
	// (since those directions are unobstructed by the bbox)
	function getRectPoints(anchor, bbox, directionList, grid, opt) {

	    var precision = opt.precision;
	    var directionMap = opt.directionMap;

	    var anchorCenterVector = anchor.difference(bbox.center());

	    var keys = isObject$1(directionMap) ? Object.keys(directionMap) : [];
	    var dirList = toArray(directionList);
	    var rectPoints = keys.reduce(function(res, key) {

	        if (dirList.includes(key)) {
	            var direction = directionMap[key];

	            // create a line that is guaranteed to intersect the bbox if bbox is in the direction
	            // even if anchor lies outside of bbox
	            var endpoint = new Point(
	                anchor.x + direction.x * (Math.abs(anchorCenterVector.x) + bbox.width),
	                anchor.y + direction.y * (Math.abs(anchorCenterVector.y) + bbox.height)
	            );
	            var intersectionLine = new Line(anchor, endpoint);

	            // get the farther intersection, in case there are two
	            // (that happens if anchor lies next to bbox)
	            var intersections = intersectionLine.intersect(bbox) || [];
	            var numIntersections = intersections.length;
	            var farthestIntersectionDistance;
	            var farthestIntersection = null;
	            for (var i = 0; i < numIntersections; i++) {
	                var currentIntersection = intersections[i];
	                var distance = anchor.squaredDistance(currentIntersection);
	                if ((farthestIntersectionDistance === undefined) || (distance > farthestIntersectionDistance)) {
	                    farthestIntersectionDistance = distance;
	                    farthestIntersection = currentIntersection;
	                }
	            }

	            // if an intersection was found in this direction, it is our rectPoint
	            if (farthestIntersection) {
	                var point = align(farthestIntersection, grid, precision);

	                // if the rectPoint lies inside the bbox, offset it by one more step
	                if (bbox.containsPoint(point)) {
	                    point = align(point.offset(direction.x * grid.x, direction.y * grid.y), grid, precision);
	                }

	                // then add the point to the result array
	                // aligned
	                res.push(point);
	            }
	        }

	        return res;
	    }, []);

	    // if anchor lies outside of bbox, add it to the array of points
	    if (!bbox.containsPoint(anchor)) {
	        // aligned
	        rectPoints.push(align(anchor, grid, precision));
	    }

	    return rectPoints;
	}

	// finds the route between two points/rectangles (`from`, `to`) implementing A* algorithm
	// rectangles get rect points assigned by getRectPoints()
	function findRoute(from, to, isPointObstacle, opt) {

	    var precision = opt.precision;

	    // Get grid for this route.

	    var sourceAnchor, targetAnchor;

	    if (from instanceof Rect) { // `from` is sourceBBox
	        sourceAnchor = round$4(getSourceAnchor$1(this, opt).clone(), precision);
	    } else {
	        sourceAnchor = round$4(from.clone(), precision);
	    }

	    if (to instanceof Rect) { // `to` is targetBBox
	        targetAnchor = round$4(getTargetAnchor$1(this, opt).clone(), precision);
	    } else {
	        targetAnchor = round$4(to.clone(), precision);
	    }

	    var grid = getGrid(opt.step, sourceAnchor, targetAnchor);

	    // Get pathfinding points.

	    var start, end; // aligned with grid by definition
	    var startPoints, endPoints; // assumed to be aligned with grid already

	    // set of points we start pathfinding from
	    if (from instanceof Rect) { // `from` is sourceBBox
	        start = sourceAnchor;
	        startPoints = getRectPoints(start, from, opt.startDirections, grid, opt);

	    } else {
	        start = sourceAnchor;
	        startPoints = [start];
	    }

	    // set of points we want the pathfinding to finish at
	    if (to instanceof Rect) { // `to` is targetBBox
	        end = targetAnchor;
	        endPoints = getRectPoints(targetAnchor, to, opt.endDirections, grid, opt);

	    } else {
	        end = targetAnchor;
	        endPoints = [end];
	    }

	    // take into account only accessible rect points (those not under obstacles)
	    startPoints = startPoints.filter(function (p) { return !isPointObstacle(p); });
	    endPoints = endPoints.filter(function (p) { return !isPointObstacle(p); });

	    // Check that there is an accessible route point on both sides.
	    // Otherwise, use fallbackRoute().
	    if (startPoints.length > 0 && endPoints.length > 0) {

	        // The set of tentative points to be evaluated, initially containing the start points.
	        // Rounded to nearest integer for simplicity.
	        var openSet = new SortedSet();
	        // Keeps reference to actual points for given elements of the open set.
	        var points = {};
	        // Keeps reference to a point that is immediate predecessor of given element.
	        var parents = {};
	        // Cost from start to a point along best known path.
	        var costs = {};

	        for (var i = 0, n = startPoints.length; i < n; i++) {
	            // startPoint is assumed to be aligned already
	            var startPoint = startPoints[i];

	            var key = getKey(startPoint);

	            openSet.add(key, estimateCost(startPoint, endPoints));
	            points[key] = startPoint;
	            costs[key] = 0;
	        }

	        var previousRouteDirectionAngle = opt.previousDirectionAngle; // undefined for first route
	        var isPathBeginning = (previousRouteDirectionAngle === undefined);

	        // directions
	        var direction, directionChange;
	        var directions = opt.directions;
	        getGridOffsets(directions, grid, opt);

	        var numDirections = directions.length;

	        var endPointsKeys = toArray(endPoints).reduce(function(res, endPoint) {
	            // endPoint is assumed to be aligned already

	            var key = getKey(endPoint);
	            res.push(key);
	            return res;
	        }, []);

	        // main route finding loop
	        var loopsRemaining = opt.maximumLoops;
	        while (!openSet.isEmpty() && loopsRemaining > 0) {

	            // remove current from the open list
	            var currentKey = openSet.pop();
	            var currentPoint = points[currentKey];
	            var currentParent = parents[currentKey];
	            var currentCost = costs[currentKey];

	            var isRouteBeginning = (currentParent === undefined); // undefined for route starts
	            var isStart = currentPoint.equals(start); // (is source anchor or `from` point) = can leave in any direction

	            var previousDirectionAngle;
	            if (!isRouteBeginning) { previousDirectionAngle = getDirectionAngle(currentParent, currentPoint, numDirections, grid, opt); } // a vertex on the route
	            else if (!isPathBeginning) { previousDirectionAngle = previousRouteDirectionAngle; } // beginning of route on the path
	            else if (!isStart) { previousDirectionAngle = getDirectionAngle(start, currentPoint, numDirections, grid, opt); } // beginning of path, start rect point
	            else { previousDirectionAngle = null; } // beginning of path, source anchor or `from` point

	            // check if we reached any endpoint
	            var samePoints = startPoints.length === endPoints.length;
	            if (samePoints) {
	                for (var j = 0; j < startPoints.length; j++) {
	                    if (!startPoints[j].equals(endPoints[j])) {
	                        samePoints = false;
	                        break;
	                    }
	                }
	            }
	            var skipEndCheck = (isRouteBeginning && samePoints);
	            if (!skipEndCheck && (endPointsKeys.indexOf(currentKey) >= 0)) {
	                opt.previousDirectionAngle = previousDirectionAngle;
	                return reconstructRoute(parents, points, currentPoint, start, end, grid, opt);
	            }

	            // go over all possible directions and find neighbors
	            for (i = 0; i < numDirections; i++) {
	                direction = directions[i];

	                var directionAngle = direction.angle;
	                directionChange = getDirectionChange(previousDirectionAngle, directionAngle);

	                // if the direction changed rapidly, don't use this point
	                // any direction is allowed for starting points
	                if (!(isPathBeginning && isStart) && directionChange > opt.maxAllowedDirectionChange) { continue; }

	                var neighborPoint = align(currentPoint.clone().offset(direction.gridOffsetX, direction.gridOffsetY), grid, precision);
	                var neighborKey = getKey(neighborPoint);

	                // Closed points from the openSet were already evaluated.
	                if (openSet.isClose(neighborKey) || isPointObstacle(neighborPoint)) { continue; }

	                // We can only enter end points at an acceptable angle.
	                if (endPointsKeys.indexOf(neighborKey) >= 0) { // neighbor is an end point

	                    var isNeighborEnd = neighborPoint.equals(end); // (is target anchor or `to` point) = can be entered in any direction

	                    if (!isNeighborEnd) {
	                        var endDirectionAngle = getDirectionAngle(neighborPoint, end, numDirections, grid, opt);
	                        var endDirectionChange = getDirectionChange(directionAngle, endDirectionAngle);

	                        if (endDirectionChange > opt.maxAllowedDirectionChange) { continue; }
	                    }
	                }

	                // The current direction is ok.

	                var neighborCost = direction.cost;
	                var neighborPenalty = isStart ? 0 : opt.penalties[directionChange]; // no penalties for start point
	                var costFromStart = currentCost + neighborCost + neighborPenalty;

	                if (!openSet.isOpen(neighborKey) || (costFromStart < costs[neighborKey])) {
	                    // neighbor point has not been processed yet
	                    // or the cost of the path from start is lower than previously calculated

	                    points[neighborKey] = neighborPoint;
	                    parents[neighborKey] = currentPoint;
	                    costs[neighborKey] = costFromStart;
	                    openSet.add(neighborKey, costFromStart + estimateCost(neighborPoint, endPoints));
	                }
	            }

	            loopsRemaining--;
	        }
	    }

	    // no route found (`to` point either wasn't accessible or finding route took
	    // way too much calculation)
	    return opt.fallbackRoute.call(this, start, end, opt);
	}

	// resolve some of the options
	function resolveOptions(opt) {

	    opt.directions = result(opt, 'directions');
	    opt.penalties = result(opt, 'penalties');
	    opt.paddingBox = result(opt, 'paddingBox');
	    opt.padding = result(opt, 'padding');

	    if (opt.padding) {
	        // if both provided, opt.padding wins over opt.paddingBox
	        var sides = normalizeSides(opt.padding);
	        opt.paddingBox = {
	            x: -sides.left,
	            y: -sides.top,
	            width: sides.left + sides.right,
	            height: sides.top + sides.bottom
	        };
	    }

	    toArray(opt.directions).forEach(function(direction) {

	        var point1 = new Point(0, 0);
	        var point2 = new Point(direction.offsetX, direction.offsetY);

	        direction.angle = normalizeAngle(point1.theta(point2));
	    });
	}

	// initialization of the route finding
	function router(vertices, opt, linkView) {

	    resolveOptions(opt);

	    // enable/disable linkView perpendicular option
	    linkView.options.perpendicular = !!opt.perpendicular;

	    var sourceBBox = getSourceBBox$1(linkView, opt);
	    var targetBBox = getTargetBBox$1(linkView, opt);

	    var sourceAnchor = getSourceAnchor$1(linkView, opt);
	    //var targetAnchor = getTargetAnchor(linkView, opt);

	    // pathfinding
	    var isPointObstacle;
	    if (typeof opt.isPointObstacle === 'function') {
	        isPointObstacle = opt.isPointObstacle;
	    } else {
	        var map = new ObstacleMap(opt);
	        map.build(linkView.paper.model, linkView.model);
	        isPointObstacle = function (point) { return !map.isPointAccessible(point); };
	    }

	    var oldVertices = toArray(vertices).map(Point);
	    var newVertices = [];
	    var tailPoint = sourceAnchor; // the origin of first route's grid, does not need snapping

	    // find a route by concatenating all partial routes (routes need to pass through vertices)
	    // source -> vertex[1] -> ... -> vertex[n] -> target
	    var to, from;

	    for (var i = 0, len = oldVertices.length; i <= len; i++) {

	        var partialRoute = null;

	        from = to || sourceBBox;
	        to = oldVertices[i];

	        if (!to) {
	            // this is the last iteration
	            // we ran through all vertices in oldVertices
	            // 'to' is not a vertex.

	            to = targetBBox;

	            // If the target is a point (i.e. it's not an element), we
	            // should use dragging route instead of main routing method if it has been provided.
	            var isEndingAtPoint = !linkView.model.get('source').id || !linkView.model.get('target').id;

	            if (isEndingAtPoint && isFunction(opt.draggingRoute)) {
	                // Make sure we are passing points only (not rects).
	                var dragFrom = (from === sourceBBox) ? sourceAnchor : from;
	                var dragTo = to.origin();

	                partialRoute = opt.draggingRoute.call(linkView, dragFrom, dragTo, opt);
	            }
	        }

	        // if partial route has not been calculated yet use the main routing method to find one
	        partialRoute = partialRoute || findRoute.call(linkView, from, to, isPointObstacle, opt);

	        if (partialRoute === null) { // the partial route cannot be found
	            return opt.fallbackRouter(vertices, opt, linkView);
	        }

	        var leadPoint = partialRoute[0];

	        // remove the first point if the previous partial route had the same point as last
	        if (leadPoint && leadPoint.equals(tailPoint)) { partialRoute.shift(); }

	        // save tailPoint for next iteration
	        tailPoint = partialRoute[partialRoute.length - 1] || tailPoint;

	        Array.prototype.push.apply(newVertices, partialRoute);
	    }

	    return newVertices;
	}

	// public function
	var manhattan = function(vertices, opt, linkView) {
	    return router(vertices, assign({}, config$2, opt), linkView);
	};

	var config$3 = {

	    maxAllowedDirectionChange: 45,

	    // cost of a diagonal step
	    diagonalCost: function() {

	        var step = this.step;
	        return Math.ceil(Math.sqrt(step * step << 1));
	    },

	    // an array of directions to find next points on the route
	    // different from start/end directions
	    directions: function() {

	        var step = this.step;
	        var cost = this.cost();
	        var diagonalCost = this.diagonalCost();

	        return [
	            { offsetX: step, offsetY: 0, cost: cost },
	            { offsetX: step, offsetY: step, cost: diagonalCost },
	            { offsetX: 0, offsetY: step, cost: cost },
	            { offsetX: -step, offsetY: step, cost: diagonalCost },
	            { offsetX: -step, offsetY: 0, cost: cost },
	            { offsetX: -step, offsetY: -step, cost: diagonalCost },
	            { offsetX: 0, offsetY: -step, cost: cost },
	            { offsetX: step, offsetY: -step, cost: diagonalCost }
	        ];
	    },

	    // a simple route used in situations when main routing method fails
	    // (exceed max number of loop iterations, inaccessible)
	    fallbackRoute: function(from, to, opt) {

	        // Find a route which breaks by 45 degrees ignoring all obstacles.

	        var theta = from.theta(to);

	        var route = [];

	        var a = { x: to.x, y: from.y };
	        var b = { x: from.x, y: to.y };

	        if (theta % 180 > 90) {
	            var t = a;
	            a = b;
	            b = t;
	        }

	        var p1 = (theta % 90) < 45 ? a : b;
	        var l1 = new Line(from, p1);

	        var alpha = 90 * Math.ceil(theta / 90);

	        var p2 = Point.fromPolar(l1.squaredLength(), toRad(alpha + 135), p1);
	        var l2 = new Line(to, p2);

	        var intersectionPoint = l1.intersection(l2);
	        var point = intersectionPoint ? intersectionPoint : to;

	        var directionFrom = intersectionPoint ? point : from;

	        var quadrant = 360 / opt.directions.length;
	        var angleTheta = directionFrom.theta(to);
	        var normalizedAngle = normalizeAngle(angleTheta + (quadrant / 2));
	        var directionAngle = quadrant * Math.floor(normalizedAngle / quadrant);

	        opt.previousDirectionAngle = directionAngle;

	        if (point) { route.push(point.round()); }
	        route.push(to);

	        return route;
	    }
	};

	// public function
	var metro = function(vertices, opt, linkView) {

	    if (!isFunction(manhattan)) {
	        throw new Error('Metro requires the manhattan router.');
	    }

	    return manhattan(vertices, assign({}, config$3, opt), linkView);
	};

	var Directions$2 = {
	    AUTO: 'auto',
	    LEFT: 'left',
	    RIGHT: 'right',
	    TOP: 'top',
	    BOTTOM: 'bottom',
	    ANCHOR_SIDE: 'anchor-side',
	    MAGNET_SIDE: 'magnet-side'
	};

	var DEFINED_DIRECTIONS = [Directions$2.LEFT, Directions$2.RIGHT, Directions$2.TOP, Directions$2.BOTTOM];

	var OPPOSITE_DIRECTIONS = {};
	OPPOSITE_DIRECTIONS[Directions$2.LEFT] = Directions$2.RIGHT;
	OPPOSITE_DIRECTIONS[Directions$2.RIGHT] = Directions$2.LEFT;
	OPPOSITE_DIRECTIONS[Directions$2.TOP] = Directions$2.BOTTOM;
	OPPOSITE_DIRECTIONS[Directions$2.BOTTOM] = Directions$2.TOP;

	var VERTICAL_DIRECTIONS = [Directions$2.TOP, Directions$2.BOTTOM];

	var ANGLE_DIRECTION_MAP = {
	    0: Directions$2.RIGHT,
	    180: Directions$2.LEFT,
	    270: Directions$2.TOP,
	    90: Directions$2.BOTTOM
	};

	function getSegmentAngle(line) {
	    // TODO: the angle() method is general and therefore unnecessarily heavy for orthogonal links
	    return line.angle();
	}

	function simplifyPoints(points) {
	    // TODO: use own more efficient implementation (filter points that do not change direction).
	    // To simplify segments that are almost aligned (start and end points differ by e.g. 0.5px), use a threshold of 1.
	    return new Polyline(points).simplify({ threshold: 1 }).points;
	}

	function resolveSides(source, target) {
	    var sourcePoint = source.point;
	    var sx0 = source.x0;
	    var sy0 = source.y0;
	    var sourceView = source.view;
	    var sourceBBox = source.bbox;
	    var sourceDirection = source.direction;
	    var targetPoint = target.point;
	    var tx0 = target.x0;
	    var ty0 = target.y0;
	    var targetView = target.view;
	    var targetBBox = target.bbox;
	    var targetDirection = target.direction;

	    var sourceSide;

	    if (!sourceView) {
	        var sourceLinkAnchorBBox = new Rect(sx0, sy0, 0, 0);
	        sourceSide = DEFINED_DIRECTIONS.includes(sourceDirection) ? sourceDirection : sourceLinkAnchorBBox.sideNearestToPoint(targetPoint);
	    } else if (sourceView.model.isLink()) {
	        sourceSide = getDirectionForLinkConnection(targetPoint, sourcePoint, sourceView);
	    } else if (sourceDirection === Directions$2.ANCHOR_SIDE) {
	        sourceSide = sourceBBox.sideNearestToPoint(sourcePoint);
	    } else if (sourceDirection === Directions$2.MAGNET_SIDE) {
	        sourceSide = sourceView.model.getBBox().sideNearestToPoint(sourcePoint);
	    } else {
	        sourceSide = sourceDirection;
	    }

	    var targetSide;

	    if (!targetView) {
	        var targetLinkAnchorBBox = new Rect(tx0, ty0, 0, 0);
	        targetSide = DEFINED_DIRECTIONS.includes(targetDirection) ? targetDirection : targetLinkAnchorBBox.sideNearestToPoint(sourcePoint);
	    } else if (targetView.model.isLink()) {
	        targetSide = getDirectionForLinkConnection(sourcePoint, targetPoint, targetView);
	    } else if (targetDirection === Directions$2.ANCHOR_SIDE) {
	        targetSide = targetBBox.sideNearestToPoint(targetPoint);
	    } else if (targetDirection === Directions$2.MAGNET_SIDE) {
	        targetSide = targetView.model.getBBox().sideNearestToPoint(targetPoint);
	    } else {
	        targetSide = targetDirection;
	    }

	    return [sourceSide, targetSide];
	}

	function resolveForTopSourceSide(source, target, nextInLine) {
	    var sx0 = source.x0;
	    var sy0 = source.y0;
	    var width = source.width;
	    var height = source.height;
	    var anchor = source.point;
	    var margin = source.margin;
	    var sx1 = sx0 + width;
	    var sy1 = sy0 + height;
	    var smx0 = sx0 - margin;
	    var smx1 = sx1 + margin;
	    var smy0 = sy0 - margin;

	    var ax = anchor.x;
	    var tx = target.x0;
	    var ty = target.y0;

	    if (tx === ax && ty < sy0) { return Directions$2.BOTTOM; }
	    if (tx < ax && ty < smy0) { return Directions$2.RIGHT; }
	    if (tx > ax && ty < smy0) { return Directions$2.LEFT; }
	    if (tx < smx0 && ty >= sy0) { return Directions$2.TOP; }
	    if (tx > smx1 && ty >= sy0) { return Directions$2.TOP; }
	    if (tx >= smx0 && tx <= ax && ty > sy1) {
	        if (nextInLine.point.x < tx) {
	            return Directions$2.RIGHT;
	        }

	        return Directions$2.LEFT;
	    }
	    if (tx <= smx1 && tx >= ax && ty > sy1) {
	        if (nextInLine.point.x < tx) {
	            return Directions$2.RIGHT;
	        }

	        return Directions$2.LEFT;
	    }

	    return Directions$2.TOP;
	}

	function resolveForBottomSourceSide(source, target, nextInLine) {
	    var sx0 = source.x0;
	    var sy0 = source.y0;
	    var width = source.width;
	    var height = source.height;
	    var anchor = source.point;
	    var margin = source.margin;
	    var sx1 = sx0 + width;
	    var sy1 = sy0 + height;
	    var smx0 = sx0 - margin;
	    var smx1 = sx1 + margin;
	    var smy1 = sy1 + margin;

	    var ax = anchor.x;
	    var tx = target.x0;
	    var ty = target.y0;

	    if (tx === ax && ty > sy1) { return Directions$2.TOP; }
	    if (tx < ax && ty > smy1) { return Directions$2.RIGHT; }
	    if (tx > ax && ty > smy1) { return Directions$2.LEFT; }
	    if (tx < smx0 && ty <= sy1) { return Directions$2.BOTTOM; }
	    if (tx > smx1 && ty <= sy1) { return Directions$2.BOTTOM; }
	    if (tx >= smx0 && tx <= ax && ty < sy0) {
	        if (nextInLine.point.x < tx) {
	            return Directions$2.RIGHT;
	        }

	        return Directions$2.LEFT;
	    }
	    if (tx <= smx1 && tx >= ax && ty < sy0) {
	        if (nextInLine.point.x < tx) {
	            return Directions$2.RIGHT;
	        }

	        return Directions$2.LEFT;
	    }

	    return Directions$2.BOTTOM;
	}

	function resolveForLeftSourceSide(source, target, nextInLine) {
	    var sy0 = source.y0;
	    var sx0 = source.x0;
	    var width = source.width;
	    var height = source.height;
	    var anchor = source.point;
	    var margin = source.margin;
	    var sx1 = sx0 + width;
	    var sy1 = sy0 + height;
	    var smx0 = sx0 - margin;
	    var smy0 = sy0 - margin;
	    var smy1 = sy1 + margin;

	    var ax = anchor.x;
	    var ay = anchor.y;
	    var tx = target.x0;
	    var ty = target.y0;

	    if (tx < ax && ty === ay) { return Directions$2.RIGHT; }
	    if (tx <= smx0 && ty < ay) { return Directions$2.BOTTOM; }
	    if (tx <= smx0 && ty > ay) { return Directions$2.TOP; }
	    if (tx >= sx0 && ty <= smy0) { return Directions$2.LEFT; }
	    if (tx >= sx0 && ty >= smy1) { return Directions$2.LEFT; }
	    if (tx > sx1 && ty >= smy0 && ty <= ay) {
	        if (nextInLine.point.y < ty) {
	            return Directions$2.BOTTOM;
	        }

	        return Directions$2.TOP;
	    }
	    if (tx > sx1 && ty <= smy1 && ty >= ay) {
	        if (nextInLine.point.y < ty) {
	            return Directions$2.BOTTOM;
	        }

	        return Directions$2.TOP;
	    }

	    return Directions$2.LEFT;
	}

	function resolveForRightSourceSide(source, target, nextInLine) {
	    var sy0 = source.y0;
	    var sx0 = source.x0;
	    var width = source.width;
	    var height = source.height;
	    var anchor = source.point;
	    var margin = source.margin;
	    var sx1 = sx0 + width;
	    var sy1 = sy0 + height;
	    var smx1 = sx1 + margin;
	    var smy0 = sy0 - margin;
	    var smy1 = sy1 + margin;

	    var ax = anchor.x;
	    var ay = anchor.y;
	    var tx = target.x0;
	    var ty = target.y0;

	    if (tx > ax && ty === ay) { return Directions$2.LEFT; }
	    if (tx >= smx1 && ty < ay) { return Directions$2.BOTTOM; }
	    if (tx >= smx1 && ty > ay) { return Directions$2.TOP; }
	    if (tx <= sx1 && ty <= smy0) { return Directions$2.RIGHT; }
	    if (tx <= sx1 && ty >= smy1) { return Directions$2.RIGHT; }
	    if (tx < sx0 && ty >= smy0 && ty <= ay) {
	        if (nextInLine.point.y < ty) {
	            return Directions$2.BOTTOM;
	        }

	        return Directions$2.TOP;
	    }
	    if (tx < sx0 && ty <= smy1 && ty >= ay) {
	        if (nextInLine.point.y < ty) {
	            return Directions$2.BOTTOM;
	        }

	        return Directions$2.TOP;
	    }

	    return Directions$2.RIGHT;
	}

	function resolveInitialDirection(source, target, nextInLine) {
	    var ref = resolveSides(source, target);
	    var sourceSide = ref[0];

	    switch (sourceSide) {
	        case Directions$2.TOP:
	            return resolveForTopSourceSide(source, target, nextInLine);
	        case Directions$2.RIGHT:
	            return resolveForRightSourceSide(source, target, nextInLine);
	        case Directions$2.BOTTOM:
	            return resolveForBottomSourceSide(source, target, nextInLine);
	        case Directions$2.LEFT:
	            return resolveForLeftSourceSide(source, target, nextInLine);
	    }
	}

	function getDirectionForLinkConnection(linkOrigin, connectionPoint, linkView) {
	    var tangent = linkView.getTangentAtLength(linkView.getClosestPointLength(connectionPoint));
	    var roundedAngle = Math.round(getSegmentAngle(tangent) / 90) * 90;

	    if (roundedAngle % 180 === 0 && linkOrigin.y === connectionPoint.y) {
	        return linkOrigin.x < connectionPoint.x ? Directions$2.LEFT : Directions$2.RIGHT;
	    } else if (linkOrigin.x === connectionPoint.x) {
	        return linkOrigin.y < connectionPoint.y ? Directions$2.TOP : Directions$2.BOTTOM;
	    }

	    switch (roundedAngle) {
	        case 0:
	        case 180:
	        case 360:
	            return linkOrigin.y < connectionPoint.y ? Directions$2.TOP : Directions$2.BOTTOM;
	        case 90:
	        case 270:
	            return linkOrigin.x < connectionPoint.x ? Directions$2.LEFT : Directions$2.RIGHT;
	    }
	}

	function pointDataFromAnchor(view, point, bbox, direction, isPort, fallBackAnchor, margin) {
	    if (direction === Directions$2.AUTO) {
	        direction = isPort ? Directions$2.MAGNET_SIDE : Directions$2.ANCHOR_SIDE;
	    }

	    var isElement = view && view.model.isElement();

	    var ref = isElement ? Rect.fromRectUnion(bbox, view.model.getBBox()) : fallBackAnchor;
	    var x0 = ref.x;
	    var y0 = ref.y;
	    var width = ref.width; if ( width === void 0 ) width = 0;
	    var height = ref.height; if ( height === void 0 ) height = 0;

	    return {
	        point: point,
	        x0: x0,
	        y0: y0,
	        view: view,
	        bbox: bbox,
	        width: width,
	        height: height,
	        direction: direction,
	        margin: isElement ? margin : 0
	    };
	}

	function pointDataFromVertex(ref) {
	    var x = ref.x;
	    var y = ref.y;

	    var point = new Point(x, y);

	    return {
	        point: point,
	        x0: point.x,
	        y0: point.y,
	        view: null,
	        bbox: new Rect(x, y, 0, 0),
	        width: 0,
	        height: 0,
	        direction: null,
	        margin: 0
	    };
	}

	function getOutsidePoint(side, pointData, margin) {
	    var outsidePoint = pointData.point.clone();

	    var x0 = pointData.x0;
	    var y0 = pointData.y0;
	    var width = pointData.width;
	    var height = pointData.height;

	    switch (side) {
	        case 'left':
	            outsidePoint.x = x0 - margin;
	            break;
	        case 'right':
	            outsidePoint.x = x0 + width + margin;
	            break;
	        case 'top':
	            outsidePoint.y = y0 - margin;
	            break;
	        case 'bottom':
	            outsidePoint.y = y0 + height + margin;
	            break;
	    }

	    return outsidePoint;
	}

	function routeBetweenPoints(source, target) {
	    var sourcePoint = source.point;
	    var sx0 = source.x0;
	    var sy0 = source.y0;
	    var sourceView = source.view;
	    var sourceWidth = source.width;
	    var sourceHeight = source.height;
	    var sourceMargin = source.margin;
	    var targetPoint = target.point;
	    var tx0 = target.x0;
	    var ty0 = target.y0;
	    var targetWidth = target.width;
	    var targetHeight = target.height;
	    var targetMargin = target.margin;

	    var tx1 = tx0 + targetWidth;
	    var ty1 = ty0 + targetHeight;
	    var sx1 = sx0 + sourceWidth;
	    var sy1 = sy0 + sourceHeight;

	    var isSourceEl = sourceView && sourceView.model.isElement();

	    // Key coordinates including the margin
	    var smx0 = sx0 - sourceMargin;
	    var smx1 = sx1 + sourceMargin;
	    var smy0 = sy0 - sourceMargin;
	    var smy1 = sy1 + sourceMargin;

	    var tmx0 = tx0 - targetMargin;
	    var tmx1 = tx1 + targetMargin;
	    var tmy0 = ty0 - targetMargin;
	    var tmy1 = ty1 + targetMargin;

	    var ref = resolveSides(source, target);
	    var sourceSide = ref[0];
	    var targetSide = ref[1];

	    var sourceOutsidePoint = getOutsidePoint(sourceSide, { point: sourcePoint, x0: sx0, y0: sy0, width: sourceWidth, height: sourceHeight }, sourceMargin);
	    var targetOutsidePoint = getOutsidePoint(targetSide, { point: targetPoint, x0: tx0, y0: ty0, width: targetWidth, height: targetHeight }, targetMargin);

	    var sox = sourceOutsidePoint.x;
	    var soy = sourceOutsidePoint.y;
	    var tox = targetOutsidePoint.x;
	    var toy = targetOutsidePoint.y;
	    var tcx = (tx0 + tx1) / 2;
	    var tcy = (ty0 + ty1) / 2;
	    var scx = (sx0 + sx1) / 2;
	    var scy = (sy0 + sy1) / 2;
	    var middleOfVerticalSides = (scx < tcx ? (sx1 + tx0) : (tx1 + sx0)) / 2;
	    var middleOfHorizontalSides = (scy < tcy ? (sy1 + ty0) : (ty1 + sy0)) / 2;

	    if (sourceSide === 'left' && targetSide === 'right') {
	        if (smx0 <= tmx1) {
	            var y = middleOfHorizontalSides;
	            if (sx1 <= tx0) {
	                if (ty1 >= smy0 && toy < soy) {
	                    y = Math.min(tmy0, smy0);
	                } else if (ty0 <= smy1 && toy >= soy) {
	                    y = Math.max(tmy1, smy1);
	                }
	            }
	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y },
	                { x: tox, y: y },
	                { x: tox, y: toy }
	            ];
	        }

	        var x = (sox + tox) / 2;
	        return [
	            { x: x, y: soy },
	            { x: x, y: toy }
	        ];
	    } else if (sourceSide === 'right' && targetSide === 'left') {
	        if (smx1 >= tmx0) {
	            var y$1 = middleOfHorizontalSides;
	            if (sox > tx1) {
	                if (ty1 >= smy0 && toy < soy) {
	                    y$1 = Math.min(tmy0, smy0);
	                } else if (ty0 <= smy1 && toy >= soy) {
	                    y$1 = Math.max(tmy1, smy1);
	                }
	            }

	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y$1 },
	                { x: tox, y: y$1 },
	                { x: tox, y: toy }
	            ];
	        }

	        var x$1 = (sox + tox) / 2;
	        return [
	            { x: x$1, y: soy },
	            { x: x$1, y: toy }
	        ];
	    } else if (sourceSide === 'top' && targetSide === 'bottom') {
	        if (soy < toy) {
	            var x$2 = middleOfVerticalSides;
	            var y$2 = soy;

	            if (soy < ty0) {
	                if (tx1 >= smx0 && tox < sox) {
	                    x$2 = Math.min(tmx0, smx0);
	                } else if (tx0 <= smx1 && tox >= sox) {
	                    x$2 = Math.max(tmx1, smx1);
	                }
	            }

	            return [
	                { x: sox, y: y$2 },
	                { x: x$2, y: y$2 },
	                { x: x$2, y: toy },
	                { x: tox, y: toy }
	            ];
	        }
	        var y$3 = (soy + toy) / 2;
	        return [
	            { x: sox, y: y$3 },
	            { x: tox, y: y$3 }
	        ];
	    } else if (sourceSide === 'bottom' && targetSide === 'top') {
	        if (soy - sourceMargin > toy) {
	            var x$3 = middleOfVerticalSides;
	            var y$4 = soy;

	            if (soy > ty1) {
	                if (tx1 >= smx0 && tox < sox) {
	                    x$3 = Math.min(tmx0, smx0);
	                } else if (tx0 <= smx1 && tox >= sox) {
	                    x$3 = Math.max(tmx1, smx1);
	                }
	            }

	            return [
	                { x: sox, y: y$4 },
	                { x: x$3, y: y$4 },
	                { x: x$3, y: toy },
	                { x: tox, y: toy }
	            ];
	        }
	        var y$5 = (soy + toy) / 2;
	        return [
	            { x: sox, y: y$5 },
	            { x: tox, y: y$5 }
	        ];
	    } else if (sourceSide === 'top' && targetSide === 'top') {
	        var x$4;
	        var y1 = Math.min((sy1 + ty0) / 2, toy);
	        var y2 = Math.min((sy0 + ty1) / 2, soy);

	        if (toy < soy) {
	            if (sox >= tmx1 || sox <= tmx0) {
	                return [
	                    { x: sox, y: Math.min(soy, toy) },
	                    { x: tox, y: Math.min(soy, toy) }
	                ];
	            } else if (tox > sox) {
	                x$4 = Math.min(sox, tmx0);
	            } else {
	                x$4 = Math.max(sox, tmx1);
	            }
	        } else {
	            if (tox >= smx1 || tox <= smx0) {
	                return [
	                    { x: sox, y: Math.min(soy, toy) },
	                    { x: tox, y: Math.min(soy, toy) }
	                ];
	            } else if (tox >= sox) {
	                x$4 = Math.max(tox, smx1);
	            } else {
	                x$4 = Math.min(tox, smx0);
	            }
	        }

	        return [
	            { x: sox, y: y2 },
	            { x: x$4, y: y2 },
	            { x: x$4, y: y1 },
	            { x: tox, y: y1 }
	        ];
	    } else if (sourceSide === 'bottom' && targetSide === 'bottom') {
	        var x$5;
	        var y1$1 = Math.max((sy0 + ty1) / 2, toy);
	        var y2$1 = Math.max((sy1 + ty0) / 2, soy);

	        if (toy > soy) {
	            if (sox >= tmx1 || sox <= tmx0) {
	                return [
	                    { x: sox, y: Math.max(soy, toy) },
	                    { x: tox, y: Math.max(soy, toy) }
	                ];
	            } else if (tox > sox) {
	                x$5 = Math.min(sox, tmx0);
	            } else {
	                x$5 = Math.max(sox, tmx1);
	            }
	        } else {
	            if (tox >= smx1 || tox <= smx0) {
	                return [
	                    { x: sox, y: Math.max(soy, toy) },
	                    { x: tox, y: Math.max(soy, toy) }
	                ];
	            } else if (tox >= sox) {
	                x$5 = Math.max(tox, smx1);
	            } else {
	                x$5 = Math.min(tox, smx0);
	            }
	        }

	        return [
	            { x: sox, y: y2$1 },
	            { x: x$5, y: y2$1 },
	            { x: x$5, y: y1$1 },
	            { x: tox, y: y1$1 }
	        ];
	    } else if (sourceSide === 'left' && targetSide === 'left') {
	        var y$6;
	        var x1 = Math.min((sx1 + tx0) / 2, tox);
	        var x2 = Math.min((sx0 + tx1) / 2, sox);

	        if (tox > sox) {
	            if (toy <= soy) {
	                y$6 = Math.min(smy0, toy);
	            } else {
	                y$6 = Math.max(smy1, toy);
	            }
	        } else {
	            if (toy >= soy) {
	                y$6 = Math.min(tmy0, soy);
	            } else {
	                y$6 = Math.max(tmy1, soy);
	            }
	        }

	        return [
	            { x: x2, y: soy },
	            { x: x2, y: y$6 },
	            { x: x1, y: y$6 },
	            { x: x1, y: toy }
	        ];
	    } else if (sourceSide === 'right' && targetSide === 'right') {
	        var y$7;
	        var x1$1 = Math.max((sx0 + tx1) / 2, tox);
	        var x2$1 = Math.max((sx1 + tx0) / 2, sox);

	        if (tox < sox) {
	            if (toy <= soy) {
	                y$7 = Math.min(smy0, toy);
	            } else {
	                y$7 = Math.max(smy1, toy);
	            }
	        } else {
	            if (toy >= soy) {
	                y$7 = Math.min(tmy0, soy);
	            } else {
	                y$7 = Math.max(tmy1, soy);
	            }
	        }

	        return [
	            { x: x2$1, y: soy },
	            { x: x2$1, y: y$7 },
	            { x: x1$1, y: y$7 },
	            { x: x1$1, y: toy }
	        ];
	    } else if (sourceSide === 'top' && targetSide === 'right') {
	        if (soy > toy) {
	            if (sox < tox) {
	                var y$8 = middleOfHorizontalSides;

	                if ((y$8 > tcy || !isSourceEl) && y$8 < tmy1 && sox < tx0) {
	                    y$8 = tmy0;
	                }
	                return [
	                    { x: sox, y: y$8 },
	                    { x: tox, y: y$8 },
	                    { x: tox, y: toy }
	                ];
	            }

	            return [{ x: sox, y: toy }];
	        }

	        var x$6 = Math.max(middleOfVerticalSides, tmx1);

	        if (tox < sox && toy > sy0 && toy < sy1) {
	            return [
	                { x: sox, y: soy },
	                { x: x$6, y: soy },
	                { x: x$6, y: toy }
	            ];
	        }

	        if ((x$6 > smx0 && toy > sy0) || tx0 > sx1) {
	            var y$9 = Math.min(sy0 - sourceMargin, ty0 - targetMargin);
	            var x$7 = Math.max(sx1 + sourceMargin, tx1 + targetMargin);
	            return [
	                { x: sox, y: y$9 },
	                { x: x$7, y: y$9 },
	                { x: x$7, y: toy }
	            ];
	        }

	        return [
	            { x: sox, y: soy },
	            { x: Math.max(x$6, tox), y: soy },
	            { x: Math.max(x$6, tox), y: toy }
	        ];
	    } else if (sourceSide === 'top' && targetSide === 'left') {
	        if (soy > toy) {
	            if (sox > tox) {
	                var y$10 = middleOfHorizontalSides;

	                if ((y$10 > tcy || !isSourceEl) && y$10 < tmy1 && sox > tx1) {
	                    y$10 = tmy0;
	                }
	                return [
	                    { x: sox, y: y$10 },
	                    { x: tox, y: y$10 },
	                    { x: tox, y: toy }
	                ];
	            }
	            return [{ x: sox, y: toy }];
	        }

	        var x$8 = Math.min(tmx0, middleOfVerticalSides);

	        if (sox < tox && sy1 >= toy) {
	            return [
	                { x: sox, y: soy },
	                { x: x$8, y: soy },
	                { x: x$8, y: toy }];
	        }

	        if (x$8 < smx1 && soy < ty1) {
	            var y$11 = Math.min(smy0, tmy0);
	            var x$9 = Math.min(smx0, tmx0);
	            return [
	                { x: sox, y: y$11 },
	                { x: x$9, y: y$11 },
	                { x: x$9, y: toy }
	            ];
	        }
	        return [
	            { x: sox, y: soy },
	            { x: x$8, y: soy },
	            { x: x$8, y: toy }
	        ];
	    } else if (sourceSide === 'bottom' && targetSide === 'right') {
	        if (soy < toy) {
	            if (sox < tox) {
	                var y$12 = middleOfHorizontalSides;

	                if ((y$12 < tcy || !isSourceEl) && y$12 > tmy0 && sox < tx0) {
	                    y$12 = tmy1;
	                }
	                return [
	                    { x: sox, y: y$12 },
	                    { x: tox, y: y$12 },
	                    { x: tox, y: toy }
	                ];
	            }
	            return [{ x: sox, y: toy }];
	        } else {
	            if (sx0 < tox) {
	                var y$13 = Math.max(smy1, tmy1);
	                var x$10 = Math.max(smx1, tmx1);
	                return [
	                    { x: sox, y: y$13 },
	                    { x: x$10, y: y$13 },
	                    { x: x$10, y: toy }
	                ];
	            }
	        }

	        var x$11 = middleOfVerticalSides;

	        return [
	            { x: sox, y: soy },
	            { x: x$11, y: soy },
	            { x: x$11, y: toy }
	        ];
	    } else if (sourceSide === 'bottom' && targetSide === 'left') {
	        if (soy < toy) {
	            if (sox > tox) {
	                var y$14 = middleOfHorizontalSides;

	                if ((y$14 < tcy || !isSourceEl) && y$14 > tmy0 && sox > tx1) {
	                    y$14 = tmy1;
	                }
	                return [
	                    { x: sox, y: y$14 },
	                    { x: tox, y: y$14 },
	                    { x: tox, y: toy }
	                ];
	            }
	            return [{ x: sox, y: toy }];
	        } else {
	            if (sx1 > tox) {
	                var y$15 = Math.max(smy1, tmy1);
	                var x$12 = Math.min(smx0, tmx0);
	                return [
	                    { x: sox, y: y$15 },
	                    { x: x$12, y: y$15 },
	                    { x: x$12, y: toy }
	                ];
	            }
	        }

	        var x$13 = middleOfVerticalSides;

	        return [
	            { x: sox, y: soy },
	            { x: x$13, y: soy },
	            { x: x$13, y: toy }
	        ];
	    }
	    else if (sourceSide === 'left' && targetSide === 'bottom') {
	        if (sox >= tox && soy >= tmy1) {
	            return [{ x: tox, y: soy }];
	        }

	        if (sox >= tx1 && soy < toy) {
	            var x$14 = middleOfVerticalSides;

	            return [
	                { x: x$14, y: soy },
	                { x: x$14, y: toy },
	                { x: tox, y: toy }
	            ];
	        }

	        if (tox < sx1 && ty1 <= sy0) {
	            var y$16 = middleOfHorizontalSides;

	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y$16 },
	                { x: tox, y: y$16 }
	            ];
	        }

	        var x$15 = Math.min(tmx0, sox);
	        var y$17 = Math.max(smy1, tmy1);

	        return [
	            { x: x$15, y: soy },
	            { x: x$15, y: y$17 },
	            { x: tox, y: y$17 }
	        ];
	    } else if (sourceSide === 'left' && targetSide === 'top') {
	        if (sox > tox && soy < tmy0) {
	            return [{ x: tox, y: soy }];
	        }

	        if (sox >= tx1) {
	            if (soy > toy) {
	                var x$16 = middleOfVerticalSides;

	                return [
	                    { x: x$16, y: soy },
	                    { x: x$16, y: toy },
	                    { x: tox, y: toy }
	                ];
	            }
	        }

	        if (tox <= sx1 && toy > soy) {
	            var y$18 = middleOfHorizontalSides;

	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y$18 },
	                { x: tox, y: y$18 } ];
	        }

	        var x$17 = toy < soy ? Math.min(smx0, tmx0) : smx0;
	        var y$19 = Math.min(smy0, tmy0);

	        return [
	            { x: x$17, y: soy },
	            { x: x$17, y: y$19 },
	            { x: tox, y: y$19 }
	        ];

	    } else if (sourceSide === 'right' && targetSide === 'top') {
	        if (sox <= tox && soy < tmy0) {
	            return [{ x: tox, y: soy }];
	        }

	        if (sx1 < tx0 && soy > toy) {
	            var x$18 = middleOfVerticalSides;

	            return [
	                { x: x$18, y: soy },
	                { x: x$18, y: toy },
	                { x: tox, y: toy }
	            ];
	        }

	        if (tox < sox && ty0 > sy1) {
	            var y$20 = middleOfHorizontalSides;

	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y$20 },
	                { x: tox, y: y$20 }
	            ];
	        }

	        var x$19 = Math.max(smx1, tmx1);
	        var y$21 = Math.min(smy0, tmy0);

	        return [
	            { x: x$19, y: soy },
	            { x: x$19, y: y$21 },
	            { x: tox, y: y$21 }
	        ];
	    } else if (sourceSide === 'right' && targetSide === 'bottom') {
	        if (sox <= tox && soy >= tmy1) {
	            return [{ x: tox, y: soy }];
	        }

	        if (sox <= tmx0 && soy < toy) {
	            var x$20 = middleOfVerticalSides;

	            return [
	                { x: x$20, y: soy },
	                { x: x$20, y: toy },
	                { x: tox, y: toy }
	            ];
	        }

	        if (tox > sx0 && ty1 < sy0) {
	            var y$22 = middleOfHorizontalSides;

	            return [
	                { x: sox, y: soy },
	                { x: sox, y: y$22 },
	                { x: tox, y: y$22 }
	            ];
	        }

	        var x$21 = Math.max(tmx1, sox);
	        var y$23 = Math.max(smy1, tmy1);

	        return [
	            { x: x$21, y: soy },
	            { x: x$21, y: y$23 },
	            { x: tox, y: y$23 }
	        ];
	    }
	}

	function rightAngleRouter(vertices, opt, linkView) {
	    var sourceDirection = opt.sourceDirection; if ( sourceDirection === void 0 ) sourceDirection = Directions$2.AUTO;
	    var targetDirection = opt.targetDirection; if ( targetDirection === void 0 ) targetDirection = Directions$2.AUTO;
	    var margin = opt.margin || 20;
	    var useVertices = opt.useVertices || false;

	    var isSourcePort = !!linkView.model.source().port;
	    var sourcePoint = pointDataFromAnchor(linkView.sourceView, linkView.sourceAnchor, linkView.sourceBBox, sourceDirection, isSourcePort, linkView.sourceAnchor, margin);

	    var isTargetPort = !!linkView.model.target().port;
	    var targetPoint = pointDataFromAnchor(linkView.targetView, linkView.targetAnchor, linkView.targetBBox, targetDirection, isTargetPort, linkView.targetAnchor, margin);

	    var resultVertices = [];

	    if (!useVertices || vertices.length === 0) {
	        return simplifyPoints(routeBetweenPoints(sourcePoint, targetPoint));
	    }

	    var verticesData = vertices.map(function (v) { return pointDataFromVertex(v); });
	    var firstVertex = verticesData[0];

	    if (sourcePoint.view && sourcePoint.view.model.isElement() && sourcePoint.view.model.getBBox().inflate(margin).containsPoint(firstVertex.point)) {
	        var ref = resolveSides(sourcePoint, firstVertex);
	        var fromDirection = ref[0];
	        var toDirection = fromDirection;
	        var dummySource = pointDataFromVertex(sourcePoint.point);
	        // Points do not usually have margin. Here we create a point with a margin.
	        dummySource.margin = margin;
	        dummySource.direction = fromDirection;
	        firstVertex.direction = toDirection;

	        resultVertices.push.apply(resultVertices, routeBetweenPoints(dummySource, firstVertex).concat( [firstVertex.point] ));
	    } else {
	        // The first point responsible for the initial direction of the route
	        var next = verticesData[1] || targetPoint;
	        var direction = resolveInitialDirection(sourcePoint, firstVertex, next);
	        firstVertex.direction = direction;

	        resultVertices.push.apply(resultVertices, routeBetweenPoints(sourcePoint, firstVertex).concat( [firstVertex.point] ));
	    }

	    for (var i = 0; i < verticesData.length - 1; i++) {
	        var from = verticesData[i];
	        var to = verticesData[i + 1];

	        var segment = new Line(from.point, to.point);
	        var segmentAngle = getSegmentAngle(segment);
	        if (segmentAngle % 90 === 0) {
	            // Since the segment is horizontal or vertical, we can skip the routing and just connect them with a straight line
	            var toDirection$1 = ANGLE_DIRECTION_MAP[segmentAngle];
	            var accessDirection = OPPOSITE_DIRECTIONS[toDirection$1];

	            if (toDirection$1 !== from.direction) {
	                resultVertices.push(from.point, to.point);
	                to.direction = accessDirection;
	            } else {
	                var angle = normalizeAngle(segmentAngle - 90);

	                var dx = 0;
	                var dy = 0;

	                if (angle === 90) {
	                    dy = -margin;
	                } else if (angle === 180) {
	                    dx = -margin;
	                } else if (angle === 270) {
	                    dy = margin;
	                } else if (angle === 0) {
	                    dx = margin;
	                }

	                var p1 = { x: from.point.x + dx, y: from.point.y + dy };
	                var p2 = { x: to.point.x + dx, y: to.point.y + dy };

	                var segment2 = new Line(to.point, p2);
	                to.direction = ANGLE_DIRECTION_MAP[getSegmentAngle(segment2)];

	                // Constructing a loop
	                resultVertices.push(from.point, p1, p2, to.point);
	            }

	            continue;
	        }

	        var ref$1 = resolveDirection(from, to);
	        var fromDirection$1 = ref$1[0];
	        var toDirection$2 = ref$1[1];

	        from.direction = fromDirection$1;
	        to.direction = toDirection$2;

	        resultVertices.push.apply(resultVertices, routeBetweenPoints(from, to).concat( [to.point] ));
	    }

	    var lastVertex = verticesData[verticesData.length - 1];

	    if (targetPoint.view && targetPoint.view.model.isElement()) {
	        if (targetPoint.view.model.getBBox().inflate(margin).containsPoint(lastVertex.point)) {
	            var ref$2 = resolveDirection(lastVertex, targetPoint);
	            var fromDirection$2 = ref$2[0];
	            var dummyTarget = pointDataFromVertex(targetPoint.point);
	            var ref$3 = resolveSides(lastVertex, targetPoint);
	            var toDirection$3 = ref$3[1];
	            // we are creating a point that has a margin
	            dummyTarget.margin = margin;
	            dummyTarget.direction = toDirection$3;
	            lastVertex.direction = fromDirection$2;

	            resultVertices.push.apply(resultVertices, routeBetweenPoints(lastVertex, dummyTarget));
	        } else {
	            // the last point of `simplified` array is the last defined vertex
	            // grab the penultimate point and construct a line segment from it to the last vertex
	            // this will ensure that the last segment continues in a straight line

	            var simplified = simplifyPoints(resultVertices);
	            var segment$1 = new Line(simplified[simplified.length - 2], lastVertex.point);
	            var definedDirection = ANGLE_DIRECTION_MAP[Math.round(getSegmentAngle(segment$1))];
	            lastVertex.direction = definedDirection;

	            var lastSegmentRoute = routeBetweenPoints(lastVertex, targetPoint);
	            var ref$4 = simplifyPoints(lastSegmentRoute.concat( [targetPoint.point]));
	            var p1$1 = ref$4[0];
	            var p2$1 = ref$4[1];

	            var lastSegment = new Line(p1$1, p2$1);
	            var roundedLastSegmentAngle = Math.round(getSegmentAngle(lastSegment));
	            var lastSegmentDirection = ANGLE_DIRECTION_MAP[roundedLastSegmentAngle];

	            if (lastSegmentDirection !== definedDirection && definedDirection === OPPOSITE_DIRECTIONS[lastSegmentDirection]) {
	                lastVertex.margin = margin;
	                lastSegmentRoute = routeBetweenPoints(lastVertex, targetPoint);
	            }

	            resultVertices.push.apply(resultVertices, lastSegmentRoute);
	        }
	    } else {
	        // since the target is only a point we can apply the same logic as if we connected two verticesData
	        var ref$5 = resolveDirection(lastVertex, targetPoint);
	        var vertexDirection = ref$5[0];
	        lastVertex.direction = vertexDirection;

	        resultVertices.push.apply(resultVertices, routeBetweenPoints(lastVertex, targetPoint));
	    }

	    return simplifyPoints(resultVertices);
	}

	function resolveDirection(from, to) {
	    var accessDirection = from.direction;
	    var isDirectionVertical = VERTICAL_DIRECTIONS.includes(accessDirection);

	    var sourceDirection = from.direction;
	    var targetDirection = to.direction;

	    if (isDirectionVertical) {
	        var isToAbove = from.point.y > to.point.y;
	        var dx = to.point.x - from.point.x;

	        if (accessDirection === Directions$2.BOTTOM) {
	            // If isToAbove === false and we need figure out if to go left or right
	            sourceDirection = isToAbove ? OPPOSITE_DIRECTIONS[accessDirection] : dx >= 0 ? Directions$2.RIGHT : Directions$2.LEFT;

	            if (dx > 0) {
	                targetDirection = isToAbove ? Directions$2.LEFT : Directions$2.TOP;
	            } else if (dx < 0) {
	                targetDirection = isToAbove ? Directions$2.RIGHT : Directions$2.TOP;
	            }
	        } else {
	            // If isToAbove === true and we need figure out if to go left or right
	            sourceDirection = isToAbove ? dx >= 0 ? Directions$2.RIGHT : Directions$2.LEFT : OPPOSITE_DIRECTIONS[accessDirection];

	            if (dx > 0) {
	                targetDirection = isToAbove ? Directions$2.BOTTOM : Directions$2.LEFT;
	            } else if (dx < 0) {
	                targetDirection = isToAbove ? Directions$2.BOTTOM : Directions$2.RIGHT;
	            }
	        }
	    } else {
	        var isToLeft = from.point.x > to.point.x;
	        var dy = to.point.y - from.point.y;

	        if (accessDirection === Directions$2.RIGHT) {
	            sourceDirection = isToLeft ? OPPOSITE_DIRECTIONS[accessDirection] : dy >= 0 ? Directions$2.BOTTOM : Directions$2.TOP;

	            if (dy > 0) {
	                targetDirection = isToLeft ? Directions$2.TOP : Directions$2.LEFT;
	            } else if (dy < 0) {
	                targetDirection = isToLeft ? Directions$2.BOTTOM : Directions$2.LEFT;
	            }
	        } else {
	            sourceDirection = isToLeft ? dy >= 0 ? Directions$2.BOTTOM : Directions$2.TOP : OPPOSITE_DIRECTIONS[accessDirection];

	            if (dy > 0) {
	                targetDirection = isToLeft ? Directions$2.RIGHT : Directions$2.TOP;
	            } else if (dy < 0) {
	                targetDirection = isToLeft ? Directions$2.RIGHT : Directions$2.BOTTOM;
	            }
	        }
	    }

	    return [sourceDirection, targetDirection];
	}

	rightAngleRouter.Directions = Directions$2;

	var rightAngle = rightAngleRouter;



	var routers = ({
		normal: normal$1,
		oneSide: oneSide,
		orthogonal: orthogonal,
		manhattan: manhattan,
		metro: metro,
		rightAngle: rightAngle
	});

	function connectionRatio(view, _magnet, _refPoint, opt) {

	    var ratio = ('ratio' in opt) ? opt.ratio : 0.5;
	    return view.getPointAtRatio(ratio);
	}

	function connectionLength(view, _magnet, _refPoint, opt) {

	    var length = ('length' in opt) ? opt.length : 20;
	    return view.getPointAtLength(length);
	}

	function _connectionPerpendicular(view, _magnet, refPoint, opt) {

	    var OFFSET = 1e6;
	    var path = view.getConnection();
	    var segmentSubdivisions = view.getConnectionSubdivisions();
	    var verticalLine = new Line(refPoint.clone().offset(0, OFFSET), refPoint.clone().offset(0, -OFFSET));
	    var horizontalLine = new Line(refPoint.clone().offset(OFFSET, 0), refPoint.clone().offset(-OFFSET, 0));
	    var verticalIntersections = verticalLine.intersect(path, { segmentSubdivisions: segmentSubdivisions });
	    var horizontalIntersections = horizontalLine.intersect(path, { segmentSubdivisions: segmentSubdivisions });
	    var intersections = [];
	    if (verticalIntersections) { Array.prototype.push.apply(intersections, verticalIntersections); }
	    if (horizontalIntersections) { Array.prototype.push.apply(intersections, horizontalIntersections); }
	    if (intersections.length > 0) { return refPoint.chooseClosest(intersections); }
	    if ('fallbackAt' in opt) {
	        return getPointAtLink(view, opt.fallbackAt);
	    }
	    return connectionClosest(view, _magnet, refPoint, opt);
	}

	function _connectionClosest(view, _magnet, refPoint, _opt) {

	    var closestPoint = view.getClosestPoint(refPoint);
	    if (!closestPoint) { return new Point(); }
	    return closestPoint;
	}

	function resolveRef(fn) {
	    return function(view, magnet, ref, opt) {
	        if (ref instanceof Element) {
	            var refView = this.paper.findView(ref);
	            var refPoint;
	            if (refView) {
	                if (refView.isNodeConnection(ref)) {
	                    var distance = ('fixedAt' in opt) ? opt.fixedAt : '50%';
	                    refPoint = getPointAtLink(refView, distance);
	                } else {
	                    refPoint = refView.getNodeBBox(ref).center();
	                }
	            } else {
	                // Something went wrong
	                refPoint = new Point();
	            }
	            return fn.call(this, view, magnet, refPoint, opt);
	        }
	        return fn.apply(this, arguments);
	    };
	}

	function getPointAtLink(view, value) {
	    var parsedValue = parseFloat(value);
	    if (isPercentage(value)) {
	        return view.getPointAtRatio(parsedValue / 100);
	    } else {
	        return view.getPointAtLength(parsedValue);
	    }
	}
	var connectionPerpendicular = resolveRef(_connectionPerpendicular);
	var connectionClosest = resolveRef(_connectionClosest);

	var linkAnchors = ({
		resolveRef: resolveRef,
		connectionRatio: connectionRatio,
		connectionLength: connectionLength,
		connectionPerpendicular: connectionPerpendicular,
		connectionClosest: connectionClosest
	});

	function bboxWrapper(method) {

	    return function(view, magnet, ref, opt) {

	        var rotate = !!opt.rotate;
	        var bbox = (rotate) ? view.getNodeUnrotatedBBox(magnet) : view.getNodeBBox(magnet);
	        var anchor = bbox[method]();

	        var dx = opt.dx;
	        if (dx) {
	            var dxPercentage = isPercentage(dx);
	            dx = parseFloat(dx);
	            if (isFinite(dx)) {
	                if (dxPercentage) {
	                    dx /= 100;
	                    dx *= bbox.width;
	                }
	                anchor.x += dx;
	            }
	        }

	        var dy = opt.dy;
	        if (dy) {
	            var dyPercentage = isPercentage(dy);
	            dy = parseFloat(dy);
	            if (isFinite(dy)) {
	                if (dyPercentage) {
	                    dy /= 100;
	                    dy *= bbox.height;
	                }
	                anchor.y += dy;
	            }
	        }

	        return (rotate) ? anchor.rotate(view.model.getBBox().center(), -view.model.angle()) : anchor;
	    };
	}

	function _perpendicular(view, magnet, refPoint, opt) {

	    var angle = view.model.angle();
	    var bbox = view.getNodeBBox(magnet);
	    var anchor = bbox.center();
	    var topLeft = bbox.origin();
	    var bottomRight = bbox.corner();

	    var padding = opt.padding;
	    if (!isFinite(padding)) { padding = 0; }

	    if ((topLeft.y + padding) <= refPoint.y && refPoint.y <= (bottomRight.y - padding)) {
	        var dy = (refPoint.y - anchor.y);
	        anchor.x += (angle === 0 || angle === 180) ? 0 : dy * 1 / Math.tan(toRad(angle));
	        anchor.y += dy;
	    } else if ((topLeft.x + padding) <= refPoint.x && refPoint.x <= (bottomRight.x - padding)) {
	        var dx = (refPoint.x - anchor.x);
	        anchor.y += (angle === 90 || angle === 270) ? 0 : dx * Math.tan(toRad(angle));
	        anchor.x += dx;
	    }

	    return anchor;
	}

	function _midSide(view, magnet, refPoint, opt) {

	    var rotate = !!opt.rotate;
	    var bbox, angle, center;
	    if (rotate) {
	        bbox = view.getNodeUnrotatedBBox(magnet);
	        center = view.model.getBBox().center();
	        angle = view.model.angle();
	    } else {
	        bbox = view.getNodeBBox(magnet);
	    }

	    var padding = opt.padding;
	    if (isFinite(padding)) { bbox.inflate(padding); }

	    if (rotate) { refPoint.rotate(center, angle); }

	    var side = bbox.sideNearestToPoint(refPoint);
	    var anchor;
	    switch (side) {
	        case 'left':
	            anchor = bbox.leftMiddle();
	            break;
	        case 'right':
	            anchor = bbox.rightMiddle();
	            break;
	        case 'top':
	            anchor = bbox.topMiddle();
	            break;
	        case 'bottom':
	            anchor = bbox.bottomMiddle();
	            break;
	    }

	    return (rotate) ? anchor.rotate(center, -angle) : anchor;
	}

	// Can find anchor from model, when there is no selector or the link end
	// is connected to a port
	function _modelCenter(view, _magnet, _refPoint, opt, endType) {
	    return view.model.getPointFromConnectedLink(this.model, endType).offset(opt.dx, opt.dy);
	}

	//joint.anchors
	var center = bboxWrapper('center');
	var top$2 = bboxWrapper('topMiddle');
	var bottom$2 = bboxWrapper('bottomMiddle');
	var left$2 = bboxWrapper('leftMiddle');
	var right$2 = bboxWrapper('rightMiddle');
	var topLeft = bboxWrapper('origin');
	var topRight = bboxWrapper('topRight');
	var bottomLeft = bboxWrapper('bottomLeft');
	var bottomRight = bboxWrapper('corner');
	var perpendicular = resolveRef(_perpendicular);
	var midSide = resolveRef(_midSide);
	var modelCenter = _modelCenter;

	var anchors = ({
		center: center,
		top: top$2,
		bottom: bottom$2,
		left: left$2,
		right: right$2,
		topLeft: topLeft,
		topRight: topRight,
		bottomLeft: bottomLeft,
		bottomRight: bottomRight,
		perpendicular: perpendicular,
		midSide: midSide,
		modelCenter: modelCenter
	});

	var GraphCells = Collection.extend({

	    initialize: function(models, opt) {

	        // Set the optional namespace where all model classes are defined.
	        if (opt.cellNamespace) {
	            this.cellNamespace = opt.cellNamespace;
	        } else {
	            /* eslint-disable no-undef */
	            this.cellNamespace = typeof joint !== 'undefined' && has$2(joint, 'shapes') ? joint.shapes : null;
	            /* eslint-enable no-undef */
	        }


	        this.graph = opt.graph;
	    },

	    model: function(attrs, opt) {

	        var collection = opt.collection;
	        var namespace = collection.cellNamespace;
	        var type = attrs.type;

	        // Find the model class based on the `type` attribute in the cell namespace
	        var ModelClass = getByPath(namespace, type, '.');
	        if (!ModelClass) {
	            throw new Error(("dia.Graph: Could not find cell constructor for type: '" + type + "'. Make sure to add the constructor to 'cellNamespace'."));
	        }

	        var cell = new ModelClass(attrs, opt);
	        // Add a reference to the graph. It is necessary to do this here because this is the earliest place
	        // where a new model is created from a plain JS object. For other objects, see `joint.dia.Graph>>_prepareCell()`.
	        if (!opt.dry) {
	            cell.graph = collection.graph;
	        }

	        return cell;
	    },

	    // `comparator` makes it easy to sort cells based on their `z` index.
	    comparator: function(model) {

	        return model.get('z') || 0;
	    }
	});


	var Graph = Model.extend({

	    initialize: function(attrs, opt) {

	        opt = opt || {};

	        // Passing `cellModel` function in the options object to graph allows for
	        // setting models based on attribute objects. This is especially handy
	        // when processing JSON graphs that are in a different than JointJS format.
	        var cells = new GraphCells([], {
	            model: opt.cellModel,
	            cellNamespace: opt.cellNamespace,
	            graph: this
	        });
	        Model.prototype.set.call(this, 'cells', cells);

	        // Make all the events fired in the `cells` collection available.
	        // to the outside world.
	        cells.on('all', this.trigger, this);

	        // JointJS automatically doesn't trigger re-sort if models attributes are changed later when
	        // they're already in the collection. Therefore, we're triggering sort manually here.
	        this.on('change:z', this._sortOnChangeZ, this);

	        // `joint.dia.Graph` keeps an internal data structure (an adjacency list)
	        // for fast graph queries. All changes that affect the structure of the graph
	        // must be reflected in the `al` object. This object provides fast answers to
	        // questions such as "what are the neighbours of this node" or "what
	        // are the sibling links of this link".

	        // Outgoing edges per node. Note that we use a hash-table for the list
	        // of outgoing edges for a faster lookup.
	        // [nodeId] -> Object [edgeId] -> true
	        this._out = {};
	        // Ingoing edges per node.
	        // [nodeId] -> Object [edgeId] -> true
	        this._in = {};
	        // `_nodes` is useful for quick lookup of all the elements in the graph, without
	        // having to go through the whole cells array.
	        // [node ID] -> true
	        this._nodes = {};
	        // `_edges` is useful for quick lookup of all the links in the graph, without
	        // having to go through the whole cells array.
	        // [edgeId] -> true
	        this._edges = {};

	        this._batches = {};

	        cells.on('add', this._restructureOnAdd, this);
	        cells.on('remove', this._restructureOnRemove, this);
	        cells.on('reset', this._restructureOnReset, this);
	        cells.on('change:source', this._restructureOnChangeSource, this);
	        cells.on('change:target', this._restructureOnChangeTarget, this);
	        cells.on('remove', this._removeCell, this);
	    },

	    _sortOnChangeZ: function() {

	        this.get('cells').sort();
	    },

	    _restructureOnAdd: function(cell) {

	        if (cell.isLink()) {
	            this._edges[cell.id] = true;
	            var ref = cell.attributes;
	            var source = ref.source;
	            var target = ref.target;
	            if (source.id) {
	                (this._out[source.id] || (this._out[source.id] = {}))[cell.id] = true;
	            }
	            if (target.id) {
	                (this._in[target.id] || (this._in[target.id] = {}))[cell.id] = true;
	            }
	        } else {
	            this._nodes[cell.id] = true;
	        }
	    },

	    _restructureOnRemove: function(cell) {

	        if (cell.isLink()) {
	            delete this._edges[cell.id];
	            var ref = cell.attributes;
	            var source = ref.source;
	            var target = ref.target;
	            if (source.id && this._out[source.id] && this._out[source.id][cell.id]) {
	                delete this._out[source.id][cell.id];
	            }
	            if (target.id && this._in[target.id] && this._in[target.id][cell.id]) {
	                delete this._in[target.id][cell.id];
	            }
	        } else {
	            delete this._nodes[cell.id];
	        }
	    },

	    _restructureOnReset: function(cells) {

	        // Normalize into an array of cells. The original `cells` is GraphCells mvc collection.
	        cells = cells.models;

	        this._out = {};
	        this._in = {};
	        this._nodes = {};
	        this._edges = {};

	        cells.forEach(this._restructureOnAdd, this);
	    },

	    _restructureOnChangeSource: function(link) {

	        var prevSource = link.previous('source');
	        if (prevSource.id && this._out[prevSource.id]) {
	            delete this._out[prevSource.id][link.id];
	        }
	        var source = link.attributes.source;
	        if (source.id) {
	            (this._out[source.id] || (this._out[source.id] = {}))[link.id] = true;
	        }
	    },

	    _restructureOnChangeTarget: function(link) {

	        var prevTarget = link.previous('target');
	        if (prevTarget.id && this._in[prevTarget.id]) {
	            delete this._in[prevTarget.id][link.id];
	        }
	        var target = link.get('target');
	        if (target.id) {
	            (this._in[target.id] || (this._in[target.id] = {}))[link.id] = true;
	        }
	    },

	    // Return all outbound edges for the node. Return value is an object
	    // of the form: [edgeId] -> true
	    getOutboundEdges: function(node) {

	        return (this._out && this._out[node]) || {};
	    },

	    // Return all inbound edges for the node. Return value is an object
	    // of the form: [edgeId] -> true
	    getInboundEdges: function(node) {

	        return (this._in && this._in[node]) || {};
	    },

	    toJSON: function() {

	        // JointJS does not recursively call `toJSON()` on attributes that are themselves models/collections.
	        // It just clones the attributes. Therefore, we must call `toJSON()` on the cells collection explicitly.
	        var json = Model.prototype.toJSON.apply(this, arguments);
	        json.cells = this.get('cells').toJSON();
	        return json;
	    },

	    fromJSON: function(json, opt) {

	        if (!json.cells) {

	            throw new Error('Graph JSON must contain cells array.');
	        }

	        return this.set(json, opt);
	    },

	    set: function(key, val, opt) {

	        var attrs;

	        // Handle both `key`, value and {key: value} style arguments.
	        if (typeof key === 'object') {
	            attrs = key;
	            opt = val;
	        } else {
	            (attrs = {})[key] = val;
	        }

	        // Make sure that `cells` attribute is handled separately via resetCells().
	        if (attrs.hasOwnProperty('cells')) {
	            this.resetCells(attrs.cells, opt);
	            attrs = omit(attrs, 'cells');
	        }

	        // The rest of the attributes are applied via original set method.
	        return Model.prototype.set.call(this, attrs, opt);
	    },

	    clear: function(opt) {

	        opt = assign({}, opt, { clear: true });

	        var collection = this.get('cells');

	        if (collection.length === 0) { return this; }

	        this.startBatch('clear', opt);

	        // The elements come after the links.
	        var cells = collection.sortBy(function(cell) {
	            return cell.isLink() ? 1 : 2;
	        });

	        do {

	            // Remove all the cells one by one.
	            // Note that all the links are removed first, so it's
	            // safe to remove the elements without removing the connected
	            // links first.
	            cells.shift().remove(opt);

	        } while (cells.length > 0);

	        this.stopBatch('clear');

	        return this;
	    },

	    _prepareCell: function(cell, opt) {

	        var attrs;
	        if (cell instanceof Model) {
	            attrs = cell.attributes;
	            if (!cell.graph && (!opt || !opt.dry)) {
	                // An element can not be member of more than one graph.
	                // A cell stops being the member of the graph after it's explicitly removed.
	                cell.graph = this;
	            }
	        } else {
	            // In case we're dealing with a plain JS object, we have to set the reference
	            // to the `graph` right after the actual model is created. This happens in the `model()` function
	            // of `joint.dia.GraphCells`.
	            attrs = cell;
	        }

	        if (!isString(attrs.type)) {
	            throw new TypeError('dia.Graph: cell type must be a string.');
	        }

	        return cell;
	    },

	    minZIndex: function() {

	        var firstCell = this.get('cells').first();
	        return firstCell ? (firstCell.get('z') || 0) : 0;
	    },

	    maxZIndex: function() {

	        var lastCell = this.get('cells').last();
	        return lastCell ? (lastCell.get('z') || 0) : 0;
	    },

	    addCell: function(cell, opt) {

	        if (Array.isArray(cell)) {

	            return this.addCells(cell, opt);
	        }

	        if (cell instanceof Model) {

	            if (!cell.has('z')) {
	                cell.set('z', this.maxZIndex() + 1);
	            }

	        } else if (cell.z === undefined) {

	            cell.z = this.maxZIndex() + 1;
	        }

	        this.get('cells').add(this._prepareCell(cell, opt), opt || {});

	        return this;
	    },

	    addCells: function(cells, opt) {

	        if (cells.length === 0) { return this; }

	        cells = flattenDeep(cells);
	        opt.maxPosition = opt.position = cells.length - 1;

	        this.startBatch('add', opt);
	        cells.forEach(function(cell) {
	            this.addCell(cell, opt);
	            opt.position--;
	        }, this);
	        this.stopBatch('add', opt);

	        return this;
	    },

	    // When adding a lot of cells, it is much more efficient to
	    // reset the entire cells collection in one go.
	    // Useful for bulk operations and optimizations.
	    resetCells: function(cells, opt) {

	        var preparedCells = toArray(cells).map(function(cell) {
	            return this._prepareCell(cell, opt);
	        }, this);
	        this.get('cells').reset(preparedCells, opt);

	        return this;
	    },

	    removeCells: function(cells, opt) {

	        if (cells.length) {

	            this.startBatch('remove');
	            invoke(cells, 'remove', opt);
	            this.stopBatch('remove');
	        }

	        return this;
	    },

	    _removeCell: function(cell, collection, options) {

	        options = options || {};

	        if (!options.clear) {
	            // Applications might provide a `disconnectLinks` option set to `true` in order to
	            // disconnect links when a cell is removed rather then removing them. The default
	            // is to remove all the associated links.
	            if (options.disconnectLinks) {

	                this.disconnectLinks(cell, options);

	            } else {

	                this.removeLinks(cell, options);
	            }
	        }
	        // Silently remove the cell from the cells collection. Silently, because
	        // `joint.dia.Cell.prototype.remove` already triggers the `remove` event which is
	        // then propagated to the graph model. If we didn't remove the cell silently, two `remove` events
	        // would be triggered on the graph model.
	        this.get('cells').remove(cell, { silent: true });

	        if (cell.graph === this) {
	            // Remove the element graph reference only if the cell is the member of this graph.
	            cell.graph = null;
	        }
	    },

	    // Get a cell by `id`.
	    getCell: function(id) {

	        return this.get('cells').get(id);
	    },

	    getCells: function() {

	        return this.get('cells').toArray();
	    },

	    getElements: function() {

	        return this.get('cells').toArray().filter(function (cell) { return cell.isElement(); });
	    },

	    getLinks: function() {

	        return this.get('cells').toArray().filter(function (cell) { return cell.isLink(); });
	    },

	    getFirstCell: function() {

	        return this.get('cells').first();
	    },

	    getLastCell: function() {

	        return this.get('cells').last();
	    },

	    // Get all inbound and outbound links connected to the cell `model`.
	    getConnectedLinks: function(model, opt) {

	        opt = opt || {};

	        var indirect = opt.indirect;
	        var inbound = opt.inbound;
	        var outbound = opt.outbound;
	        if ((inbound === undefined) && (outbound === undefined)) {
	            inbound = outbound = true;
	        }

	        // the final array of connected link models
	        var links = [];
	        // a hash table of connected edges of the form: [edgeId] -> true
	        // used for quick lookups to check if we already added a link
	        var edges = {};

	        if (outbound) {
	            addOutbounds(this, model);
	        }
	        if (inbound) {
	            addInbounds(this, model);
	        }

	        function addOutbounds(graph, model) {
	            forIn(graph.getOutboundEdges(model.id), function(_, edge) {
	                // skip links that were already added
	                // (those must be self-loop links)
	                // (because they are inbound and outbound edges of the same two elements)
	                if (edges[edge]) { return; }
	                var link = graph.getCell(edge);
	                links.push(link);
	                edges[edge] = true;
	                if (indirect) {
	                    if (inbound) { addInbounds(graph, link); }
	                    if (outbound) { addOutbounds(graph, link); }
	                }
	            }.bind(graph));
	            if (indirect && model.isLink()) {
	                var outCell = model.getTargetCell();
	                if (outCell && outCell.isLink()) {
	                    if (!edges[outCell.id]) {
	                        links.push(outCell);
	                        addOutbounds(graph, outCell);
	                    }
	                }
	            }
	        }

	        function addInbounds(graph, model) {
	            forIn(graph.getInboundEdges(model.id), function(_, edge) {
	                // skip links that were already added
	                // (those must be self-loop links)
	                // (because they are inbound and outbound edges of the same two elements)
	                if (edges[edge]) { return; }
	                var link = graph.getCell(edge);
	                links.push(link);
	                edges[edge] = true;
	                if (indirect) {
	                    if (inbound) { addInbounds(graph, link); }
	                    if (outbound) { addOutbounds(graph, link); }
	                }
	            }.bind(graph));
	            if (indirect && model.isLink()) {
	                var inCell = model.getSourceCell();
	                if (inCell && inCell.isLink()) {
	                    if (!edges[inCell.id]) {
	                        links.push(inCell);
	                        addInbounds(graph, inCell);
	                    }
	                }
	            }
	        }

	        // if `deep` option is `true`, check also all the links that are connected to any of the descendant cells
	        if (opt.deep) {

	            var embeddedCells = model.getEmbeddedCells({ deep: true });

	            // in the first round, we collect all the embedded elements
	            var embeddedElements = {};
	            embeddedCells.forEach(function(cell) {
	                if (cell.isElement()) {
	                    embeddedElements[cell.id] = true;
	                }
	            });

	            embeddedCells.forEach(function(cell) {
	                if (cell.isLink()) { return; }
	                if (outbound) {
	                    forIn(this.getOutboundEdges(cell.id), function(exists, edge) {
	                        if (!edges[edge]) {
	                            var edgeCell = this.getCell(edge);
	                            var ref = edgeCell.attributes;
	                            var source = ref.source;
	                            var target = ref.target;
	                            var sourceId = source.id;
	                            var targetId = target.id;

	                            // if `includeEnclosed` option is falsy, skip enclosed links
	                            if (!opt.includeEnclosed
	                                && (sourceId && embeddedElements[sourceId])
	                                && (targetId && embeddedElements[targetId])) {
	                                return;
	                            }

	                            links.push(this.getCell(edge));
	                            edges[edge] = true;
	                        }
	                    }.bind(this));
	                }
	                if (inbound) {
	                    forIn(this.getInboundEdges(cell.id), function(exists, edge) {
	                        if (!edges[edge]) {
	                            var edgeCell = this.getCell(edge);
	                            var ref = edgeCell.attributes;
	                            var source = ref.source;
	                            var target = ref.target;
	                            var sourceId = source.id;
	                            var targetId = target.id;

	                            // if `includeEnclosed` option is falsy, skip enclosed links
	                            if (!opt.includeEnclosed
	                                && (sourceId && embeddedElements[sourceId])
	                                && (targetId && embeddedElements[targetId])) {
	                                return;
	                            }

	                            links.push(this.getCell(edge));
	                            edges[edge] = true;
	                        }
	                    }.bind(this));
	                }
	            }, this);
	        }

	        return links;
	    },

	    getNeighbors: function(model, opt) {

	        opt || (opt = {});

	        var inbound = opt.inbound;
	        var outbound = opt.outbound;
	        if (inbound === undefined && outbound === undefined) {
	            inbound = outbound = true;
	        }

	        var neighbors = this.getConnectedLinks(model, opt).reduce(function(res, link) {

	            var ref = link.attributes;
	            var source = ref.source;
	            var target = ref.target;
	            var loop = link.hasLoop(opt);

	            // Discard if it is a point, or if the neighbor was already added.
	            if (inbound && has$2(source, 'id') && !res[source.id]) {

	                var sourceElement = this.getCell(source.id);
	                if (sourceElement.isElement()) {
	                    if (loop || (sourceElement && sourceElement !== model && (!opt.deep || !sourceElement.isEmbeddedIn(model)))) {
	                        res[source.id] = sourceElement;
	                    }
	                }
	            }

	            // Discard if it is a point, or if the neighbor was already added.
	            if (outbound && has$2(target, 'id') && !res[target.id]) {

	                var targetElement = this.getCell(target.id);
	                if (targetElement.isElement()) {
	                    if (loop || (targetElement && targetElement !== model && (!opt.deep || !targetElement.isEmbeddedIn(model)))) {
	                        res[target.id] = targetElement;
	                    }
	                }
	            }

	            return res;
	        }.bind(this), {});

	        if (model.isLink()) {
	            if (inbound) {
	                var sourceCell = model.getSourceCell();
	                if (sourceCell && sourceCell.isElement() && !neighbors[sourceCell.id]) {
	                    neighbors[sourceCell.id] = sourceCell;
	                }
	            }
	            if (outbound) {
	                var targetCell = model.getTargetCell();
	                if (targetCell && targetCell.isElement() && !neighbors[targetCell.id]) {
	                    neighbors[targetCell.id] = targetCell;
	                }
	            }
	        }

	        return toArray(neighbors);
	    },

	    getCommonAncestor: function(/* cells */) {

	        var cellsAncestors = Array.from(arguments).map(function(cell) {

	            var ancestors = [];
	            var parentId = cell.get('parent');

	            while (parentId) {

	                ancestors.push(parentId);
	                parentId = this.getCell(parentId).get('parent');
	            }

	            return ancestors;

	        }, this);

	        cellsAncestors = cellsAncestors.sort(function(a, b) {
	            return a.length - b.length;
	        });

	        var commonAncestor = toArray(cellsAncestors.shift()).find(function(ancestor) {
	            return cellsAncestors.every(function(cellAncestors) {
	                return cellAncestors.includes(ancestor);
	            });
	        });

	        return this.getCell(commonAncestor);
	    },

	    // Find the whole branch starting at `element`.
	    // If `opt.deep` is `true`, take into account embedded elements too.
	    // If `opt.breadthFirst` is `true`, use the Breadth-first search algorithm, otherwise use Depth-first search.
	    getSuccessors: function(element, opt) {

	        opt = opt || {};
	        var res = [];
	        // Modify the options so that it includes the `outbound` neighbors only. In other words, search forwards.
	        this.search(element, function(el) {
	            if (el !== element) {
	                res.push(el);
	            }
	        }, assign({}, opt, { outbound: true }));
	        return res;
	    },

	    cloneCells: cloneCells,
	    // Clone the whole subgraph (including all the connected links whose source/target is in the subgraph).
	    // If `opt.deep` is `true`, also take into account all the embedded cells of all the subgraph cells.
	    // Return a map of the form: [original cell ID] -> [clone].
	    cloneSubgraph: function(cells, opt) {

	        var subgraph = this.getSubgraph(cells, opt);
	        return this.cloneCells(subgraph);
	    },

	    // Return `cells` and all the connected links that connect cells in the `cells` array.
	    // If `opt.deep` is `true`, return all the cells including all their embedded cells
	    // and all the links that connect any of the returned cells.
	    // For example, for a single shallow element, the result is that very same element.
	    // For two elements connected with a link: `A --- L ---> B`, the result for
	    // `getSubgraph([A, B])` is `[A, L, B]`. The same goes for `getSubgraph([L])`, the result is again `[A, L, B]`.
	    getSubgraph: function(cells, opt) {

	        opt = opt || {};

	        var subgraph = [];
	        // `cellMap` is used for a quick lookup of existence of a cell in the `cells` array.
	        var cellMap = {};
	        var elements = [];
	        var links = [];

	        toArray(cells).forEach(function(cell) {
	            if (!cellMap[cell.id]) {
	                subgraph.push(cell);
	                cellMap[cell.id] = cell;
	                if (cell.isLink()) {
	                    links.push(cell);
	                } else {
	                    elements.push(cell);
	                }
	            }

	            if (opt.deep) {
	                var embeds = cell.getEmbeddedCells({ deep: true });
	                embeds.forEach(function(embed) {
	                    if (!cellMap[embed.id]) {
	                        subgraph.push(embed);
	                        cellMap[embed.id] = embed;
	                        if (embed.isLink()) {
	                            links.push(embed);
	                        } else {
	                            elements.push(embed);
	                        }
	                    }
	                });
	            }
	        });

	        links.forEach(function(link) {
	            // For links, return their source & target (if they are elements - not points).
	            var ref = link.attributes;
	            var source = ref.source;
	            var target = ref.target;
	            if (source.id && !cellMap[source.id]) {
	                var sourceElement = this.getCell(source.id);
	                subgraph.push(sourceElement);
	                cellMap[sourceElement.id] = sourceElement;
	                elements.push(sourceElement);
	            }
	            if (target.id && !cellMap[target.id]) {
	                var targetElement = this.getCell(target.id);
	                subgraph.push(this.getCell(target.id));
	                cellMap[targetElement.id] = targetElement;
	                elements.push(targetElement);
	            }
	        }, this);

	        elements.forEach(function(element) {
	            // For elements, include their connected links if their source/target is in the subgraph;
	            var links = this.getConnectedLinks(element, opt);
	            links.forEach(function(link) {
	                var ref = link.attributes;
	                var source = ref.source;
	                var target = ref.target;
	                if (!cellMap[link.id] && source.id && cellMap[source.id] && target.id && cellMap[target.id]) {
	                    subgraph.push(link);
	                    cellMap[link.id] = link;
	                }
	            });
	        }, this);

	        return subgraph;
	    },

	    // Find all the predecessors of `element`. This is a reverse operation of `getSuccessors()`.
	    // If `opt.deep` is `true`, take into account embedded elements too.
	    // If `opt.breadthFirst` is `true`, use the Breadth-first search algorithm, otherwise use Depth-first search.
	    getPredecessors: function(element, opt) {

	        opt = opt || {};
	        var res = [];
	        // Modify the options so that it includes the `inbound` neighbors only. In other words, search backwards.
	        this.search(element, function(el) {
	            if (el !== element) {
	                res.push(el);
	            }
	        }, assign({}, opt, { inbound: true }));
	        return res;
	    },

	    // Perform search on the graph.
	    // If `opt.breadthFirst` is `true`, use the Breadth-first Search algorithm, otherwise use Depth-first search.
	    // By setting `opt.inbound` to `true`, you can reverse the direction of the search.
	    // If `opt.deep` is `true`, take into account embedded elements too.
	    // `iteratee` is a function of the form `function(element) {}`.
	    // If `iteratee` explicitly returns `false`, the searching stops.
	    search: function(element, iteratee, opt) {

	        opt = opt || {};
	        if (opt.breadthFirst) {
	            this.bfs(element, iteratee, opt);
	        } else {
	            this.dfs(element, iteratee, opt);
	        }
	    },

	    // Breadth-first search.
	    // If `opt.deep` is `true`, take into account embedded elements too.
	    // If `opt.inbound` is `true`, reverse the search direction (it's like reversing all the link directions).
	    // `iteratee` is a function of the form `function(element, distance) {}`.
	    // where `element` is the currently visited element and `distance` is the distance of that element
	    // from the root `element` passed the `bfs()`, i.e. the element we started the search from.
	    // Note that the `distance` is not the shortest or longest distance, it is simply the number of levels
	    // crossed till we visited the `element` for the first time. It is especially useful for tree graphs.
	    // If `iteratee` explicitly returns `false`, the searching stops.
	    bfs: function(element, iteratee, opt) {
	        if ( opt === void 0 ) opt = {};


	        var visited = {};
	        var distance = {};
	        var queue = [];

	        queue.push(element);
	        distance[element.id] = 0;

	        while (queue.length > 0) {
	            var next = queue.shift();
	            if (visited[next.id]) { continue; }
	            visited[next.id] = true;
	            if (iteratee.call(this, next, distance[next.id]) === false) { continue; }
	            var neighbors = this.getNeighbors(next, opt);
	            for (var i = 0, n = neighbors.length; i < n; i++) {
	                var neighbor = neighbors[i];
	                distance[neighbor.id] = distance[next.id] + 1;
	                queue.push(neighbor);
	            }
	        }
	    },

	    // Depth-first search.
	    // If `opt.deep` is `true`, take into account embedded elements too.
	    // If `opt.inbound` is `true`, reverse the search direction (it's like reversing all the link directions).
	    // `iteratee` is a function of the form `function(element, distance) {}`.
	    // If `iteratee` explicitly returns `false`, the search stops.
	    dfs: function(element, iteratee, opt) {
	        if ( opt === void 0 ) opt = {};


	        var visited = {};
	        var distance = {};
	        var queue = [];

	        queue.push(element);
	        distance[element.id] = 0;

	        while (queue.length > 0) {
	            var next = queue.pop();
	            if (visited[next.id]) { continue; }
	            visited[next.id] = true;
	            if (iteratee.call(this, next, distance[next.id]) === false) { continue; }
	            var neighbors = this.getNeighbors(next, opt);
	            var lastIndex = queue.length;
	            for (var i = 0, n = neighbors.length; i < n; i++) {
	                var neighbor = neighbors[i];
	                distance[neighbor.id] = distance[next.id] + 1;
	                queue.splice(lastIndex, 0, neighbor);
	            }
	        }
	    },

	    // Get all the roots of the graph. Time complexity: O(|V|).
	    getSources: function() {

	        var sources = [];
	        forIn(this._nodes, function(exists, node) {
	            if (!this._in[node] || isEmpty(this._in[node])) {
	                sources.push(this.getCell(node));
	            }
	        }.bind(this));
	        return sources;
	    },

	    // Get all the leafs of the graph. Time complexity: O(|V|).
	    getSinks: function() {

	        var sinks = [];
	        forIn(this._nodes, function(exists, node) {
	            if (!this._out[node] || isEmpty(this._out[node])) {
	                sinks.push(this.getCell(node));
	            }
	        }.bind(this));
	        return sinks;
	    },

	    // Return `true` if `element` is a root. Time complexity: O(1).
	    isSource: function(element) {

	        return !this._in[element.id] || isEmpty(this._in[element.id]);
	    },

	    // Return `true` if `element` is a leaf. Time complexity: O(1).
	    isSink: function(element) {

	        return !this._out[element.id] || isEmpty(this._out[element.id]);
	    },

	    // Return `true` is `elementB` is a successor of `elementA`. Return `false` otherwise.
	    isSuccessor: function(elementA, elementB) {

	        var isSuccessor = false;
	        this.search(elementA, function(element) {
	            if (element === elementB && element !== elementA) {
	                isSuccessor = true;
	                return false;
	            }
	        }, { outbound: true });
	        return isSuccessor;
	    },

	    // Return `true` is `elementB` is a predecessor of `elementA`. Return `false` otherwise.
	    isPredecessor: function(elementA, elementB) {

	        var isPredecessor = false;
	        this.search(elementA, function(element) {
	            if (element === elementB && element !== elementA) {
	                isPredecessor = true;
	                return false;
	            }
	        }, { inbound: true });
	        return isPredecessor;
	    },

	    // Return `true` is `elementB` is a neighbor of `elementA`. Return `false` otherwise.
	    // `opt.deep` controls whether to take into account embedded elements as well. See `getNeighbors()`
	    // for more details.
	    // If `opt.outbound` is set to `true`, return `true` only if `elementB` is a successor neighbor.
	    // Similarly, if `opt.inbound` is set to `true`, return `true` only if `elementB` is a predecessor neighbor.
	    isNeighbor: function(elementA, elementB, opt) {

	        opt = opt || {};

	        var inbound = opt.inbound;
	        var outbound = opt.outbound;
	        if ((inbound === undefined) && (outbound === undefined)) {
	            inbound = outbound = true;
	        }

	        var isNeighbor = false;

	        this.getConnectedLinks(elementA, opt).forEach(function(link) {

	            var ref = link.attributes;
	            var source = ref.source;
	            var target = ref.target;

	            // Discard if it is a point.
	            if (inbound && has$2(source, 'id') && (source.id === elementB.id)) {
	                isNeighbor = true;
	                return false;
	            }

	            // Discard if it is a point, or if the neighbor was already added.
	            if (outbound && has$2(target, 'id') && (target.id === elementB.id)) {
	                isNeighbor = true;
	                return false;
	            }
	        });

	        return isNeighbor;
	    },

	    // Disconnect links connected to the cell `model`.
	    disconnectLinks: function(model, opt) {

	        this.getConnectedLinks(model).forEach(function(link) {

	            link.set((link.attributes.source.id === model.id ? 'source' : 'target'), { x: 0, y: 0 }, opt);
	        });
	    },

	    // Remove links connected to the cell `model` completely.
	    removeLinks: function(model, opt) {

	        invoke(this.getConnectedLinks(model), 'remove', opt);
	    },

	    // Find all elements at given point
	    findModelsFromPoint: function(p) {
	        return this.getElements().filter(function (el) { return el.getBBox({ rotate: true }).containsPoint(p); });
	    },

	    // Find all elements in given area
	    findModelsInArea: function(rect, opt) {
	        if ( opt === void 0 ) opt = {};

	        var r = new Rect(rect);
	        var strict = opt.strict; if ( strict === void 0 ) strict = false;
	        var method = strict ? 'containsRect' : 'intersect';
	        return this.getElements().filter(function (el) { return r[method](el.getBBox({ rotate: true })); });
	    },

	    // Find all elements under the given element.
	    findModelsUnderElement: function(element, opt) {
	        if ( opt === void 0 ) opt = {};

	        var searchBy = opt.searchBy; if ( searchBy === void 0 ) searchBy = 'bbox';
	        var bbox = element.getBBox().rotateAroundCenter(element.angle());
	        var elements = (searchBy === 'bbox')
	            ? this.findModelsInArea(bbox)
	            : this.findModelsFromPoint(getRectPoint(bbox, searchBy));
	        // don't account element itself or any of its descendants
	        return elements.filter(function (el) { return element.id !== el.id && !el.isEmbeddedIn(element); });
	    },

	    // Return bounding box of all elements.
	    getBBox: function() {

	        return this.getCellsBBox(this.getCells());
	    },

	    // Return the bounding box of all cells in array provided.
	    getCellsBBox: function(cells, opt) {
	        if ( opt === void 0 ) opt = {};

	        var rotate = opt.rotate; if ( rotate === void 0 ) rotate = true;
	        return toArray(cells).reduce(function(memo, cell) {
	            var rect = cell.getBBox({ rotate: rotate });
	            if (!rect) { return memo; }
	            if (memo) {
	                return memo.union(rect);
	            }
	            return rect;
	        }, null);
	    },

	    translate: function(dx, dy, opt) {

	        // Don't translate cells that are embedded in any other cell.
	        var cells = this.getCells().filter(function(cell) {
	            return !cell.isEmbedded();
	        });

	        invoke(cells, 'translate', dx, dy, opt);

	        return this;
	    },

	    resize: function(width, height, opt) {

	        return this.resizeCells(width, height, this.getCells(), opt);
	    },

	    resizeCells: function(width, height, cells, opt) {

	        // `getBBox` method returns `null` if no elements provided.
	        // i.e. cells can be an array of links
	        var bbox = this.getCellsBBox(cells);
	        if (bbox) {
	            var sx = Math.max(width / bbox.width, 0);
	            var sy = Math.max(height / bbox.height, 0);
	            invoke(cells, 'scale', sx, sy, bbox.origin(), opt);
	        }

	        return this;
	    },

	    startBatch: function(name, data) {

	        data = data || {};
	        this._batches[name] = (this._batches[name] || 0) + 1;

	        return this.trigger('batch:start', assign({}, data, { batchName: name }));
	    },

	    stopBatch: function(name, data) {

	        data = data || {};
	        this._batches[name] = (this._batches[name] || 0) - 1;

	        return this.trigger('batch:stop', assign({}, data, { batchName: name }));
	    },

	    hasActiveBatch: function(name) {

	        var batches = this._batches;
	        var names;

	        if (arguments.length === 0) {
	            names = Object.keys(batches);
	        } else if (Array.isArray(name)) {
	            names = name;
	        } else {
	            names = [name];
	        }

	        return names.some(function (batch) { return batches[batch] > 0; });
	    }

	}, {

	    validations: {

	        multiLinks: function(graph, link) {

	            // Do not allow multiple links to have the same source and target.
	            var ref = link.attributes;
	            var source = ref.source;
	            var target = ref.target;

	            if (source.id && target.id) {

	                var sourceModel = link.getSourceCell();
	                if (sourceModel) {

	                    var connectedLinks = graph.getConnectedLinks(sourceModel, { outbound: true });
	                    var sameLinks = connectedLinks.filter(function(_link) {

	                        var ref = _link.attributes;
	                        var _source = ref.source;
	                        var _target = ref.target;
	                        return _source && _source.id === source.id &&
	                            (!_source.port || (_source.port === source.port)) &&
	                            _target && _target.id === target.id &&
	                            (!_target.port || (_target.port === target.port));

	                    });

	                    if (sameLinks.length > 1) {
	                        return false;
	                    }
	                }
	            }

	            return true;
	        },

	        linkPinning: function(_graph, link) {
	            var ref = link.attributes;
	            var source = ref.source;
	            var target = ref.target;
	            return source.id && target.id;
	        }
	    }

	});

	wrapWith(Graph.prototype, ['resetCells', 'addCells', 'removeCells'], wrappers.cells);

	var LayersNames = {
	    GRID: 'grid',
	    CELLS: 'cells',
	    BACK: 'back',
	    FRONT: 'front',
	    TOOLS: 'tools',
	    LABELS: 'labels'
	};

	var PaperLayer = View.extend({

	    tagName: 'g',
	    svgElement: true,
	    pivotNodes: null,
	    defaultTheme: null,

	    options: {
	        name: ''
	    },

	    className: function() {
	        return addClassNamePrefix(((this.options.name) + "-layer"));
	    },

	    init: function() {
	        this.pivotNodes = {};
	    },

	    insertSortedNode: function(node, z) {
	        this.el.insertBefore(node, this.insertPivot(z));
	    },

	    insertNode: function(node) {
	        var ref = this;
	        var el = ref.el;
	        if (node.parentNode !== el) {
	            el.appendChild(node);
	        }
	    },

	    insertPivot: function(z) {
	        var ref = this;
	        var el = ref.el;
	        var pivotNodes = ref.pivotNodes;
	        z = +z;
	        z || (z = 0);
	        var pivotNode = pivotNodes[z];
	        if (pivotNode) { return pivotNode; }
	        pivotNode = pivotNodes[z] = document.createComment('z-index:' + (z + 1));
	        var neighborZ = -Infinity;
	        for (var currentZ in pivotNodes) {
	            currentZ = +currentZ;
	            if (currentZ < z && currentZ > neighborZ) {
	                neighborZ = currentZ;
	                if (neighborZ === z - 1) { continue; }
	            }
	        }
	        if (neighborZ !== -Infinity) {
	            var neighborPivot = pivotNodes[neighborZ];
	            // Insert After
	            el.insertBefore(pivotNode, neighborPivot.nextSibling);
	        } else {
	            // First Child
	            el.insertBefore(pivotNode, el.firstChild);
	        }
	        return pivotNode;
	    },

	    removePivots: function() {
	        var ref = this;
	        var el = ref.el;
	        var pivotNodes = ref.pivotNodes;
	        for (var z in pivotNodes) { el.removeChild(pivotNodes[z]); }
	        this.pivotNodes = {};
	    }

	});

	var calcAttributesList = [
	    'transform',
	    'x',
	    'y',
	    'cx',
	    'cy',
	    'dx',
	    'dy',
	    'x1',
	    'y1',
	    'x2',
	    'y2',
	    'points',
	    'd',
	    'r',
	    'rx',
	    'ry',
	    'width',
	    'height',
	    'stroke-width',
	    'font-size' ];

	var positiveValueList = [
	    'r',
	    'rx',
	    'ry',
	    'width',
	    'height',
	    'stroke-width',
	    'font-size' ];

	var calcAttributes = calcAttributesList.reduce(function (acc, attrName) {
	    acc[attrName] = true;
	    return acc;
	}, {});

	var positiveValueAttributes = positiveValueList.reduce(function (acc, attrName) {
	    acc[attrName] = true;
	    return acc;
	}, {});

	function evalAttributes(attrs, refBBox) {
	    var evalAttrs = {};
	    for (var attrName in attrs) {
	        if (!attrs.hasOwnProperty(attrName)) { continue; }
	        evalAttrs[attrName] = evalAttribute(attrName, attrs[attrName], refBBox);
	    }
	    return evalAttrs;
	}

	function evalAttribute(attrName, attrValue, refBBox) {
	    if (attrName in calcAttributes && isCalcAttribute(attrValue)) {
	        var evalAttrValue = evalCalcAttribute(attrValue, refBBox);
	        if (attrName in positiveValueAttributes) {
	            evalAttrValue = Math.max(0, evalAttrValue);
	        }
	        return evalAttrValue;
	    }
	    return attrValue;
	}

	var HighlightingTypes = {
	    DEFAULT: 'default',
	    EMBEDDING: 'embedding',
	    CONNECTING: 'connecting',
	    MAGNET_AVAILABILITY: 'magnetAvailability',
	    ELEMENT_AVAILABILITY: 'elementAvailability'
	};

	var Flags = {
	    TOOLS: 'TOOLS',
	};

	// CellView base view and controller.
	// --------------------------------------------

	// This is the base view and controller for `ElementView` and `LinkView`.
	var CellView = View.extend({

	    tagName: 'g',

	    svgElement: true,

	    selector: 'root',

	    metrics: null,

	    className: function() {

	        var classNames = ['cell'];
	        var type = this.model.get('type');

	        if (type) {

	            type.toLowerCase().split('.').forEach(function(value, index, list) {
	                classNames.push('type-' + list.slice(0, index + 1).join('-'));
	            });
	        }

	        return classNames.join(' ');
	    },

	    _presentationAttributes: null,
	    _flags: null,

	    setFlags: function() {
	        var flags = {};
	        var attributes = {};
	        var shift = 0;
	        var i, n, label;
	        var presentationAttributes = result(this, 'presentationAttributes');
	        for (var attribute in presentationAttributes) {
	            if (!presentationAttributes.hasOwnProperty(attribute)) { continue; }
	            var labels = presentationAttributes[attribute];
	            if (!Array.isArray(labels)) { labels = [labels]; }
	            for (i = 0, n = labels.length; i < n; i++) {
	                label = labels[i];
	                var flag = flags[label];
	                if (!flag) {
	                    flag = flags[label] = 1<<(shift++);
	                }
	                attributes[attribute] |= flag;
	            }
	        }
	        var initFlag = result(this, 'initFlag');
	        if (!Array.isArray(initFlag)) { initFlag = [initFlag]; }
	        for (i = 0, n = initFlag.length; i < n; i++) {
	            label = initFlag[i];
	            if (!flags[label]) { flags[label] = 1<<(shift++); }
	        }

	        // 26 - 30 are reserved for paper flags
	        // 31+ overflows maximal number
	        if (shift > 25) { throw new Error('dia.CellView: Maximum number of flags exceeded.'); }

	        this._flags = flags;
	        this._presentationAttributes = attributes;
	    },

	    hasFlag: function(flag, label) {
	        return flag & this.getFlag(label);
	    },

	    removeFlag: function(flag, label) {
	        return flag ^ (flag & this.getFlag(label));
	    },

	    getFlag: function(label) {
	        var flags = this._flags;
	        if (!flags) { return 0; }
	        var flag = 0;
	        if (Array.isArray(label)) {
	            for (var i = 0, n = label.length; i < n; i++) { flag |= flags[label[i]]; }
	        } else {
	            flag |= flags[label];
	        }
	        return flag;
	    },

	    attributes: function() {
	        var cell = this.model;
	        return {
	            'model-id': cell.id,
	            'data-type': cell.attributes.type
	        };
	    },

	    constructor: function(options) {

	        // Make sure a global unique id is assigned to this view. Store this id also to the properties object.
	        // The global unique id makes sure that the same view can be rendered on e.g. different machines and
	        // still be associated to the same object among all those clients. This is necessary for real-time
	        // collaboration mechanism.
	        options.id = options.id || guid(this);

	        View.call(this, options);
	    },

	    initialize: function() {

	        this.setFlags();

	        View.prototype.initialize.apply(this, arguments);

	        this.cleanNodesCache();

	        this.startListening();
	    },

	    startListening: function() {
	        this.listenTo(this.model, 'change', this.onAttributesChange);
	    },

	    onAttributesChange: function(model, opt) {
	        var flag = model.getChangeFlag(this._presentationAttributes);
	        if (opt.updateHandled || !flag) { return; }
	        if (opt.dirty && this.hasFlag(flag, 'UPDATE')) { flag |= this.getFlag('RENDER'); }
	        // TODO: tool changes does not need to be sync
	        // Fix Segments tools
	        if (opt.tool) { opt.async = false; }
	        this.requestUpdate(flag, opt);
	    },

	    requestUpdate: function(flags, opt) {
	        var ref = this;
	        var paper = ref.paper;
	        if (paper && flags > 0) {
	            paper.requestViewUpdate(this, flags, this.UPDATE_PRIORITY, opt);
	        }
	    },

	    parseDOMJSON: function(markup, root) {

	        var doc = parseDOMJSON(markup);
	        var selectors = doc.selectors;
	        var groups = doc.groupSelectors;
	        for (var group in groups) {
	            if (selectors[group]) { throw new Error('dia.CellView: ambiguous group selector'); }
	            selectors[group] = groups[group];
	        }
	        if (root) {
	            var rootSelector = this.selector;
	            if (selectors[rootSelector]) { throw new Error('dia.CellView: ambiguous root selector.'); }
	            selectors[rootSelector] = root;
	        }
	        return { fragment: doc.fragment, selectors: selectors };
	    },

	    // Return `true` if cell link is allowed to perform a certain UI `feature`.
	    // Example: `can('labelMove')`.
	    can: function(feature) {

	        var interactive = isFunction(this.options.interactive)
	            ? this.options.interactive(this)
	            : this.options.interactive;

	        return (isObject$1(interactive) && interactive[feature] !== false) ||
	            (isBoolean(interactive) && interactive !== false);
	    },

	    findBySelector: function(selector, root, selectors) {

	        // These are either descendants of `this.$el` of `this.$el` itself.
	        // `.` is a special selector used to select the wrapping `<g>` element.
	        if (!selector || selector === '.') { return [root]; }
	        if (selectors) {
	            var nodes = selectors[selector];
	            if (nodes) {
	                if (Array.isArray(nodes)) { return nodes; }
	                return [nodes];
	            }
	        }

	        // Maintaining backwards compatibility
	        // e.g. `circle:first` would fail with querySelector() call
	        if (this.useCSSSelectors) { return $(root).find(selector).toArray(); }

	        return [];
	    },

	    findNodes: function(selector) {
	        return this.findBySelector(selector, this.el, this.selectors);
	    },

	    findNode: function(selector) {
	        var ref = this.findNodes(selector);
	        var node = ref[0]; if ( node === void 0 ) node = null;
	        return node;
	    },

	    notify: function(eventName) {

	        if (this.paper) {

	            var args = Array.prototype.slice.call(arguments, 1);

	            // Trigger the event on both the element itself and also on the paper.
	            this.trigger.apply(this, [eventName].concat(args));

	            // Paper event handlers receive the view object as the first argument.
	            this.paper.trigger.apply(this.paper, [eventName, this].concat(args));
	        }
	    },

	    getBBox: function(opt) {

	        var bbox;
	        if (opt && opt.useModelGeometry) {
	            var model = this.model;
	            bbox = model.getBBox().bbox(model.angle());
	        } else {
	            bbox = this.getNodeBBox(this.el);
	        }

	        return this.paper.localToPaperRect(bbox);
	    },

	    getNodeBBox: function(magnet) {

	        var rect = this.getNodeBoundingRect(magnet);
	        var transformMatrix = this.getRootTranslateMatrix().multiply(this.getNodeRotateMatrix(magnet));
	        var magnetMatrix = this.getNodeMatrix(magnet);
	        return V.transformRect(rect, transformMatrix.multiply(magnetMatrix));
	    },

	    getNodeRotateMatrix: function getNodeRotateMatrix(node) {
	        if (!this.rotatableNode || this.rotatableNode.contains(node)) {
	            // Rotate transformation is applied to all nodes when no rotatableGroup
	            // is present or to nodes inside the rotatableGroup only.
	            return this.getRootRotateMatrix();
	        }
	        // Nodes outside the rotatable group
	        return V.createSVGMatrix();
	    },

	    getNodeUnrotatedBBox: function(magnet) {

	        var rect = this.getNodeBoundingRect(magnet);
	        var magnetMatrix = this.getNodeMatrix(magnet);
	        var translateMatrix = this.getRootTranslateMatrix();
	        return V.transformRect(rect, translateMatrix.multiply(magnetMatrix));
	    },

	    getRootTranslateMatrix: function() {

	        var model = this.model;
	        var position = model.position();
	        var mt = V.createSVGMatrix().translate(position.x, position.y);
	        return mt;
	    },

	    getRootRotateMatrix: function() {

	        var mr = V.createSVGMatrix();
	        var model = this.model;
	        var angle = model.angle();
	        if (angle) {
	            var bbox = model.getBBox();
	            var cx = bbox.width / 2;
	            var cy = bbox.height / 2;
	            mr = mr.translate(cx, cy).rotate(angle).translate(-cx, -cy);
	        }
	        return mr;
	    },

	    _notifyHighlight: function(eventName, el, opt) {
	        var assign;

	        if ( opt === void 0 ) opt = {};
	        var ref = this;
	        var rootNode = ref.el;
	        var node;
	        if (typeof el === 'string') {
	            node = this.findNode(el) || rootNode;
	        } else {
	            (assign = this.$(el), node = assign[0], node = node === void 0 ? rootNode : node);
	        }
	        // set partial flag if the highlighted element is not the entire view.
	        opt.partial = (node !== rootNode);
	        // translate type flag into a type string
	        if (opt.type === undefined) {
	            var type;
	            switch (true) {
	                case opt.embedding:
	                    type = HighlightingTypes.EMBEDDING;
	                    break;
	                case opt.connecting:
	                    type = HighlightingTypes.CONNECTING;
	                    break;
	                case opt.magnetAvailability:
	                    type = HighlightingTypes.MAGNET_AVAILABILITY;
	                    break;
	                case opt.elementAvailability:
	                    type = HighlightingTypes.ELEMENT_AVAILABILITY;
	                    break;
	                default:
	                    type = HighlightingTypes.DEFAULT;
	                    break;
	            }
	            opt.type = type;
	        }
	        this.notify(eventName, node, opt);
	        return this;
	    },

	    highlight: function(el, opt) {
	        return this._notifyHighlight('cell:highlight', el, opt);
	    },

	    unhighlight: function(el, opt) {
	        if ( opt === void 0 ) opt = {};

	        return this._notifyHighlight('cell:unhighlight', el, opt);
	    },

	    // Find the closest element that has the `magnet` attribute set to `true`. If there was not such
	    // an element found, return the root element of the cell view.
	    findMagnet: function(el) {

	        var root = this.el;
	        var magnet = this.$(el)[0];
	        if (!magnet) {
	            magnet = root;
	        }

	        do {
	            var magnetAttribute = magnet.getAttribute('magnet');
	            var isMagnetRoot = (magnet === root);
	            if ((magnetAttribute || isMagnetRoot) && magnetAttribute !== 'false') {
	                return magnet;
	            }
	            if (isMagnetRoot) {
	                // If the overall cell has set `magnet === false`, then return `undefined` to
	                // announce there is no magnet found for this cell.
	                // This is especially useful to set on cells that have 'ports'. In this case,
	                // only the ports have set `magnet === true` and the overall element has `magnet === false`.
	                return undefined;
	            }
	            magnet = magnet.parentNode;
	        } while (magnet);

	        return undefined;
	    },

	    findProxyNode: function(el, type) {
	        el || (el = this.el);
	        var nodeSelector = el.getAttribute((type + "-selector"));
	        if (nodeSelector) {
	            var proxyNode = this.findNode(nodeSelector);
	            if (proxyNode) { return proxyNode; }
	        }
	        return el;
	    },

	    // Construct a unique selector for the `el` element within this view.
	    // `prevSelector` is being collected through the recursive call.
	    // No value for `prevSelector` is expected when using this method.
	    getSelector: function(el, prevSelector) {

	        var selector;

	        if (el === this.el) {
	            if (typeof prevSelector === 'string') { selector = ':scope > ' + prevSelector; }
	            return selector;
	        }

	        if (el) {

	            var nthChild = V(el).index() + 1;
	            selector = el.tagName + ':nth-child(' + nthChild + ')';

	            if (prevSelector) {
	                selector += ' > ' + prevSelector;
	            }

	            selector = this.getSelector(el.parentNode, selector);
	        }

	        return selector;
	    },

	    addLinkFromMagnet: function(magnet, x, y) {

	        var paper = this.paper;
	        var graph = paper.model;

	        var link = paper.getDefaultLink(this, magnet);
	        link.set({
	            source: this.getLinkEnd(magnet, x, y, link, 'source'),
	            target: { x: x, y: y }
	        }).addTo(graph, {
	            async: false,
	            ui: true
	        });

	        return link.findView(paper);
	    },

	    getLinkEnd: function(magnet) {
	        var ref;

	        var args = [], len = arguments.length - 1;
	        while ( len-- > 0 ) args[ len ] = arguments[ len + 1 ];

	        var model = this.model;
	        var id = model.id;
	        var port = this.findAttribute('port', magnet);
	        // Find a unique `selector` of the element under pointer that is a magnet.
	        var selector = magnet.getAttribute('joint-selector');

	        var end = { id: id };
	        if (selector != null) { end.magnet = selector; }
	        if (port != null) {
	            end.port = port;
	            if (!model.hasPort(port) && !selector) {
	                // port created via the `port` attribute (not API)
	                end.selector = this.getSelector(magnet);
	            }
	        } else if (selector == null && this.el !== magnet) {
	            end.selector = this.getSelector(magnet);
	        }

	        return (ref = this).customizeLinkEnd.apply(ref, [ end, magnet ].concat( args ));
	    },

	    customizeLinkEnd: function(end, magnet, x, y, link, endType) {
	        var ref = this;
	        var paper = ref.paper;
	        var ref$1 = paper.options;
	        var connectionStrategy = ref$1.connectionStrategy;
	        if (typeof connectionStrategy === 'function') {
	            var strategy = connectionStrategy.call(paper, end, this, magnet, new Point(x, y), link, endType, paper);
	            if (strategy) { return strategy; }
	        }
	        return end;
	    },

	    getMagnetFromLinkEnd: function(end) {

	        var port = end.port;
	        var selector = end.magnet;
	        var model = this.model;
	        var magnet;
	        if (port != null && model.isElement() && model.hasPort(port)) {
	            magnet = this.findPortNode(port, selector) || this.el;
	        } else {
	            if (!selector) { selector = end.selector; }
	            if (!selector && port != null) {
	                // link end has only `id` and `port` property referencing
	                // a port created via the `port` attribute (not API).
	                selector = '[port="' + port + '"]';
	            }
	            magnet = this.findNode(selector);
	        }

	        return this.findProxyNode(magnet, 'magnet');
	    },

	    dragLinkStart: function(evt, magnet, x, y) {
	        this.model.startBatch('add-link');
	        var linkView = this.addLinkFromMagnet(magnet, x, y);
	        // backwards compatibility events
	        linkView.notifyPointerdown(evt, x, y);
	        linkView.eventData(evt, linkView.startArrowheadMove('target', { whenNotAllowed: 'remove' }));
	        this.eventData(evt, { linkView: linkView });
	    },

	    dragLink: function(evt, x, y) {
	        var data = this.eventData(evt);
	        var linkView = data.linkView;
	        if (linkView) {
	            linkView.pointermove(evt, x, y);
	        } else {
	            var paper = this.paper;
	            var magnetThreshold = paper.options.magnetThreshold;
	            var currentTarget = this.getEventTarget(evt);
	            var targetMagnet = data.targetMagnet;
	            if (magnetThreshold === 'onleave') {
	                // magnetThreshold when the pointer leaves the magnet
	                if (targetMagnet === currentTarget || V(targetMagnet).contains(currentTarget)) { return; }
	            } else {
	                // magnetThreshold defined as a number of movements
	                if (paper.eventData(evt).mousemoved <= magnetThreshold) { return; }
	            }
	            this.dragLinkStart(evt, targetMagnet, x, y);
	        }
	    },

	    dragLinkEnd: function(evt, x, y) {
	        var data = this.eventData(evt);
	        var linkView = data.linkView;
	        if (!linkView) { return; }
	        linkView.pointerup(evt, x, y);
	        this.model.stopBatch('add-link');
	    },

	    getAttributeDefinition: function(attrName) {

	        return this.model.constructor.getAttributeDefinition(attrName);
	    },

	    setNodeAttributes: function(node, attrs) {

	        if (!isEmpty(attrs)) {
	            if (node instanceof SVGElement) {
	                V(node).attr(attrs);
	            } else {
	                $(node).attr(attrs);
	            }
	        }
	    },

	    processNodeAttributes: function(node, attrs) {

	        var attrName, attrVal, def, i, n;
	        var normalAttrs, setAttrs, positionAttrs, offsetAttrs;
	        var relatives = [];
	        var rawAttrs = {};
	        for (attrName in attrs) {
	            if (!attrs.hasOwnProperty(attrName)) { continue; }
	            rawAttrs[V.attributeNames[attrName]] = attrs[attrName];
	        }
	        // divide the attributes between normal and special
	        for (attrName in rawAttrs) {
	            if (!rawAttrs.hasOwnProperty(attrName)) { continue; }
	            attrVal = rawAttrs[attrName];
	            def = this.getAttributeDefinition(attrName);
	            if (def && (!isFunction(def.qualify) || def.qualify.call(this, attrVal, node, rawAttrs, this))) {
	                if (isString(def.set)) {
	                    normalAttrs || (normalAttrs = {});
	                    normalAttrs[def.set] = attrVal;
	                }
	                if (attrVal !== null) {
	                    relatives.push(attrName, def);
	                }
	            } else {
	                normalAttrs || (normalAttrs = {});
	                normalAttrs[attrName] = attrVal;
	            }
	        }

	        // handle the rest of attributes via related method
	        // from the special attributes namespace.
	        for (i = 0, n = relatives.length; i < n; i+=2) {
	            attrName = relatives[i];
	            def = relatives[i+1];
	            attrVal = attrs[attrName];
	            if (isFunction(def.set)) {
	                setAttrs || (setAttrs = {});
	                setAttrs[attrName] = attrVal;
	            }
	            if (isFunction(def.position)) {
	                positionAttrs || (positionAttrs = {});
	                positionAttrs[attrName] = attrVal;
	            }
	            if (isFunction(def.offset)) {
	                offsetAttrs || (offsetAttrs = {});
	                offsetAttrs[attrName] = attrVal;
	            }
	        }

	        return {
	            raw: rawAttrs,
	            normal: normalAttrs,
	            set: setAttrs,
	            position: positionAttrs,
	            offset: offsetAttrs
	        };
	    },

	    updateRelativeAttributes: function(node, attrs, refBBox, opt) {

	        opt || (opt = {});

	        var attrName, attrVal, def;
	        var evalAttrs = evalAttributes(attrs.raw || {}, refBBox);
	        var nodeAttrs = attrs.normal || {};
	        for (var nodeAttrName in nodeAttrs) {
	            nodeAttrs[nodeAttrName] = evalAttrs[nodeAttrName];
	        }
	        var setAttrs = attrs.set;
	        var positionAttrs = attrs.position;
	        var offsetAttrs = attrs.offset;

	        for (attrName in setAttrs) {
	            attrVal = evalAttrs[attrName];
	            def = this.getAttributeDefinition(attrName);
	            // SET - set function should return attributes to be set on the node,
	            // which will affect the node dimensions based on the reference bounding
	            // box. e.g. `width`, `height`, `d`, `rx`, `ry`, `points
	            var setResult = def.set.call(this, attrVal, refBBox.clone(), node, evalAttrs, this);
	            if (isObject$1(setResult)) {
	                assign(nodeAttrs, setResult);
	            } else if (setResult !== undefined) {
	                nodeAttrs[attrName] = setResult;
	            }
	        }

	        if (node instanceof HTMLElement) {
	            // TODO: setting the `transform` attribute on HTMLElements
	            // via `node.style.transform = 'matrix(...)';` would introduce
	            // a breaking change (e.g. basic.TextBlock).
	            this.setNodeAttributes(node, nodeAttrs);
	            return;
	        }

	        // The final translation of the subelement.
	        var nodeTransform = nodeAttrs.transform;
	        var nodeMatrix = V.transformStringToMatrix(nodeTransform);
	        var nodePosition = Point(nodeMatrix.e, nodeMatrix.f);
	        if (nodeTransform) {
	            nodeAttrs = omit(nodeAttrs, 'transform');
	            nodeMatrix.e = nodeMatrix.f = 0;
	        }

	        // Calculate node scale determined by the scalable group
	        // only if later needed.
	        var sx, sy, translation;
	        if (positionAttrs || offsetAttrs) {
	            var nodeScale = this.getNodeScale(node, opt.scalableNode);
	            sx = nodeScale.sx;
	            sy = nodeScale.sy;
	        }

	        var positioned = false;
	        for (attrName in positionAttrs) {
	            attrVal = evalAttrs[attrName];
	            def = this.getAttributeDefinition(attrName);
	            // POSITION - position function should return a point from the
	            // reference bounding box. The default position of the node is x:0, y:0 of
	            // the reference bounding box or could be further specify by some
	            // SVG attributes e.g. `x`, `y`
	            translation = def.position.call(this, attrVal, refBBox.clone(), node, evalAttrs, this);
	            if (translation) {
	                nodePosition.offset(Point(translation).scale(sx, sy));
	                positioned || (positioned = true);
	            }
	        }

	        // The node bounding box could depend on the `size` set from the previous loop.
	        // Here we know, that all the size attributes have been already set.
	        this.setNodeAttributes(node, nodeAttrs);

	        var offseted = false;
	        if (offsetAttrs) {
	            // Check if the node is visible
	            var nodeBoundingRect = this.getNodeBoundingRect(node);
	            if (nodeBoundingRect.width > 0 && nodeBoundingRect.height > 0) {
	                var nodeBBox = V.transformRect(nodeBoundingRect, nodeMatrix).scale(1 / sx, 1 / sy);
	                for (attrName in offsetAttrs) {
	                    attrVal = evalAttrs[attrName];
	                    def = this.getAttributeDefinition(attrName);
	                    // OFFSET - offset function should return a point from the element
	                    // bounding box. The default offset point is x:0, y:0 (origin) or could be further
	                    // specify with some SVG attributes e.g. `text-anchor`, `cx`, `cy`
	                    translation = def.offset.call(this, attrVal, nodeBBox, node, evalAttrs, this);
	                    if (translation) {
	                        nodePosition.offset(Point(translation).scale(sx, sy));
	                        offseted || (offseted = true);
	                    }
	                }
	            }
	        }

	        // Do not touch node's transform attribute if there is no transformation applied.
	        if (nodeTransform !== undefined || positioned || offseted) {
	            // Round the coordinates to 1 decimal point.
	            nodePosition.round(1);
	            nodeMatrix.e = nodePosition.x;
	            nodeMatrix.f = nodePosition.y;
	            node.setAttribute('transform', V.matrixToTransformString(nodeMatrix));
	            // TODO: store nodeMatrix metrics?
	        }
	    },

	    getNodeScale: function(node, scalableNode) {

	        // Check if the node is a descendant of the scalable group.
	        var sx, sy;
	        if (scalableNode && scalableNode.contains(node)) {
	            var scale = scalableNode.scale();
	            sx = 1 / scale.sx;
	            sy = 1 / scale.sy;
	        } else {
	            sx = 1;
	            sy = 1;
	        }

	        return { sx: sx, sy: sy };
	    },

	    cleanNodesCache: function() {
	        this.metrics = {};
	    },

	    nodeCache: function(magnet) {

	        var metrics = this.metrics;
	        // Don't use cache? It most likely a custom view with overridden update.
	        if (!metrics) { return {}; }
	        var id = V.ensureId(magnet);
	        var value = metrics[id];
	        if (!value) { value = metrics[id] = {}; }
	        return value;
	    },

	    getNodeData: function(magnet) {

	        var metrics = this.nodeCache(magnet);
	        if (!metrics.data) { metrics.data = {}; }
	        return metrics.data;
	    },

	    getNodeBoundingRect: function(magnet) {

	        var metrics = this.nodeCache(magnet);
	        if (metrics.boundingRect === undefined) { metrics.boundingRect = V(magnet).getBBox(); }
	        return new Rect(metrics.boundingRect);
	    },

	    getNodeMatrix: function(magnet) {

	        var metrics = this.nodeCache(magnet);
	        if (metrics.magnetMatrix === undefined) {
	            var ref = this;
	            var rotatableNode = ref.rotatableNode;
	            var el = ref.el;
	            var target;
	            if (rotatableNode && rotatableNode.contains(magnet)) {
	                target = rotatableNode;
	            } else {
	                target = el;
	            }
	            metrics.magnetMatrix = V(magnet).getTransformToElement(target);
	        }
	        return V.createSVGMatrix(metrics.magnetMatrix);
	    },

	    getNodeShape: function(magnet) {

	        var metrics = this.nodeCache(magnet);
	        if (metrics.geometryShape === undefined) { metrics.geometryShape = V(magnet).toGeometryShape(); }
	        return metrics.geometryShape.clone();
	    },

	    isNodeConnection: function(node) {
	        return this.model.isLink() && (!node || node === this.el);
	    },

	    findNodesAttributes: function(attrs, root, selectorCache, selectors) {

	        var i, n, nodeAttrs, nodeId;
	        var nodesAttrs = {};
	        var mergeIds = [];
	        for (var selector in attrs) {
	            if (!attrs.hasOwnProperty(selector)) { continue; }
	            nodeAttrs = attrs[selector];
	            if (!isPlainObject(nodeAttrs)) { continue; } // Not a valid selector-attributes pair
	            var selected = selectorCache[selector] = this.findBySelector(selector, root, selectors);
	            for (i = 0, n = selected.length; i < n; i++) {
	                var node = selected[i];
	                nodeId = V.ensureId(node);
	                // "unique" selectors are selectors that referencing a single node (defined by `selector`)
	                // groupSelector referencing a single node is not "unique"
	                var unique = (selectors && selectors[selector] === node);
	                var prevNodeAttrs = nodesAttrs[nodeId];
	                if (prevNodeAttrs) {
	                    // Note, that nodes referenced by deprecated `CSS selectors` are not taken into account.
	                    // e.g. css:`.circle` and selector:`circle` can be applied in a random order
	                    if (!prevNodeAttrs.array) {
	                        mergeIds.push(nodeId);
	                        prevNodeAttrs.array = true;
	                        prevNodeAttrs.attributes = [prevNodeAttrs.attributes];
	                        prevNodeAttrs.selectedLength = [prevNodeAttrs.selectedLength];
	                    }
	                    var attributes = prevNodeAttrs.attributes;
	                    var selectedLength = prevNodeAttrs.selectedLength;
	                    if (unique) {
	                        // node referenced by `selector`
	                        attributes.unshift(nodeAttrs);
	                        selectedLength.unshift(-1);
	                    } else {
	                        // node referenced by `groupSelector`
	                        var sortIndex = sortedIndex(selectedLength, n);
	                        attributes.splice(sortIndex, 0, nodeAttrs);
	                        selectedLength.splice(sortIndex, 0, n);
	                    }
	                } else {
	                    nodesAttrs[nodeId] = {
	                        attributes: nodeAttrs,
	                        selectedLength: unique ? -1 : n,
	                        node: node,
	                        array: false
	                    };
	                }
	            }
	        }

	        for (i = 0, n = mergeIds.length; i < n; i++) {
	            nodeId = mergeIds[i];
	            nodeAttrs = nodesAttrs[nodeId];
	            nodeAttrs.attributes = merge.apply(void 0, [ {} ].concat( nodeAttrs.attributes.reverse() ));
	        }

	        return nodesAttrs;
	    },

	    getEventTarget: function(evt, opt) {
	        if ( opt === void 0 ) opt = {};

	        var target = evt.target;
	        var type = evt.type;
	        var clientX = evt.clientX; if ( clientX === void 0 ) clientX = 0;
	        var clientY = evt.clientY; if ( clientY === void 0 ) clientY = 0;
	        if (
	            // Explicitly defined `fromPoint` option
	            opt.fromPoint ||
	            // Touchmove/Touchend event's target is not reflecting the element under the coordinates as mousemove does.
	            // It holds the element when a touchstart triggered.
	            type === 'touchmove' || type === 'touchend' ||
	            // Pointermove/Pointerup event with the pointer captured
	            ('pointerId' in evt && target.hasPointerCapture(evt.pointerId))
	        ) {
	            return document.elementFromPoint(clientX, clientY);
	        }

	        return target;
	    },

	    // Default is to process the `model.attributes.attrs` object and set attributes on subelements based on the selectors,
	    // unless `attrs` parameter was passed.
	    updateDOMSubtreeAttributes: function(rootNode, attrs, opt) {

	        opt || (opt = {});
	        opt.rootBBox || (opt.rootBBox = Rect());
	        opt.selectors || (opt.selectors = this.selectors); // selector collection to use

	        // Cache table for query results and bounding box calculation.
	        // Note that `selectorCache` needs to be invalidated for all
	        // `updateAttributes` calls, as the selectors might pointing
	        // to nodes designated by an attribute or elements dynamically
	        // created.
	        var selectorCache = {};
	        var bboxCache = {};
	        var relativeItems = [];
	        var relativeRefItems = [];
	        var item, node, nodeAttrs, nodeData, processedAttrs;

	        var roAttrs = opt.roAttributes;
	        var nodesAttrs = this.findNodesAttributes(roAttrs || attrs, rootNode, selectorCache, opt.selectors);
	        // `nodesAttrs` are different from all attributes, when
	        // rendering only  attributes sent to this method.
	        var nodesAllAttrs = (roAttrs)
	            ? this.findNodesAttributes(attrs, rootNode, selectorCache, opt.selectors)
	            : nodesAttrs;

	        for (var nodeId in nodesAttrs) {
	            nodeData = nodesAttrs[nodeId];
	            nodeAttrs = nodeData.attributes;
	            node = nodeData.node;
	            processedAttrs = this.processNodeAttributes(node, nodeAttrs);

	            if (!processedAttrs.set && !processedAttrs.position && !processedAttrs.offset && !processedAttrs.raw.ref) {
	                // Set all the normal attributes right on the SVG/HTML element.
	                this.setNodeAttributes(node, evalAttributes(processedAttrs.normal, opt.rootBBox));

	            } else {

	                var nodeAllAttrs = nodesAllAttrs[nodeId] && nodesAllAttrs[nodeId].attributes;
	                var refSelector = (nodeAllAttrs && (nodeAttrs.ref === undefined))
	                    ? nodeAllAttrs.ref
	                    : nodeAttrs.ref;

	                var refNode;
	                if (refSelector) {
	                    refNode = (selectorCache[refSelector] || this.findBySelector(refSelector, rootNode, opt.selectors))[0];
	                    if (!refNode) {
	                        throw new Error('dia.CellView: "' + refSelector + '" reference does not exist.');
	                    }
	                } else {
	                    refNode = null;
	                }

	                item = {
	                    node: node,
	                    refNode: refNode,
	                    processedAttributes: processedAttrs,
	                    allAttributes: nodeAllAttrs
	                };

	                if (refNode) {
	                    // If an element in the list is positioned relative to this one, then
	                    // we want to insert this one before it in the list.
	                    var itemIndex = relativeRefItems.findIndex(function(item) {
	                        return item.refNode === node;
	                    });

	                    if (itemIndex > -1) {
	                        relativeRefItems.splice(itemIndex, 0, item);
	                    } else {
	                        relativeRefItems.push(item);
	                    }
	                } else {
	                    // A node with no ref attribute. To be updated before the nodes referencing other nodes.
	                    // The order of no-ref-items is not specified/important.
	                    relativeItems.push(item);
	                }
	            }
	        }

	        relativeItems.push.apply(relativeItems, relativeRefItems);

	        for (var i = 0, n = relativeItems.length; i < n; i++) {
	            item = relativeItems[i];
	            node = item.node;
	            refNode = item.refNode;

	            // Find the reference element bounding box. If no reference was provided, we
	            // use the optional bounding box.
	            var refNodeId = refNode ? V.ensureId(refNode) : '';
	            var refBBox = bboxCache[refNodeId];
	            if (!refBBox) {
	                // Get the bounding box of the reference element using to the common ancestor
	                // transformation space.
	                //
	                // @example 1
	                // <g transform="translate(11, 13)">
	                //     <rect @selector="b" x="1" y="2" width="3" height="4"/>
	                //     <rect @selector="a"/>
	                // </g>
	                //
	                // In this case, the reference bounding box can not be affected
	                // by the `transform` attribute of the `<g>` element,
	                // because the exact transformation will be applied to the `a` element
	                // as well as to the `b` element.
	                //
	                // @example 2
	                // <g transform="translate(11, 13)">
	                //     <rect @selector="b" x="1" y="2" width="3" height="4"/>
	                // </g>
	                // <rect @selector="a"/>
	                //
	                // In this case, the reference bounding box have to be affected by the
	                // `transform` attribute of the `<g>` element, because the `a` element
	                // is not descendant of the `<g>` element and will not be affected
	                // by the transformation.
	                refBBox = bboxCache[refNodeId] = (refNode)
	                    ? V(refNode).getBBox({ target: getCommonAncestorNode(node, refNode) })
	                    : opt.rootBBox;
	            }

	            if (roAttrs) {
	                // if there was a special attribute affecting the position amongst passed-in attributes
	                // we have to merge it with the rest of the element's attributes as they are necessary
	                // to update the position relatively (i.e `ref-x` && 'ref-dx')
	                processedAttrs = this.processNodeAttributes(node, item.allAttributes);
	                this.mergeProcessedAttributes(processedAttrs, item.processedAttributes);

	            } else {
	                processedAttrs = item.processedAttributes;
	            }

	            this.updateRelativeAttributes(node, processedAttrs, refBBox, opt);
	        }
	    },

	    mergeProcessedAttributes: function(processedAttrs, roProcessedAttrs) {

	        processedAttrs.set || (processedAttrs.set = {});
	        processedAttrs.position || (processedAttrs.position = {});
	        processedAttrs.offset || (processedAttrs.offset = {});

	        assign(processedAttrs.set, roProcessedAttrs.set);
	        assign(processedAttrs.position, roProcessedAttrs.position);
	        assign(processedAttrs.offset, roProcessedAttrs.offset);

	        // Handle also the special transform property.
	        var transform = processedAttrs.normal && processedAttrs.normal.transform;
	        if (transform !== undefined && roProcessedAttrs.normal) {
	            roProcessedAttrs.normal.transform = transform;
	        }
	        processedAttrs.normal = roProcessedAttrs.normal;
	    },

	    // Lifecycle methods

	    // Called when the view is attached to the DOM,
	    // as result of `cell.addTo(graph)` being called (isInitialMount === true)
	    // or `paper.options.viewport` returning `true` (isInitialMount === false).
	    onMount: function onMount(isInitialMount) {
	        if (isInitialMount) { return; }
	        this.mountTools();
	        HighlighterView.mount(this);
	    },

	    // Called when the view is detached from the DOM,
	    // as result of `paper.options.viewport` returning `false`.
	    onDetach: function onDetach() {
	        this.unmountTools();
	        HighlighterView.unmount(this);
	    },

	    // Called when the view is removed from the DOM
	    // as result of `cell.remove()`.
	    onRemove: function() {
	        this.removeTools();
	        this.removeHighlighters();
	    },

	    _toolsView: null,

	    hasTools: function(name) {
	        var toolsView = this._toolsView;
	        if (!toolsView) { return false; }
	        if (!name) { return true; }
	        return (toolsView.getName() === name);
	    },

	    addTools: function(toolsView) {

	        this.removeTools();

	        if (toolsView) {
	            this._toolsView = toolsView;
	            toolsView.configure({ relatedView: this });
	            toolsView.listenTo(this.paper, 'tools:event', this.onToolEvent.bind(this));
	        }
	        return this;
	    },

	    unmountTools: function unmountTools() {
	        var toolsView = this._toolsView;
	        if (toolsView) { toolsView.unmount(); }
	        return this;
	    },

	    mountTools: function mountTools() {
	        var toolsView = this._toolsView;
	        // Prevent unnecessary re-appending of the tools.
	        if (toolsView && !toolsView.isMounted()) { toolsView.mount(); }
	        return this;
	    },

	    updateTools: function(opt) {

	        var toolsView = this._toolsView;
	        if (toolsView) { toolsView.update(opt); }
	        return this;
	    },

	    removeTools: function() {

	        var toolsView = this._toolsView;
	        if (toolsView) {
	            toolsView.remove();
	            this._toolsView = null;
	        }
	        return this;
	    },

	    hideTools: function() {

	        var toolsView = this._toolsView;
	        if (toolsView) { toolsView.hide(); }
	        return this;
	    },

	    showTools: function() {

	        var toolsView = this._toolsView;
	        if (toolsView) { toolsView.show(); }
	        return this;
	    },

	    onToolEvent: function(event) {
	        switch (event) {
	            case 'remove':
	                this.removeTools();
	                break;
	            case 'hide':
	                this.hideTools();
	                break;
	            case 'show':
	                this.showTools();
	                break;
	        }
	    },

	    removeHighlighters: function() {
	        HighlighterView.remove(this);
	    },

	    updateHighlighters: function(dirty) {
	        if ( dirty === void 0 ) dirty = false;

	        HighlighterView.update(this, null, dirty);
	    },

	    transformHighlighters: function() {
	        HighlighterView.transform(this);
	    },

	    // Interaction. The controller part.
	    // ---------------------------------

	    preventDefaultInteraction: function preventDefaultInteraction(evt) {
	        this.eventData(evt, { defaultInteractionPrevented: true  });
	    },

	    isDefaultInteractionPrevented: function isDefaultInteractionPrevented(evt) {
	        var ref = this.eventData(evt);
	        var defaultInteractionPrevented = ref.defaultInteractionPrevented; if ( defaultInteractionPrevented === void 0 ) defaultInteractionPrevented = false;
	        return defaultInteractionPrevented;
	    },

	    // Interaction is handled by the paper and delegated to the view in interest.
	    // `x` & `y` parameters passed to these functions represent the coordinates already snapped to the paper grid.
	    // If necessary, real coordinates can be obtained from the `evt` event object.

	    // These functions are supposed to be overridden by the views that inherit from `joint.dia.Cell`,
	    // i.e. `joint.dia.Element` and `joint.dia.Link`.

	    pointerdblclick: function(evt, x, y) {

	        this.notify('cell:pointerdblclick', evt, x, y);
	    },

	    pointerclick: function(evt, x, y) {

	        this.notify('cell:pointerclick', evt, x, y);
	    },

	    contextmenu: function(evt, x, y) {

	        this.notify('cell:contextmenu', evt, x, y);
	    },

	    pointerdown: function(evt, x, y) {

	        var ref = this;
	        var model = ref.model;
	        var graph = model.graph;
	        if (graph) {
	            model.startBatch('pointer');
	            this.eventData(evt, { graph: graph });
	        }

	        this.notify('cell:pointerdown', evt, x, y);
	    },

	    pointermove: function(evt, x, y) {

	        this.notify('cell:pointermove', evt, x, y);
	    },

	    pointerup: function(evt, x, y) {

	        var ref = this.eventData(evt);
	        var graph = ref.graph;

	        this.notify('cell:pointerup', evt, x, y);

	        if (graph) {
	            // we don't want to trigger event on model as model doesn't
	            // need to be member of collection anymore (remove)
	            graph.stopBatch('pointer', { cell: this.model });
	        }
	    },

	    mouseover: function(evt) {

	        this.notify('cell:mouseover', evt);
	    },

	    mouseout: function(evt) {

	        this.notify('cell:mouseout', evt);
	    },

	    mouseenter: function(evt) {

	        this.notify('cell:mouseenter', evt);
	    },

	    mouseleave: function(evt) {

	        this.notify('cell:mouseleave', evt);
	    },

	    mousewheel: function(evt, x, y, delta) {

	        this.notify('cell:mousewheel', evt, x, y, delta);
	    },

	    onevent: function(evt, eventName, x, y) {

	        this.notify(eventName, evt, x, y);
	    },

	    onmagnet: function() {

	        // noop
	    },

	    magnetpointerdblclick: function() {

	        // noop
	    },

	    magnetcontextmenu: function() {

	        // noop
	    },

	    checkMouseleave: function checkMouseleave(evt) {
	        var ref = this;
	        var paper = ref.paper;
	        var model = ref.model;
	        if (paper.isAsync()) {
	            // Make sure the source/target views are updated before this view.
	            // It's not 100% bulletproof (see below) but it's a good enough solution for now.
	            // The connected cells could be links as well. In that case, we would
	            // need to recursively go through all the connected links and update
	            // their source/target views as well.
	            if (model.isLink()) {
	                // The `this.sourceView` and `this.targetView` might not be updated yet.
	                // We need to find the view by the model.
	                var sourceElement = model.getSourceElement();
	                if (sourceElement) {
	                    var sourceView = paper.findViewByModel(sourceElement);
	                    if (sourceView) {
	                        paper.dumpView(sourceView);
	                        paper.checkViewVisibility(sourceView);
	                    }
	                }
	                var targetElement = model.getTargetElement();
	                if (targetElement) {
	                    var targetView = paper.findViewByModel(targetElement);
	                    if (targetView) {
	                        paper.dumpView(targetView);
	                        paper.checkViewVisibility(targetView);
	                    }
	                }
	            }
	            // Do the updates of the current view synchronously now
	            paper.dumpView(this);
	            paper.checkViewVisibility(this);
	        }
	        var target = this.getEventTarget(evt, { fromPoint: true });
	        var view = paper.findView(target);
	        if (view === this) { return; }
	        // Leaving the current view
	        this.mouseleave(evt);
	        if (!view) { return; }
	        // Entering another view
	        view.mouseenter(evt);
	    },

	    setInteractivity: function(value) {

	        this.options.interactive = value;
	    }
	}, {

	    Flags: Flags,

	    Highlighting: HighlightingTypes,

	    addPresentationAttributes: function(presentationAttributes) {
	        return merge({}, result(this.prototype, 'presentationAttributes'), presentationAttributes, function(a, b) {
	            if (!a || !b) { return; }
	            if (typeof a === 'string') { a = [a]; }
	            if (typeof b === 'string') { b = [b]; }
	            if (Array.isArray(a) && Array.isArray(b)) { return uniq(a.concat(b)); }
	        });
	    },

	    evalAttribute: evalAttribute,

	});


	Object.defineProperty(CellView.prototype, 'useCSSSelectors', {
	    get: function get() {
	        var localUse = this.model.useCSSSelectors;
	        if (localUse !== undefined) { return localUse; }
	        return config.useCSSSelectors;
	    }
	});

	// TODO: Move to Vectorizer library.
	function getCommonAncestorNode(node1, node2) {
	    var parent = node1;
	    do {
	        if (parent.contains(node2)) { return parent; }
	        parent = parent.parentNode;
	    } while (parent);
	    return null;
	}

	var Flags$1 = {
	    TOOLS: CellView.Flags.TOOLS,
	    UPDATE: 'UPDATE',
	    TRANSLATE: 'TRANSLATE',
	    RESIZE: 'RESIZE',
	    PORTS: 'PORTS',
	    ROTATE: 'ROTATE',
	    RENDER: 'RENDER'
	};

	var DragActions = {
	    MOVE: 'move',
	    MAGNET: 'magnet',
	};
	// Element base view and controller.
	// -------------------------------------------

	var ElementView = CellView.extend({

	    /**
	     * @abstract
	     */
	    _removePorts: function() {
	        // implemented in ports.js
	    },

	    /**
	     *
	     * @abstract
	     */
	    _renderPorts: function() {
	        // implemented in ports.js
	    },

	    className: function() {

	        var classNames = CellView.prototype.className.apply(this).split(' ');

	        classNames.push('element');

	        return classNames.join(' ');
	    },

	    initialize: function() {

	        CellView.prototype.initialize.apply(this, arguments);

	        this._initializePorts();
	    },

	    presentationAttributes: {
	        'attrs': [Flags$1.UPDATE],
	        'position': [Flags$1.TRANSLATE, Flags$1.TOOLS],
	        'size': [Flags$1.RESIZE, Flags$1.PORTS, Flags$1.TOOLS],
	        'angle': [Flags$1.ROTATE, Flags$1.TOOLS],
	        'markup': [Flags$1.RENDER],
	        'ports': [Flags$1.PORTS],
	    },

	    initFlag: [Flags$1.RENDER],

	    UPDATE_PRIORITY: 0,

	    confirmUpdate: function(flag, opt) {

	        var ref = this;
	        var useCSSSelectors = ref.useCSSSelectors;
	        if (this.hasFlag(flag, Flags$1.PORTS)) {
	            this._removePorts();
	            this._cleanPortsCache();
	        }
	        var transformHighlighters = false;
	        if (this.hasFlag(flag, Flags$1.RENDER)) {
	            this.render();
	            this.updateTools(opt);
	            this.updateHighlighters(true);
	            transformHighlighters = true;
	            flag = this.removeFlag(flag, [Flags$1.RENDER, Flags$1.UPDATE, Flags$1.RESIZE, Flags$1.TRANSLATE, Flags$1.ROTATE, Flags$1.PORTS, Flags$1.TOOLS]);
	        } else {
	            var updateHighlighters = false;

	            // Skip this branch if render is required
	            if (this.hasFlag(flag, Flags$1.RESIZE)) {
	                this.resize(opt);
	                updateHighlighters = true;
	                // Resize method is calling `update()` internally
	                flag = this.removeFlag(flag, [Flags$1.RESIZE, Flags$1.UPDATE]);
	                if (useCSSSelectors) {
	                    // `resize()` rendered the ports when useCSSSelectors are enabled
	                    flag = this.removeFlag(flag, Flags$1.PORTS);
	                }
	            }
	            if (this.hasFlag(flag, Flags$1.UPDATE)) {
	                this.update(this.model, null, opt);
	                flag = this.removeFlag(flag, Flags$1.UPDATE);
	                updateHighlighters = true;
	                if (useCSSSelectors) {
	                    // `update()` will render ports when useCSSSelectors are enabled
	                    flag = this.removeFlag(flag, Flags$1.PORTS);
	                }
	            }
	            if (this.hasFlag(flag, Flags$1.TRANSLATE)) {
	                this.translate();
	                flag = this.removeFlag(flag, Flags$1.TRANSLATE);
	                transformHighlighters = true;
	            }
	            if (this.hasFlag(flag, Flags$1.ROTATE)) {
	                this.rotate();
	                flag = this.removeFlag(flag, Flags$1.ROTATE);
	                transformHighlighters = true;
	            }
	            if (this.hasFlag(flag, Flags$1.PORTS)) {
	                this._renderPorts();
	                updateHighlighters = true;
	                flag = this.removeFlag(flag, Flags$1.PORTS);
	            }

	            if (updateHighlighters) {
	                this.updateHighlighters(false);
	            }
	        }

	        if (transformHighlighters) {
	            this.transformHighlighters();
	        }

	        if (this.hasFlag(flag, Flags$1.TOOLS)) {
	            this.updateTools(opt);
	            flag = this.removeFlag(flag, Flags$1.TOOLS);
	        }

	        return flag;
	    },

	    /**
	     * @abstract
	     */
	    _initializePorts: function() {

	    },

	    update: function(_, renderingOnlyAttrs) {

	        this.cleanNodesCache();

	        // When CSS selector strings are used, make sure no rule matches port nodes.
	        var ref = this;
	        var useCSSSelectors = ref.useCSSSelectors;
	        if (useCSSSelectors) { this._removePorts(); }

	        var model = this.model;
	        var modelAttrs = model.attr();
	        this.updateDOMSubtreeAttributes(this.el, modelAttrs, {
	            rootBBox: new Rect(model.size()),
	            selectors: this.selectors,
	            scalableNode: this.scalableNode,
	            rotatableNode: this.rotatableNode,
	            // Use rendering only attributes if they differs from the model attributes
	            roAttributes: (renderingOnlyAttrs === modelAttrs) ? null : renderingOnlyAttrs
	        });

	        if (useCSSSelectors) {
	            this._renderPorts();
	        }
	    },

	    rotatableSelector: 'rotatable',
	    scalableSelector: 'scalable',
	    scalableNode: null,
	    rotatableNode: null,

	    // `prototype.markup` is rendered by default. Set the `markup` attribute on the model if the
	    // default markup is not desirable.
	    renderMarkup: function() {

	        var element = this.model;
	        var markup = element.get('markup') || element.markup;
	        if (!markup) { throw new Error('dia.ElementView: markup required'); }
	        if (Array.isArray(markup)) { return this.renderJSONMarkup(markup); }
	        if (typeof markup === 'string') { return this.renderStringMarkup(markup); }
	        throw new Error('dia.ElementView: invalid markup');
	    },

	    renderJSONMarkup: function(markup) {

	        var doc = this.parseDOMJSON(markup, this.el);
	        var selectors = this.selectors = doc.selectors;
	        this.rotatableNode = V(selectors[this.rotatableSelector]) || null;
	        this.scalableNode = V(selectors[this.scalableSelector]) || null;
	        // Fragment
	        this.vel.append(doc.fragment);
	    },

	    renderStringMarkup: function(markup) {

	        var vel = this.vel;
	        vel.append(V(markup));
	        // Cache transformation groups
	        this.rotatableNode = vel.findOne('.rotatable');
	        this.scalableNode = vel.findOne('.scalable');

	        var selectors = this.selectors = {};
	        selectors[this.selector] = this.el;
	    },

	    render: function() {

	        this.vel.empty();
	        this.renderMarkup();
	        if (this.scalableNode) {
	            // Double update is necessary for elements with the scalable group only
	            // Note the resize() triggers the other `update`.
	            this.update();
	        }
	        this.resize();
	        if (this.rotatableNode) {
	            // Translate transformation is applied on `this.el` while the rotation transformation
	            // on `this.rotatableNode`
	            this.rotate();
	            this.translate();
	        } else {
	            this.updateTransformation();
	        }
	        if (!this.useCSSSelectors) { this._renderPorts(); }
	        return this;
	    },

	    resize: function(opt) {

	        if (this.scalableNode) { return this.sgResize(opt); }
	        if (this.model.attributes.angle) { this.rotate(); }
	        this.update();
	    },

	    translate: function() {

	        if (this.rotatableNode) { return this.rgTranslate(); }
	        this.updateTransformation();
	    },

	    rotate: function() {

	        if (this.rotatableNode) {
	            this.rgRotate();
	            // It's necessary to call the update for the nodes outside
	            // the rotatable group referencing nodes inside the group
	            this.update();
	            return;
	        }
	        this.updateTransformation();
	    },

	    updateTransformation: function() {

	        var transformation = this.getTranslateString();
	        var rotateString = this.getRotateString();
	        if (rotateString) { transformation += ' ' + rotateString; }
	        this.vel.attr('transform', transformation);
	    },

	    getTranslateString: function() {

	        var position = this.model.attributes.position;
	        return 'translate(' + position.x + ',' + position.y + ')';
	    },

	    getRotateString: function() {
	        var attributes = this.model.attributes;
	        var angle = attributes.angle;
	        if (!angle) { return null; }
	        var size = attributes.size;
	        return 'rotate(' + angle + ',' + (size.width / 2) + ',' + (size.height / 2) + ')';
	    },

	    // Rotatable & Scalable Group
	    // always slower, kept mainly for backwards compatibility

	    rgRotate: function() {

	        this.rotatableNode.attr('transform', this.getRotateString());
	    },

	    rgTranslate: function() {

	        this.vel.attr('transform', this.getTranslateString());
	    },

	    sgResize: function(opt) {

	        var model = this.model;
	        var angle = model.angle();
	        var size = model.size();
	        var scalable = this.scalableNode;

	        // Getting scalable group's bbox.
	        // Due to a bug in webkit's native SVG .getBBox implementation, the bbox of groups with path children includes the paths' control points.
	        // To work around the issue, we need to check whether there are any path elements inside the scalable group.
	        var recursive = false;
	        if (scalable.node.getElementsByTagName('path').length > 0) {
	            // If scalable has at least one descendant that is a path, we need to switch to recursive bbox calculation.
	            // If there are no path descendants, group bbox calculation works and so we can use the (faster) native function directly.
	            recursive = true;
	        }
	        var scalableBBox = scalable.getBBox({ recursive: recursive });

	        // Make sure `scalableBbox.width` and `scalableBbox.height` are not zero which can happen if the element does not have any content. By making
	        // the width/height 1, we prevent HTML errors of the type `scale(Infinity, Infinity)`.
	        var sx = (size.width / (scalableBBox.width || 1));
	        var sy = (size.height / (scalableBBox.height || 1));
	        scalable.attr('transform', 'scale(' + sx + ',' + sy + ')');

	        // Now the interesting part. The goal is to be able to store the object geometry via just `x`, `y`, `angle`, `width` and `height`
	        // Order of transformations is significant but we want to reconstruct the object always in the order:
	        // resize(), rotate(), translate() no matter of how the object was transformed. For that to work,
	        // we must adjust the `x` and `y` coordinates of the object whenever we resize it (because the origin of the
	        // rotation changes). The new `x` and `y` coordinates are computed by canceling the previous rotation
	        // around the center of the resized object (which is a different origin then the origin of the previous rotation)
	        // and getting the top-left corner of the resulting object. Then we clean up the rotation back to what it originally was.

	        // Cancel the rotation but now around a different origin, which is the center of the scaled object.
	        var rotatable = this.rotatableNode;
	        var rotation = rotatable && rotatable.attr('transform');
	        if (rotation) {

	            rotatable.attr('transform', rotation + ' rotate(' + (-angle) + ',' + (size.width / 2) + ',' + (size.height / 2) + ')');
	            var rotatableBBox = scalable.getBBox({ target: this.paper.cells });

	            // Store new x, y and perform rotate() again against the new rotation origin.
	            model.set('position', { x: rotatableBBox.x, y: rotatableBBox.y }, assign({ updateHandled: true }, opt));
	            this.translate();
	            this.rotate();
	        }

	        // Update must always be called on non-rotated element. Otherwise, relative positioning
	        // would work with wrong (rotated) bounding boxes.
	        this.update();
	    },

	    // Embedding mode methods.
	    // -----------------------

	    prepareEmbedding: function(data) {
	        if ( data === void 0 ) data = {};


	        var element = data.model || this.model;
	        var paper = data.paper || this.paper;
	        var graph = paper.model;

	        var initialZIndices = data.initialZIndices = {};
	        var embeddedCells = element.getEmbeddedCells({ deep: true });
	        var connectedLinks = graph.getConnectedLinks(element, { deep: true, includeEnclosed: true });

	        // Note: an embedded cell can be a connect link, but it's fine
	        // to iterate over the cell twice.
	        [
	            element ].concat( embeddedCells,
	            connectedLinks
	        ).forEach(function (cell) { return initialZIndices[cell.id] = cell.attributes.z; });

	        element.startBatch('to-front');

	        // Bring the model to the front with all his embeds.
	        element.toFront({ deep: true, ui: true });

	        // Note that at this point cells in the collection are not sorted by z index (it's running in the batch, see
	        // the dia.Graph._sortOnChangeZ), so we can't assume that the last cell in the collection has the highest z.
	        var maxZ = graph.getElements().reduce(function (max, cell) { return Math.max(max, cell.attributes.z || 0); }, 0);

	        // Move to front also all the inbound and outbound links that are connected
	        // to any of the element descendant. If we bring to front only embedded elements,
	        // links connected to them would stay in the background.
	        connectedLinks.forEach(function (link) {
	            if (link.attributes.z <= maxZ) {
	                link.set('z', maxZ + 1, { ui: true });
	            }
	        });

	        element.stopBatch('to-front');

	        // Before we start looking for suitable parent we remove the current one.
	        var parentId = element.parent();
	        if (parentId) {
	            var parent = graph.getCell(parentId);
	            parent.unembed(element, { ui: true });
	            data.initialParentId = parentId;
	        } else {
	            data.initialParentId = null;
	        }
	    },

	    processEmbedding: function(data, evt, x, y) {
	        if ( data === void 0 ) data = {};


	        var model = data.model || this.model;
	        var paper = data.paper || this.paper;
	        var graph = paper.model;
	        var ref = paper.options;
	        var findParentBy = ref.findParentBy;
	        var frontParentOnly = ref.frontParentOnly;
	        var validateEmbedding = ref.validateEmbedding;

	        var candidates;
	        if (isFunction(findParentBy)) {
	            candidates = toArray(findParentBy.call(graph, this, evt, x, y));
	        } else if (findParentBy === 'pointer') {
	            candidates = toArray(graph.findModelsFromPoint({ x: x, y: y }));
	        } else {
	            candidates = graph.findModelsUnderElement(model, { searchBy: findParentBy });
	        }

	        candidates = candidates.filter(function (el) {
	            return (el instanceof Cell) && (model.id !== el.id) && !el.isEmbeddedIn(model);
	        });

	        if (frontParentOnly) {
	            // pick the element with the highest `z` index
	            candidates = candidates.slice(-1);
	        }

	        var newCandidateView = null;
	        var prevCandidateView = data.candidateEmbedView;

	        // iterate over all candidates starting from the last one (has the highest z-index).
	        for (var i = candidates.length - 1; i >= 0; i--) {
	            var candidate = candidates[i];
	            if (prevCandidateView && prevCandidateView.model.id == candidate.id) {
	                // candidate remains the same
	                newCandidateView = prevCandidateView;
	                break;
	            } else {
	                var view = candidate.findView(paper);
	                if (!isFunction(validateEmbedding) || validateEmbedding.call(paper, this, view)) {
	                    // flip to the new candidate
	                    newCandidateView = view;
	                    break;
	                }
	            }
	        }

	        if (newCandidateView && newCandidateView != prevCandidateView) {
	            // A new candidate view found. Highlight the new one.
	            this.clearEmbedding(data);
	            data.candidateEmbedView = newCandidateView.highlight(
	                newCandidateView.findProxyNode(null, 'container'),
	                { embedding: true }
	            );
	        }

	        if (!newCandidateView && prevCandidateView) {
	            // No candidate view found. Unhighlight the previous candidate.
	            this.clearEmbedding(data);
	        }
	    },

	    clearEmbedding: function(data) {

	        data || (data = {});

	        var candidateView = data.candidateEmbedView;
	        if (candidateView) {
	            // No candidate view found. Unhighlight the previous candidate.
	            candidateView.unhighlight(
	                candidateView.findProxyNode(null, 'container'),
	                { embedding: true }
	            );
	            data.candidateEmbedView = null;
	        }
	    },

	    finalizeEmbedding: function(data) {
	        if ( data === void 0 ) data = {};


	        var candidateView = data.candidateEmbedView;
	        var element = data.model || this.model;
	        var paper = data.paper || this.paper;

	        if (candidateView) {

	            // We finished embedding. Candidate view is chosen to become the parent of the model.
	            candidateView.model.embed(element, { ui: true });
	            candidateView.unhighlight(candidateView.findProxyNode(null, 'container'), { embedding: true });

	            data.candidateEmbedView = null;

	        } else {

	            var ref = paper.options;
	            var validateUnembedding = ref.validateUnembedding;
	            var initialParentId = data.initialParentId;
	            // The element was originally embedded into another element.
	            // The interaction would unembed the element. Let's validate
	            // if the element can be unembedded.
	            if (
	                initialParentId &&
	                typeof validateUnembedding === 'function' &&
	                !validateUnembedding.call(paper, this)
	            ) {
	                this._disallowUnembed(data);
	                return;
	            }
	        }

	        paper.model.getConnectedLinks(element, { deep: true }).forEach(function (link) {
	            link.reparent({ ui: true });
	        });
	    },

	    _disallowUnembed: function(data) {
	        var model = data.model;
	        var whenNotAllowed = data.whenNotAllowed; if ( whenNotAllowed === void 0 ) whenNotAllowed = 'revert';
	        var element = model || this.model;
	        var paper = data.paper || this.paper;
	        var graph = paper.model;
	        switch (whenNotAllowed) {
	            case 'remove': {
	                element.remove({ ui: true });
	                break;
	            }
	            case 'revert': {
	                var initialParentId = data.initialParentId;
	                var initialPosition = data.initialPosition;
	                var initialZIndices = data.initialZIndices;
	                // Revert the element's position (and the position of its embedded cells if any)
	                if (initialPosition) {
	                    var x = initialPosition.x;
	                    var y = initialPosition.y;
	                    element.position(x, y, { deep: true, ui: true });
	                }
	                // Revert all the z-indices changed during the embedding
	                if (initialZIndices) {
	                    Object.keys(initialZIndices).forEach(function (id) {
	                        var cell = graph.getCell(id);
	                        if (cell) {
	                            cell.set('z', initialZIndices[id], { ui: true });
	                        }
	                    });
	                }
	                // Revert the original parent
	                var parent = graph.getCell(initialParentId);
	                if (parent) {
	                    parent.embed(element, { ui: true });
	                }
	                break;
	            }
	        }
	    },

	    getDelegatedView: function() {

	        var view = this;
	        var model = view.model;
	        var paper = view.paper;

	        while (view) {
	            if (model.isLink()) { break; }
	            if (!model.isEmbedded() || view.can('stopDelegation')) { return view; }
	            model = model.getParentCell();
	            view = paper.findViewByModel(model);
	        }

	        return null;
	    },

	    findProxyNode: function(el, type) {
	        el || (el = this.el);
	        var nodeSelector = el.getAttribute((type + "-selector"));
	        if (nodeSelector) {
	            var port = this.findAttribute('port', el);
	            if (port) {
	                var proxyPortNode = this.findPortNode(port, nodeSelector);
	                if (proxyPortNode) { return proxyPortNode; }
	            } else {
	                var proxyNode = this.findNode(nodeSelector);
	                if (proxyNode) { return proxyNode; }
	            }
	        }
	        return el;
	    },

	    // Interaction. The controller part.
	    // ---------------------------------

	    notifyPointerdown: function notifyPointerdown(evt, x, y) {
	        CellView.prototype.pointerdown.call(this, evt, x, y);
	        this.notify('element:pointerdown', evt, x, y);
	    },

	    notifyPointermove: function notifyPointermove(evt, x, y) {
	        CellView.prototype.pointermove.call(this, evt, x, y);
	        this.notify('element:pointermove', evt, x, y);
	    },

	    notifyPointerup: function notifyPointerup(evt, x, y) {
	        this.notify('element:pointerup', evt, x, y);
	        CellView.prototype.pointerup.call(this, evt, x, y);
	    },

	    pointerdblclick: function(evt, x, y) {

	        CellView.prototype.pointerdblclick.apply(this, arguments);
	        this.notify('element:pointerdblclick', evt, x, y);
	    },

	    pointerclick: function(evt, x, y) {

	        CellView.prototype.pointerclick.apply(this, arguments);
	        this.notify('element:pointerclick', evt, x, y);
	    },

	    contextmenu: function(evt, x, y) {

	        CellView.prototype.contextmenu.apply(this, arguments);
	        this.notify('element:contextmenu', evt, x, y);
	    },

	    pointerdown: function(evt, x, y) {

	        this.notifyPointerdown(evt, x, y);
	        this.dragStart(evt, x, y);
	    },

	    pointermove: function(evt, x, y) {

	        var data = this.eventData(evt);
	        var targetMagnet = data.targetMagnet;
	        var action = data.action;
	        var delegatedView = data.delegatedView;

	        if (targetMagnet) {
	            this.magnetpointermove(evt, targetMagnet, x, y);
	        }

	        switch (action) {
	            case DragActions.MAGNET:
	                this.dragMagnet(evt, x, y);
	                break;
	            case DragActions.MOVE:
	                (delegatedView || this).drag(evt, x, y);
	            // eslint: no-fallthrough=false
	            default:
	                if (data.preventPointerEvents) { break; }
	                this.notifyPointermove(evt, x, y);
	                break;
	        }

	        // Make sure the element view data is passed along.
	        // It could have been wiped out in the handlers above.
	        this.eventData(evt, data);
	    },

	    pointerup: function(evt, x, y) {

	        var data = this.eventData(evt);
	        var targetMagnet = data.targetMagnet;
	        var action = data.action;
	        var delegatedView = data.delegatedView;

	        if (targetMagnet) {
	            this.magnetpointerup(evt, targetMagnet, x, y);
	        }

	        switch (action) {
	            case DragActions.MAGNET:
	                this.dragMagnetEnd(evt, x, y);
	                break;
	            case DragActions.MOVE:
	                (delegatedView || this).dragEnd(evt, x, y);
	            // eslint: no-fallthrough=false
	            default:
	                if (data.preventPointerEvents) { break; }
	                this.notifyPointerup(evt, x, y);
	        }

	        if (targetMagnet) {
	            this.magnetpointerclick(evt, targetMagnet, x, y);
	        }

	        this.checkMouseleave(evt);
	    },

	    mouseover: function(evt) {

	        CellView.prototype.mouseover.apply(this, arguments);
	        this.notify('element:mouseover', evt);
	    },

	    mouseout: function(evt) {

	        CellView.prototype.mouseout.apply(this, arguments);
	        this.notify('element:mouseout', evt);
	    },

	    mouseenter: function(evt) {

	        CellView.prototype.mouseenter.apply(this, arguments);
	        this.notify('element:mouseenter', evt);
	    },

	    mouseleave: function(evt) {

	        CellView.prototype.mouseleave.apply(this, arguments);
	        this.notify('element:mouseleave', evt);
	    },

	    mousewheel: function(evt, x, y, delta) {

	        CellView.prototype.mousewheel.apply(this, arguments);
	        this.notify('element:mousewheel', evt, x, y, delta);
	    },

	    onmagnet: function(evt, x, y) {

	        var targetMagnet = evt.currentTarget;
	        this.magnetpointerdown(evt, targetMagnet, x, y);
	        this.eventData(evt, { targetMagnet: targetMagnet });
	        this.dragMagnetStart(evt, x, y);
	    },

	    magnetpointerdown: function(evt, magnet, x, y) {

	        this.notify('element:magnet:pointerdown', evt, magnet, x, y);
	    },

	    magnetpointermove: function(evt, magnet, x, y) {

	        this.notify('element:magnet:pointermove', evt, magnet, x, y);
	    },

	    magnetpointerup: function(evt, magnet, x, y) {

	        this.notify('element:magnet:pointerup', evt, magnet, x, y);
	    },

	    magnetpointerdblclick: function(evt, magnet, x, y) {

	        this.notify('element:magnet:pointerdblclick', evt, magnet, x, y);
	    },

	    magnetcontextmenu: function(evt, magnet, x, y) {

	        this.notify('element:magnet:contextmenu', evt, magnet, x, y);
	    },

	    // Drag Start Handlers

	    dragStart: function(evt, x, y) {

	        if (this.isDefaultInteractionPrevented(evt)) { return; }

	        var view = this.getDelegatedView();
	        if (!view || !view.can('elementMove')) { return; }

	        this.eventData(evt, {
	            action: DragActions.MOVE,
	            delegatedView: view
	        });

	        var position = view.model.position();
	        view.eventData(evt, {
	            initialPosition: position,
	            pointerOffset: position.difference(x, y),
	            restrictedArea: this.paper.getRestrictedArea(view, x, y)
	        });
	    },

	    dragMagnetStart: function(evt, x, y) {

	        var ref = this;
	        var paper = ref.paper;
	        var isPropagationAlreadyStopped = evt.isPropagationStopped();
	        if (isPropagationAlreadyStopped) {
	            // Special case when the propagation was already stopped
	            // on the `element:magnet:pointerdown` event.
	            // Do not trigger any `element:pointer*` events
	            // but still start the magnet dragging.
	            this.eventData(evt, { preventPointerEvents: true });
	        }

	        if (this.isDefaultInteractionPrevented(evt) || !this.can('addLinkFromMagnet')) {
	            // Stop the default action, which is to start dragging a link.
	            return;
	        }

	        var ref$1 = this.eventData(evt);
	        var targetMagnet = ref$1.targetMagnet; if ( targetMagnet === void 0 ) targetMagnet = evt.currentTarget;
	        evt.stopPropagation();

	        // Invalid (Passive) magnet. Start dragging the element.
	        if (!paper.options.validateMagnet.call(paper, this, targetMagnet, evt)) {
	            if (isPropagationAlreadyStopped) {
	                // Do not trigger `element:pointerdown` and start element dragging
	                // if the propagation was stopped.
	                this.dragStart(evt, x, y);
	                // The `element:pointerdown` event is not triggered because
	                // of `preventPointerEvents` flag.
	            } else {
	                // We need to reset the action
	                // to `MOVE` so that the element is dragged.
	                this.pointerdown(evt, x, y);
	            }
	            return;
	        }

	        // Valid magnet. Start dragging a link.
	        if (paper.options.magnetThreshold <= 0) {
	            this.dragLinkStart(evt, targetMagnet, x, y);
	        }
	        this.eventData(evt, { action: DragActions.MAGNET });
	    },

	    // Drag Handlers

	    drag: function(evt, x, y) {

	        var paper = this.paper;
	        var grid = paper.options.gridSize;
	        var element = this.model;
	        var data = this.eventData(evt);
	        var pointerOffset = data.pointerOffset;
	        var restrictedArea = data.restrictedArea;
	        var embedding = data.embedding;

	        // Make sure the new element's position always snaps to the current grid
	        var elX = snapToGrid(x + pointerOffset.x, grid);
	        var elY = snapToGrid(y + pointerOffset.y, grid);

	        element.position(elX, elY, { restrictedArea: restrictedArea, deep: true, ui: true });

	        if (paper.options.embeddingMode) {
	            if (!embedding) {
	                // Prepare the element for embedding only if the pointer moves.
	                // We don't want to do unnecessary action with the element
	                // if an user only clicks/dblclicks on it.
	                this.prepareEmbedding(data);
	                embedding = true;
	            }
	            this.processEmbedding(data, evt, x, y);
	        }

	        this.eventData(evt, {
	            embedding: embedding
	        });
	    },

	    dragMagnet: function(evt, x, y) {
	        this.dragLink(evt, x, y);
	    },

	    // Drag End Handlers

	    dragEnd: function(evt, x, y) {

	        var data = this.eventData(evt);
	        if (data.embedding) { this.finalizeEmbedding(data); }
	    },

	    dragMagnetEnd: function(evt, x, y) {
	        this.dragLinkEnd(evt, x, y);
	    },

	    magnetpointerclick: function(evt, magnet, x, y) {
	        var paper = this.paper;
	        if (paper.eventData(evt).mousemoved > paper.options.clickThreshold) { return; }
	        this.notify('element:magnet:pointerclick', evt, magnet, x, y);
	    }

	}, {

	    Flags: Flags$1,
	});

	assign(ElementView.prototype, elementViewPortPrototype);

	var Flags$2 = {
	    TOOLS: CellView.Flags.TOOLS,
	    RENDER: 'RENDER',
	    UPDATE: 'UPDATE',
	    LABELS: 'LABELS',
	    SOURCE: 'SOURCE',
	    TARGET: 'TARGET',
	    CONNECTOR: 'CONNECTOR'
	};

	// Link base view and controller.
	// ----------------------------------------

	var LinkView = CellView.extend({

	    className: function() {

	        var classNames = CellView.prototype.className.apply(this).split(' ');

	        classNames.push('link');

	        return classNames.join(' ');
	    },

	    _labelCache: null,
	    _labelSelectors: null,
	    _V: null,
	    _dragData: null, // deprecated

	    metrics: null,
	    decimalsRounding: 2,

	    initialize: function() {

	        CellView.prototype.initialize.apply(this, arguments);

	        // `_.labelCache` is a mapping of indexes of labels in the `this.get('labels')` array to
	        // `<g class="label">` nodes wrapped by Vectorizer. This allows for quick access to the
	        // nodes in `updateLabelPosition()` in order to update the label positions.
	        this._labelCache = {};

	        // a cache of label selectors
	        this._labelSelectors = {};

	        // cache of default markup nodes
	        this._V = {};

	        // connection path metrics
	        this.cleanNodesCache();
	    },

	    presentationAttributes: {
	        markup: [Flags$2.RENDER],
	        attrs: [Flags$2.UPDATE],
	        router: [Flags$2.UPDATE],
	        connector: [Flags$2.CONNECTOR],
	        labels: [Flags$2.LABELS],
	        labelMarkup: [Flags$2.LABELS],
	        vertices: [Flags$2.UPDATE],
	        source: [Flags$2.SOURCE, Flags$2.UPDATE],
	        target: [Flags$2.TARGET, Flags$2.UPDATE]
	    },

	    initFlag: [Flags$2.RENDER, Flags$2.SOURCE, Flags$2.TARGET, Flags$2.TOOLS],

	    UPDATE_PRIORITY: 1,

	    confirmUpdate: function(flags, opt) {

	        opt || (opt = {});

	        if (this.hasFlag(flags, Flags$2.SOURCE)) {
	            if (!this.updateEndProperties('source')) { return flags; }
	            flags = this.removeFlag(flags, Flags$2.SOURCE);
	        }

	        if (this.hasFlag(flags, Flags$2.TARGET)) {
	            if (!this.updateEndProperties('target')) { return flags; }
	            flags = this.removeFlag(flags, Flags$2.TARGET);
	        }

	        var ref = this;
	        var paper = ref.paper;
	        var sourceView = ref.sourceView;
	        var targetView = ref.targetView;
	        if (paper && ((sourceView && !paper.isViewMounted(sourceView)) || (targetView && !paper.isViewMounted(targetView)))) {
	            // Wait for the sourceView and targetView to be rendered
	            return flags;
	        }

	        if (this.hasFlag(flags, Flags$2.RENDER)) {
	            this.render();
	            this.updateHighlighters(true);
	            this.updateTools(opt);
	            flags = this.removeFlag(flags, [Flags$2.RENDER, Flags$2.UPDATE, Flags$2.LABELS, Flags$2.TOOLS, Flags$2.CONNECTOR]);
	            return flags;
	        }

	        var updateHighlighters = false;

	        var ref$1 = this;
	        var model = ref$1.model;
	        var attributes = model.attributes;
	        var updateLabels = this.hasFlag(flags, Flags$2.LABELS);

	        if (updateLabels) {
	            this.onLabelsChange(model, attributes.labels, opt);
	            flags = this.removeFlag(flags, Flags$2.LABELS);
	            updateHighlighters = true;
	        }

	        var updateAll = this.hasFlag(flags, Flags$2.UPDATE);
	        var updateConnector = this.hasFlag(flags, Flags$2.CONNECTOR);
	        if (updateAll || updateConnector) {
	            if (!updateAll) {
	                // Keep the current route and update the geometry
	                this.updatePath();
	                this.updateDOM();
	            } else if (opt.translateBy && model.isRelationshipEmbeddedIn(opt.translateBy)) {
	                // The link is being translated by an ancestor that will
	                // shift source point, target point and all vertices
	                // by an equal distance.
	                this.translate(opt.tx, opt.ty);
	            } else {
	                this.update();
	            }
	            this.updateTools(opt);
	            flags = this.removeFlag(flags, [Flags$2.UPDATE, Flags$2.TOOLS, Flags$2.CONNECTOR]);
	            updateLabels = false;
	            updateHighlighters = true;
	        }

	        if (updateLabels) {
	            this.updateLabelPositions();
	        }

	        if (updateHighlighters) {
	            this.updateHighlighters();
	        }

	        if (this.hasFlag(flags, Flags$2.TOOLS)) {
	            this.updateTools(opt);
	            flags = this.removeFlag(flags, Flags$2.TOOLS);
	        }

	        return flags;
	    },

	    requestConnectionUpdate: function(opt) {
	        this.requestUpdate(this.getFlag(Flags$2.UPDATE), opt);
	    },

	    isLabelsRenderRequired: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var previousLabels = this.model.previous('labels');
	        if (!previousLabels) { return true; }

	        // Here is an optimization for cases when we know, that change does
	        // not require re-rendering of all labels.
	        if (('propertyPathArray' in opt) && ('propertyValue' in opt)) {
	            // The label is setting by `prop()` method
	            var pathArray = opt.propertyPathArray || [];
	            var pathLength = pathArray.length;
	            if (pathLength > 1) {
	                // We are changing a single label here e.g. 'labels/0/position'
	                var labelExists = !!previousLabels[pathArray[1]];
	                if (labelExists) {
	                    if (pathLength === 2) {
	                        // We are changing the entire label. Need to check if the
	                        // markup is also being changed.
	                        return ('markup' in Object(opt.propertyValue));
	                    } else if (pathArray[2] !== 'markup') {
	                        // We are changing a label property but not the markup
	                        return false;
	                    }
	                }
	            }
	        }

	        return true;
	    },

	    onLabelsChange: function(_link, _labels, opt) {

	        // Note: this optimization works in async=false mode only
	        if (this.isLabelsRenderRequired(opt)) {
	            this.renderLabels();
	        } else {
	            this.updateLabels();
	        }
	    },

	    // Rendering.
	    // ----------

	    render: function() {

	        this.vel.empty();
	        this.unmountLabels();
	        this._V = {};
	        this.renderMarkup();
	        // rendering labels has to be run after the link is appended to DOM tree. (otherwise <Text> bbox
	        // returns zero values)
	        this.renderLabels();
	        this.update();

	        return this;
	    },

	    renderMarkup: function() {

	        var link = this.model;
	        var markup = link.get('markup') || link.markup;
	        if (!markup) { throw new Error('dia.LinkView: markup required'); }
	        if (Array.isArray(markup)) { return this.renderJSONMarkup(markup); }
	        if (typeof markup === 'string') { return this.renderStringMarkup(markup); }
	        throw new Error('dia.LinkView: invalid markup');
	    },

	    renderJSONMarkup: function(markup) {

	        var doc = this.parseDOMJSON(markup, this.el);
	        // Selectors
	        this.selectors = doc.selectors;
	        // Fragment
	        this.vel.append(doc.fragment);
	    },

	    renderStringMarkup: function(markup) {

	        // A special markup can be given in the `properties.markup` property. This might be handy
	        // if e.g. arrowhead markers should be `<image>` elements or any other element than `<path>`s.
	        // `.connection`, `.connection-wrap`, `.marker-source` and `.marker-target` selectors
	        // of elements with special meaning though. Therefore, those classes should be preserved in any
	        // special markup passed in `properties.markup`.
	        var children = V(markup);
	        // custom markup may contain only one children
	        if (!Array.isArray(children)) { children = [children]; }

	        this.vel.append(children);
	    },

	    _getLabelMarkup: function(labelMarkup) {

	        if (!labelMarkup) { return undefined; }

	        if (Array.isArray(labelMarkup)) { return this.parseDOMJSON(labelMarkup, null); }
	        if (typeof labelMarkup === 'string') { return this._getLabelStringMarkup(labelMarkup); }
	        throw new Error('dia.linkView: invalid label markup');
	    },

	    _getLabelStringMarkup: function(labelMarkup) {

	        var children = V(labelMarkup);
	        var fragment = document.createDocumentFragment();

	        if (!Array.isArray(children)) {
	            fragment.appendChild(children.node);

	        } else {
	            for (var i = 0, n = children.length; i < n; i++) {
	                var currentChild = children[i].node;
	                fragment.appendChild(currentChild);
	            }
	        }

	        return { fragment: fragment, selectors: {}}; // no selectors
	    },

	    // Label markup fragment may come wrapped in <g class="label" />, or not.
	    // If it doesn't, add the <g /> container here.
	    _normalizeLabelMarkup: function(markup) {

	        if (!markup) { return undefined; }

	        var fragment = markup.fragment;
	        if (!(markup.fragment instanceof DocumentFragment) || !markup.fragment.hasChildNodes()) { throw new Error('dia.LinkView: invalid label markup.'); }

	        var vNode;
	        var childNodes = fragment.childNodes;

	        if ((childNodes.length > 1) || childNodes[0].nodeName.toUpperCase() !== 'G') {
	            // default markup fragment is not wrapped in <g />
	            // add a <g /> container
	            vNode = V('g').append(fragment);
	        } else {
	            vNode = V(childNodes[0]);
	        }

	        vNode.addClass('label');

	        return { node: vNode.node, selectors: markup.selectors };
	    },

	    renderLabels: function() {

	        var cache = this._V;
	        var vLabels = cache.labels;
	        var labelCache = this._labelCache = {};
	        var labelSelectors = this._labelSelectors = {};
	        var model = this.model;
	        var labels = model.attributes.labels || [];
	        var labelsCount = labels.length;

	        if (labelsCount === 0) {
	            if (vLabels) { vLabels.remove(); }
	            return this;
	        }

	        if (vLabels) {
	            vLabels.empty();
	        }  else {
	            // there is no label container in the markup but some labels are defined
	            // add a <g class="labels" /> container
	            vLabels = cache.labels = V('g').addClass('labels');
	            if (this.options.labelsLayer) {
	                vLabels.addClass(addClassNamePrefix(result(this, 'className')));
	                vLabels.attr('model-id', model.id);
	            }
	        }

	        for (var i = 0; i < labelsCount; i++) {

	            var label = labels[i];
	            var labelMarkup = this._normalizeLabelMarkup(this._getLabelMarkup(label.markup));
	            var labelNode;
	            var selectors;
	            if (labelMarkup) {

	                labelNode = labelMarkup.node;
	                selectors = labelMarkup.selectors;

	            } else {

	                var builtinDefaultLabel =  model._builtins.defaultLabel;
	                var builtinDefaultLabelMarkup = this._normalizeLabelMarkup(this._getLabelMarkup(builtinDefaultLabel.markup));
	                var defaultLabel = model._getDefaultLabel();
	                var defaultLabelMarkup = this._normalizeLabelMarkup(this._getLabelMarkup(defaultLabel.markup));
	                var defaultMarkup = defaultLabelMarkup || builtinDefaultLabelMarkup;

	                labelNode = defaultMarkup.node;
	                selectors = defaultMarkup.selectors;
	            }

	            labelNode.setAttribute('label-idx', i); // assign label-idx
	            vLabels.append(labelNode);
	            labelCache[i] = labelNode; // cache node for `updateLabels()` so it can just update label node positions

	            var rootSelector = this.selector;
	            if (selectors[rootSelector]) { throw new Error('dia.LinkView: ambiguous label root selector.'); }
	            selectors[rootSelector] = labelNode;

	            labelSelectors[i] = selectors; // cache label selectors for `updateLabels()`
	        }
	        if (!vLabels.parent()) {
	            this.mountLabels();
	        }

	        this.updateLabels();

	        return this;
	    },

	    mountLabels: function() {
	        var ref = this;
	        var el = ref.el;
	        var paper = ref.paper;
	        var model = ref.model;
	        var _V = ref._V;
	        var options = ref.options;
	        var vLabels = _V.labels;
	        if (!vLabels || !model.hasLabels()) { return; }
	        var node = vLabels.node;
	        if (options.labelsLayer) {
	            paper.getLayerView(options.labelsLayer).insertSortedNode(node, model.get('z'));
	        } else {
	            if (node.parentNode !== el) {
	                el.appendChild(node);
	            }
	        }
	    },

	    unmountLabels: function() {
	        var ref = this;
	        var options = ref.options;
	        var _V = ref._V;
	        if (!_V) { return; }
	        var vLabels = _V.labels;
	        if (vLabels && options.labelsLayer) {
	            vLabels.remove();
	        }
	    },

	    findLabelNodes: function(labelIndex, selector) {
	        var labelRoot = this._labelCache[labelIndex];
	        if (!labelRoot) { return []; }
	        var labelSelectors = this._labelSelectors[labelIndex];
	        return this.findBySelector(selector, labelRoot, labelSelectors);
	    },

	    findLabelNode: function(labelIndex, selector) {
	        var ref = this.findLabelNodes(labelIndex, selector);
	        var node = ref[0]; if ( node === void 0 ) node = null;
	        return node;
	    },

	    // merge default label attrs into label attrs (or use built-in default label attrs if neither is provided)
	    // keep `undefined` or `null` because `{}` means something else
	    _mergeLabelAttrs: function(hasCustomMarkup, labelAttrs, defaultLabelAttrs, builtinDefaultLabelAttrs) {

	        if (labelAttrs === null) { return null; }
	        if (labelAttrs === undefined) {

	            if (defaultLabelAttrs === null) { return null; }
	            if (defaultLabelAttrs === undefined) {

	                if (hasCustomMarkup) { return undefined; }
	                return builtinDefaultLabelAttrs;
	            }

	            if (hasCustomMarkup) { return defaultLabelAttrs; }
	            return merge({}, builtinDefaultLabelAttrs, defaultLabelAttrs);
	        }

	        if (hasCustomMarkup) { return merge({}, defaultLabelAttrs, labelAttrs); }
	        return merge({}, builtinDefaultLabelAttrs, defaultLabelAttrs, labelAttrs);
	    },

	    // merge default label size into label size (no built-in default)
	    // keep `undefined` or `null` because `{}` means something else
	    _mergeLabelSize: function(labelSize, defaultLabelSize) {

	        if (labelSize === null) { return null; }
	        if (labelSize === undefined) {

	            if (defaultLabelSize === null) { return null; }
	            if (defaultLabelSize === undefined) { return undefined; }

	            return defaultLabelSize;
	        }

	        return merge({}, defaultLabelSize, labelSize);
	    },

	    updateLabels: function() {

	        if (!this._V.labels) { return this; }

	        var model = this.model;
	        var labels = model.get('labels') || [];
	        var canLabelMove = this.can('labelMove');

	        var builtinDefaultLabel = model._builtins.defaultLabel;
	        var builtinDefaultLabelAttrs = builtinDefaultLabel.attrs;

	        var defaultLabel = model._getDefaultLabel();
	        var defaultLabelMarkup = defaultLabel.markup;
	        var defaultLabelAttrs = defaultLabel.attrs;
	        var defaultLabelSize = defaultLabel.size;

	        for (var i = 0, n = labels.length; i < n; i++) {

	            var labelNode = this._labelCache[i];
	            labelNode.setAttribute('cursor', (canLabelMove ? 'move' : 'default'));

	            var selectors = this._labelSelectors[i];

	            var label = labels[i];
	            var labelMarkup = label.markup;
	            var labelAttrs = label.attrs;
	            var labelSize = label.size;

	            var attrs = this._mergeLabelAttrs(
	                (labelMarkup || defaultLabelMarkup),
	                labelAttrs,
	                defaultLabelAttrs,
	                builtinDefaultLabelAttrs
	            );

	            var size = this._mergeLabelSize(
	                labelSize,
	                defaultLabelSize
	            );

	            this.updateDOMSubtreeAttributes(labelNode, attrs, {
	                rootBBox: new Rect(size),
	                selectors: selectors
	            });
	        }

	        return this;
	    },

	    // remove vertices that lie on (or nearly on) straight lines within the link
	    // return the number of removed points
	    removeRedundantLinearVertices: function(opt) {

	        var SIMPLIFY_THRESHOLD = 0.001;

	        var link = this.model;
	        var vertices = link.vertices();
	        var routePoints = [this.sourceAnchor ].concat( vertices, [this.targetAnchor]);
	        var numRoutePoints = routePoints.length;

	        // put routePoints into a polyline and try to simplify
	        var polyline = new Polyline(routePoints);
	        polyline.simplify({ threshold: SIMPLIFY_THRESHOLD });
	        var polylinePoints = polyline.points.map(function (point) { return (point.toJSON()); }); // JSON of points after simplification
	        var numPolylinePoints = polylinePoints.length; // number of points after simplification

	        // shortcut if simplification did not remove any redundant vertices:
	        if (numRoutePoints === numPolylinePoints) { return 0; }

	        // else: set simplified polyline points as link vertices
	        // remove first and last polyline points again (= source/target anchors)
	        link.vertices(polylinePoints.slice(1, numPolylinePoints - 1), opt);
	        return (numRoutePoints - numPolylinePoints);
	    },

	    getEndView: function(type) {
	        switch (type) {
	            case 'source':
	                return this.sourceView || null;
	            case 'target':
	                return this.targetView || null;
	            default:
	                throw new Error('dia.LinkView: type parameter required.');
	        }
	    },

	    getEndAnchor: function(type) {
	        switch (type) {
	            case 'source':
	                return new Point(this.sourceAnchor);
	            case 'target':
	                return new Point(this.targetAnchor);
	            default:
	                throw new Error('dia.LinkView: type parameter required.');
	        }
	    },

	    getEndConnectionPoint: function(type) {
	        switch (type) {
	            case 'source':
	                return new Point(this.sourcePoint);
	            case 'target':
	                return new Point(this.targetPoint);
	            default:
	                throw new Error('dia.LinkView: type parameter required.');
	        }
	    },

	    getEndMagnet: function(type) {
	        switch (type) {
	            case 'source':
	                var sourceView = this.sourceView;
	                if (!sourceView) { break; }
	                return this.sourceMagnet || sourceView.el;
	            case 'target':
	                var targetView = this.targetView;
	                if (!targetView) { break; }
	                return this.targetMagnet || targetView.el;
	            default:
	                throw new Error('dia.LinkView: type parameter required.');
	        }
	        return null;
	    },


	    // Updating.
	    // ---------

	    update: function() {
	        this.updateRoute();
	        this.updatePath();
	        this.updateDOM();
	        return this;
	    },

	    translate: function(tx, ty) {
	        if ( tx === void 0 ) tx = 0;
	        if ( ty === void 0 ) ty = 0;

	        var ref = this;
	        var route = ref.route;
	        var path = ref.path;
	        if (!route || !path) { return; }
	        // translate the route
	        var polyline = new Polyline(route);
	        polyline.translate(tx, ty);
	        this.route = polyline.points;
	        // translate source and target connection and anchor points.
	        this.sourcePoint.offset(tx, ty);
	        this.targetPoint.offset(tx, ty);
	        this.sourceAnchor.offset(tx, ty);
	        this.targetAnchor.offset(tx, ty);
	        // translate the geometry path
	        path.translate(tx, ty);
	        this.updateDOM();
	    },

	    updateDOM: function updateDOM() {
	        var ref = this;
	        var el = ref.el;
	        var model = ref.model;
	        var selectors = ref.selectors;
	        this.cleanNodesCache();
	        // update SVG attributes defined by 'attrs/'.
	        this.updateDOMSubtreeAttributes(el, model.attr(), { selectors: selectors });
	        // update the label position etc.
	        this.updateLabelPositions();
	        // *Deprecated*
	        // Local perpendicular flag (as opposed to one defined on paper).
	        // Could be enabled inside a connector/router. It's valid only
	        // during the update execution.
	        this.options.perpendicular = null;
	    },

	    updateRoute: function() {
	        var ref = this;
	        var model = ref.model;
	        var vertices = model.vertices();
	        // 1. Find Anchors
	        var anchors = this.findAnchors(vertices);
	        var sourceAnchor = this.sourceAnchor = anchors.source;
	        var targetAnchor = this.targetAnchor = anchors.target;
	        // 2. Find Route
	        var route = this.findRoute(vertices);
	        this.route = route;
	        // 3. Find Connection Points
	        var connectionPoints = this.findConnectionPoints(route, sourceAnchor, targetAnchor);
	        this.sourcePoint = connectionPoints.source;
	        this.targetPoint = connectionPoints.target;
	    },

	    updatePath: function() {
	        var ref = this;
	        var route = ref.route;
	        var sourcePoint = ref.sourcePoint;
	        var targetPoint = ref.targetPoint;
	        // 4. Find Connection
	        var path = this.findPath(route, sourcePoint.clone(), targetPoint.clone());
	        this.path = path;
	    },

	    findAnchorsOrdered: function(firstEndType, firstRef, secondEndType, secondRef) {

	        var firstAnchor, secondAnchor;
	        var firstAnchorRef, secondAnchorRef;
	        var model = this.model;
	        var firstDef = model.get(firstEndType);
	        var secondDef = model.get(secondEndType);
	        var firstView = this.getEndView(firstEndType);
	        var secondView = this.getEndView(secondEndType);
	        var firstMagnet = this.getEndMagnet(firstEndType);
	        var secondMagnet = this.getEndMagnet(secondEndType);

	        // Anchor first
	        if (firstView) {
	            if (firstRef) {
	                firstAnchorRef = new Point(firstRef);
	            } else if (secondView) {
	                firstAnchorRef = secondMagnet;
	            } else {
	                firstAnchorRef = new Point(secondDef);
	            }
	            firstAnchor = this.getAnchor(firstDef.anchor, firstView, firstMagnet, firstAnchorRef, firstEndType);
	        } else {
	            firstAnchor = new Point(firstDef);
	        }

	        // Anchor second
	        if (secondView) {
	            secondAnchorRef = new Point(secondRef || firstAnchor);
	            secondAnchor = this.getAnchor(secondDef.anchor, secondView, secondMagnet, secondAnchorRef, secondEndType);
	        } else {
	            secondAnchor = new Point(secondDef);
	        }

	        var res = {};
	        res[firstEndType] = firstAnchor;
	        res[secondEndType] = secondAnchor;
	        return res;
	    },

	    findAnchors: function(vertices) {

	        var model = this.model;
	        var firstVertex = vertices[0];
	        var lastVertex = vertices[vertices.length - 1];

	        if (model.target().priority && !model.source().priority) {
	            // Reversed order
	            return this.findAnchorsOrdered('target', lastVertex, 'source', firstVertex);
	        }

	        // Usual order
	        return this.findAnchorsOrdered('source', firstVertex, 'target', lastVertex);
	    },

	    findConnectionPoints: function(route, sourceAnchor, targetAnchor) {

	        var firstWaypoint = route[0];
	        var lastWaypoint = route[route.length - 1];
	        var model = this.model;
	        var sourceDef = model.get('source');
	        var targetDef = model.get('target');
	        var sourceView = this.sourceView;
	        var targetView = this.targetView;
	        var paperOptions = this.paper.options;
	        var sourceMagnet, targetMagnet;

	        // Connection Point Source
	        var sourcePoint;
	        if (sourceView && !sourceView.isNodeConnection(this.sourceMagnet)) {
	            sourceMagnet = (this.sourceMagnet || sourceView.el);
	            var sourceConnectionPointDef = sourceDef.connectionPoint || paperOptions.defaultConnectionPoint;
	            var sourcePointRef = firstWaypoint || targetAnchor;
	            var sourceLine = new Line(sourcePointRef, sourceAnchor);
	            sourcePoint = this.getConnectionPoint(
	                sourceConnectionPointDef,
	                sourceView,
	                sourceMagnet,
	                sourceLine,
	                'source'
	            );
	        } else {
	            sourcePoint = sourceAnchor;
	        }
	        // Connection Point Target
	        var targetPoint;
	        if (targetView && !targetView.isNodeConnection(this.targetMagnet)) {
	            targetMagnet = (this.targetMagnet || targetView.el);
	            var targetConnectionPointDef = targetDef.connectionPoint || paperOptions.defaultConnectionPoint;
	            var targetPointRef = lastWaypoint || sourceAnchor;
	            var targetLine = new Line(targetPointRef, targetAnchor);
	            targetPoint = this.getConnectionPoint(
	                targetConnectionPointDef,
	                targetView,
	                targetMagnet,
	                targetLine,
	                'target'
	            );
	        } else {
	            targetPoint = targetAnchor;
	        }

	        return {
	            source: sourcePoint,
	            target: targetPoint
	        };
	    },

	    getAnchor: function(anchorDef, cellView, magnet, ref, endType) {

	        var isConnection = cellView.isNodeConnection(magnet);
	        var paperOptions = this.paper.options;
	        if (!anchorDef) {
	            if (isConnection) {
	                anchorDef = paperOptions.defaultLinkAnchor;
	            } else {
	                if (this.options.perpendicular) {
	                    // Backwards compatibility
	                    // See `manhattan` router for more details
	                    anchorDef = { name: 'perpendicular' };
	                } else {
	                    anchorDef = paperOptions.defaultAnchor;
	                }
	            }
	        }

	        if (!anchorDef) { throw new Error('Anchor required.'); }
	        var anchorFn;
	        if (typeof anchorDef === 'function') {
	            anchorFn = anchorDef;
	        } else {
	            var anchorName = anchorDef.name;
	            var anchorNamespace = isConnection ? 'linkAnchorNamespace' : 'anchorNamespace';
	            anchorFn = paperOptions[anchorNamespace][anchorName];
	            if (typeof anchorFn !== 'function') { throw new Error('Unknown anchor: ' + anchorName); }
	        }
	        var anchor = anchorFn.call(
	            this,
	            cellView,
	            magnet,
	            ref,
	            anchorDef.args || {},
	            endType,
	            this
	        );
	        if (!anchor) { return new Point(); }
	        return anchor.round(this.decimalsRounding);
	    },


	    getConnectionPoint: function(connectionPointDef, view, magnet, line, endType) {

	        var connectionPoint;
	        var anchor = line.end;
	        var paperOptions = this.paper.options;

	        if (!connectionPointDef) { return anchor; }
	        var connectionPointFn;
	        if (typeof connectionPointDef === 'function') {
	            connectionPointFn = connectionPointDef;
	        } else {
	            var connectionPointName = connectionPointDef.name;
	            connectionPointFn = paperOptions.connectionPointNamespace[connectionPointName];
	            if (typeof connectionPointFn !== 'function') { throw new Error('Unknown connection point: ' + connectionPointName); }
	        }
	        connectionPoint = connectionPointFn.call(this, line, view, magnet, connectionPointDef.args || {}, endType, this);
	        if (!connectionPoint) { return anchor; }
	        return connectionPoint.round(this.decimalsRounding);
	    },

	    // combine default label position with built-in default label position
	    _getDefaultLabelPositionProperty: function() {

	        var model = this.model;

	        var builtinDefaultLabel = model._builtins.defaultLabel;
	        var builtinDefaultLabelPosition = builtinDefaultLabel.position;

	        var defaultLabel = model._getDefaultLabel();
	        var defaultLabelPosition = this._normalizeLabelPosition(defaultLabel.position);

	        return merge({}, builtinDefaultLabelPosition, defaultLabelPosition);
	    },

	    // if label position is a number, normalize it to a position object
	    // this makes sure that label positions can be merged properly
	    _normalizeLabelPosition: function(labelPosition) {

	        if (typeof labelPosition === 'number') { return { distance: labelPosition, offset: null, angle: 0, args: null }; }
	        return labelPosition;
	    },

	    // expects normalized position properties
	    // e.g. `this._normalizeLabelPosition(labelPosition)` and `this._getDefaultLabelPositionProperty()`
	    _mergeLabelPositionProperty: function(normalizedLabelPosition, normalizedDefaultLabelPosition) {

	        if (normalizedLabelPosition === null) { return null; }
	        if (normalizedLabelPosition === undefined) {

	            if (normalizedDefaultLabelPosition === null) { return null; }
	            return normalizedDefaultLabelPosition;
	        }

	        return merge({}, normalizedDefaultLabelPosition, normalizedLabelPosition);
	    },

	    updateLabelPositions: function() {

	        if (!this._V.labels) { return this; }

	        var path = this.path;
	        if (!path) { return this; }

	        // This method assumes all the label nodes are stored in the `this._labelCache` hash table
	        // by their indices in the `this.get('labels')` array. This is done in the `renderLabels()` method.

	        var model = this.model;
	        var labels = model.get('labels') || [];
	        if (!labels.length) { return this; }

	        var defaultLabelPosition = this._getDefaultLabelPositionProperty();

	        for (var idx = 0, n = labels.length; idx < n; idx++) {
	            var labelNode = this._labelCache[idx];
	            if (!labelNode) { continue; }
	            var label = labels[idx];
	            var labelPosition = this._normalizeLabelPosition(label.position);
	            var position = this._mergeLabelPositionProperty(labelPosition, defaultLabelPosition);
	            var transformationMatrix = this._getLabelTransformationMatrix(position);
	            labelNode.setAttribute('transform', V.matrixToTransformString(transformationMatrix));
	            this._cleanLabelMatrices(idx);
	        }

	        return this;
	    },

	    _cleanLabelMatrices: function(index) {
	        // Clean magnetMatrix for all nodes of the label.
	        // Cached BoundingRect does not need to updated when the position changes
	        // TODO: this doesn't work for labels with XML String markups.
	        var ref = this;
	        var metrics = ref.metrics;
	        var _labelSelectors = ref._labelSelectors;
	        var selectors = _labelSelectors[index];
	        if (!selectors) { return; }
	        for (var selector in selectors) {
	            var ref$1 = selectors[selector];
	            var id = ref$1.id;
	            if (id && (id in metrics)) { delete metrics[id].magnetMatrix; }
	        }
	    },

	    updateEndProperties: function(endType) {

	        var ref = this;
	        var model = ref.model;
	        var paper = ref.paper;
	        var endViewProperty = endType + "View";
	        var endDef = model.get(endType);
	        var endId = endDef && endDef.id;

	        if (!endId) {
	            // the link end is a point ~ rect 0x0
	            this[endViewProperty] = null;
	            this.updateEndMagnet(endType);
	            return true;
	        }

	        var endModel = paper.getModelById(endId);
	        if (!endModel) { throw new Error('LinkView: invalid ' + endType + ' cell.'); }

	        var endView = endModel.findView(paper);
	        if (!endView) {
	            // A view for a model should always exist
	            return false;
	        }

	        this[endViewProperty] = endView;
	        this.updateEndMagnet(endType);
	        return true;
	    },

	    updateEndMagnet: function(endType) {

	        var endMagnetProperty = endType + "Magnet";
	        var endView = this.getEndView(endType);
	        if (endView) {
	            var connectedMagnet = endView.getMagnetFromLinkEnd(this.model.get(endType));
	            if (connectedMagnet === endView.el) { connectedMagnet = null; }
	            this[endMagnetProperty] = connectedMagnet;
	        } else {
	            this[endMagnetProperty] = null;
	        }
	    },

	    _getLabelPositionProperty: function(idx) {

	        return (this.model.label(idx).position || {});
	    },

	    _getLabelPositionAngle: function(idx) {

	        var labelPosition = this._getLabelPositionProperty(idx);
	        return (labelPosition.angle || 0);
	    },

	    _getLabelPositionArgs: function(idx) {

	        var labelPosition = this._getLabelPositionProperty(idx);
	        return labelPosition.args;
	    },

	    _getDefaultLabelPositionArgs: function() {

	        var defaultLabel = this.model._getDefaultLabel();
	        var defaultLabelPosition = defaultLabel.position || {};
	        return defaultLabelPosition.args;
	    },

	    // merge default label position args into label position args
	    // keep `undefined` or `null` because `{}` means something else
	    _mergeLabelPositionArgs: function(labelPositionArgs, defaultLabelPositionArgs) {

	        if (labelPositionArgs === null) { return null; }
	        if (labelPositionArgs === undefined) {

	            if (defaultLabelPositionArgs === null) { return null; }
	            return defaultLabelPositionArgs;
	        }

	        return merge({}, defaultLabelPositionArgs, labelPositionArgs);
	    },

	    // Add default label at given position at end of `labels` array.
	    // Four signatures:
	    // - obj, obj = point, opt
	    // - obj, num, obj = point, angle, opt
	    // - num, num, obj = x, y, opt
	    // - num, num, num, obj = x, y, angle, opt
	    // Assigns relative coordinates by default:
	    // `opt.absoluteDistance` forces absolute coordinates.
	    // `opt.reverseDistance` forces reverse absolute coordinates (if absoluteDistance = true).
	    // `opt.absoluteOffset` forces absolute coordinates for offset.
	    // Additional args:
	    // `opt.keepGradient` auto-adjusts the angle of the label to match path gradient at position.
	    // `opt.ensureLegibility` rotates labels so they are never upside-down.
	    addLabel: function(p1, p2, p3, p4) {

	        // normalize data from the four possible signatures
	        var localX;
	        var localY;
	        var localAngle = 0;
	        var localOpt;
	        if (typeof p1 !== 'number') {
	            // {x, y} object provided as first parameter
	            localX = p1.x;
	            localY = p1.y;
	            if (typeof p2 === 'number') {
	                // angle and opt provided as second and third parameters
	                localAngle = p2;
	                localOpt = p3;
	            } else {
	                // opt provided as second parameter
	                localOpt = p2;
	            }
	        } else {
	            // x and y provided as first and second parameters
	            localX = p1;
	            localY = p2;
	            if (typeof p3 === 'number') {
	                // angle and opt provided as third and fourth parameters
	                localAngle = p3;
	                localOpt = p4;
	            } else {
	                // opt provided as third parameter
	                localOpt = p3;
	            }
	        }

	        // merge label position arguments
	        var defaultLabelPositionArgs = this._getDefaultLabelPositionArgs();
	        var labelPositionArgs = localOpt;
	        var positionArgs = this._mergeLabelPositionArgs(labelPositionArgs, defaultLabelPositionArgs);

	        // append label to labels array
	        var label = { position: this.getLabelPosition(localX, localY, localAngle, positionArgs) };
	        var idx = -1;
	        this.model.insertLabel(idx, label, localOpt);
	        return idx;
	    },

	    // Add a new vertex at calculated index to the `vertices` array.
	    addVertex: function(x, y, opt) {

	        // accept input in form `{ x, y }, opt` or `x, y, opt`
	        var isPointProvided = (typeof x !== 'number');
	        var localX = isPointProvided ? x.x : x;
	        var localY = isPointProvided ? x.y : y;
	        var localOpt = isPointProvided ? y : opt;

	        var vertex = { x: localX, y: localY };
	        var idx = this.getVertexIndex(localX, localY);
	        this.model.insertVertex(idx, vertex, localOpt);
	        return idx;
	    },

	    // Send a token (an SVG element, usually a circle) along the connection path.
	    // Example: `link.findView(paper).sendToken(V('circle', { r: 7, fill: 'green' }).node)`
	    // `opt.duration` is optional and is a time in milliseconds that the token travels from the source to the target of the link. Default is `1000`.
	    // `opt.direction` is optional and it determines whether the token goes from source to target or other way round (`reverse`)
	    // `opt.connection` is an optional selector to the connection path.
	    // `callback` is optional and is a function to be called once the token reaches the target.
	    sendToken: function(token, opt, callback) {

	        function onAnimationEnd(vToken, callback) {
	            return function() {
	                vToken.remove();
	                if (typeof callback === 'function') {
	                    callback();
	                }
	            };
	        }

	        var duration, isReversed, selector;
	        if (isObject$1(opt)) {
	            duration = opt.duration;
	            isReversed = (opt.direction === 'reverse');
	            selector = opt.connection;
	        } else {
	            // Backwards compatibility
	            duration = opt;
	            isReversed = false;
	            selector = null;
	        }

	        duration = duration || 1000;

	        var animationAttributes = {
	            dur: duration + 'ms',
	            repeatCount: 1,
	            calcMode: 'linear',
	            fill: 'freeze'
	        };

	        if (isReversed) {
	            animationAttributes.keyPoints = '1;0';
	            animationAttributes.keyTimes = '0;1';
	        }

	        var vToken = V(token);
	        var connection;
	        if (typeof selector === 'string') {
	            // Use custom connection path.
	            connection = this.findNode(selector);
	        } else {
	            // Select connection path automatically.
	            var cache = this._V;
	            connection = (cache.connection) ? cache.connection.node : this.el.querySelector('path');
	        }

	        if (!(connection instanceof SVGPathElement)) {
	            throw new Error('dia.LinkView: token animation requires a valid connection path.');
	        }

	        vToken
	            .appendTo(this.paper.cells)
	            .animateAlongPath(animationAttributes, connection);

	        setTimeout(onAnimationEnd(vToken, callback), duration);
	    },

	    findRoute: function(vertices) {

	        vertices || (vertices = []);

	        var namespace = this.paper.options.routerNamespace || routers;
	        var router = this.model.router();
	        var defaultRouter = this.paper.options.defaultRouter;

	        if (!router) {
	            if (defaultRouter) { router = defaultRouter; }
	            else { return vertices.map(Point); } // no router specified
	        }

	        var routerFn = isFunction(router) ? router : namespace[router.name];
	        if (!isFunction(routerFn)) {
	            throw new Error('dia.LinkView: unknown router: "' + router.name + '".');
	        }

	        var args = router.args || {};

	        var route = routerFn.call(
	            this, // context
	            vertices, // vertices
	            args, // options
	            this // linkView
	        );

	        if (!route) { return vertices.map(Point); }
	        return route;
	    },

	    // Return the `d` attribute value of the `<path>` element representing the link
	    // between `source` and `target`.
	    findPath: function(route, sourcePoint, targetPoint) {

	        var namespace = this.paper.options.connectorNamespace || connectors;
	        var connector = this.model.connector();
	        var defaultConnector = this.paper.options.defaultConnector;

	        if (!connector) {
	            connector = defaultConnector || {};
	        }

	        var connectorFn = isFunction(connector) ? connector : namespace[connector.name];
	        if (!isFunction(connectorFn)) {
	            throw new Error('dia.LinkView: unknown connector: "' + connector.name + '".');
	        }

	        var args = clone(connector.args || {});
	        args.raw = true; // Request raw g.Path as the result.

	        var path = connectorFn.call(
	            this, // context
	            sourcePoint, // start point
	            targetPoint, // end point
	            route, // vertices
	            args, // options
	            this // linkView
	        );

	        if (typeof path === 'string') {
	            // Backwards compatibility for connectors not supporting `raw` option.
	            path = new Path(V.normalizePathData(path));
	        }

	        return path;
	    },

	    // Public API.
	    // -----------

	    getConnection: function() {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.clone();
	    },

	    getSerializedConnection: function() {

	        var path = this.path;
	        if (!path) { return null; }

	        var metrics = this.metrics;
	        if (metrics.hasOwnProperty('data')) { return metrics.data; }
	        var data = path.serialize();
	        metrics.data = data;
	        return data;
	    },

	    getConnectionSubdivisions: function() {

	        var path = this.path;
	        if (!path) { return null; }

	        var metrics = this.metrics;
	        if (metrics.hasOwnProperty('segmentSubdivisions')) { return metrics.segmentSubdivisions; }
	        var subdivisions = path.getSegmentSubdivisions();
	        metrics.segmentSubdivisions = subdivisions;
	        return subdivisions;
	    },

	    getConnectionLength: function() {

	        var path = this.path;
	        if (!path) { return 0; }

	        var metrics = this.metrics;
	        if (metrics.hasOwnProperty('length')) { return metrics.length; }
	        var length = path.length({ segmentSubdivisions: this.getConnectionSubdivisions() });
	        metrics.length = length;
	        return length;
	    },

	    getPointAtLength: function(length) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.pointAtLength(length, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getPointAtRatio: function(ratio) {

	        var path = this.path;
	        if (!path) { return null; }
	        if (isPercentage(ratio)) { ratio = parseFloat(ratio) / 100; }
	        return path.pointAt(ratio, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getTangentAtLength: function(length) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.tangentAtLength(length, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getTangentAtRatio: function(ratio) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.tangentAt(ratio, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getClosestPoint: function(point) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.closestPoint(point, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getClosestPointLength: function(point) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.closestPointLength(point, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    getClosestPointRatio: function(point) {

	        var path = this.path;
	        if (!path) { return null; }

	        return path.closestPointNormalizedLength(point, { segmentSubdivisions: this.getConnectionSubdivisions() });
	    },

	    // Get label position object based on two provided coordinates, x and y.
	    // (Used behind the scenes when user moves labels around.)
	    // Two signatures:
	    // - num, num, obj = x, y, options
	    // - num, num, num, obj = x, y, angle, options
	    // Accepts distance/offset options = `absoluteDistance: boolean`, `reverseDistance: boolean`, `absoluteOffset: boolean`
	    // - `absoluteOffset` is necessary in order to move beyond connection endpoints
	    // Additional options = `keepGradient: boolean`, `ensureLegibility: boolean`
	    getLabelPosition: function(x, y, p3, p4) {

	        var position = {};

	        // normalize data from the two possible signatures
	        var localAngle = 0;
	        var localOpt;
	        if (typeof p3 === 'number') {
	            // angle and opt provided as third and fourth argument
	            localAngle = p3;
	            localOpt = p4;
	        } else {
	            // opt provided as third argument
	            localOpt = p3;
	        }

	        // save localOpt as `args` of the position object that is passed along
	        if (localOpt) { position.args = localOpt; }

	        // identify distance/offset settings
	        var isDistanceRelative = !(localOpt && localOpt.absoluteDistance); // relative by default
	        var isDistanceAbsoluteReverse = (localOpt && localOpt.absoluteDistance && localOpt.reverseDistance); // non-reverse by default
	        var isOffsetAbsolute = localOpt && localOpt.absoluteOffset; // offset is non-absolute by default

	        // find closest point t
	        var path = this.path;
	        var pathOpt = { segmentSubdivisions: this.getConnectionSubdivisions() };
	        var labelPoint = new Point(x, y);
	        var t = path.closestPointT(labelPoint, pathOpt);

	        // DISTANCE:
	        var labelDistance = path.lengthAtT(t, pathOpt);
	        if (isDistanceRelative) { labelDistance = (labelDistance / this.getConnectionLength()) || 0; } // fix to prevent NaN for 0 length
	        if (isDistanceAbsoluteReverse) { labelDistance = (-1 * (this.getConnectionLength() - labelDistance)) || 1; } // fix for end point (-0 => 1)
	        position.distance = labelDistance;

	        // OFFSET:
	        // use absolute offset if:
	        // - opt.absoluteOffset is true,
	        // - opt.absoluteOffset is not true but there is no tangent
	        var tangent;
	        if (!isOffsetAbsolute) { tangent = path.tangentAtT(t); }
	        var labelOffset;
	        if (tangent) {
	            labelOffset = tangent.pointOffset(labelPoint);
	        } else {
	            var closestPoint = path.pointAtT(t);
	            var labelOffsetDiff = labelPoint.difference(closestPoint);
	            labelOffset = { x: labelOffsetDiff.x, y: labelOffsetDiff.y };
	        }
	        position.offset = labelOffset;

	        // ANGLE:
	        position.angle = localAngle;

	        return position;
	    },

	    _getLabelTransformationMatrix: function(labelPosition) {

	        var labelDistance;
	        var labelAngle = 0;
	        var args = {};
	        if (typeof labelPosition === 'number') {
	            labelDistance = labelPosition;
	        } else if (typeof labelPosition.distance === 'number') {
	            args = labelPosition.args || {};
	            labelDistance = labelPosition.distance;
	            labelAngle = labelPosition.angle || 0;
	        } else {
	            throw new Error('dia.LinkView: invalid label position distance.');
	        }

	        var isDistanceRelative = ((labelDistance > 0) && (labelDistance <= 1));

	        var labelOffset = 0;
	        var labelOffsetCoordinates = { x: 0, y: 0 };
	        if (labelPosition.offset) {
	            var positionOffset = labelPosition.offset;
	            if (typeof positionOffset === 'number') { labelOffset = positionOffset; }
	            if (positionOffset.x) { labelOffsetCoordinates.x = positionOffset.x; }
	            if (positionOffset.y) { labelOffsetCoordinates.y = positionOffset.y; }
	        }

	        var isOffsetAbsolute = ((labelOffsetCoordinates.x !== 0) || (labelOffsetCoordinates.y !== 0) || labelOffset === 0);

	        var isKeepGradient = args.keepGradient;
	        var isEnsureLegibility = args.ensureLegibility;

	        var path = this.path;
	        var pathOpt = { segmentSubdivisions: this.getConnectionSubdivisions() };

	        var distance = isDistanceRelative ? (labelDistance * this.getConnectionLength()) : labelDistance;
	        var tangent = path.tangentAtLength(distance, pathOpt);

	        var translation;
	        var angle = labelAngle;
	        if (tangent) {
	            if (isOffsetAbsolute) {
	                translation = tangent.start.clone();
	                translation.offset(labelOffsetCoordinates);
	            } else {
	                var normal = tangent.clone();
	                normal.rotate(tangent.start, -90);
	                normal.setLength(labelOffset);
	                translation = normal.end;
	            }

	            if (isKeepGradient) {
	                angle = (tangent.angle() + labelAngle);
	                if (isEnsureLegibility) {
	                    angle = normalizeAngle(((angle + 90) % 180) - 90);
	                }
	            }

	        } else {
	            // fallback - the connection has zero length
	            translation = path.start.clone();
	            if (isOffsetAbsolute) { translation.offset(labelOffsetCoordinates); }
	        }

	        return V.createSVGMatrix()
	            .translate(translation.x, translation.y)
	            .rotate(angle);
	    },

	    getLabelCoordinates: function(labelPosition) {

	        var transformationMatrix = this._getLabelTransformationMatrix(labelPosition);
	        return new Point(transformationMatrix.e, transformationMatrix.f);
	    },

	    getVertexIndex: function(x, y) {

	        var model = this.model;
	        var vertices = model.vertices();

	        var vertexLength = this.getClosestPointLength(new Point(x, y));

	        var idx = 0;
	        for (var n = vertices.length; idx < n; idx++) {
	            var currentVertex = vertices[idx];
	            var currentVertexLength = this.getClosestPointLength(currentVertex);
	            if (vertexLength < currentVertexLength) { break; }
	        }

	        return idx;
	    },

	    // Interaction. The controller part.
	    // ---------------------------------

	    notifyPointerdown: function notifyPointerdown(evt, x, y) {
	        CellView.prototype.pointerdown.call(this, evt, x, y);
	        this.notify('link:pointerdown', evt, x, y);
	    },

	    notifyPointermove: function notifyPointermove(evt, x, y) {
	        CellView.prototype.pointermove.call(this, evt, x, y);
	        this.notify('link:pointermove', evt, x, y);
	    },

	    notifyPointerup: function notifyPointerup(evt, x, y) {
	        this.notify('link:pointerup', evt, x, y);
	        CellView.prototype.pointerup.call(this, evt, x, y);
	    },

	    pointerdblclick: function(evt, x, y) {

	        CellView.prototype.pointerdblclick.apply(this, arguments);
	        this.notify('link:pointerdblclick', evt, x, y);
	    },

	    pointerclick: function(evt, x, y) {

	        CellView.prototype.pointerclick.apply(this, arguments);
	        this.notify('link:pointerclick', evt, x, y);
	    },

	    contextmenu: function(evt, x, y) {

	        CellView.prototype.contextmenu.apply(this, arguments);
	        this.notify('link:contextmenu', evt, x, y);
	    },

	    pointerdown: function(evt, x, y) {

	        this.notifyPointerdown(evt, x, y);
	        this.dragStart(evt, x, y);
	    },

	    pointermove: function(evt, x, y) {

	        // Backwards compatibility
	        var dragData = this._dragData;
	        if (dragData) { this.eventData(evt, dragData); }

	        var data = this.eventData(evt);
	        switch (data.action) {

	            case 'label-move':
	                this.dragLabel(evt, x, y);
	                break;

	            case 'arrowhead-move':
	                this.dragArrowhead(evt, x, y);
	                break;

	            case 'move':
	                this.drag(evt, x, y);
	                break;
	        }

	        // Backwards compatibility
	        if (dragData) { assign(dragData, this.eventData(evt)); }

	        this.notifyPointermove(evt, x, y);
	    },

	    pointerup: function(evt, x, y) {

	        // Backwards compatibility
	        var dragData = this._dragData;
	        if (dragData) {
	            this.eventData(evt, dragData);
	            this._dragData = null;
	        }

	        var data = this.eventData(evt);
	        switch (data.action) {

	            case 'label-move':
	                this.dragLabelEnd(evt, x, y);
	                break;

	            case 'arrowhead-move':
	                this.dragArrowheadEnd(evt, x, y);
	                break;

	            case 'move':
	                this.dragEnd(evt, x, y);
	        }

	        this.notifyPointerup(evt, x, y);
	        this.checkMouseleave(evt);
	    },

	    mouseover: function(evt) {

	        CellView.prototype.mouseover.apply(this, arguments);
	        this.notify('link:mouseover', evt);
	    },

	    mouseout: function(evt) {

	        CellView.prototype.mouseout.apply(this, arguments);
	        this.notify('link:mouseout', evt);
	    },

	    mouseenter: function(evt) {

	        CellView.prototype.mouseenter.apply(this, arguments);
	        this.notify('link:mouseenter', evt);
	    },

	    mouseleave: function(evt) {

	        CellView.prototype.mouseleave.apply(this, arguments);
	        this.notify('link:mouseleave', evt);
	    },

	    mousewheel: function(evt, x, y, delta) {

	        CellView.prototype.mousewheel.apply(this, arguments);
	        this.notify('link:mousewheel', evt, x, y, delta);
	    },

	    onlabel: function(evt, x, y) {

	        this.notifyPointerdown(evt, x, y);

	        this.dragLabelStart(evt, x, y);

	        var stopPropagation = this.eventData(evt).stopPropagation;
	        if (stopPropagation) { evt.stopPropagation(); }
	    },

	    // Drag Start Handlers

	    dragLabelStart: function(evt, x, y) {

	        if (this.can('labelMove')) {

	            if (this.isDefaultInteractionPrevented(evt)) { return; }

	            var labelNode = evt.currentTarget;
	            var labelIdx = parseInt(labelNode.getAttribute('label-idx'), 10);

	            var defaultLabelPosition = this._getDefaultLabelPositionProperty();
	            var initialLabelPosition = this._normalizeLabelPosition(this._getLabelPositionProperty(labelIdx));
	            var position = this._mergeLabelPositionProperty(initialLabelPosition, defaultLabelPosition);

	            var coords = this.getLabelCoordinates(position);
	            var dx = coords.x - x; // how much needs to be added to cursor x to get to label x
	            var dy = coords.y - y; // how much needs to be added to cursor y to get to label y

	            var positionAngle = this._getLabelPositionAngle(labelIdx);
	            var labelPositionArgs = this._getLabelPositionArgs(labelIdx);
	            var defaultLabelPositionArgs = this._getDefaultLabelPositionArgs();
	            var positionArgs = this._mergeLabelPositionArgs(labelPositionArgs, defaultLabelPositionArgs);

	            this.eventData(evt, {
	                action: 'label-move',
	                labelIdx: labelIdx,
	                dx: dx,
	                dy: dy,
	                positionAngle: positionAngle,
	                positionArgs: positionArgs,
	                stopPropagation: true
	            });

	        } else {

	            // Backwards compatibility:
	            // If labels can't be dragged no default action is triggered.
	            this.eventData(evt, { stopPropagation: true });
	        }

	        this.paper.delegateDragEvents(this, evt.data);
	    },

	    dragArrowheadStart: function(evt, x, y) {

	        if (!this.can('arrowheadMove')) { return; }

	        var arrowheadNode = evt.target;
	        var arrowheadType = arrowheadNode.getAttribute('end');
	        var data = this.startArrowheadMove(arrowheadType, { ignoreBackwardsCompatibility: true });

	        this.eventData(evt, data);
	    },

	    dragStart: function(evt, x, y) {

	        if (this.isDefaultInteractionPrevented(evt)) { return; }

	        if (!this.can('linkMove')) { return; }

	        this.eventData(evt, {
	            action: 'move',
	            dx: x,
	            dy: y
	        });
	    },

	    // Drag Handlers
	    dragLabel: function(evt, x, y) {

	        var data = this.eventData(evt);
	        var label = { position: this.getLabelPosition((x + data.dx), (y + data.dy), data.positionAngle, data.positionArgs) };
	        if (this.paper.options.snapLabels) { delete label.position.offset; }
	        // The `touchmove' events are not fired
	        // when the original event target is removed from the DOM.
	        // The labels are currently re-rendered completely when only
	        // the position changes. This is why we need to make sure that
	        // the label is updated synchronously.
	        // TODO: replace `touchmove` with `pointermove` (breaking change).
	        var setOptions = { ui: true };
	        if (this.paper.isAsync() && evt.type === 'touchmove') {
	            setOptions.async = false;
	        }
	        this.model.label(data.labelIdx, label, setOptions);
	    },

	    dragArrowhead: function(evt, x, y) {
	        if (this.paper.options.snapLinks) {
	            var isSnapped = this._snapArrowhead(evt, x, y);
	            if (!isSnapped && this.paper.options.snapLinksSelf) {
	                this._snapArrowheadSelf(evt, x, y);
	            }
	        } else {
	            if (this.paper.options.snapLinksSelf) {
	                this._snapArrowheadSelf(evt, x, y);
	            } else {
	                this._connectArrowhead(this.getEventTarget(evt), x, y, this.eventData(evt));
	            }
	        }
	    },

	    drag: function(evt, x, y) {

	        var data = this.eventData(evt);
	        this.model.translate(x - data.dx, y - data.dy, { ui: true });
	        this.eventData(evt, {
	            dx: x,
	            dy: y
	        });
	    },

	    // Drag End Handlers

	    dragLabelEnd: function() {
	        // noop
	    },

	    dragArrowheadEnd: function(evt, x, y) {

	        var data = this.eventData(evt);
	        var paper = this.paper;

	        if (paper.options.snapLinks) {
	            this._snapArrowheadEnd(data);
	        } else {
	            this._connectArrowheadEnd(data, x, y);
	        }

	        if (!paper.linkAllowed(this)) {
	            // If the changed link is not allowed, revert to its previous state.
	            this._disallow(data);
	        } else {
	            this._finishEmbedding(data);
	            this._notifyConnectEvent(data, evt);
	        }

	        this._afterArrowheadMove(data);
	    },

	    dragEnd: function() {
	        // noop
	    },

	    _disallow: function(data) {

	        switch (data.whenNotAllowed) {

	            case 'remove':
	                this.model.remove({ ui: true });
	                break;

	            case 'revert':
	            default:
	                this.model.set(data.arrowhead, data.initialEnd, { ui: true });
	                break;
	        }
	    },

	    _finishEmbedding: function(data) {

	        // Reparent the link if embedding is enabled
	        if (this.paper.options.embeddingMode && this.model.reparent()) {
	            // Make sure we don't reverse to the original 'z' index (see afterArrowheadMove()).
	            data.z = null;
	        }
	    },

	    _notifyConnectEvent: function(data, evt) {

	        var arrowhead = data.arrowhead;
	        var initialEnd = data.initialEnd;
	        var currentEnd = this.model.prop(arrowhead);
	        var endChanged = currentEnd && !Link.endsEqual(initialEnd, currentEnd);
	        if (endChanged) {
	            var paper = this.paper;
	            if (initialEnd.id) {
	                this.notify('link:disconnect', evt, paper.findViewByModel(initialEnd.id), data.initialMagnet, arrowhead);
	            }
	            if (currentEnd.id) {
	                this.notify('link:connect', evt, paper.findViewByModel(currentEnd.id), data.magnetUnderPointer, arrowhead);
	            }
	        }
	    },

	    _snapToPoints: function(snapPoint, points, radius) {
	        var closestPointX = null;
	        var closestDistanceX = Infinity;

	        var closestPointY = null;
	        var closestDistanceY = Infinity;

	        var x = snapPoint.x;
	        var y = snapPoint.y;

	        for (var i = 0; i < points.length; i++) {
	            var distX = Math.abs(points[i].x - snapPoint.x);
	            if (distX < closestDistanceX) {
	                closestDistanceX = distX;
	                closestPointX = points[i];
	            }

	            var distY = Math.abs(points[i].y - snapPoint.y);
	            if (distY < closestDistanceY) {
	                closestDistanceY = distY;
	                closestPointY = points[i];
	            }
	        }

	        if (closestDistanceX < radius) {
	            x = closestPointX.x;
	        }
	        if (closestDistanceY < radius) {
	            y = closestPointY.y;
	        }

	        return { x: x, y: y };
	    },

	    _snapArrowheadSelf: function(evt, x, y) {

	        var ref = this;
	        var paper = ref.paper;
	        var model = ref.model;
	        var ref$1 = paper.options;
	        var snapLinksSelf = ref$1.snapLinksSelf;
	        var data = this.eventData(evt);
	        var radius = snapLinksSelf.radius || 20;

	        var anchor = this.getEndAnchor(data.arrowhead === 'source' ? 'target' : 'source');
	        var vertices = model.vertices();
	        var points = [anchor ].concat( vertices);

	        var snapPoint = this._snapToPoints({ x: x, y: y }, points, radius);

	        var point = paper.localToClientPoint(snapPoint);
	        this._connectArrowhead(document.elementFromPoint(point.x, point.y), snapPoint.x, snapPoint.y, this.eventData(evt));
	    },

	    _snapArrowhead: function(evt, x, y) {

	        var ref = this;
	        var paper = ref.paper;
	        var ref$1 = paper.options;
	        var snapLinks = ref$1.snapLinks;
	        var connectionStrategy = ref$1.connectionStrategy;
	        var data = this.eventData(evt);
	        var isSnapped = false;
	        // checking view in close area of the pointer

	        var r = snapLinks.radius || 50;
	        var viewsInArea = paper.findViewsInArea({ x: x - r, y: y - r, width: 2 * r, height: 2 * r });

	        var prevClosestView = data.closestView || null;
	        var prevClosestMagnet = data.closestMagnet || null;
	        var prevMagnetProxy = data.magnetProxy || null;

	        data.closestView = data.closestMagnet = data.magnetProxy = null;

	        var minDistance = Number.MAX_VALUE;
	        var pointer = new Point(x, y);

	        viewsInArea.forEach(function(view) {
	            var candidates = [];
	            // skip connecting to the element in case '.': { magnet: false } attribute present
	            if (view.el.getAttribute('magnet') !== 'false') {
	                candidates.push({
	                    bbox: view.model.getBBox(),
	                    magnet: view.el
	                });
	            }

	            view.$('[magnet]').toArray().forEach(function (magnet) {
	                candidates.push({
	                    bbox: view.getNodeBBox(magnet),
	                    magnet: magnet
	                });
	            });

	            candidates.forEach(function (candidate) {
	                var magnet = candidate.magnet;
	                var bbox = candidate.bbox;
	                // find distance from the center of the model to pointer coordinates
	                var distance = bbox.center().squaredDistance(pointer);
	                // the connection is looked up in a circle area by `distance < r`
	                if (distance < minDistance) {
	                    var isAlreadyValidated = prevClosestMagnet === magnet;
	                    if (isAlreadyValidated || paper.options.validateConnection.apply(
	                        paper, data.validateConnectionArgs(view, (view.el === magnet) ? null : magnet)
	                    )) {
	                        minDistance = distance;
	                        data.closestView = view;
	                        data.closestMagnet = magnet;
	                    }
	                }
	            });

	        }, this);

	        var end;
	        var magnetProxy = null;
	        var closestView = data.closestView;
	        var closestMagnet = data.closestMagnet;
	        if (closestMagnet) {
	            magnetProxy = data.magnetProxy = closestView.findProxyNode(closestMagnet, 'highlighter');
	        }
	        var endType = data.arrowhead;
	        var newClosestMagnet = (prevClosestMagnet !== closestMagnet);
	        if (prevClosestView && newClosestMagnet) {
	            prevClosestView.unhighlight(prevMagnetProxy, {
	                connecting: true,
	                snapping: true
	            });
	        }

	        if (closestView) {
	            var prevEnd = data.prevEnd;
	            var prevX = data.prevX;
	            var prevY = data.prevY;
	            data.prevX = x;
	            data.prevY = y;
	            isSnapped = true;

	            if (!newClosestMagnet)  {
	                if (typeof connectionStrategy !== 'function' || (prevX === x && prevY === y)) {
	                    // the magnet has not changed and the link's end does not depend on the x and y
	                    return isSnapped;
	                }
	            }

	            end = closestView.getLinkEnd(closestMagnet, x, y, this.model, endType);
	            if (!newClosestMagnet && isEqual(prevEnd, end)) {
	                // the source/target json has not changed
	                return isSnapped;
	            }

	            data.prevEnd = end;

	            if (newClosestMagnet) {
	                closestView.highlight(magnetProxy, {
	                    connecting: true,
	                    snapping: true
	                });
	            }

	        } else {

	            end = { x: x, y: y };
	        }

	        this.model.set(endType, end || { x: x, y: y }, { ui: true });

	        if (prevClosestView) {
	            this.notify('link:snap:disconnect', evt, prevClosestView, prevClosestMagnet, endType);
	        }
	        if (closestView) {
	            this.notify('link:snap:connect', evt, closestView, closestMagnet, endType);
	        }

	        return isSnapped;
	    },

	    _snapArrowheadEnd: function(data) {

	        // Finish off link snapping.
	        // Everything except view unhighlighting was already done on pointermove.
	        var closestView = data.closestView;
	        var closestMagnet = data.closestMagnet;
	        if (closestView && closestMagnet) {

	            closestView.unhighlight(data.magnetProxy, { connecting: true, snapping: true });
	            data.magnetUnderPointer = closestView.findMagnet(closestMagnet);
	        }

	        data.closestView = data.closestMagnet = null;
	    },

	    _connectArrowhead: function(target, x, y, data) {

	        // checking views right under the pointer
	        var ref = this;
	        var paper = ref.paper;
	        var model = ref.model;

	        if (data.eventTarget !== target) {
	            // Unhighlight the previous view under pointer if there was one.
	            if (data.magnetProxy) {
	                data.viewUnderPointer.unhighlight(data.magnetProxy, {
	                    connecting: true
	                });
	            }

	            var viewUnderPointer = data.viewUnderPointer = paper.findView(target);
	            if (viewUnderPointer) {
	                // If we found a view that is under the pointer, we need to find the closest
	                // magnet based on the real target element of the event.
	                var magnetUnderPointer = data.magnetUnderPointer = viewUnderPointer.findMagnet(target);
	                var magnetProxy = data.magnetProxy = viewUnderPointer.findProxyNode(magnetUnderPointer, 'highlighter');

	                if (magnetUnderPointer && this.paper.options.validateConnection.apply(
	                    paper,
	                    data.validateConnectionArgs(viewUnderPointer, magnetUnderPointer)
	                )) {
	                    // If there was no magnet found, do not highlight anything and assume there
	                    // is no view under pointer we're interested in reconnecting to.
	                    // This can only happen if the overall element has the attribute `'.': { magnet: false }`.
	                    if (magnetProxy) {
	                        viewUnderPointer.highlight(magnetProxy, {
	                            connecting: true
	                        });
	                    }
	                } else {
	                    // This type of connection is not valid. Disregard this magnet.
	                    data.magnetUnderPointer = null;
	                    data.magnetProxy = null;
	                }
	            } else {
	                // Make sure we'll unset previous magnet.
	                data.magnetUnderPointer = null;
	                data.magnetProxy = null;
	            }
	        }

	        data.eventTarget = target;

	        model.set(data.arrowhead, { x: x, y: y }, { ui: true });
	    },

	    _connectArrowheadEnd: function(data, x, y) {
	        if ( data === void 0 ) data = {};


	        var ref = this;
	        var model = ref.model;
	        var viewUnderPointer = data.viewUnderPointer;
	        var magnetUnderPointer = data.magnetUnderPointer;
	        var magnetProxy = data.magnetProxy;
	        var arrowhead = data.arrowhead;

	        if (!magnetUnderPointer || !magnetProxy || !viewUnderPointer) { return; }

	        viewUnderPointer.unhighlight(magnetProxy, { connecting: true });

	        // The link end is taken from the magnet under the pointer, not the proxy.
	        var end = viewUnderPointer.getLinkEnd(magnetUnderPointer, x, y, model, arrowhead);
	        model.set(arrowhead, end, { ui: true });
	    },

	    _beforeArrowheadMove: function(data) {

	        data.z = this.model.get('z');
	        this.model.toFront();

	        // Let the pointer propagate through the link view elements so that
	        // the `evt.target` is another element under the pointer, not the link itself.
	        var style = this.el.style;
	        data.pointerEvents = style.pointerEvents;
	        style.pointerEvents = 'none';

	        if (this.paper.options.markAvailable) {
	            this._markAvailableMagnets(data);
	        }
	    },

	    _afterArrowheadMove: function(data) {

	        if (data.z !== null) {
	            this.model.set('z', data.z, { ui: true });
	            data.z = null;
	        }

	        // Put `pointer-events` back to its original value. See `_beforeArrowheadMove()` for explanation.
	        this.el.style.pointerEvents = data.pointerEvents;

	        if (this.paper.options.markAvailable) {
	            this._unmarkAvailableMagnets(data);
	        }
	    },

	    _createValidateConnectionArgs: function(arrowhead) {
	        // It makes sure the arguments for validateConnection have the following form:
	        // (source view, source magnet, target view, target magnet and link view)
	        var args = [];

	        args[4] = arrowhead;
	        args[5] = this;

	        var oppositeArrowhead;
	        var i = 0;
	        var j = 0;

	        if (arrowhead === 'source') {
	            i = 2;
	            oppositeArrowhead = 'target';
	        } else {
	            j = 2;
	            oppositeArrowhead = 'source';
	        }

	        var end = this.model.get(oppositeArrowhead);

	        if (end.id) {
	            var view = args[i] = this.paper.findViewByModel(end.id);
	            var magnet = view.getMagnetFromLinkEnd(end);
	            if (magnet === view.el) { magnet = undefined; }
	            args[i + 1] = magnet;
	        }

	        function validateConnectionArgs(cellView, magnet) {
	            args[j] = cellView;
	            args[j + 1] = cellView.el === magnet ? undefined : magnet;
	            return args;
	        }

	        return validateConnectionArgs;
	    },

	    _markAvailableMagnets: function(data) {

	        function isMagnetAvailable(view, magnet) {
	            var paper = view.paper;
	            var validate = paper.options.validateConnection;
	            return validate.apply(paper, this.validateConnectionArgs(view, magnet));
	        }

	        var paper = this.paper;
	        var elements = paper.model.getCells();
	        data.marked = {};

	        for (var i = 0, n = elements.length; i < n; i++) {
	            var view = elements[i].findView(paper);

	            if (!view) {
	                continue;
	            }

	            var magnets = Array.prototype.slice.call(view.el.querySelectorAll('[magnet]'));
	            if (view.el.getAttribute('magnet') !== 'false') {
	                // Element wrapping group is also a magnet
	                magnets.push(view.el);
	            }

	            var availableMagnets = magnets.filter(isMagnetAvailable.bind(data, view));

	            if (availableMagnets.length > 0) {
	                // highlight all available magnets
	                for (var j = 0, m = availableMagnets.length; j < m; j++) {
	                    view.highlight(availableMagnets[j], { magnetAvailability: true });
	                }
	                // highlight the entire view
	                view.highlight(null, { elementAvailability: true });

	                data.marked[view.model.id] = availableMagnets;
	            }
	        }
	    },

	    _unmarkAvailableMagnets: function(data) {

	        var markedKeys = Object.keys(data.marked);
	        var id;
	        var markedMagnets;

	        for (var i = 0, n = markedKeys.length; i < n; i++) {
	            id = markedKeys[i];
	            markedMagnets = data.marked[id];

	            var view = this.paper.findViewByModel(id);
	            if (view) {
	                for (var j = 0, m = markedMagnets.length; j < m; j++) {
	                    view.unhighlight(markedMagnets[j], { magnetAvailability: true });
	                }
	                view.unhighlight(null, { elementAvailability: true });
	            }
	        }

	        data.marked = null;
	    },

	    startArrowheadMove: function(end, opt) {

	        opt || (opt = {});

	        // Allow to delegate events from an another view to this linkView in order to trigger arrowhead
	        // move without need to click on the actual arrowhead dom element.
	        var data = {
	            action: 'arrowhead-move',
	            arrowhead: end,
	            whenNotAllowed: opt.whenNotAllowed || 'revert',
	            initialMagnet: this[end + 'Magnet'] || (this[end + 'View'] ? this[end + 'View'].el : null),
	            initialEnd: clone(this.model.get(end)),
	            validateConnectionArgs: this._createValidateConnectionArgs(end)
	        };

	        this._beforeArrowheadMove(data);

	        if (opt.ignoreBackwardsCompatibility !== true) {
	            this._dragData = data;
	        }

	        return data;
	    },

	    // Lifecycle methods

	    onMount: function() {
	        CellView.prototype.onMount.apply(this, arguments);
	        this.mountLabels();
	    },

	    onDetach: function() {
	        CellView.prototype.onDetach.apply(this, arguments);
	        this.unmountLabels();
	    },

	    onRemove: function() {
	        CellView.prototype.onRemove.apply(this, arguments);
	        this.unmountLabels();
	    }

	}, {

	    Flags: Flags$2,
	});

	Object.defineProperty(LinkView.prototype, 'sourceBBox', {

	    enumerable: true,

	    get: function() {
	        var sourceView = this.sourceView;
	        if (!sourceView) {
	            var sourceDef = this.model.source();
	            return new Rect(sourceDef.x, sourceDef.y);
	        }
	        var sourceMagnet = this.sourceMagnet;
	        if (sourceView.isNodeConnection(sourceMagnet)) {
	            return new Rect(this.sourceAnchor);
	        }
	        return sourceView.getNodeBBox(sourceMagnet || sourceView.el);
	    }

	});

	Object.defineProperty(LinkView.prototype, 'targetBBox', {

	    enumerable: true,

	    get: function() {
	        var targetView = this.targetView;
	        if (!targetView) {
	            var targetDef = this.model.target();
	            return new Rect(targetDef.x, targetDef.y);
	        }
	        var targetMagnet = this.targetMagnet;
	        if (targetView.isNodeConnection(targetMagnet)) {
	            return new Rect(this.targetAnchor);
	        }
	        return targetView.getNodeBBox(targetMagnet || targetView.el);
	    }
	});

	var GridLayer = PaperLayer.extend({

	    style: {
	        'pointer-events': 'none'
	    },

	    _gridCache: null,
	    _gridSettings: null,

	    init: function init() {
	        PaperLayer.prototype.init.apply(this, arguments);
	        var ref = this;
	        var paper = ref.options.paper;
	        this._gridCache = null;
	        this._gridSettings = [];
	        this.listenTo(paper, 'transform resize', this.updateGrid);
	    },

	    setGrid: function setGrid(drawGrid) {
	        this._gridSettings = this.getGridSettings(drawGrid);
	        this.renderGrid();
	    },

	    getGridSettings: function getGridSettings(drawGrid) {
	        var this$1 = this;

	        var gridSettings = [];
	        if (drawGrid) {
	            var optionsList = Array.isArray(drawGrid) ? drawGrid : [drawGrid || {}];
	            optionsList.forEach(function (item) {
	                gridSettings.push.apply(gridSettings, this$1._resolveDrawGridOption(item));
	            });
	        }
	        return gridSettings;
	    },

	    removeGrid: function removeGrid() {
	        var ref = this;
	        var grid = ref._gridCache;
	        if (!grid) { return; }
	        grid.root.remove();
	        this._gridCache = null;
	    },

	    renderGrid: function renderGrid() {

	        var ref = this;
	        var paper = ref.options.paper;
	        var ref$1 = this;
	        var gridSettings = ref$1._gridSettings;

	        this.removeGrid();

	        if (gridSettings.length === 0) { return; }

	        var gridSize = paper.options.drawGridSize || paper.options.gridSize;
	        if (gridSize <= 1) {
	            return;
	        }

	        var refs = this._getGridRefs();

	        gridSettings.forEach(function (gridLayerSetting, index) {

	            var id = 'pattern_' + index;
	            var options = merge({}, gridLayerSetting);
	            var scaleFactor = options.scaleFactor; if ( scaleFactor === void 0 ) scaleFactor = 1;
	            options.width = gridSize * scaleFactor || 1;
	            options.height = gridSize * scaleFactor || 1;

	            var vPattern;
	            if (!refs.exist(id)) {
	                vPattern = V('pattern', { id: id, patternUnits: 'userSpaceOnUse' }, V(options.markup));
	                refs.add(id, vPattern);
	            } else {
	                vPattern = refs.get(id);
	            }

	            if (isFunction(options.render)) {
	                options.render(vPattern.node.firstChild, options, paper);
	            }
	            vPattern.attr({
	                width: options.width,
	                height: options.height
	            });
	        });

	        refs.root.appendTo(this.el);
	        this.updateGrid();
	    },

	    updateGrid: function updateGrid() {

	        var ref = this;
	        var grid = ref._gridCache;
	        var gridSettings = ref._gridSettings;
	        var paper = ref.options.paper;
	        if (!grid) { return; }
	        var vSvg = grid.root;
	        var patterns = grid.patterns;
	        var ref$1 = paper.getArea();
	        var x = ref$1.x;
	        var y = ref$1.y;
	        var width = ref$1.width;
	        var height = ref$1.height;
	        vSvg.attr({ x: x, y: y, width: width, height: height });
	        for (var patternId in patterns) {
	            var vPattern = patterns[patternId];
	            vPattern.attr({ x: -x, y: -y });
	        }
	        gridSettings.forEach(function (options, index) {
	            if (isFunction(options.update)) {
	                var vPattern = patterns['pattern_' + index];
	                options.update(vPattern.node.firstChild, options, paper);
	            }
	        });
	    },

	    _getGridRefs: function _getGridRefs() {
	        var ref = this;
	        var grid = ref._gridCache;
	        if (grid) { return grid; }
	        var defsVEl = V('defs');
	        var svgVEl = V('svg', { width: '100%', height: '100%' }, [defsVEl]);
	        grid = this._gridCache = {
	            root: svgVEl,
	            patterns: {},
	            add: function(id, patternVEl) {
	                var rectVEl = V('rect', { width: '100%', height: '100%', fill: ("url(#" + id + ")") });
	                defsVEl.append(patternVEl);
	                svgVEl.append(rectVEl);
	                this.patterns[id] = patternVEl;
	            },
	            get: function(id) {
	                return this.patterns[id];
	            },
	            exist: function(id) {
	                return this.patterns[id] !== undefined;
	            }
	        };
	        return grid;
	    },

	    _resolveDrawGridOption: function _resolveDrawGridOption(opt) {

	        var namespace = this.options.patterns;
	        if (isString(opt) && Array.isArray(namespace[opt])) {
	            return namespace[opt].map(function(item) {
	                return assign({}, item);
	            });
	        }

	        var options = opt || { args: [{}] };
	        var isArray = Array.isArray(options);
	        var name = options.name;

	        if (!isArray && !name && !options.markup) {
	            name = 'dot';
	        }

	        if (name && Array.isArray(namespace[name])) {
	            var pattern = namespace[name].map(function(item) {
	                return assign({}, item);
	            });

	            var args = Array.isArray(options.args) ? options.args : [options.args || {}];

	            defaults(args[0], omit(opt, 'args'));
	            for (var i = 0; i < args.length; i++) {
	                if (pattern[i]) {
	                    assign(pattern[i], args[i]);
	                }
	            }
	            return pattern;
	        }

	        return isArray ? options : [options];
	    },

	});

	var sortingTypes = {
	    NONE: 'sorting-none',
	    APPROX: 'sorting-approximate',
	    EXACT: 'sorting-exact'
	};

	var WHEEL_CAP = 50;
	var WHEEL_WAIT_MS = 20;
	var MOUNT_BATCH_SIZE = 1000;
	var UPDATE_BATCH_SIZE = Infinity;
	var MIN_PRIORITY = 9007199254740991; // Number.MAX_SAFE_INTEGER

	var HighlightingTypes$1 = CellView.Highlighting;

	var defaultHighlighting = {};
	defaultHighlighting[HighlightingTypes$1.DEFAULT] = {
	        name: 'stroke',
	        options: {
	            padding: 3
	        }
	    };
	defaultHighlighting[HighlightingTypes$1.MAGNET_AVAILABILITY] = {
	        name: 'addClass',
	        options: {
	            className: 'available-magnet'
	        }
	    };
	defaultHighlighting[HighlightingTypes$1.ELEMENT_AVAILABILITY] = {
	        name: 'addClass',
	        options: {
	            className: 'available-cell'
	        }
	    };

	var defaultLayers = [{
	    name: LayersNames.GRID,
	}, {
	    name: LayersNames.BACK,
	}, {
	    name: LayersNames.CELLS,
	}, {
	    name: LayersNames.LABELS,
	}, {
	    name: LayersNames.FRONT
	}, {
	    name: LayersNames.TOOLS
	}];

	var Paper = View.extend({

	    className: 'paper',

	    options: {

	        width: 800,
	        height: 600,
	        gridSize: 1,
	        // Whether or not to draw the grid lines on the paper's DOM element.
	        // e.g drawGrid: true, drawGrid: { color: 'red', thickness: 2 }
	        drawGrid: false,
	        // If not set, the size of the visual grid is the same as the `gridSize`.
	        drawGridSize: null,

	        // Whether or not to draw the background on the paper's DOM element.
	        // e.g. background: { color: 'lightblue', image: '/paper-background.png', repeat: 'flip-xy' }
	        background: false,

	        elementView: ElementView,
	        linkView: LinkView,
	        snapLabels: false, // false, true
	        snapLinks: false, // false, true, { radius: value }
	        snapLinksSelf: false, // false, true, { radius: value }

	        // Should the link labels be rendered into its own layer?
	        // `false` - the labels are part of the links
	        // `true` - the labels are appended to LayersName.LABELS
	        // [LayersName] - the labels are appended to the layer specified
	        labelsLayer: false,

	        // When set to FALSE, an element may not have more than 1 link with the same source and target element.
	        multiLinks: true,

	        // For adding custom guard logic.
	        guard: function(evt, view) {

	            // FALSE means the event isn't guarded.
	            return false;
	        },

	        highlighting: defaultHighlighting,

	        // Prevent the default context menu from being displayed.
	        preventContextMenu: true,

	        // Prevent the default action for blank:pointer<action>.
	        preventDefaultBlankAction: true,

	        // Prevent the default action for cell:pointer<action>.
	        preventDefaultViewAction: true,

	        // Restrict the translation of elements by given bounding box.
	        // Option accepts a boolean:
	        //  true - the translation is restricted to the paper area
	        //  false - no restrictions
	        // A method:
	        // restrictTranslate: function(elementView) {
	        //     var parentId = elementView.model.get('parent');
	        //     return parentId && this.model.getCell(parentId).getBBox();
	        // },
	        // Or a bounding box:
	        // restrictTranslate: { x: 10, y: 10, width: 790, height: 590 }
	        restrictTranslate: false,

	        // Marks all available magnets with 'available-magnet' class name and all available cells with
	        // 'available-cell' class name. Marks them when dragging a link is started and unmark
	        // when the dragging is stopped.
	        markAvailable: false,

	        // Defines what link model is added to the graph after an user clicks on an active magnet.
	        // Value could be the mvc.model or a function returning the mvc.model
	        // defaultLink: (elementView, magnet) => {
	        //   return condition ? new customLink1() : new customLink2()
	        // }
	        defaultLink: function() {
	            // Do not create hard dependency on the joint.shapes.standard namespace (by importing the standard.Link model directly)
	            var ref = this.model.get('cells');
	            var cellNamespace = ref.cellNamespace;
	            var ctor = getByPath(cellNamespace, ['standard', 'Link']);
	            if (!ctor) { throw new Error('dia.Paper: no default link model found. Use `options.defaultLink` to specify a default link model.'); }
	            return new ctor();
	        },

	        // A connector that is used by links with no connector defined on the model.
	        // e.g. { name: 'rounded', args: { radius: 5 }} or a function
	        defaultConnector: { name: 'normal' },

	        // A router that is used by links with no router defined on the model.
	        // e.g. { name: 'oneSide', args: { padding: 10 }} or a function
	        defaultRouter: { name: 'normal' },

	        defaultAnchor: { name: 'center' },

	        defaultLinkAnchor: { name: 'connectionRatio' },

	        defaultConnectionPoint: { name: 'boundary' },

	        /* CONNECTING */

	        connectionStrategy: null,

	        // Check whether to add a new link to the graph when user clicks on an a magnet.
	        validateMagnet: function(_cellView, magnet, _evt) {
	            return magnet.getAttribute('magnet') !== 'passive';
	        },

	        // Check whether to allow or disallow the link connection while an arrowhead end (source/target)
	        // being changed.
	        validateConnection: function(cellViewS, _magnetS, cellViewT, _magnetT, end, _linkView) {
	            return (end === 'target' ? cellViewT : cellViewS) instanceof ElementView;
	        },

	        /* EMBEDDING */

	        // Enables embedding. Re-parent the dragged element with elements under it and makes sure that
	        // all links and elements are visible taken the level of embedding into account.
	        embeddingMode: false,

	        // Check whether to allow or disallow the element embedding while an element being translated.
	        validateEmbedding: function(childView, parentView) {
	            // by default all elements can be in relation child-parent
	            return true;
	        },

	        // Check whether to allow or disallow an embedded element to be unembedded / to become a root.
	        validateUnembedding: function(childView) {
	            // by default all elements can become roots
	            return true;
	        },

	        // Determines the way how a cell finds a suitable parent when it's dragged over the paper.
	        // The cell with the highest z-index (visually on the top) will be chosen.
	        findParentBy: 'bbox', // 'bbox'|'center'|'origin'|'corner'|'topRight'|'bottomLeft'

	        // If enabled only the element on the very front is taken into account for the embedding.
	        // If disabled the elements under the dragged view are tested one by one
	        // (from front to back) until a valid parent found.
	        frontParentOnly: true,

	        // Interactive flags. See online docs for the complete list of interactive flags.
	        interactive: {
	            labelMove: false
	        },

	        // When set to true the links can be pinned to the paper.
	        // i.e. link source/target can be a point e.g. link.get('source') ==> { x: 100, y: 100 };
	        linkPinning: true,

	        // Custom validation after an interaction with a link ends.
	        // Recognizes a function. If `false` is returned, the link is disallowed (removed or reverted)
	        // (linkView, paper) => boolean
	        allowLink: null,

	        // Allowed number of mousemove events after which the pointerclick event will be still triggered.
	        clickThreshold: 0,

	        // Number of required mousemove events before the first pointermove event will be triggered.
	        moveThreshold: 0,

	        // Number of required mousemove events before a link is created out of the magnet.
	        // Or string `onleave` so the link is created when the pointer leaves the magnet
	        magnetThreshold: 0,

	        // Rendering Options

	        sorting: sortingTypes.APPROX,

	        frozen: false,

	        autoFreeze: false,

	        // no docs yet
	        onViewUpdate: function(view, flag, priority, opt, paper) {
	            // Do not update connected links when:
	            // 1. the view was just inserted (added to the graph and rendered)
	            // 2. the view was just mounted (added back to the paper by viewport function)
	            // 3. the change was marked as `isolate`.
	            // 4. the view model was just removed from the graph
	            if ((flag & (view.FLAG_INSERT | view.FLAG_REMOVE)) || opt.mounting || opt.isolate) { return; }
	            paper.requestConnectedLinksUpdate(view, priority, opt);
	        },

	        // no docs yet
	        onViewPostponed: function(view, flag, paper) {
	            return paper.forcePostponedViewUpdate(view, flag);
	        },

	        beforeRender: null, // function(opt, paper) { },

	        afterRender: null, // function(stats, opt, paper) {

	        viewport: null,

	        // Default namespaces

	        cellViewNamespace: null,

	        routerNamespace: null,

	        connectorNamespace: null,

	        highlighterNamespace: highlighters,

	        anchorNamespace: anchors,

	        linkAnchorNamespace: linkAnchors,

	        connectionPointNamespace: connectionPoints,

	        overflow: false
	    },

	    events: {
	        'dblclick': 'pointerdblclick',
	        'dbltap': 'pointerdblclick',
	        'contextmenu': 'contextmenu',
	        'mousedown': 'pointerdown',
	        'touchstart': 'pointerdown',
	        'mouseover': 'mouseover',
	        'mouseout': 'mouseout',
	        'mouseenter': 'mouseenter',
	        'mouseleave': 'mouseleave',
	        'wheel': 'mousewheel',
	        'mouseenter .joint-cell': 'mouseenter',
	        'mouseleave .joint-cell': 'mouseleave',
	        'mouseenter .joint-tools': 'mouseenter',
	        'mouseleave .joint-tools': 'mouseleave',
	        'dblclick .joint-cell [magnet]': 'magnetpointerdblclick',
	        'contextmenu .joint-cell [magnet]': 'magnetcontextmenu',
	        'mousedown .joint-link .label': 'onlabel', // interaction with link label
	        'touchstart .joint-link .label': 'onlabel',
	        'dragstart .joint-cell image': 'onImageDragStart' // firefox fix
	    },

	    documentEvents: {
	        'mousemove': 'pointermove',
	        'touchmove': 'pointermove',
	        'mouseup': 'pointerup',
	        'touchend': 'pointerup',
	        'touchcancel': 'pointerup'
	    },

	    /* CSS within the SVG document
	    * 1. Adding vector-effect: non-scaling-stroke; to prevent the stroke width from scaling for
	    *    elements that use the `scalable` group.
	    */
	    stylesheet: /*css*/"\n        .joint-element .scalable * {\n            vector-effect: non-scaling-stroke;\n        }\n    ",

	    svg: null,
	    viewport: null,
	    defs: null,
	    tools: null,
	    layers: null,

	    // For storing the current transformation matrix (CTM) of the paper's viewport.
	    _viewportMatrix: null,
	    // For verifying whether the CTM is up-to-date. The viewport transform attribute
	    // could have been manipulated directly.
	    _viewportTransformString: null,
	    // Updates data (priorities, unmounted views etc.)
	    _updates: null,
	    // Paper Layers
	    _layers: null,

	    SORT_DELAYING_BATCHES: ['add', 'to-front', 'to-back'],
	    UPDATE_DELAYING_BATCHES: ['translate'],
	    // If you interact with these elements,
	    // the default interaction such as `element move` is prevented.
	    FORM_CONTROL_TAG_NAMES: ['TEXTAREA', 'INPUT', 'BUTTON', 'SELECT', 'OPTION'] ,
	    // If you interact with these elements, the events are not propagated to the paper
	    // i.e. paper events such as `element:pointerdown` are not triggered.
	    GUARDED_TAG_NAMES: [
	        // Guard <select> for consistency. When you click on it:
	        // Chrome: triggers `pointerdown`, `pointerup`, `pointerclick` to open
	        // Firefox: triggers `pointerdown` on open, `pointerup` (and `pointerclick` only if you haven't moved).
	        //          on close. However, if you open and then close by clicking elsewhere on the page,
	        //           no other event is triggered.
	        // Safari: when you open it, it triggers `pointerdown`. That's it.
	        'SELECT' ],
	    MIN_SCALE: 1e-6,

	    init: function() {

	        var ref = this;
	        var options = ref.options;
	        if (!options.cellViewNamespace) {
	            /* eslint-disable no-undef */
	            options.cellViewNamespace = typeof joint !== 'undefined' && has$2(joint, 'shapes') ? joint.shapes : null;
	            /* eslint-enable no-undef */
	        }

	        var model = this.model = options.model || new Graph;

	        // Layers (SVGGroups)
	        this._layers = {};

	        this.cloneOptions();
	        this.render();
	        this._setDimensions();
	        this.startListening();

	        // Hash of all cell views.
	        this._views = {};

	        // Mouse wheel events buffer
	        this._mw_evt_buffer = {
	            event: null,
	            deltas: [],
	        };

	        // Render existing cells in the graph
	        this.resetViews(model.attributes.cells.models);
	        // Start the Rendering Loop
	        if (!this.isFrozen() && this.isAsync()) { this.updateViewsAsync(); }
	    },

	    _resetUpdates: function() {
	        return this._updates = {
	            id: null,
	            priorities: [{}, {}, {}],
	            unmountedCids: [],
	            mountedCids: [],
	            unmounted: {},
	            mounted: {},
	            count: 0,
	            keyFrozen: false,
	            freezeKey: null,
	            sort: false,
	            disabled: false,
	            idle: false
	        };
	    },

	    startListening: function() {
	        var model = this.model;
	        this.listenTo(model, 'add', this.onCellAdded)
	            .listenTo(model, 'remove', this.onCellRemoved)
	            .listenTo(model, 'change', this.onCellChange)
	            .listenTo(model, 'reset', this.onGraphReset)
	            .listenTo(model, 'sort', this.onGraphSort)
	            .listenTo(model, 'batch:stop', this.onGraphBatchStop);
	        this.on('cell:highlight', this.onCellHighlight)
	            .on('cell:unhighlight', this.onCellUnhighlight)
	            .on('transform', this.update);
	    },

	    onCellAdded: function(cell, _, opt) {
	        var position = opt.position;
	        if (this.isAsync() || !isNumber(position)) {
	            this.renderView(cell, opt);
	        } else {
	            if (opt.maxPosition === position) { this.freeze({ key: 'addCells' }); }
	            this.renderView(cell, opt);
	            if (position === 0) { this.unfreeze({ key: 'addCells' }); }
	        }
	    },

	    onCellRemoved: function(cell, _, opt) {
	        var view = this.findViewByModel(cell);
	        if (view) { this.requestViewUpdate(view, view.FLAG_REMOVE, view.UPDATE_PRIORITY, opt); }
	    },

	    onCellChange: function(cell, opt) {
	        if (cell === this.model.attributes.cells) { return; }
	        if (cell.hasChanged('z') && this.options.sorting === sortingTypes.APPROX) {
	            var view = this.findViewByModel(cell);
	            if (view) { this.requestViewUpdate(view, view.FLAG_INSERT, view.UPDATE_PRIORITY, opt); }
	        }
	    },

	    onGraphReset: function(collection, opt) {
	        this.resetLayers();
	        this.resetViews(collection.models, opt);
	    },

	    onGraphSort: function() {
	        if (this.model.hasActiveBatch(this.SORT_DELAYING_BATCHES)) { return; }
	        this.sortViews();
	    },

	    onGraphBatchStop: function(data) {
	        if (this.isFrozen()) { return; }
	        var name = data && data.batchName;
	        var graph = this.model;
	        if (!this.isAsync()) {
	            var updateDelayingBatches = this.UPDATE_DELAYING_BATCHES;
	            if (updateDelayingBatches.includes(name) && !graph.hasActiveBatch(updateDelayingBatches)) {
	                this.updateViews(data);
	            }
	        }
	        var sortDelayingBatches = this.SORT_DELAYING_BATCHES;
	        if (sortDelayingBatches.includes(name) && !graph.hasActiveBatch(sortDelayingBatches)) {
	            this.sortViews();
	        }
	    },

	    cloneOptions: function() {

	        var ref = this;
	        var options = ref.options;
	        var defaultConnector = options.defaultConnector;
	        var defaultRouter = options.defaultRouter;
	        var defaultConnectionPoint = options.defaultConnectionPoint;
	        var defaultAnchor = options.defaultAnchor;
	        var defaultLinkAnchor = options.defaultLinkAnchor;
	        var highlighting = options.highlighting;
	        var cellViewNamespace = options.cellViewNamespace;
	        var interactive = options.interactive;

	        // Default cellView namespace for ES5
	        /* eslint-disable no-undef */
	        if (!cellViewNamespace && typeof joint !== 'undefined' && has$2(joint, 'shapes')) {
	            options.cellViewNamespace = joint.shapes;
	        }
	        /* eslint-enable no-undef */

	        // Here if a function was provided, we can not clone it, as this would result in loosing the function.
	        // If the default is used, the cloning is necessary in order to prevent modifying the options on prototype.
	        if (!isFunction(defaultConnector)) {
	            options.defaultConnector = cloneDeep(defaultConnector);
	        }
	        if (!isFunction(defaultRouter)) {
	            options.defaultRouter = cloneDeep(defaultRouter);
	        }
	        if (!isFunction(defaultConnectionPoint)) {
	            options.defaultConnectionPoint = cloneDeep(defaultConnectionPoint);
	        }
	        if (!isFunction(defaultAnchor)) {
	            options.defaultAnchor = cloneDeep(defaultAnchor);
	        }
	        if (!isFunction(defaultLinkAnchor)) {
	            options.defaultLinkAnchor = cloneDeep(defaultLinkAnchor);
	        }
	        if (isPlainObject(interactive)) {
	            options.interactive = assign({}, interactive);
	        }
	        if (isPlainObject(highlighting)) {
	            // Return the default highlighting options into the user specified options.
	            options.highlighting = defaultsDeep({}, highlighting, defaultHighlighting);
	        }
	    },

	    children: function() {
	        var ns = V.namespace;
	        return [{
	            namespaceURI: ns.xhtml,
	            tagName: 'div',
	            className: addClassNamePrefix('paper-background'),
	            selector: 'background',
	            style: {
	                position: 'absolute',
	                inset: 0
	            }
	        }, {
	            namespaceURI: ns.svg,
	            tagName: 'svg',
	            attributes: {
	                'width': '100%',
	                'height': '100%',
	                'xmlns:xlink': ns.xlink
	            },
	            selector: 'svg',
	            style: {
	                position: 'absolute',
	                inset: 0
	            },
	            children: [{
	                // Append `<defs>` element to the SVG document. This is useful for filters and gradients.
	                // It's desired to have the defs defined before the viewport (e.g. to make a PDF document pick up defs properly).
	                tagName: 'defs',
	                selector: 'defs'
	            }, {
	                tagName: 'g',
	                className: addClassNamePrefix('layers'),
	                selector: 'layers'
	            }]
	        }];
	    },

	    hasLayerView: function hasLayerView(layerName) {
	        return  (layerName in this._layers);
	    },

	    getLayerView: function getLayerView(layerName) {
	        var ref = this;
	        var _layers = ref._layers;
	        if (layerName in _layers) { return _layers[layerName]; }
	        throw new Error(("dia.Paper: Unknown layer \"" + layerName + "\""));
	    },

	    getLayerNode: function getLayerNode(layerName) {
	        return this.getLayerView(layerName).el;
	    },

	    render: function() {

	        this.renderChildren();
	        var ref = this;
	        var el = ref.el;
	        var childNodes = ref.childNodes;
	        var options = ref.options;
	        var stylesheet = ref.stylesheet;
	        var svg = childNodes.svg;
	        var defs = childNodes.defs;
	        var layers = childNodes.layers;

	        el.style.position = 'relative';
	        svg.style.overflow = options.overflow ? 'visible' : 'hidden';

	        this.svg = svg;
	        this.defs = defs;
	        this.layers = layers;

	        this.renderLayers();

	        V.ensureId(svg);

	        this.addStylesheet(stylesheet);

	        if (options.background) {
	            this.drawBackground(options.background);
	        }

	        if (options.drawGrid) {
	            this.setGrid(options.drawGrid);
	        }

	        return this;
	    },

	    addStylesheet: function(css) {
	        if (!css) { return; }
	        V(this.svg).prepend(V.createSVGStyle(css));
	    },

	    createLayer: function createLayer(name) {
	        switch (name) {
	            case LayersNames.GRID:
	                return new GridLayer({ name: name, paper: this, patterns: this.constructor.gridPatterns });
	            default:
	                return new PaperLayer({ name: name });
	        }
	    },

	    renderLayers: function(layers) {
	        var this$1 = this;
	        if ( layers === void 0 ) layers = defaultLayers;

	        this.removeLayers();
	        // TODO: Layers to be read from the graph `layers` attribute
	        layers.forEach(function (ref) {
	            var name = ref.name;
	            var sorted = ref.sorted;

	            var layerView = this$1.createLayer(name);
	            this$1.layers.appendChild(layerView.el);
	            this$1._layers[name] = layerView;
	        });
	        // Throws an exception if doesn't exist
	        var cellsLayerView = this.getLayerView(LayersNames.CELLS);
	        var toolsLayerView = this.getLayerView(LayersNames.TOOLS);
	        var labelsLayerView = this.getLayerView(LayersNames.LABELS);
	        // backwards compatibility
	        this.tools = toolsLayerView.el;
	        this.cells = this.viewport = cellsLayerView.el;
	        // user-select: none;
	        cellsLayerView.vel.addClass(addClassNamePrefix('viewport'));
	        labelsLayerView.vel.addClass(addClassNamePrefix('viewport'));
	        cellsLayerView.el.style.webkitUserSelect = 'none';
	        cellsLayerView.el.style.userSelect = 'none';
	        labelsLayerView.el.style.webkitUserSelect = 'none';
	        labelsLayerView.el.style.userSelect = 'none';
	    },

	    removeLayers: function() {
	        var ref = this;
	        var _layers = ref._layers;
	        Object.keys(_layers).forEach(function (name) {
	            _layers[name].remove();
	            delete _layers[name];
	        });
	    },

	    resetLayers: function() {
	        var ref = this;
	        var _layers = ref._layers;
	        Object.keys(_layers).forEach(function (name) {
	            _layers[name].removePivots();
	        });
	    },

	    update: function() {

	        if (this._background) {
	            this.updateBackgroundImage(this._background);
	        }

	        return this;
	    },

	    scale: function(sx, sy, data) {
	        var ctm = this.matrix();
	        // getter
	        if (sx === undefined) {
	            return V.matrixToScale(ctm);
	        }
	        // setter
	        if (sy === undefined) {
	            sy = sx;
	        }
	        sx = Math.max(sx || 0, this.MIN_SCALE);
	        sy = Math.max(sy || 0, this.MIN_SCALE);
	        ctm.a = sx;
	        ctm.d = sy;
	        this.matrix(ctm, data);
	        return this;
	    },

	    scaleUniformAtPoint: function(scale, point, data) {
	        var ref = this.matrix();
	        var sx = ref.a;
	        var sy = ref.d;
	        var tx = ref.e;
	        var ty = ref.f;
	        scale = Math.max(scale || 0, this.MIN_SCALE);
	        if (scale === sx && scale === sy) {
	            // The scale is the same as the current one.
	            return this;
	        }
	        var matrix = V.createSVGMatrix()
	            .translate(
	                tx - point.x * (scale - sx),
	                ty - point.y * (scale - sy)
	            )
	            .scale(scale, scale);
	        this.matrix(matrix, data);
	        return this;
	    },

	    translate: function(tx, ty, data) {
	        var ctm = this.matrix();
	        // getter
	        if (tx === undefined) {
	            return V.matrixToTranslate(ctm);
	        }
	        // setter
	        tx || (tx = 0);
	        ty || (ty = 0);
	        if (ctm.e === tx && ctm.f === ty) { return this; }
	        ctm.e = tx;
	        ctm.f = ty;
	        this.matrix(ctm, data);
	        return this;
	    },

	    matrix: function(ctm, data) {
	        if ( data === void 0 ) data = {};


	        var viewport = this.layers;

	        // Getter:
	        if (ctm === undefined) {

	            var transformString = viewport.getAttribute('transform');

	            if ((this._viewportTransformString || null) === transformString) {
	                // It's ok to return the cached matrix. The transform attribute has not changed since
	                // the matrix was stored.
	                ctm = this._viewportMatrix;
	            } else {
	                // The viewport transform attribute has changed. Measure the matrix and cache again.
	                ctm = viewport.getCTM();
	                this._viewportMatrix = ctm;
	                this._viewportTransformString = transformString;
	            }

	            // Clone the cached current transformation matrix.
	            // If no matrix previously stored the identity matrix is returned.
	            return V.createSVGMatrix(ctm);
	        }

	        // Setter:
	        var prev = this.matrix();
	        var current = V.createSVGMatrix(ctm);
	        var currentTransformString = this._viewportTransformString;
	        var ctmString = V.matrixToTransformString(current);
	        if (ctmString === currentTransformString) {
	            // The new transform string is the same as the current one.
	            // No need to update the transform attribute.
	            return this;
	        }
	        if (!currentTransformString && V.matrixToTransformString() === ctmString) {
	            // The current transform string is empty and the new one is an identity matrix.
	            // No need to update the transform attribute.
	            return this;
	        }

	        var a = current.a;
	        var d = current.d;
	        var e = current.e;
	        var f = current.f;

	        viewport.setAttribute('transform', ctmString);
	        this._viewportMatrix = current;
	        this._viewportTransformString = viewport.getAttribute('transform');

	        // scale event
	        if (a !== prev.a || d !== prev.d) {
	            this.trigger('scale', a, d, data);
	        }

	        // translate event
	        if (e !== prev.e || f !== prev.f) {
	            this.trigger('translate', e, f, data);
	        }

	        this.trigger('transform', current, data);
	        return this;
	    },

	    clientMatrix: function() {

	        return V.createSVGMatrix(this.cells.getScreenCTM());
	    },

	    requestConnectedLinksUpdate: function(view, priority, opt) {
	        if (view instanceof CellView) {
	            var model = view.model;
	            var links = this.model.getConnectedLinks(model);
	            for (var j = 0, n = links.length; j < n; j++) {
	                var link = links[j];
	                var linkView = this.findViewByModel(link);
	                if (!linkView) { continue; }
	                var flagLabels = ['UPDATE'];
	                if (link.getTargetCell() === model) { flagLabels.push('TARGET'); }
	                if (link.getSourceCell() === model) { flagLabels.push('SOURCE'); }
	                var nextPriority = Math.max(priority + 1, linkView.UPDATE_PRIORITY);
	                this.scheduleViewUpdate(linkView, linkView.getFlag(flagLabels), nextPriority, opt);
	            }
	        }
	    },

	    forcePostponedViewUpdate: function(view, flag) {
	        if (!view || !(view instanceof CellView)) { return false; }
	        var model = view.model;
	        if (model.isElement()) { return false; }
	        if ((flag & view.getFlag(['SOURCE', 'TARGET'])) === 0) {
	            var dumpOptions = { silent: true };
	            // LinkView is waiting for the target or the source cellView to be rendered
	            // This can happen when the cells are not in the viewport.
	            var sourceFlag = 0;
	            var sourceView = this.findViewByModel(model.getSourceCell());
	            if (sourceView && !this.isViewMounted(sourceView)) {
	                sourceFlag = this.dumpView(sourceView, dumpOptions);
	                view.updateEndMagnet('source');
	            }
	            var targetFlag = 0;
	            var targetView = this.findViewByModel(model.getTargetCell());
	            if (targetView && !this.isViewMounted(targetView)) {
	                targetFlag = this.dumpView(targetView, dumpOptions);
	                view.updateEndMagnet('target');
	            }
	            if (sourceFlag === 0 && targetFlag === 0) {
	                // If leftover flag is 0, all view updates were done.
	                return !this.dumpView(view, dumpOptions);
	            }
	        }
	        return false;
	    },

	    requestViewUpdate: function(view, flag, priority, opt) {
	        opt || (opt = {});
	        this.scheduleViewUpdate(view, flag, priority, opt);
	        var isAsync = this.isAsync();
	        if (this.isFrozen() || (isAsync && opt.async !== false)) { return; }
	        if (this.model.hasActiveBatch(this.UPDATE_DELAYING_BATCHES)) { return; }
	        var stats = this.updateViews(opt);
	        if (isAsync) { this.notifyAfterRender(stats, opt); }
	    },

	    scheduleViewUpdate: function(view, type, priority, opt) {
	        var ref = this;
	        var updates = ref._updates;
	        var options = ref.options;
	        if (updates.idle) {
	            if (options.autoFreeze) {
	                updates.idle = false;
	                this.unfreeze();
	            }
	        }
	        var FLAG_REMOVE = view.FLAG_REMOVE;
	        var FLAG_INSERT = view.FLAG_INSERT;
	        var UPDATE_PRIORITY = view.UPDATE_PRIORITY;
	        var cid = view.cid;
	        var priorityUpdates = updates.priorities[priority];
	        if (!priorityUpdates) { priorityUpdates = updates.priorities[priority] = {}; }
	        // Move higher priority updates to this priority
	        if (priority > UPDATE_PRIORITY) {
	            // Not the default priority for this view. It's most likely a link view
	            // connected to another link view, which triggered the update.
	            // TODO: If there is an update scheduled with a lower priority already, we should
	            // change the requested priority to the lowest one. Does not seem to be critical
	            // right now, as it "only" results in multiple updates on the same view.
	            for (var i = priority - 1; i >= UPDATE_PRIORITY; i--) {
	                var prevPriorityUpdates = updates.priorities[i];
	                if (!prevPriorityUpdates || !(cid in prevPriorityUpdates)) { continue; }
	                priorityUpdates[cid] |= prevPriorityUpdates[cid];
	                delete prevPriorityUpdates[cid];
	            }
	        }
	        var currentType = priorityUpdates[cid] || 0;
	        // Prevent cycling
	        if ((currentType & type) === type) { return; }
	        if (!currentType) { updates.count++; }
	        if (type & FLAG_REMOVE && currentType & FLAG_INSERT) {
	            // When a view is removed we need to remove the insert flag as this is a reinsert
	            priorityUpdates[cid] ^= FLAG_INSERT;
	        } else if (type & FLAG_INSERT && currentType & FLAG_REMOVE) {
	            // When a view is added we need to remove the remove flag as this is view was previously removed
	            priorityUpdates[cid] ^= FLAG_REMOVE;
	        }
	        priorityUpdates[cid] |= type;
	        var viewUpdateFn = options.onViewUpdate;
	        if (typeof viewUpdateFn === 'function') { viewUpdateFn.call(this, view, type, priority, opt || {}, this); }
	    },

	    dumpViewUpdate: function(view) {
	        if (!view) { return 0; }
	        var updates = this._updates;
	        var cid = view.cid;
	        var priorityUpdates = updates.priorities[view.UPDATE_PRIORITY];
	        var flag = this.registerMountedView(view) | priorityUpdates[cid];
	        delete priorityUpdates[cid];
	        return flag;
	    },

	    dumpView: function(view, opt) {
	        if ( opt === void 0 ) opt = {};

	        var flag = this.dumpViewUpdate(view);
	        if (!flag) { return 0; }
	        var shouldNotify = !opt.silent;
	        if (shouldNotify) { this.notifyBeforeRender(opt); }
	        var leftover = this.updateView(view, flag, opt);
	        if (shouldNotify) {
	            var stats = { updated: 1, priority: view.UPDATE_PRIORITY };
	            this.notifyAfterRender(stats, opt);
	        }
	        return leftover;
	    },

	    updateView: function(view, flag, opt) {
	        if (!view) { return 0; }
	        var FLAG_REMOVE = view.FLAG_REMOVE;
	        var FLAG_INSERT = view.FLAG_INSERT;
	        var FLAG_INIT = view.FLAG_INIT;
	        var model = view.model;
	        if (view instanceof CellView) {
	            if (flag & FLAG_REMOVE) {
	                this.removeView(model);
	                return 0;
	            }
	            if (flag & FLAG_INSERT) {
	                var isInitialInsert = !!(flag & FLAG_INIT);
	                if (isInitialInsert) {
	                    flag ^= FLAG_INIT;
	                }
	                this.insertView(view, isInitialInsert);
	                flag ^= FLAG_INSERT;
	            }
	        }
	        if (!flag) { return 0; }
	        return view.confirmUpdate(flag, opt || {});
	    },

	    requireView: function(model, opt) {
	        var view = this.findViewByModel(model);
	        if (!view) { return null; }
	        this.dumpView(view, opt);
	        return view;
	    },

	    registerUnmountedView: function(view) {
	        var cid = view.cid;
	        var updates = this._updates;
	        if (cid in updates.unmounted) { return 0; }
	        var flag = updates.unmounted[cid] |= view.FLAG_INSERT;
	        updates.unmountedCids.push(cid);
	        delete updates.mounted[cid];
	        return flag;
	    },

	    registerMountedView: function(view) {
	        var cid = view.cid;
	        var updates = this._updates;
	        if (cid in updates.mounted) { return 0; }
	        updates.mounted[cid] = true;
	        updates.mountedCids.push(cid);
	        var flag = updates.unmounted[cid] || 0;
	        delete updates.unmounted[cid];
	        return flag;
	    },

	    isViewMounted: function(view) {
	        if (!view) { return false; }
	        var cid = view.cid;
	        var updates = this._updates;
	        return (cid in updates.mounted);
	    },

	    dumpViews: function(opt) {
	        var passingOpt = defaults({}, opt, { viewport: null });
	        this.checkViewport(passingOpt);
	        this.updateViews(passingOpt);
	    },

	    // Synchronous views update
	    updateViews: function(opt) {
	        this.notifyBeforeRender(opt);
	        var batchStats;
	        var updateCount = 0;
	        var batchCount = 0;
	        var priority = MIN_PRIORITY;
	        do {
	            batchCount++;
	            batchStats = this.updateViewsBatch(opt);
	            updateCount += batchStats.updated;
	            priority = Math.min(batchStats.priority, priority);
	        } while (!batchStats.empty);
	        var stats = { updated: updateCount, batches: batchCount, priority: priority };
	        this.notifyAfterRender(stats, opt);
	        return stats;
	    },

	    hasScheduledUpdates: function() {
	        var priorities = this._updates.priorities;
	        var priorityIndexes = Object.keys(priorities); // convert priorities to a dense array
	        var i = priorityIndexes.length;
	        while (i > 0 && i--) {
	            // a faster way how to check if an object is empty
	            for (var _key in priorities[priorityIndexes[i]]) { return true; }
	        }
	        return false;
	    },

	    updateViewsAsync: function(opt, data) {
	        opt || (opt = {});
	        data || (data = { processed: 0, priority: MIN_PRIORITY });
	        var ref = this;
	        var updates = ref._updates;
	        var options = ref.options;
	        var id = updates.id;
	        if (id) {
	            cancelFrame(id);
	            if (data.processed === 0 && this.hasScheduledUpdates()) {
	                this.notifyBeforeRender(opt);
	            }
	            var stats = this.updateViewsBatch(opt);
	            var passingOpt = defaults({}, opt, {
	                mountBatchSize: MOUNT_BATCH_SIZE - stats.mounted,
	                unmountBatchSize: MOUNT_BATCH_SIZE - stats.unmounted
	            });
	            var checkStats = this.checkViewport(passingOpt);
	            var unmountCount = checkStats.unmounted;
	            var mountCount = checkStats.mounted;
	            var processed = data.processed;
	            var total = updates.count;
	            if (stats.updated > 0) {
	                // Some updates have been just processed
	                processed += stats.updated + stats.unmounted;
	                stats.processed = processed;
	                data.priority = Math.min(stats.priority, data.priority);
	                if (stats.empty && mountCount === 0) {
	                    stats.unmounted += unmountCount;
	                    stats.mounted += mountCount;
	                    stats.priority = data.priority;
	                    this.notifyAfterRender(stats, opt);
	                    data.processed = 0;
	                    data.priority = MIN_PRIORITY;
	                    updates.count = 0;
	                } else {
	                    data.processed = processed;
	                }
	            } else {
	                if (!updates.idle) {
	                    if (options.autoFreeze) {
	                        this.freeze();
	                        updates.idle = true;
	                        this.trigger('render:idle', opt);
	                    }
	                }
	            }
	            // Progress callback
	            var progressFn = opt.progress;
	            if (total && typeof progressFn === 'function') {
	                progressFn.call(this, stats.empty, processed, total, stats, this);
	            }
	            // The current frame could have been canceled in a callback
	            if (updates.id !== id) { return; }
	        }
	        if (updates.disabled) {
	            throw new Error('dia.Paper: can not unfreeze the paper after it was removed');
	        }
	        updates.id = nextFrame(this.updateViewsAsync, this, opt, data);
	    },

	    notifyBeforeRender: function(opt) {
	        if ( opt === void 0 ) opt = {};

	        var beforeFn = opt.beforeRender;
	        if (typeof beforeFn !== 'function') {
	            beforeFn = this.options.beforeRender;
	            if (typeof beforeFn !== 'function') { return; }
	        }
	        beforeFn.call(this, opt, this);
	    },

	    notifyAfterRender: function(stats, opt) {
	        if ( opt === void 0 ) opt = {};

	        var afterFn = opt.afterRender;
	        if (typeof afterFn !== 'function') {
	            afterFn = this.options.afterRender;
	        }
	        if (typeof afterFn === 'function') {
	            afterFn.call(this, stats, opt, this);
	        }
	        this.trigger('render:done', stats, opt);
	    },

	    updateViewsBatch: function(opt) {
	        opt || (opt = {});
	        var batchSize = opt.batchSize || UPDATE_BATCH_SIZE;
	        var updates = this._updates;
	        var updateCount = 0;
	        var postponeCount = 0;
	        var unmountCount = 0;
	        var mountCount = 0;
	        var maxPriority = MIN_PRIORITY;
	        var empty = true;
	        var options = this.options;
	        var priorities = updates.priorities;
	        var viewportFn = 'viewport' in opt ? opt.viewport : options.viewport;
	        if (typeof viewportFn !== 'function') { viewportFn = null; }
	        var postponeViewFn = options.onViewPostponed;
	        if (typeof postponeViewFn !== 'function') { postponeViewFn = null; }
	        var priorityIndexes = Object.keys(priorities); // convert priorities to a dense array
	        main: for (var i = 0, n = priorityIndexes.length; i < n; i++) {
	            var priority = +priorityIndexes[i];
	            var priorityUpdates = priorities[priority];
	            for (var cid in priorityUpdates) {
	                if (updateCount >= batchSize) {
	                    empty = false;
	                    break main;
	                }
	                var view = views[cid];
	                if (!view) {
	                    // This should not occur
	                    delete priorityUpdates[cid];
	                    continue;
	                }
	                var currentFlag = priorityUpdates[cid];
	                if ((currentFlag & view.FLAG_REMOVE) === 0) {
	                    // We should never check a view for viewport if we are about to remove the view
	                    var isDetached = cid in updates.unmounted;
	                    if (view.DETACHABLE && viewportFn && !viewportFn.call(this, view, !isDetached, this)) {
	                        // Unmount View
	                        if (!isDetached) {
	                            this.registerUnmountedView(view);
	                            this.detachView(view);
	                        }
	                        updates.unmounted[cid] |= currentFlag;
	                        delete priorityUpdates[cid];
	                        unmountCount++;
	                        continue;
	                    }
	                    // Mount View
	                    if (isDetached) {
	                        currentFlag |= view.FLAG_INSERT;
	                        mountCount++;
	                    }
	                    currentFlag |= this.registerMountedView(view);
	                }
	                var leftoverFlag = this.updateView(view, currentFlag, opt);
	                if (leftoverFlag > 0) {
	                    // View update has not finished completely
	                    priorityUpdates[cid] = leftoverFlag;
	                    if (!postponeViewFn || !postponeViewFn.call(this, view, leftoverFlag, this) || priorityUpdates[cid]) {
	                        postponeCount++;
	                        empty = false;
	                        continue;
	                    }
	                }
	                if (maxPriority > priority) { maxPriority = priority; }
	                updateCount++;
	                delete priorityUpdates[cid];
	            }
	        }
	        return {
	            priority: maxPriority,
	            updated: updateCount,
	            postponed: postponeCount,
	            unmounted: unmountCount,
	            mounted: mountCount,
	            empty: empty
	        };
	    },

	    getUnmountedViews: function() {
	        var updates = this._updates;
	        var unmountedCids = Object.keys(updates.unmounted);
	        var n = unmountedCids.length;
	        var unmountedViews = new Array(n);
	        for (var i = 0; i < n; i++) {
	            unmountedViews[i] = views[unmountedCids[i]];
	        }
	        return unmountedViews;
	    },

	    getMountedViews: function() {
	        var updates = this._updates;
	        var mountedCids = Object.keys(updates.mounted);
	        var n = mountedCids.length;
	        var mountedViews = new Array(n);
	        for (var i = 0; i < n; i++) {
	            mountedViews[i] = views[mountedCids[i]];
	        }
	        return mountedViews;
	    },

	    checkUnmountedViews: function(viewportFn, opt) {
	        opt || (opt  = {});
	        var mountCount = 0;
	        if (typeof viewportFn !== 'function') { viewportFn = null; }
	        var batchSize = 'mountBatchSize' in opt ? opt.mountBatchSize : Infinity;
	        var updates = this._updates;
	        var unmountedCids = updates.unmountedCids;
	        var unmounted = updates.unmounted;
	        for (var i = 0, n = Math.min(unmountedCids.length, batchSize); i < n; i++) {
	            var cid = unmountedCids[i];
	            if (!(cid in unmounted)) { continue; }
	            var view = views[cid];
	            if (!view) { continue; }
	            if (view.DETACHABLE && viewportFn && !viewportFn.call(this, view, false, this)) {
	                // Push at the end of all unmounted ids, so this can be check later again
	                unmountedCids.push(cid);
	                continue;
	            }
	            mountCount++;
	            var flag = this.registerMountedView(view);
	            if (flag) { this.scheduleViewUpdate(view, flag, view.UPDATE_PRIORITY, { mounting: true }); }
	        }
	        // Get rid of views, that have been mounted
	        unmountedCids.splice(0, i);
	        return mountCount;
	    },

	    checkMountedViews: function(viewportFn, opt) {
	        opt || (opt = {});
	        var unmountCount = 0;
	        if (typeof viewportFn !== 'function') { return unmountCount; }
	        var batchSize = 'unmountBatchSize' in opt ? opt.unmountBatchSize : Infinity;
	        var updates = this._updates;
	        var mountedCids = updates.mountedCids;
	        var mounted = updates.mounted;
	        for (var i = 0, n = Math.min(mountedCids.length, batchSize); i < n; i++) {
	            var cid = mountedCids[i];
	            if (!(cid in mounted)) { continue; }
	            var view = views[cid];
	            if (!view) { continue; }
	            if (!view.DETACHABLE || viewportFn.call(this, view, true, this)) {
	                // Push at the end of all mounted ids, so this can be check later again
	                mountedCids.push(cid);
	                continue;
	            }
	            unmountCount++;
	            var flag = this.registerUnmountedView(view);
	            if (flag) { this.detachView(view); }
	        }
	        // Get rid of views, that have been unmounted
	        mountedCids.splice(0, i);
	        return unmountCount;
	    },

	    checkViewVisibility: function(cellView, opt) {
	        if ( opt === void 0 ) opt = {};

	        var viewportFn = 'viewport' in opt ? opt.viewport : this.options.viewport;
	        if (typeof viewportFn !== 'function') { viewportFn = null; }
	        var updates = this._updates;
	        var mounted = updates.mounted;
	        var unmounted = updates.unmounted;
	        var visible = !cellView.DETACHABLE || !viewportFn || viewportFn.call(this, cellView, false, this);

	        var isUnmounted = false;
	        var isMounted = false;

	        if (cellView.cid in mounted && !visible) {
	            var flag$1 = this.registerUnmountedView(cellView);
	            if (flag$1) { this.detachView(cellView); }
	            var i = updates.mountedCids.indexOf(cellView.cid);
	            updates.mountedCids.splice(i, 1);
	            isUnmounted = true;
	        }

	        if (!isUnmounted && cellView.cid in unmounted && visible) {
	            var i$1 = updates.unmountedCids.indexOf(cellView.cid);
	            updates.unmountedCids.splice(i$1, 1);
	            var flag = this.registerMountedView(cellView);
	            if (flag) { this.scheduleViewUpdate(cellView, flag, cellView.UPDATE_PRIORITY, { mounting: true }); }
	            isMounted = true;
	        }

	        return {
	            mounted: isMounted ? 1 : 0,
	            unmounted: isUnmounted ? 1 : 0
	        };
	    },

	    checkViewport: function(opt) {
	        var passingOpt = defaults({}, opt, {
	            mountBatchSize: Infinity,
	            unmountBatchSize: Infinity
	        });
	        var viewportFn = 'viewport' in passingOpt ? passingOpt.viewport : this.options.viewport;
	        var unmountedCount = this.checkMountedViews(viewportFn, passingOpt);
	        if (unmountedCount > 0) {
	            // Do not check views, that have been just unmounted and pushed at the end of the cids array
	            var unmountedCids = this._updates.unmountedCids;
	            passingOpt.mountBatchSize = Math.min(unmountedCids.length - unmountedCount, passingOpt.mountBatchSize);
	        }
	        var mountedCount = this.checkUnmountedViews(viewportFn, passingOpt);
	        return {
	            mounted: mountedCount,
	            unmounted: unmountedCount
	        };
	    },

	    freeze: function(opt) {
	        opt || (opt = {});
	        var updates = this._updates;
	        var key = opt.key;
	        var isFrozen = this.options.frozen;
	        var freezeKey = updates.freezeKey;
	        if (key && key !== freezeKey)  {
	            // key passed, but the paper is already freezed with another key
	            if (isFrozen && freezeKey) { return; }
	            updates.freezeKey = key;
	            updates.keyFrozen = isFrozen;
	        }
	        this.options.frozen = true;
	        var id = updates.id;
	        updates.id = null;
	        if (this.isAsync() && id) { cancelFrame(id); }
	    },

	    unfreeze: function(opt) {
	        opt || (opt = {});
	        var updates = this._updates;
	        var key = opt.key;
	        var freezeKey = updates.freezeKey;
	        // key passed, but the paper is already freezed with another key
	        if (key && freezeKey && key !== freezeKey) { return; }
	        updates.freezeKey = null;
	        // key passed, but the paper is already freezed
	        if (key && key === freezeKey && updates.keyFrozen) { return; }
	        if (this.isAsync()) {
	            this.freeze();
	            this.updateViewsAsync(opt);
	        } else {
	            this.updateViews(opt);
	        }
	        this.options.frozen = updates.keyFrozen = false;
	        if (updates.sort) {
	            this.sortViews();
	            updates.sort = false;
	        }
	    },

	    isAsync: function() {
	        return !!this.options.async;
	    },

	    isFrozen: function() {
	        return !!this.options.frozen;
	    },

	    isExactSorting: function() {
	        return this.options.sorting === sortingTypes.EXACT;
	    },

	    onRemove: function() {

	        this.freeze();
	        this._updates.disabled = true;
	        //clean up all DOM elements/views to prevent memory leaks
	        this.removeLayers();
	        this.removeViews();
	    },

	    getComputedSize: function() {

	        var options = this.options;
	        var w = options.width;
	        var h = options.height;
	        if (!isNumber(w)) { w = this.el.clientWidth; }
	        if (!isNumber(h)) { h = this.el.clientHeight; }
	        return { width: w, height: h };
	    },

	    setDimensions: function(width, height, data) {
	        if ( data === void 0 ) data = {};

	        var ref = this;
	        var options = ref.options;
	        var currentWidth = options.width;
	        var currentHeight = options.height;
	        var w = (width === undefined) ? currentWidth : width;
	        var h = (height === undefined) ? currentHeight : height;
	        if (currentWidth === w && currentHeight === h) { return; }
	        options.width = w;
	        options.height = h;
	        this._setDimensions();
	        var computedSize = this.getComputedSize();
	        this.trigger('resize', computedSize.width, computedSize.height, data);
	    },

	    _setDimensions: function() {
	        var ref = this;
	        var options = ref.options;
	        var w = options.width;
	        var h = options.height;
	        if (isNumber(w)) { w = (Math.round(w)) + "px"; }
	        if (isNumber(h)) { h = (Math.round(h)) + "px"; }
	        this.$el.css({
	            width: (w === null) ? '' : w,
	            height: (h === null) ? '' : h
	        });
	    },

	    // Expand/shrink the paper to fit the content.
	    // Alternatively signature function(opt)
	    fitToContent: function(gridWidth, gridHeight, padding, opt) {

	        if (isObject$1(gridWidth)) {
	            // first parameter is an option object
	            opt = gridWidth;
	        } else {
	            // Support for a deprecated signature
	            opt = assign({ gridWidth: gridWidth, gridHeight: gridHeight, padding: padding }, opt);
	        }

	        var ref = this.getFitToContentArea(opt);
	        var x = ref.x;
	        var y = ref.y;
	        var width = ref.width;
	        var height = ref.height;
	        var ref$1 = this.scale();
	        var sx = ref$1.sx;
	        var sy = ref$1.sy;

	        this.translate(-x * sx, -y * sy, opt);
	        this.setDimensions(width * sx, height * sy, opt);

	        return new Rect(x, y, width, height);
	    },

	    getFitToContentArea: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        // Calculate the paper size to accommodate all the graph's elements.

	        var gridWidth = opt.gridWidth || 1;
	        var gridHeight = opt.gridHeight || 1;
	        var padding = normalizeSides(opt.padding || 0);

	        var minWidth = Math.max(opt.minWidth || 0, gridWidth);
	        var minHeight = Math.max(opt.minHeight || 0, gridHeight);
	        var maxWidth = opt.maxWidth || Number.MAX_VALUE;
	        var maxHeight = opt.maxHeight || Number.MAX_VALUE;
	        var newOrigin = opt.allowNewOrigin;

	        var area = ('contentArea' in opt) ? new Rect(opt.contentArea) : this.getContentArea(opt);
	        var ref = this.scale();
	        var sx = ref.sx;
	        var sy = ref.sy;
	        area.x *= sx;
	        area.y *= sy;
	        area.width *= sx;
	        area.height *= sy;

	        var calcWidth = Math.ceil((area.width + area.x) / gridWidth);
	        var calcHeight = Math.ceil((area.height + area.y) / gridHeight);
	        if (!opt.allowNegativeBottomRight) {
	            calcWidth = Math.max(calcWidth, 1);
	            calcHeight = Math.max(calcHeight, 1);
	        }
	        calcWidth *= gridWidth;
	        calcHeight *= gridHeight;

	        var tx = 0;
	        if ((newOrigin === 'negative' && area.x < 0) || (newOrigin === 'positive' && area.x >= 0) || newOrigin === 'any') {
	            tx = Math.ceil(-area.x / gridWidth) * gridWidth;
	            tx += padding.left;
	            calcWidth += tx;
	        }

	        var ty = 0;
	        if ((newOrigin === 'negative' && area.y < 0) || (newOrigin === 'positive' && area.y >= 0) || newOrigin === 'any') {
	            ty = Math.ceil(-area.y / gridHeight) * gridHeight;
	            ty += padding.top;
	            calcHeight += ty;
	        }

	        calcWidth += padding.right;
	        calcHeight += padding.bottom;

	        // Make sure the resulting width and height are greater than minimum.
	        calcWidth = Math.max(calcWidth, minWidth);
	        calcHeight = Math.max(calcHeight, minHeight);

	        // Make sure the resulting width and height are lesser than maximum.
	        calcWidth = Math.min(calcWidth, maxWidth);
	        calcHeight = Math.min(calcHeight, maxHeight);

	        return new Rect(-tx / sx, -ty / sy, calcWidth / sx, calcHeight / sy);
	    },

	    transformToFitContent: function(opt) {
	        opt || (opt = {});

	        var contentBBox, contentLocalOrigin;
	        if ('contentArea' in opt) {
	            var contentArea = opt.contentArea;
	            contentBBox = this.localToPaperRect(contentArea);
	            contentLocalOrigin = new Point(contentArea);
	        } else {
	            contentBBox = this.getContentBBox(opt);
	            contentLocalOrigin = this.paperToLocalPoint(contentBBox);
	        }

	        if (!contentBBox.width || !contentBBox.height) { return; }

	        defaults(opt, {
	            padding: 0,
	            preserveAspectRatio: true,
	            scaleGrid: null,
	            minScale: 0,
	            maxScale: Number.MAX_VALUE,
	            verticalAlign: 'top',
	            horizontalAlign: 'left',
	            //minScaleX
	            //minScaleY
	            //maxScaleX
	            //maxScaleY
	            //fittingBBox
	        });

	        var padding = normalizeSides(opt.padding);

	        var minScaleX = opt.minScaleX || opt.minScale;
	        var maxScaleX = opt.maxScaleX || opt.maxScale;
	        var minScaleY = opt.minScaleY || opt.minScale;
	        var maxScaleY = opt.maxScaleY || opt.maxScale;

	        var fittingBBox;
	        if (opt.fittingBBox) {
	            fittingBBox = opt.fittingBBox;
	        } else {
	            var currentTranslate = this.translate();
	            var computedSize = this.getComputedSize();
	            fittingBBox = {
	                x: currentTranslate.tx,
	                y: currentTranslate.ty,
	                width: computedSize.width,
	                height: computedSize.height
	            };
	        }

	        fittingBBox = new Rect(fittingBBox).moveAndExpand({
	            x: padding.left,
	            y: padding.top,
	            width: -padding.left - padding.right,
	            height: -padding.top - padding.bottom
	        });

	        var ctm = this.matrix();
	        var sx = ctm.a;
	        var sy = ctm.d;
	        var tx = ctm.e;
	        var ty = ctm.f;

	        var newSx = fittingBBox.width / contentBBox.width * sx;
	        var newSy = fittingBBox.height / contentBBox.height * sy;

	        if (opt.preserveAspectRatio) {
	            newSx = newSy = Math.min(newSx, newSy);
	        }

	        // snap scale to a grid
	        if (opt.scaleGrid) {

	            var gridSize = opt.scaleGrid;

	            newSx = gridSize * Math.floor(newSx / gridSize);
	            newSy = gridSize * Math.floor(newSy / gridSize);
	        }

	        // scale min/max boundaries
	        newSx = Math.min(maxScaleX, Math.max(minScaleX, newSx));
	        newSy = Math.min(maxScaleY, Math.max(minScaleY, newSy));

	        var scaleDiff = {
	            x: newSx / sx,
	            y: newSy / sy
	        };

	        var newOx = fittingBBox.x - contentLocalOrigin.x * newSx - tx;
	        var newOy = fittingBBox.y - contentLocalOrigin.y * newSy - ty;

	        switch (opt.verticalAlign) {
	            case 'middle':
	                newOy = newOy + (fittingBBox.height - contentBBox.height * scaleDiff.y) / 2;
	                break;
	            case 'bottom':
	                newOy = newOy + (fittingBBox.height - contentBBox.height * scaleDiff.y);
	                break;
	            case 'top':
	            default:
	                break;
	        }

	        switch (opt.horizontalAlign) {
	            case 'middle':
	                newOx = newOx + (fittingBBox.width - contentBBox.width * scaleDiff.x) / 2;
	                break;
	            case 'right':
	                newOx = newOx + (fittingBBox.width - contentBBox.width * scaleDiff.x);
	                break;
	            case 'left':
	            default:
	                break;
	        }

	        ctm.a = newSx;
	        ctm.d = newSy;
	        ctm.e = newOx;
	        ctm.f = newOy;
	        this.matrix(ctm, opt);
	    },

	    scaleContentToFit: function(opt) {
	        this.transformToFitContent(opt);
	    },

	    // Return the dimensions of the content area in local units (without transformations).
	    getContentArea: function(opt) {

	        if (opt && opt.useModelGeometry) {
	            return this.model.getBBox() || new Rect();
	        }

	        return V(this.cells).getBBox();
	    },

	    // Return the dimensions of the content bbox in the paper units (as it appears on screen).
	    getContentBBox: function(opt) {

	        return this.localToPaperRect(this.getContentArea(opt));
	    },

	    // Returns a geometry rectangle representing the entire
	    // paper area (coordinates from the left paper border to the right one
	    // and the top border to the bottom one).
	    getArea: function() {

	        return this.paperToLocalRect(this.getComputedSize());
	    },

	    getRestrictedArea: function() {
	        var args = [], len = arguments.length;
	        while ( len-- ) args[ len ] = arguments[ len ];


	        var ref = this.options;
	        var restrictTranslate = ref.restrictTranslate;

	        var restrictedArea;
	        if (isFunction(restrictTranslate)) {
	            // A method returning a bounding box
	            restrictedArea = restrictTranslate.apply(this, args);
	        } else if (restrictTranslate === true) {
	            // The paper area
	            restrictedArea = this.getArea();
	        } else if (!restrictTranslate) {
	            // falsy value
	            restrictedArea = null;
	        } else {
	            // any other value
	            restrictedArea = new Rect(restrictTranslate);
	        }

	        return restrictedArea;
	    },

	    createViewForModel: function(cell) {

	        var ref = this;
	        var options = ref.options;
	        // A class taken from the paper options.
	        var optionalViewClass;

	        // A default basic class (either dia.ElementView or dia.LinkView)
	        var defaultViewClass;

	        // A special class defined for this model in the corresponding namespace.
	        // e.g. joint.shapes.standard.Rectangle searches for joint.shapes.standard.RectangleView
	        var namespace = options.cellViewNamespace;
	        var type = cell.get('type') + 'View';
	        var namespaceViewClass = getByPath(namespace, type, '.');

	        if (cell.isLink()) {
	            optionalViewClass = options.linkView;
	            defaultViewClass = LinkView;
	        } else {
	            optionalViewClass = options.elementView;
	            defaultViewClass = ElementView;
	        }

	        // a) the paper options view is a class (deprecated)
	        //  1. search the namespace for a view
	        //  2. if no view was found, use view from the paper options
	        // b) the paper options view is a function
	        //  1. call the function from the paper options
	        //  2. if no view was return, search the namespace for a view
	        //  3. if no view was found, use the default
	        var ViewClass = (optionalViewClass.prototype instanceof ViewBase)
	            ? namespaceViewClass || optionalViewClass
	            : optionalViewClass.call(this, cell) || namespaceViewClass || defaultViewClass;

	        return new ViewClass({
	            model: cell,
	            interactive: options.interactive,
	            labelsLayer: options.labelsLayer === true ? LayersNames.LABELS : options.labelsLayer
	        });
	    },

	    removeView: function(cell) {

	        var id = cell.id;
	        var ref = this;
	        var _views = ref._views;
	        var _updates = ref._updates;
	        var view = _views[id];
	        if (view) {
	            var cid = view.cid;
	            var mounted = _updates.mounted;
	            var unmounted = _updates.unmounted;
	            view.remove();
	            delete _views[id];
	            delete mounted[cid];
	            delete unmounted[cid];
	        }
	        return view;
	    },

	    renderView: function(cell, opt) {

	        var id = cell.id;
	        var views = this._views;
	        var view, flag;
	        var create = true;
	        if (id in views) {
	            view = views[id];
	            if (view.model === cell) {
	                flag = view.FLAG_INSERT;
	                create = false;
	            } else {
	                // The view for this `id` already exist.
	                // The cell is a new instance of the model with identical id
	                // We simply remove the existing view and create a new one
	                this.removeView(cell);
	            }
	        }
	        if (create) {
	            view = views[id] = this.createViewForModel(cell);
	            view.paper = this;
	            flag = this.registerUnmountedView(view) | this.FLAG_INIT | view.getFlag(result(view, 'initFlag'));
	        }
	        this.requestViewUpdate(view, flag, view.UPDATE_PRIORITY, opt);
	        return view;
	    },

	    onImageDragStart: function() {
	        // This is the only way to prevent image dragging in Firefox that works.
	        // Setting -moz-user-select: none, draggable="false" attribute or user-drag: none didn't help.

	        return false;
	    },

	    resetViews: function(cells, opt) {
	        opt || (opt = {});
	        cells || (cells = []);
	        this._resetUpdates();
	        // clearing views removes any event listeners
	        this.removeViews();
	        // Allows to unfreeze normally while in the idle state using autoFreeze option
	        var key = this.options.autoFreeze ? null : 'reset';
	        this.freeze({ key: key });
	        for (var i = 0, n = cells.length; i < n; i++) {
	            this.renderView(cells[i], opt);
	        }
	        this.unfreeze({ key: key });
	        this.sortViews();
	    },

	    removeViews: function() {

	        invoke(this._views, 'remove');

	        this._views = {};
	    },

	    sortViews: function() {

	        if (!this.isExactSorting()) {
	            // noop
	            return;
	        }
	        if (this.isFrozen()) {
	            // sort views once unfrozen
	            this._updates.sort = true;
	            return;
	        }
	        this.sortViewsExact();
	    },

	    sortViewsExact: function() {

	        // Run insertion sort algorithm in order to efficiently sort DOM elements according to their
	        // associated model `z` attribute.

	        var cellNodes = Array.from(this.cells.childNodes).filter(function (node) { return node.getAttribute('model-id'); });
	        var cells = this.model.get('cells');

	        sortElements(cellNodes, function(a, b) {
	            var cellA = cells.get(a.getAttribute('model-id'));
	            var cellB = cells.get(b.getAttribute('model-id'));
	            var zA = cellA.attributes.z || 0;
	            var zB = cellB.attributes.z || 0;
	            return (zA === zB) ? 0 : (zA < zB) ? -1 : 1;
	        });
	    },

	    insertView: function(view, isInitialInsert) {
	        var layerView = this.getLayerView(LayersNames.CELLS);
	        var el = view.el;
	        var model = view.model;
	        switch (this.options.sorting) {
	            case sortingTypes.APPROX:
	                layerView.insertSortedNode(el, model.get('z'));
	                break;
	            case sortingTypes.EXACT:
	            default:
	                layerView.insertNode(el);
	                break;
	        }
	        view.onMount(isInitialInsert);
	    },

	    detachView: function detachView(view) {
	        view.unmount();
	        view.onDetach();
	    },

	    // Find the first view climbing up the DOM tree starting at element `el`. Note that `el` can also
	    // be a selector or a jQuery object.
	    findView: function($el) {

	        var el = isString($el)
	            ? this.cells.querySelector($el)
	            : $el instanceof $ ? $el[0] : $el;

	        var id = this.findAttribute('model-id', el);
	        if (id) { return this._views[id]; }

	        return undefined;
	    },

	    // Find a view for a model `cell`. `cell` can also be a string or number representing a model `id`.
	    findViewByModel: function(cell) {

	        var id = (isString(cell) || isNumber(cell)) ? cell : (cell && cell.id);

	        return this._views[id];
	    },

	    // Find all views at given point
	    findViewsFromPoint: function(p) {

	        p = new Point(p);

	        var views = this.model.getElements().map(this.findViewByModel, this);

	        return views.filter(function(view) {
	            return view && view.vel.getBBox({ target: this.cells }).containsPoint(p);
	        }, this);
	    },

	    // Find all views in given area
	    findViewsInArea: function(rect, opt) {

	        opt = defaults(opt || {}, { strict: false });
	        rect = new Rect(rect);

	        var views = this.model.getElements().map(this.findViewByModel, this);
	        var method = opt.strict ? 'containsRect' : 'intersect';

	        return views.filter(function(view) {
	            return view && rect[method](view.vel.getBBox({ target: this.cells }));
	        }, this);
	    },

	    removeTools: function() {
	        this.dispatchToolsEvent('remove');
	        return this;
	    },

	    hideTools: function() {
	        this.dispatchToolsEvent('hide');
	        return this;
	    },

	    showTools: function() {
	        this.dispatchToolsEvent('show');
	        return this;
	    },

	    dispatchToolsEvent: function(event) {
	        var ref;

	        var args = [], len = arguments.length - 1;
	        while ( len-- > 0 ) args[ len ] = arguments[ len + 1 ];
	        if (typeof event !== 'string') { return; }
	        (ref = this).trigger.apply(ref, [ 'tools:event', event ].concat( args ));
	    },


	    getModelById: function(id) {

	        return this.model.getCell(id);
	    },

	    snapToGrid: function(x, y) {

	        // Convert global coordinates to the local ones of the `viewport`. Otherwise,
	        // improper transformation would be applied when the viewport gets transformed (scaled/rotated).
	        return this.clientToLocalPoint(x, y).snapToGrid(this.options.gridSize);
	    },

	    localToPaperPoint: function(x, y) {
	        // allow `x` to be a point and `y` undefined
	        var localPoint = new Point(x, y);
	        var paperPoint = V.transformPoint(localPoint, this.matrix());
	        return paperPoint;
	    },

	    localToPaperRect: function(x, y, width, height) {
	        // allow `x` to be a rectangle and rest arguments undefined
	        var localRect = new Rect(x, y, width, height);
	        var paperRect = V.transformRect(localRect, this.matrix());
	        return paperRect;
	    },

	    paperToLocalPoint: function(x, y) {
	        // allow `x` to be a point and `y` undefined
	        var paperPoint = new Point(x, y);
	        var localPoint = V.transformPoint(paperPoint, this.matrix().inverse());
	        return localPoint;
	    },

	    paperToLocalRect: function(x, y, width, height) {
	        // allow `x` to be a rectangle and rest arguments undefined
	        var paperRect = new Rect(x, y, width, height);
	        var localRect = V.transformRect(paperRect, this.matrix().inverse());
	        return localRect;
	    },

	    localToClientPoint: function(x, y) {
	        // allow `x` to be a point and `y` undefined
	        var localPoint = new Point(x, y);
	        var clientPoint = V.transformPoint(localPoint, this.clientMatrix());
	        return clientPoint;
	    },

	    localToClientRect: function(x, y, width, height) {
	        // allow `x` to be a point and `y` undefined
	        var localRect = new Rect(x, y, width, height);
	        var clientRect = V.transformRect(localRect, this.clientMatrix());
	        return clientRect;
	    },

	    // Transform client coordinates to the paper local coordinates.
	    // Useful when you have a mouse event object and you'd like to get coordinates
	    // inside the paper that correspond to `evt.clientX` and `evt.clientY` point.
	    // Example: var localPoint = paper.clientToLocalPoint({ x: evt.clientX, y: evt.clientY });
	    clientToLocalPoint: function(x, y) {
	        // allow `x` to be a point and `y` undefined
	        var clientPoint = new Point(x, y);
	        var localPoint = V.transformPoint(clientPoint, this.clientMatrix().inverse());
	        return localPoint;
	    },

	    clientToLocalRect: function(x, y, width, height) {
	        // allow `x` to be a point and `y` undefined
	        var clientRect = new Rect(x, y, width, height);
	        var localRect = V.transformRect(clientRect, this.clientMatrix().inverse());
	        return localRect;
	    },

	    localToPagePoint: function(x, y) {

	        return this.localToPaperPoint(x, y).offset(this.pageOffset());
	    },

	    localToPageRect: function(x, y, width, height) {

	        return this.localToPaperRect(x, y, width, height).offset(this.pageOffset());
	    },

	    pageToLocalPoint: function(x, y) {

	        var pagePoint = new Point(x, y);
	        var paperPoint = pagePoint.difference(this.pageOffset());
	        return this.paperToLocalPoint(paperPoint);
	    },

	    pageToLocalRect: function(x, y, width, height) {

	        var pageOffset = this.pageOffset();
	        var paperRect = new Rect(x, y, width, height);
	        paperRect.x -= pageOffset.x;
	        paperRect.y -= pageOffset.y;
	        return this.paperToLocalRect(paperRect);
	    },

	    clientOffset: function() {

	        var clientRect = this.svg.getBoundingClientRect();
	        return new Point(clientRect.left, clientRect.top);
	    },

	    pageOffset: function() {

	        return this.clientOffset().offset(window.scrollX, window.scrollY);
	    },

	    linkAllowed: function(linkView) {

	        if (!(linkView instanceof LinkView)) {
	            throw new Error('Must provide a linkView.');
	        }

	        var link = linkView.model;
	        var paperOptions = this.options;
	        var graph = this.model;
	        var ns = graph.constructor.validations;

	        if (!paperOptions.multiLinks) {
	            if (!ns.multiLinks.call(this, graph, link)) { return false; }
	        }

	        if (!paperOptions.linkPinning) {
	            // Link pinning is not allowed and the link is not connected to the target.
	            if (!ns.linkPinning.call(this, graph, link)) { return false; }
	        }

	        if (typeof paperOptions.allowLink === 'function') {
	            if (!paperOptions.allowLink.call(this, linkView, this)) { return false; }
	        }

	        return true;
	    },

	    getDefaultLink: function(cellView, magnet) {

	        return isFunction(this.options.defaultLink)
	        // default link is a function producing link model
	            ? this.options.defaultLink.call(this, cellView, magnet)
	        // default link is the mvc model
	            : this.options.defaultLink.clone();
	    },

	    // Cell highlighting.
	    // ------------------

	    resolveHighlighter: function(opt) {
	        if ( opt === void 0 ) opt = {};


	        var highlighterDef = opt.highlighter;
	        var type = opt.type;
	        var ref = this.options;
	        var highlighting = ref.highlighting;
	        var highlighterNamespace = ref.highlighterNamespace;

	        /*
	            Expecting opt.highlighter to have the following structure:
	            {
	                name: 'highlighter-name',
	                options: {
	                    some: 'value'
	                }
	            }
	        */
	        if (highlighterDef === undefined) {

	            // Is highlighting disabled?
	            if (!highlighting) { return false; }
	            // check for built-in types
	            if (type) {
	                highlighterDef = highlighting[type];
	                // Is a specific type highlight disabled?
	                if (highlighterDef === false) { return false; }
	            }
	            if (!highlighterDef) {
	                // Type not defined use default highlight
	                highlighterDef = highlighting['default'];
	            }
	        }

	        // Do nothing if opt.highlighter is falsy.
	        // This allows the case to not highlight cell(s) in certain cases.
	        // For example, if you want to NOT highlight when embedding elements
	        // or use a custom highlighter.
	        if (!highlighterDef) { return false; }

	        // Allow specifying a highlighter by name.
	        if (isString(highlighterDef)) {
	            highlighterDef = {
	                name: highlighterDef
	            };
	        }

	        var name = highlighterDef.name;
	        var highlighter = highlighterNamespace[name];

	        // Highlighter validation
	        if (!highlighter) {
	            throw new Error('Unknown highlighter ("' + name + '")');
	        }
	        if (typeof highlighter.highlight !== 'function') {
	            throw new Error('Highlighter ("' + name + '") is missing required highlight() method');
	        }
	        if (typeof highlighter.unhighlight !== 'function') {
	            throw new Error('Highlighter ("' + name + '") is missing required unhighlight() method');
	        }

	        return {
	            highlighter: highlighter,
	            options: highlighterDef.options || {},
	            name: name
	        };
	    },

	    onCellHighlight: function(cellView, magnetEl, opt) {
	        var highlighterDescriptor = this.resolveHighlighter(opt);
	        if (!highlighterDescriptor) { return; }
	        var highlighter = highlighterDescriptor.highlighter;
	        var options = highlighterDescriptor.options;
	        highlighter.highlight(cellView, magnetEl, options);
	    },

	    onCellUnhighlight: function(cellView, magnetEl, opt) {
	        var highlighterDescriptor = this.resolveHighlighter(opt);
	        if (!highlighterDescriptor) { return; }
	        var highlighter = highlighterDescriptor.highlighter;
	        var options = highlighterDescriptor.options;
	        highlighter.unhighlight(cellView, magnetEl, options);
	    },

	    // Interaction.
	    // ------------

	    pointerdblclick: function(evt) {

	        evt.preventDefault();

	        // magnetpointerdblclick can stop propagation

	        evt = normalizeEvent(evt);

	        var view = this.findView(evt.target);
	        if (this.guard(evt, view)) { return; }

	        var localPoint = this.snapToGrid(evt.clientX, evt.clientY);

	        if (view) {
	            view.pointerdblclick(evt, localPoint.x, localPoint.y);

	        } else {
	            this.trigger('blank:pointerdblclick', evt, localPoint.x, localPoint.y);
	        }
	    },

	    pointerclick: function(evt) {

	        // magnetpointerclick can stop propagation

	        var data = this.eventData(evt);
	        // Trigger event only if mouse has not moved.
	        if (data.mousemoved <= this.options.clickThreshold) {

	            evt = normalizeEvent(evt);

	            var view = this.findView(evt.target);
	            if (this.guard(evt, view)) { return; }

	            var localPoint = this.snapToGrid(evt.clientX, evt.clientY);

	            if (view) {
	                view.pointerclick(evt, localPoint.x, localPoint.y);

	            } else {
	                this.trigger('blank:pointerclick', evt, localPoint.x, localPoint.y);
	            }
	        }
	    },

	    contextmenu: function(evt) {

	        if (this.options.preventContextMenu) { evt.preventDefault(); }

	        if (this.contextMenuFired) {
	            this.contextMenuFired = false;
	            return;
	        }

	        evt = normalizeEvent(evt);

	        this.contextMenuTrigger(evt);
	    },

	    contextMenuTrigger: function(evt) {
	        var view = this.findView(evt.target);
	        if (this.guard(evt, view)) { return; }

	        var localPoint = this.snapToGrid(evt.clientX, evt.clientY);

	        if (view) {
	            view.contextmenu(evt, localPoint.x, localPoint.y);

	        } else {
	            this.trigger('blank:contextmenu', evt, localPoint.x, localPoint.y);
	        }
	    },

	    pointerdown: function(evt) {

	        evt = normalizeEvent(evt);

	        var target = evt.target;
	        var button = evt.button;
	        var view = this.findView(target);
	        var isContextMenu = (button === 2);

	        if (view) {

	            if (!isContextMenu && this.guard(evt, view)) { return; }

	            var isTargetFormNode = this.FORM_CONTROL_TAG_NAMES.includes(target.tagName);

	            if (this.options.preventDefaultViewAction && !isTargetFormNode) {
	                // If the target is a form element, we do not want to prevent the default action.
	                // For example, we want to be able to select text in a text input or
	                // to be able to click on a checkbox.
	                evt.preventDefault();
	            }

	            if (isTargetFormNode) {
	                // If the target is a form element, we do not want to start dragging the element.
	                // For example, we want to be able to select text by dragging the mouse.
	                view.preventDefaultInteraction(evt);
	            }

	            // Custom event
	            var eventEvt = this.customEventTrigger(evt, view);
	            if (eventEvt) {
	            // `onevent` could have stopped propagation
	                if (eventEvt.isPropagationStopped()) { return; }

	                evt.data = eventEvt.data;
	            }

	            // Element magnet
	            var magnetNode = target.closest('[magnet]');
	            if (magnetNode && view.el !== magnetNode && view.el.contains(magnetNode)) {
	                var magnetEvt = normalizeEvent(new $.Event(evt.originalEvent, {
	                    data: evt.data,
	                    // Originally the event listener was attached to the magnet element.
	                    currentTarget: magnetNode
	                }));
	                this.onmagnet(magnetEvt);
	                if (magnetEvt.isDefaultPrevented()) {
	                    evt.preventDefault();
	                }
	                // `onmagnet` stops propagation when `addLinkFromMagnet` is allowed
	                if (magnetEvt.isPropagationStopped()) {
	                    // `magnet:pointermove` and `magnet:pointerup` events must be fired
	                    if (isContextMenu) { return; }
	                    this.delegateDragEvents(view, magnetEvt.data);
	                    return;
	                }
	                evt.data = magnetEvt.data;
	            }
	        }

	        if (isContextMenu) {
	            this.contextMenuFired = true;
	            var contextmenuEvt = new $.Event(evt.originalEvent, { type: 'contextmenu', data: evt.data });
	            this.contextMenuTrigger(contextmenuEvt);
	        } else {
	            var localPoint = this.snapToGrid(evt.clientX, evt.clientY);
	            if (view) {
	                view.pointerdown(evt, localPoint.x, localPoint.y);
	            } else {
	                if (this.options.preventDefaultBlankAction) {
	                    evt.preventDefault();
	                }
	                this.trigger('blank:pointerdown', evt, localPoint.x, localPoint.y);
	            }

	            this.delegateDragEvents(view, evt.data);
	        }

	    },

	    pointermove: function(evt) {

	        // mouse moved counter
	        var data = this.eventData(evt);
	        if (!data.mousemoved) {
	            data.mousemoved = 0;
	            // Make sure that events like `mouseenter` and `mouseleave` are
	            // not triggered while the user is dragging a cellView.
	            this.undelegateEvents();
	            // Note: the events are undelegated after the first `pointermove` event.
	            // Not on `pointerdown` to make sure that `dbltap` is recognized.
	        }

	        var mousemoved = ++data.mousemoved;

	        if (mousemoved <= this.options.moveThreshold) { return; }

	        evt = normalizeEvent(evt);

	        var localPoint = this.snapToGrid(evt.clientX, evt.clientY);

	        var view = data.sourceView;
	        if (view) {
	            view.pointermove(evt, localPoint.x, localPoint.y);
	        } else {
	            this.trigger('blank:pointermove', evt, localPoint.x, localPoint.y);
	        }

	        this.eventData(evt, data);
	    },

	    pointerup: function(evt) {

	        this.undelegateDocumentEvents();

	        var normalizedEvt = normalizeEvent(evt);

	        var localPoint = this.snapToGrid(normalizedEvt.clientX, normalizedEvt.clientY);

	        var view = this.eventData(evt).sourceView;
	        if (view) {
	            view.pointerup(normalizedEvt, localPoint.x, localPoint.y);
	        } else {
	            this.trigger('blank:pointerup', normalizedEvt, localPoint.x, localPoint.y);
	        }

	        if (!normalizedEvt.isPropagationStopped()) {
	            this.pointerclick(new $.Event(evt.originalEvent, { type: 'click', data: evt.data }));
	        }

	        this.delegateEvents();
	    },

	    mouseover: function(evt) {

	        evt = normalizeEvent(evt);

	        var view = this.findView(evt.target);
	        if (this.guard(evt, view)) { return; }

	        if (view) {
	            view.mouseover(evt);

	        } else {
	            if (this.el === evt.target) { return; } // prevent border of paper from triggering this
	            this.trigger('blank:mouseover', evt);
	        }
	    },

	    mouseout: function(evt) {

	        evt = normalizeEvent(evt);

	        var view = this.findView(evt.target);
	        if (this.guard(evt, view)) { return; }

	        if (view) {
	            view.mouseout(evt);

	        } else {
	            if (this.el === evt.target) { return; } // prevent border of paper from triggering this
	            this.trigger('blank:mouseout', evt);
	        }
	    },

	    mouseenter: function(evt) {

	        evt = normalizeEvent(evt);

	        var target = evt.target;
	        var relatedTarget = evt.relatedTarget;
	        var currentTarget = evt.currentTarget;
	        var view = this.findView(target);
	        if (this.guard(evt, view)) { return; }
	        var relatedView = this.findView(relatedTarget);
	        if (view) {
	            if (relatedView === view) {
	                // Mouse left a cell tool
	                return;
	            }
	            view.mouseenter(evt);
	            if (this.el.contains(relatedTarget)) {
	                // The pointer remains inside the paper.
	                return;
	            }
	        }
	        if (relatedView) {
	            return;
	        }
	        // prevent double `mouseenter` event if the `relatedTarget` is outside the paper
	        // (mouseenter method would be fired twice)
	        if (currentTarget === this.el) {
	            // `paper` (more descriptive), not `blank`
	            this.trigger('paper:mouseenter', evt);
	        }
	    },

	    mouseleave: function(evt) {

	        evt = normalizeEvent(evt);

	        var target = evt.target;
	        var relatedTarget = evt.relatedTarget;
	        var currentTarget = evt.currentTarget;
	        var view = this.findView(target);
	        if (this.guard(evt, view)) { return; }
	        var relatedView = this.findView(relatedTarget);
	        if (view) {
	            if (relatedView === view) {
	                // Mouse entered a cell tool
	                return;
	            }
	            view.mouseleave(evt);
	            if (this.el.contains(relatedTarget)) {
	                // The pointer has exited a cellView. The pointer is still inside of the paper.
	                return;
	            }
	        }
	        if (relatedView) {
	            // The pointer has entered a new cellView
	            return;
	        }
	        // prevent double `mouseleave` event if the `relatedTarget` is outside the paper
	        // (mouseleave method would be fired twice)
	        if (currentTarget === this.el) {
	            // There is no cellView under the pointer, nor the blank area of the paper
	            this.trigger('paper:mouseleave', evt);
	        }
	    },

	    _processMouseWheelEvtBuf: debounce(function() {
	        var ref = this._mw_evt_buffer;
	        var event = ref.event;
	        var deltas = ref.deltas;
	        var deltaY = deltas.reduce(function (acc, deltaY) { return acc + cap(deltaY, WHEEL_CAP); }, 0);

	        var scale = Math.pow(0.995, deltaY); // 1.005 for inverted pinch/zoom
	        var ref$1 = this.clientToLocalPoint(event.clientX, event.clientY);
	        var x = ref$1.x;
	        var y = ref$1.y;
	        this.trigger('paper:pinch', event, x, y, scale);

	        this._mw_evt_buffer = {
	            event: null,
	            deltas: [],
	        };
	    }, WHEEL_WAIT_MS, { maxWait: WHEEL_WAIT_MS }),

	    mousewheel: function(evt) {

	        evt = normalizeEvent(evt);

	        var view = this.findView(evt.target);
	        if (this.guard(evt, view)) { return; }

	        var originalEvent = evt.originalEvent;
	        var localPoint = this.snapToGrid(originalEvent.clientX, originalEvent.clientY);
	        var ref = normalizeWheel(originalEvent);
	        var deltaX = ref.deltaX;
	        var deltaY = ref.deltaY;

	        var pinchHandlers = this._events['paper:pinch'];

	        // Touchpad devices will send a fake CTRL press when a pinch is performed
	        //
	        // We also check if there are any subscribers to paper:pinch event. If there are none,
	        // just skip the entire block of code (we don't want to blindly call
	        // .preventDefault() if we really don't have to).
	        if (evt.ctrlKey && pinchHandlers && pinchHandlers.length > 0) {
	            // This is a pinch gesture, it's safe to assume that we must call .preventDefault()
	            originalEvent.preventDefault();
	            this._mw_evt_buffer.event = evt;
	            this._mw_evt_buffer.deltas.push(deltaY);
	            this._processMouseWheelEvtBuf();
	        } else {
	            var delta = Math.max(-1, Math.min(1, originalEvent.wheelDelta));
	            if (view) {
	                view.mousewheel(evt, localPoint.x, localPoint.y, delta);

	            } else {
	                this.trigger('blank:mousewheel', evt, localPoint.x, localPoint.y, delta);
	            }

	            this.trigger('paper:pan', evt, deltaX, deltaY);
	        }
	    },

	    onevent: function(evt) {

	        var eventNode = evt.currentTarget;
	        var eventName = eventNode.getAttribute('event');
	        if (eventName) {
	            var view = this.findView(eventNode);
	            if (view) {

	                evt = normalizeEvent(evt);
	                if (this.guard(evt, view)) { return; }

	                var localPoint = this.snapToGrid(evt.clientX, evt.clientY);
	                view.onevent(evt, eventName, localPoint.x, localPoint.y);
	            }
	        }
	    },

	    magnetEvent: function(evt, handler) {

	        var magnetNode = evt.currentTarget;
	        var magnetValue = magnetNode.getAttribute('magnet');
	        if (magnetValue) {
	            var view = this.findView(magnetNode);
	            if (view) {
	                evt = normalizeEvent(evt);
	                if (this.guard(evt, view)) { return; }
	                var localPoint = this.snapToGrid(evt.clientX, evt.clientY);
	                handler.call(this, view, evt, magnetNode, localPoint.x, localPoint.y);
	            }
	        }
	    },

	    onmagnet: function(evt) {

	        if (evt.button === 2) {
	            this.contextMenuFired = true;
	            this.magnetContextMenuFired = true;
	            var contextmenuEvt = new $.Event(evt.originalEvent, {
	                type: 'contextmenu',
	                data: evt.data,
	                currentTarget: evt.currentTarget,
	            });
	            this.magnetContextMenuTrigger(contextmenuEvt);
	            if (contextmenuEvt.isPropagationStopped()) {
	                evt.stopPropagation();
	            }
	        } else {
	            this.magnetEvent(evt, function(view, evt, _, x, y) {
	                view.onmagnet(evt, x, y);
	            });
	        }
	    },

	    magnetpointerdblclick: function(evt) {

	        this.magnetEvent(evt, function(view, evt, magnet, x, y) {
	            view.magnetpointerdblclick(evt, magnet, x, y);
	        });
	    },

	    magnetcontextmenu: function(evt) {
	        if (this.options.preventContextMenu) { evt.preventDefault(); }

	        if (this.magnetContextMenuFired) {
	            this.magnetContextMenuFired = false;
	            return;
	        }

	        this.magnetContextMenuTrigger(evt);
	    },

	    magnetContextMenuTrigger: function(evt) {
	        this.magnetEvent(evt, function(view, evt, magnet, x, y) {
	            view.magnetcontextmenu(evt, magnet, x, y);
	        });
	    },

	    onlabel: function(evt) {

	        var labelNode = evt.currentTarget;

	        var view = this.findView(labelNode);
	        if (!view) { return; }

	        evt = normalizeEvent(evt);
	        if (this.guard(evt, view)) { return; }

	        // Custom event
	        var eventEvt = this.customEventTrigger(evt, view, labelNode);
	        if (eventEvt) {
	            // `onevent` could have stopped propagation
	            if (eventEvt.isPropagationStopped()) { return; }

	            evt.data = eventEvt.data;
	        }

	        var localPoint = this.snapToGrid(evt.clientX, evt.clientY);
	        view.onlabel(evt, localPoint.x, localPoint.y);
	    },

	    getPointerArgs: function getPointerArgs(evt) {
	        var normalizedEvt = normalizeEvent(evt);
	        var ref = this.snapToGrid(normalizedEvt.clientX, normalizedEvt.clientY);
	        var x = ref.x;
	        var y = ref.y;
	        return [normalizedEvt, x, y];
	    },

	    delegateDragEvents: function(view, data) {

	        data || (data = {});
	        this.eventData({ data: data }, { sourceView: view || null, mousemoved: 0 });
	        this.delegateDocumentEvents(null, data);
	    },

	    // Guard the specified event. If the event should be ignored, guard returns `true`.
	    // Otherwise, it returns `false`.
	    guard: function(evt, view) {

	        if (evt.type === 'mousedown' && evt.button === 2) {
	            // handled as `contextmenu` type
	            return true;
	        }

	        if (this.options.guard && this.options.guard(evt, view)) {
	            return true;
	        }

	        if (evt.data && evt.data.guarded !== undefined) {
	            return evt.data.guarded;
	        }

	        var target = evt.target;

	        if (this.GUARDED_TAG_NAMES.includes(target.tagName)) {
	            return true;
	        }

	        if (view && view.model && (view.model instanceof Cell)) {
	            return false;
	        }

	        if (this.el === target || this.svg.contains(target)) {
	            return false;
	        }

	        return true;    // Event guarded. Paper should not react on it in any way.
	    },

	    setGridSize: function(gridSize) {
	        var ref = this;
	        var options = ref.options;
	        options.gridSize = gridSize;
	        if (options.drawGrid && !options.drawGridSize) {
	            // Do not redraw the grid if the `drawGridSize` is set.
	            this.getLayerView(LayersNames.GRID).renderGrid();
	        }
	        return this;
	    },

	    setGrid: function(drawGrid) {
	        this.getLayerView(LayersNames.GRID).setGrid(drawGrid);
	        return this;
	    },

	    updateBackgroundImage: function(opt) {

	        opt = opt || {};

	        var backgroundPosition = opt.position || 'center';
	        var backgroundSize = opt.size || 'auto auto';

	        var currentScale = this.scale();
	        var currentTranslate = this.translate();

	        // backgroundPosition
	        if (isObject$1(backgroundPosition)) {
	            var x = currentTranslate.tx + (currentScale.sx * (backgroundPosition.x || 0));
	            var y = currentTranslate.ty + (currentScale.sy * (backgroundPosition.y || 0));
	            backgroundPosition = x + 'px ' + y + 'px';
	        }

	        // backgroundSize
	        if (isObject$1(backgroundSize)) {
	            backgroundSize = new Rect(backgroundSize).scale(currentScale.sx, currentScale.sy);
	            backgroundSize = backgroundSize.width + 'px ' + backgroundSize.height + 'px';
	        }

	        var ref = this.childNodes;
	        var background = ref.background;
	        background.style.backgroundSize = backgroundSize;
	        background.style.backgroundPosition = backgroundPosition;
	    },

	    drawBackgroundImage: function(img, opt) {

	        // Clear the background image if no image provided
	        if (!(img instanceof HTMLImageElement)) {
	            this.childNodes.background.style.backgroundImage = '';
	            return;
	        }

	        if (!this._background || this._background.id !== opt.id) {
	            // Draw only the last image requested (see drawBackground())
	            return;
	        }

	        opt = opt || {};

	        var backgroundImage;
	        var backgroundSize = opt.size;
	        var backgroundRepeat = opt.repeat || 'no-repeat';
	        var backgroundOpacity = opt.opacity || 1;
	        var backgroundQuality = Math.abs(opt.quality) || 1;
	        var backgroundPattern = this.constructor.backgroundPatterns[camelCase(backgroundRepeat)];

	        if (isFunction(backgroundPattern)) {
	            // 'flip-x', 'flip-y', 'flip-xy', 'watermark' and custom
	            img.width *= backgroundQuality;
	            img.height *= backgroundQuality;
	            var canvas = backgroundPattern(img, opt);
	            if (!(canvas instanceof HTMLCanvasElement)) {
	                throw new Error('dia.Paper: background pattern must return an HTML Canvas instance');
	            }

	            backgroundImage = canvas.toDataURL('image/png');
	            backgroundRepeat = 'repeat';
	            if (isObject$1(backgroundSize)) {
	                // recalculate the tile size if an object passed in
	                backgroundSize.width *= canvas.width / img.width;
	                backgroundSize.height *= canvas.height / img.height;
	            } else if (backgroundSize === undefined) {
	                // calculate the tile size if no provided
	                opt.size = {
	                    width: canvas.width / backgroundQuality,
	                    height: canvas.height / backgroundQuality
	                };
	            }
	        } else {
	            // backgroundRepeat:
	            // no-repeat', 'round', 'space', 'repeat', 'repeat-x', 'repeat-y'
	            backgroundImage = img.src;
	            if (backgroundSize === undefined) {
	                // pass the image size for  the backgroundSize if no size provided
	                opt.size = {
	                    width: img.width,
	                    height: img.height
	                };
	            }
	        }

	        this.childNodes.background.style.opacity = backgroundOpacity;
	        this.childNodes.background.style.backgroundRepeat = backgroundRepeat;
	        this.childNodes.background.style.backgroundImage = "url(" + backgroundImage + ")";

	        this.updateBackgroundImage(opt);
	    },

	    updateBackgroundColor: function(color) {

	        this.$el.css('backgroundColor', color || '');
	    },

	    drawBackground: function(opt) {

	        opt = opt || {};

	        this.updateBackgroundColor(opt.color);

	        if (opt.image) {
	            opt = this._background = cloneDeep(opt);
	            guid(opt);
	            var img = document.createElement('img');
	            img.onload = this.drawBackgroundImage.bind(this, img, opt);
	            img.src = opt.image;
	        } else {
	            this.drawBackgroundImage(null);
	            this._background = null;
	        }

	        return this;
	    },

	    setInteractivity: function(value) {

	        this.options.interactive = value;

	        invoke(this._views, 'setInteractivity', value);
	    },

	    // Paper definitions.
	    // ------------------

	    isDefined: function(defId) {

	        return !!this.svg.getElementById(defId);
	    },

	    defineFilter: function(filter$1) {

	        if (!isObject$1(filter$1)) {
	            throw new TypeError('dia.Paper: defineFilter() requires 1. argument to be an object.');
	        }

	        var filterId = filter$1.id;
	        var name = filter$1.name;
	        // Generate a hash code from the stringified filter definition. This gives us
	        // a unique filter ID for different definitions.
	        if (!filterId) {
	            filterId = name + this.svg.id + hashCode(JSON.stringify(filter$1));
	        }
	        // If the filter already exists in the document,
	        // we're done and we can just use it (reference it using `url()`).
	        // If not, create one.
	        if (!this.isDefined(filterId)) {

	            var namespace = filter;
	            var filterSVGString = namespace[name] && namespace[name](filter$1.args || {});
	            if (!filterSVGString) {
	                throw new Error('Non-existing filter ' + name);
	            }

	            // SVG <filter/> attributes
	            var filterAttrs = assign({
	                filterUnits: 'userSpaceOnUse',
	            }, filter$1.attrs, {
	                id: filterId
	            });

	            V(filterSVGString, filterAttrs).appendTo(this.defs);
	        }

	        return filterId;
	    },

	    defineGradient: function(gradient) {
	        if (!isObject$1(gradient)) {
	            throw new TypeError('dia.Paper: defineGradient() requires 1. argument to be an object.');
	        }
	        var ref = this;
	        var svg = ref.svg;
	        var defs = ref.defs;
	        var type = gradient.type;
	        var id = gradient.id; if ( id === void 0 ) id = type + svg.id + hashCode(JSON.stringify(gradient));
	        var stops = gradient.stops;
	        var attrs = gradient.attrs; if ( attrs === void 0 ) attrs = {};
	        // If the gradient already exists in the document,
	        // we're done and we can just use it (reference it using `url()`).
	        if (this.isDefined(id)) { return id; }
	        // If not, create one.
	        var stopVEls = toArray(stops).map(function (ref) {
	            var offset = ref.offset;
	            var color = ref.color;
	            var opacity = ref.opacity;

	            return V('stop').attr({
	                'offset': offset,
	                'stop-color': color,
	                'stop-opacity': Number.isFinite(opacity) ? opacity : 1
	            });
	        });
	        var gradientVEl = V(type, attrs, stopVEls);
	        gradientVEl.id = id;
	        gradientVEl.appendTo(defs);
	        return id;
	    },

	    definePattern: function(pattern) {
	        if (!isObject$1(pattern)) {
	            throw new TypeError('dia.Paper: definePattern() requires 1. argument to be an object.');
	        }
	        var ref = this;
	        var svg = ref.svg;
	        var defs = ref.defs;
	        var id = pattern.id; if ( id === void 0 ) id = svg.id + hashCode(JSON.stringify(pattern));
	        var markup = pattern.markup;
	        var attrs = pattern.attrs; if ( attrs === void 0 ) attrs = {};
	        if (!markup) {
	            throw new TypeError('dia.Paper: definePattern() requires markup.');
	        }
	        // If the gradient already exists in the document,
	        // we're done and we can just use it (reference it using `url()`).
	        if (this.isDefined(id)) { return id; }
	        // If not, create one.
	        var patternVEl = V('pattern', {
	            patternUnits: 'userSpaceOnUse'
	        });
	        patternVEl.id = id;
	        patternVEl.attr(attrs);
	        if (typeof markup === 'string') {
	            patternVEl.append(V(markup));
	        } else {
	            var ref$1 = parseDOMJSON(markup);
	            var fragment = ref$1.fragment;
	            patternVEl.append(fragment);
	        }
	        patternVEl.appendTo(defs);
	        return id;
	    },

	    defineMarker: function(marker) {
	        if (!isObject$1(marker)) {
	            throw new TypeError('dia.Paper: defineMarker() requires the first argument to be an object.');
	        }
	        var ref = this;
	        var svg = ref.svg;
	        var defs = ref.defs;
	        var id = marker.id; if ( id === void 0 ) id = svg.id + hashCode(JSON.stringify(marker));
	        var markup = marker.markup;
	        var attrs = marker.attrs; if ( attrs === void 0 ) attrs = {};
	        var markerUnits = marker.markerUnits; if ( markerUnits === void 0 ) markerUnits = 'userSpaceOnUse';
	        // If the marker already exists in the document,
	        // we're done and we can just use it (reference it using `url()`).
	        if (this.isDefined(id)) { return id; }
	        // If not, create one.
	        var markerVEl = V('marker', {
	            orient: 'auto',
	            overflow: 'visible',
	            markerUnits: markerUnits
	        });
	        markerVEl.id = id;
	        markerVEl.attr(attrs);
	        var markerContentVEl;
	        if (markup) {
	            var markupVEl;
	            if (typeof markup === 'string') {
	                // Marker object has a `markup` property of type string.
	                // - Construct V from the provided string.
	                markupVEl = V(markup);
	                // `markupVEl` is now either a single VEl, or an array of VEls.
	                // - Coerce it to an array.
	                markupVEl = (Array.isArray(markupVEl) ? markupVEl : [markupVEl]);
	            } else {
	                // Marker object has a `markup` property of type object.
	                // - Construct V from the object by parsing it as DOM JSON.
	                var ref$1 = parseDOMJSON(markup);
	                var fragment = ref$1.fragment;
	                markupVEl = V(fragment).children();
	            }
	            // `markupVEl` is an array with one or more VEls inside.
	            // - If there are multiple VEls, wrap them in a newly-constructed <g> element
	            if (markupVEl.length > 1) {
	                markerContentVEl = V('g').append(markupVEl);
	            } else {
	                markerContentVEl = markupVEl[0];
	            }
	        } else {
	            // Marker object is a flat structure.
	            // - Construct a new V of type `marker.type`.
	            var type = marker.type; if ( type === void 0 ) type = 'path';
	            markerContentVEl = V(type);
	        }
	        // `markerContentVEl` is a single VEl.
	        // Assign additional attributes to it (= context attributes + marker attributes):
	        // - Attribute values are taken from non-special properties of `marker`.
	        var markerAttrs = omit(marker, 'type', 'id', 'markup', 'attrs', 'markerUnits');
	        var markerAttrsKeys = Object.keys(markerAttrs);
	        markerAttrsKeys.forEach(function (key) {
	            var value = markerAttrs[key];
	            var markupValue = markerContentVEl.attr(key); // value coming from markupVEl (if any) = higher priority
	            if (markupValue == null) {
	                // Default logic:
	                markerContentVEl.attr(key, value);
	            } else {
	                // Properties with special logic should be added as cases to this switch block:
	                switch(key) {
	                    case 'transform':
	                        // - Prepend `transform` to existing value.
	                        markerContentVEl.attr(key, (value + ' ' + markupValue));
	                        break;
	                }
	            }
	        });
	        markerContentVEl.appendTo(markerVEl);
	        markerVEl.appendTo(defs);
	        return id;
	    },

	    customEventTrigger: function(evt, view, rootNode) {
	        if ( rootNode === void 0 ) rootNode = view.el;


	        var eventNode = evt.target.closest('[event]');

	        if (eventNode && rootNode !== eventNode && view.el.contains(eventNode)) {
	            var eventEvt = normalizeEvent(new $.Event(evt.originalEvent, {
	                data: evt.data,
	                // Originally the event listener was attached to the event element.
	                currentTarget: eventNode
	            }));

	            this.onevent(eventEvt);

	            if (eventEvt.isDefaultPrevented()) {
	                evt.preventDefault();
	            }

	            return eventEvt;
	        }

	        return null;
	    }

	}, {

	    sorting: sortingTypes,

	    Layers: LayersNames,

	    backgroundPatterns: {

	        flipXy: function(img) {
	            // d b
	            // q p

	            var canvas = document.createElement('canvas');
	            var imgWidth = img.width;
	            var imgHeight = img.height;

	            canvas.width = 2 * imgWidth;
	            canvas.height = 2 * imgHeight;

	            var ctx = canvas.getContext('2d');
	            // top-left image
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);
	            // xy-flipped bottom-right image
	            ctx.setTransform(-1, 0, 0, -1, canvas.width, canvas.height);
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);
	            // x-flipped top-right image
	            ctx.setTransform(-1, 0, 0, 1, canvas.width, 0);
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);
	            // y-flipped bottom-left image
	            ctx.setTransform(1, 0, 0, -1, 0, canvas.height);
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);

	            return canvas;
	        },

	        flipX: function(img) {
	            // d b
	            // d b

	            var canvas = document.createElement('canvas');
	            var imgWidth = img.width;
	            var imgHeight = img.height;

	            canvas.width = imgWidth * 2;
	            canvas.height = imgHeight;

	            var ctx = canvas.getContext('2d');
	            // left image
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);
	            // flipped right image
	            ctx.translate(2 * imgWidth, 0);
	            ctx.scale(-1, 1);
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);

	            return canvas;
	        },

	        flipY: function(img) {
	            // d d
	            // q q

	            var canvas = document.createElement('canvas');
	            var imgWidth = img.width;
	            var imgHeight = img.height;

	            canvas.width = imgWidth;
	            canvas.height = imgHeight * 2;

	            var ctx = canvas.getContext('2d');
	            // top image
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);
	            // flipped bottom image
	            ctx.translate(0, 2 * imgHeight);
	            ctx.scale(1, -1);
	            ctx.drawImage(img, 0, 0, imgWidth, imgHeight);

	            return canvas;
	        },

	        watermark: function(img, opt) {
	            //   d
	            // d

	            opt = opt || {};

	            var imgWidth = img.width;
	            var imgHeight = img.height;

	            var canvas = document.createElement('canvas');
	            canvas.width = imgWidth * 3;
	            canvas.height = imgHeight * 3;

	            var ctx = canvas.getContext('2d');
	            var angle = isNumber(opt.watermarkAngle) ? -opt.watermarkAngle : -20;
	            var radians = toRad(angle);
	            var stepX = canvas.width / 4;
	            var stepY = canvas.height / 4;

	            for (var i = 0; i < 4; i++) {
	                for (var j = 0; j < 4; j++) {
	                    if ((i + j) % 2 > 0) {
	                        // reset the current transformations
	                        ctx.setTransform(1, 0, 0, 1, (2 * i - 1) * stepX, (2 * j - 1) * stepY);
	                        ctx.rotate(radians);
	                        ctx.drawImage(img, -imgWidth / 2, -imgHeight / 2, imgWidth, imgHeight);
	                    }
	                }
	            }

	            return canvas;
	        }
	    },

	    gridPatterns: {
	        dot: [{
	            color: '#AAAAAA',
	            thickness: 1,
	            markup: 'rect',
	            render: function(el, opt) {
	                V(el).attr({
	                    width: opt.thickness,
	                    height: opt.thickness,
	                    fill: opt.color
	                });
	            }
	        }],
	        fixedDot: [{
	            color: '#AAAAAA',
	            thickness: 1,
	            markup: 'rect',
	            render: function(el, opt) {
	                V(el).attr({ fill: opt.color });
	            },
	            update: function(el, opt, paper) {
	                var ref = paper.scale();
	                var sx = ref.sx;
	                var sy = ref.sy;
	                var width = sx <= 1 ? opt.thickness : opt.thickness / sx;
	                var height = sy <= 1 ? opt.thickness : opt.thickness / sy;
	                V(el).attr({ width: width, height: height });
	            }
	        }],
	        mesh: [{
	            color: '#AAAAAA',
	            thickness: 1,
	            markup: 'path',
	            render: function(el, opt) {

	                var d;
	                var width = opt.width;
	                var height = opt.height;
	                var thickness = opt.thickness;

	                if (width - thickness >= 0 && height - thickness >= 0) {
	                    d = ['M', width, 0, 'H0 M0 0 V0', height].join(' ');
	                } else {
	                    d = 'M 0 0 0 0';
	                }

	                V(el).attr({ 'd': d, stroke: opt.color, 'stroke-width': opt.thickness });
	            }
	        }],
	        doubleMesh: [{
	            color: '#AAAAAA',
	            thickness: 1,
	            markup: 'path',
	            render: function(el, opt) {

	                var d;
	                var width = opt.width;
	                var height = opt.height;
	                var thickness = opt.thickness;

	                if (width - thickness >= 0 && height - thickness >= 0) {
	                    d = ['M', width, 0, 'H0 M0 0 V0', height].join(' ');
	                } else {
	                    d = 'M 0 0 0 0';
	                }

	                V(el).attr({ 'd': d, stroke: opt.color, 'stroke-width': opt.thickness });
	            }
	        }, {
	            color: '#000000',
	            thickness: 3,
	            scaleFactor: 4,
	            markup: 'path',
	            render: function(el, opt) {

	                var d;
	                var width = opt.width;
	                var height = opt.height;
	                var thickness = opt.thickness;

	                if (width - thickness >= 0 && height - thickness >= 0) {
	                    d = ['M', width, 0, 'H0 M0 0 V0', height].join(' ');
	                } else {
	                    d = 'M 0 0 0 0';
	                }

	                V(el).attr({ 'd': d, stroke: opt.color, 'stroke-width': opt.thickness });
	            }
	        }]
	    }
	});

	var ToolView = View.extend({
	    name: null,
	    tagName: 'g',
	    className: 'tool',
	    svgElement: true,
	    _visible: true,

	    init: function() {
	        var name = this.name;
	        if (name) { this.vel.attr('data-tool-name', name); }
	    },

	    configure: function(view, toolsView) {
	        this.relatedView = view;
	        this.paper = view.paper;
	        this.parentView = toolsView;
	        this.simulateRelatedView(this.el);
	        // Delegate events in case the ToolView was removed from the DOM and reused.
	        this.delegateEvents();
	        return this;
	    },

	    simulateRelatedView: function(el) {
	        if (el) { el.setAttribute('model-id', this.relatedView.model.id); }
	    },

	    getName: function() {
	        return this.name;
	    },

	    show: function() {
	        this.el.style.display = '';
	        this._visible = true;
	    },

	    hide: function() {
	        this.el.style.display = 'none';
	        this._visible = false;
	    },

	    isVisible: function() {
	        return !!this._visible;
	    },

	    focus: function() {
	        var opacity = this.options.focusOpacity;
	        if (isFinite(opacity)) { this.el.style.opacity = opacity; }
	        this.parentView.focusTool(this);
	    },

	    blur: function() {
	        this.el.style.opacity = '';
	        this.parentView.blurTool(this);
	    },

	    update: function() {
	        // to be overridden
	    },

	    guard: function(evt) {
	        // Let the context-menu event bubble up to the relatedView
	        var ref = this;
	        var paper = ref.paper;
	        var relatedView = ref.relatedView;
	        if (!paper || !relatedView) { return true; }
	        return paper.guard(evt, relatedView);
	    }
	});

	var ToolsView = View.extend({
	    tagName: 'g',
	    className: 'tools',
	    svgElement: true,
	    tools: null,
	    isRendered: false,
	    options: {
	        tools: null,
	        relatedView: null,
	        name: null,
	        // layer?: LayersNames.TOOLS
	        // z?: number
	    },

	    configure: function(options) {
	        options = assign(this.options, options);
	        var tools = options.tools;
	        if (!Array.isArray(tools)) { return this; }
	        var relatedView = options.relatedView;
	        if (!(relatedView instanceof CellView)) { return this; }
	        var views = this.tools = [];
	        for (var i = 0, n = tools.length; i < n; i++) {
	            var tool = tools[i];
	            if (!(tool instanceof ToolView)) { continue; }
	            tool.configure(relatedView, this);
	            this.vel.append(tool.el);
	            views.push(tool);
	        }
	        this.isRendered = false;
	        relatedView.requestUpdate(relatedView.getFlag('TOOLS'));
	        return this;
	    },

	    getName: function() {
	        return this.options.name;
	    },

	    update: function(opt) {

	        opt || (opt = {});
	        var tools = this.tools;
	        if (!tools) { return this; }
	        var isRendered = this.isRendered;
	        for (var i = 0, n = tools.length; i < n; i++) {
	            var tool = tools[i];
	            if (!isRendered) {
	                // First update executes render()
	                tool.render();
	            } else if (opt.tool !== tool.cid && tool.isVisible()) {
	                tool.update();
	            }
	        }
	        if (!this.isMounted()) {
	            this.mount();
	        }
	        if (!isRendered) {
	            // Make sure tools are visible (if they were hidden and the tool removed)
	            this.blurTool();
	            this.isRendered = true;
	        }
	        return this;
	    },

	    focusTool: function(focusedTool) {

	        var tools = this.tools;
	        if (!tools) { return this; }
	        for (var i = 0, n = tools.length; i < n; i++) {
	            var tool = tools[i];
	            if (focusedTool === tool) {
	                tool.show();
	            } else {
	                tool.hide();
	            }
	        }
	        return this;
	    },

	    blurTool: function(blurredTool) {
	        var tools = this.tools;
	        if (!tools) { return this; }
	        for (var i = 0, n = tools.length; i < n; i++) {
	            var tool = tools[i];
	            if (tool !== blurredTool && !tool.isVisible()) {
	                tool.show();
	                tool.update();
	            }
	        }
	        return this;
	    },

	    hide: function() {
	        return this.focusTool(null);
	    },

	    show: function() {
	        return this.blurTool(null);
	    },

	    onRemove: function() {
	        var tools = this.tools;
	        if (!tools) { return this; }
	        for (var i = 0, n = tools.length; i < n; i++) {
	            tools[i].remove();
	        }
	        this.tools = null;
	    },

	    mount: function() {
	        var ref = this;
	        var options = ref.options;
	        var el = ref.el;
	        var relatedView = options.relatedView;
	        var layer = options.layer; if ( layer === void 0 ) layer = LayersNames.TOOLS;
	        var z = options.z;
	        if (relatedView) {
	            if (layer) {
	                relatedView.paper.getLayerView(layer).insertSortedNode(el, z);
	            } else {
	                relatedView.el.appendChild(el);
	            }
	        }
	        return this;
	    }

	});



	var index$4 = ({
		Graph: Graph,
		attributes: attributes,
		LayersNames: LayersNames,
		PaperLayer: PaperLayer,
		Cell: Cell,
		CellView: CellView,
		Element: Element$1,
		ElementView: ElementView,
		Link: Link,
		LinkView: LinkView,
		Paper: Paper,
		ToolView: ToolView,
		ToolsView: ToolsView,
		HighlighterView: HighlighterView
	});

	// Vertex Handles
	var VertexHandle = View.extend({
	    tagName: 'circle',
	    svgElement: true,
	    className: 'marker-vertex',
	    events: {
	        mousedown: 'onPointerDown',
	        touchstart: 'onPointerDown',
	        dblclick: 'onDoubleClick',
	        dbltap: 'onDoubleClick'
	    },
	    documentEvents: {
	        mousemove: 'onPointerMove',
	        touchmove: 'onPointerMove',
	        mouseup: 'onPointerUp',
	        touchend: 'onPointerUp',
	        touchcancel: 'onPointerUp'
	    },
	    attributes: {
	        'r': 6,
	        'fill': '#33334F',
	        'stroke': '#FFFFFF',
	        'stroke-width': 2,
	        'cursor': 'move'
	    },
	    position: function(x, y) {
	        var ref = this;
	        var vel = ref.vel;
	        var options = ref.options;
	        var scale = options.scale;
	        var matrix = V.createSVGMatrix().translate(x, y);
	        if (scale) { matrix = matrix.scale(scale); }
	        vel.transform(matrix, { absolute: true });
	    },
	    onPointerDown: function(evt) {
	        if (this.options.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        this.options.paper.undelegateEvents();
	        this.delegateDocumentEvents(null, evt.data);
	        this.trigger('will-change', this, evt);
	    },
	    onPointerMove: function(evt) {
	        this.trigger('changing', this, evt);
	    },
	    onDoubleClick: function(evt) {
	        this.trigger('remove', this, evt);
	    },
	    onPointerUp: function(evt) {
	        this.trigger('changed', this, evt);
	        this.undelegateDocumentEvents();
	        this.options.paper.delegateEvents();
	    }
	});

	var Vertices = ToolView.extend({
	    name: 'vertices',
	    options: {
	        handleClass: VertexHandle,
	        snapRadius: 20,
	        redundancyRemoval: true,
	        vertexAdding: true,
	        stopPropagation: true,
	        scale: null
	    },
	    children: [{
	        tagName: 'path',
	        selector: 'connection',
	        className: 'joint-vertices-path',
	        attributes: {
	            'fill': 'none',
	            'stroke': 'transparent',
	            'stroke-width': 10,
	            'cursor': 'cell'
	        }
	    }],
	    handles: null,
	    events: {
	        'mousedown .joint-vertices-path': 'onPathPointerDown',
	        'touchstart .joint-vertices-path': 'onPathPointerDown'
	    },
	    onRender: function() {
	        if (this.options.vertexAdding) {
	            this.renderChildren();
	            this.updatePath();
	        }
	        this.resetHandles();
	        this.renderHandles();
	        return this;
	    },
	    update: function() {
	        var relatedView = this.relatedView;
	        var vertices = relatedView.model.vertices();
	        if (vertices.length === this.handles.length) {
	            this.updateHandles();
	        } else {
	            this.resetHandles();
	            this.renderHandles();
	        }
	        if (this.options.vertexAdding) {
	            this.updatePath();
	        }
	        return this;
	    },
	    resetHandles: function() {
	        var handles = this.handles;
	        this.handles = [];
	        this.stopListening();
	        if (!Array.isArray(handles)) { return; }
	        for (var i = 0, n = handles.length; i < n; i++) {
	            handles[i].remove();
	        }
	    },
	    renderHandles: function() {
	        var this$1 = this;

	        var relatedView = this.relatedView;
	        var vertices = relatedView.model.vertices();
	        for (var i = 0, n = vertices.length; i < n; i++) {
	            var vertex = vertices[i];
	            var handle = new (this.options.handleClass)({
	                index: i,
	                paper: this.paper,
	                scale: this.options.scale,
	                guard: function (evt) { return this$1.guard(evt); }
	            });
	            handle.render();
	            handle.position(vertex.x, vertex.y);
	            this.simulateRelatedView(handle.el);
	            handle.vel.appendTo(this.el);
	            this.handles.push(handle);
	            this.startHandleListening(handle);
	        }
	    },
	    updateHandles: function() {
	        var relatedView = this.relatedView;
	        var vertices = relatedView.model.vertices();
	        for (var i = 0, n = vertices.length; i < n; i++) {
	            var vertex = vertices[i];
	            var handle = this.handles[i];
	            if (!handle) { return; }
	            handle.position(vertex.x, vertex.y);
	        }
	    },
	    updatePath: function() {
	        var connection = this.childNodes.connection;
	        if (connection) { connection.setAttribute('d', this.relatedView.getSerializedConnection()); }
	    },
	    startHandleListening: function(handle) {
	        var ref = this.options;
	        var vertexRemoving = ref.vertexRemoving; if ( vertexRemoving === void 0 ) vertexRemoving = true;
	        var vertexMoving = ref.vertexMoving; if ( vertexMoving === void 0 ) vertexMoving = true;
	        if (vertexMoving) {
	            this.listenTo(handle, 'will-change', this.onHandleWillChange);
	            this.listenTo(handle, 'changing', this.onHandleChanging);
	            this.listenTo(handle, 'changed', this.onHandleChanged);
	        }
	        if (vertexRemoving) {
	            this.listenTo(handle, 'remove', this.onHandleRemove);
	        }
	    },
	    getNeighborPoints: function(index) {
	        var linkView = this.relatedView;
	        var vertices = linkView.model.vertices();
	        var prev = (index > 0) ? vertices[index - 1] : linkView.sourceAnchor;
	        var next = (index < vertices.length - 1) ? vertices[index + 1] : linkView.targetAnchor;
	        return {
	            prev: new Point(prev),
	            next: new Point(next)
	        };
	    },
	    onHandleWillChange: function(_handle, evt) {
	        this.focus();
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var options = ref.options;
	        relatedView.model.startBatch('vertex-move', { ui: true, tool: this.cid });
	        if (!options.stopPropagation) { relatedView.notifyPointerdown.apply(relatedView, relatedView.paper.getPointerArgs(evt)); }
	    },
	    onHandleChanging: function(handle, evt) {
	        var ref = this;
	        var options = ref.options;
	        var linkView = ref.relatedView;
	        var index = handle.options.index;
	        var ref$1 = linkView.paper.getPointerArgs(evt);
	        var normalizedEvent = ref$1[0];
	        var x = ref$1[1];
	        var y = ref$1[2];
	        var vertex = { x: x, y: y };
	        this.snapVertex(vertex, index);
	        linkView.model.vertex(index, vertex, { ui: true, tool: this.cid });
	        handle.position(vertex.x, vertex.y);
	        if (!options.stopPropagation) { linkView.notifyPointermove(normalizedEvent, x, y); }
	    },
	    onHandleChanged: function(_handle, evt) {
	        var ref = this;
	        var options = ref.options;
	        var linkView = ref.relatedView;
	        if (options.vertexAdding) { this.updatePath(); }
	        if (!options.redundancyRemoval) {
	            linkView.checkMouseleave(normalizeEvent(evt));
	            return;
	        }
	        var verticesRemoved = linkView.removeRedundantLinearVertices({ ui: true, tool: this.cid });
	        if (verticesRemoved) { this.render(); }
	        this.blur();
	        linkView.model.stopBatch('vertex-move', { ui: true, tool: this.cid });
	        if (this.eventData(evt).vertexAdded) {
	            linkView.model.stopBatch('vertex-add', { ui: true, tool: this.cid });
	        }
	        var ref$1 = linkView.paper.getPointerArgs(evt);
	        var normalizedEvt = ref$1[0];
	        var x = ref$1[1];
	        var y = ref$1[2];
	        if (!options.stopPropagation) { linkView.notifyPointerup(normalizedEvt, x, y); }
	        linkView.checkMouseleave(normalizedEvt);
	    },
	    snapVertex: function(vertex, index) {
	        var snapRadius = this.options.snapRadius;
	        if (snapRadius > 0) {
	            var neighbors = this.getNeighborPoints(index);
	            var prev = neighbors.prev;
	            var next = neighbors.next;
	            if (Math.abs(vertex.x - prev.x) < snapRadius) {
	                vertex.x = prev.x;
	            } else if (Math.abs(vertex.x - next.x) < snapRadius) {
	                vertex.x = next.x;
	            }
	            if (Math.abs(vertex.y - prev.y) < snapRadius) {
	                vertex.y = neighbors.prev.y;
	            } else if (Math.abs(vertex.y - next.y) < snapRadius) {
	                vertex.y = next.y;
	            }
	        }
	    },
	    onHandleRemove: function(handle, evt) {
	        var index$1 = handle.options.index;
	        var linkView = this.relatedView;
	        linkView.model.removeVertex(index$1, { ui: true });
	        if (this.options.vertexAdding) { this.updatePath(); }
	        linkView.checkMouseleave(normalizeEvent(evt));
	    },
	    onPathPointerDown: function(evt) {
	        if (this.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        var normalizedEvent = normalizeEvent(evt);
	        var vertex = this.paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY).toJSON();
	        var relatedView = this.relatedView;
	        relatedView.model.startBatch('vertex-add', { ui: true, tool: this.cid });
	        var index$1 = relatedView.getVertexIndex(vertex.x, vertex.y);
	        this.snapVertex(vertex, index$1);
	        relatedView.model.insertVertex(index$1, vertex, { ui: true, tool: this.cid });
	        this.update();
	        var handle = this.handles[index$1];
	        this.eventData(normalizedEvent, { vertexAdded: true });
	        handle.onPointerDown(normalizedEvent);
	    },
	    onRemove: function() {
	        this.resetHandles();
	    }
	}, {
	    VertexHandle: VertexHandle // keep as class property
	});

	function getViewBBox(view, useModelGeometry) {
	    var model = view.model;
	    if (useModelGeometry) { return model.getBBox(); }
	    return (model.isLink()) ? view.getConnection().bbox() : view.getNodeUnrotatedBBox(view.el);
	}

	function getAnchor(coords, view, magnet) {
	    // take advantage of an existing logic inside of the
	    // pin relative connection strategy
	    var end = pinRelative.call(
	        this.paper,
	        {},
	        view,
	        magnet,
	        coords,
	        this.model
	    );
	    return end.anchor;
	}

	function snapAnchor(coords, view, magnet, type, relatedView, toolView) {
	    var snapRadius = toolView.options.snapRadius;
	    var isSource = (type === 'source');
	    var refIndex = (isSource ? 0 : -1);
	    var ref = this.model.vertex(refIndex) || this.getEndAnchor(isSource ? 'target' : 'source');
	    if (ref) {
	        if (Math.abs(ref.x - coords.x) < snapRadius) { coords.x = ref.x; }
	        if (Math.abs(ref.y - coords.y) < snapRadius) { coords.y = ref.y; }
	    }
	    return coords;
	}

	var SegmentHandle = View.extend({
	    tagName: 'g',
	    svgElement: true,
	    className: 'marker-segment',
	    events: {
	        mousedown: 'onPointerDown',
	        touchstart: 'onPointerDown'
	    },
	    documentEvents: {
	        mousemove: 'onPointerMove',
	        touchmove: 'onPointerMove',
	        mouseup: 'onPointerUp',
	        touchend: 'onPointerUp',
	        touchcancel: 'onPointerUp'
	    },
	    children: [{
	        tagName: 'line',
	        selector: 'line',
	        attributes: {
	            'stroke': '#33334F',
	            'stroke-width': 2,
	            'fill': 'none',
	            'pointer-events': 'none'
	        }
	    }, {
	        tagName: 'rect',
	        selector: 'handle',
	        attributes: {
	            'width': 20,
	            'height': 8,
	            'x': -10,
	            'y': -4,
	            'rx': 4,
	            'ry': 4,
	            'fill': '#33334F',
	            'stroke': '#FFFFFF',
	            'stroke-width': 2
	        }
	    }],
	    onRender: function() {
	        this.renderChildren();
	    },
	    position: function(x, y, angle, view) {
	        var ref = this.options;
	        var scale = ref.scale;
	        var matrix = V.createSVGMatrix().translate(x, y).rotate(angle);
	        if (scale) { matrix = matrix.scale(scale); }

	        var handle = this.childNodes.handle;
	        handle.setAttribute('transform', V.matrixToTransformString(matrix));
	        handle.setAttribute('cursor', (angle % 180 === 0) ? 'row-resize' : 'col-resize');

	        var viewPoint = view.getClosestPoint(new Point(x, y));
	        var line = this.childNodes.line;
	        line.setAttribute('x1', x);
	        line.setAttribute('y1', y);
	        line.setAttribute('x2', viewPoint.x);
	        line.setAttribute('y2', viewPoint.y);
	    },
	    onPointerDown: function(evt) {
	        if (this.options.guard(evt)) { return; }
	        this.trigger('change:start', this, evt);
	        evt.stopPropagation();
	        evt.preventDefault();
	        this.options.paper.undelegateEvents();
	        this.delegateDocumentEvents(null, evt.data);
	    },
	    onPointerMove: function(evt) {
	        this.trigger('changing', this, evt);
	    },
	    onPointerUp: function(evt) {
	        this.undelegateDocumentEvents();
	        this.options.paper.delegateEvents();
	        this.trigger('change:end', this, evt);
	    },
	    show: function() {
	        this.el.style.display = '';
	    },
	    hide: function() {
	        this.el.style.display = 'none';
	    }
	});

	var Segments = ToolView.extend({
	    name: 'segments',
	    precision: .5,
	    options: {
	        handleClass: SegmentHandle,
	        segmentLengthThreshold: 40,
	        redundancyRemoval: true,
	        anchor: getAnchor,
	        snapRadius: 10,
	        snapHandle: true,
	        stopPropagation: true
	    },
	    handles: null,
	    onRender: function() {
	        this.resetHandles();
	        var relatedView = this.relatedView;
	        var vertices = relatedView.model.vertices();
	        vertices.unshift(relatedView.sourcePoint);
	        vertices.push(relatedView.targetPoint);
	        for (var i = 0, n = vertices.length; i < n - 1; i++) {
	            var vertex = vertices[i];
	            var nextVertex = vertices[i + 1];
	            var handle = this.renderHandle(vertex, nextVertex);
	            this.simulateRelatedView(handle.el);
	            this.handles.push(handle);
	            handle.options.index = i;
	        }
	        return this;
	    },
	    renderHandle: function(vertex, nextVertex) {
	        var this$1 = this;

	        var handle = new (this.options.handleClass)({
	            paper: this.paper,
	            scale: this.options.scale,
	            guard: function (evt) { return this$1.guard(evt); }
	        });
	        handle.render();
	        this.updateHandle(handle, vertex, nextVertex);
	        handle.vel.appendTo(this.el);
	        this.startHandleListening(handle);
	        return handle;
	    },
	    update: function() {
	        this.render();
	        return this;
	    },
	    startHandleListening: function(handle) {
	        this.listenTo(handle, 'change:start', this.onHandleChangeStart);
	        this.listenTo(handle, 'changing', this.onHandleChanging);
	        this.listenTo(handle, 'change:end', this.onHandleChangeEnd);
	    },
	    resetHandles: function() {
	        var handles = this.handles;
	        this.handles = [];
	        this.stopListening();
	        if (!Array.isArray(handles)) { return; }
	        for (var i = 0, n = handles.length; i < n; i++) {
	            handles[i].remove();
	        }
	    },
	    shiftHandleIndexes: function(value) {
	        var handles = this.handles;
	        for (var i = 0, n = handles.length; i < n; i++) { handles[i].options.index += value; }
	    },
	    resetAnchor: function(type, anchor) {
	        var relatedModel = this.relatedView.model;
	        if (anchor) {
	            relatedModel.prop([type, 'anchor'], anchor, {
	                rewrite: true,
	                ui: true,
	                tool: this.cid
	            });
	        } else {
	            relatedModel.removeProp([type, 'anchor'], {
	                ui: true,
	                tool: this.cid
	            });
	        }
	    },
	    snapHandle: function(handle, position, data) {

	        var index = handle.options.index;
	        var linkView = this.relatedView;
	        var link = linkView.model;
	        var vertices = link.vertices();
	        var axis = handle.options.axis;
	        var prev = vertices[index - 2] || data.sourceAnchor;
	        var next = vertices[index + 1] || data.targetAnchor;
	        var snapRadius = this.options.snapRadius;
	        if (Math.abs(position[axis] - prev[axis]) < snapRadius) {
	            position[axis] = prev[axis];
	        } else if (Math.abs(position[axis] - next[axis]) < snapRadius) {
	            position[axis] = next[axis];
	        }
	        return position;
	    },

	    onHandleChanging: function(handle, evt) {

	        var ref = this;
	        var options = ref.options;
	        var data = this.eventData(evt);
	        var relatedView = this.relatedView;
	        var paper = relatedView.paper;
	        var index$1 = handle.options.index - 1;
	        var normalizedEvent = normalizeEvent(evt);
	        var coords = paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        var position = this.snapHandle(handle, coords.clone(), data);
	        var axis = handle.options.axis;
	        var offset = (this.options.snapHandle) ? 0 : (coords[axis] - position[axis]);
	        var link = relatedView.model;
	        var vertices = cloneDeep(link.vertices());
	        var anchorFn = this.options.anchor;
	        if (typeof anchorFn !== 'function') { anchorFn = null; }

	        var handleIndex = handle.options.index;

	        var vertexPoints = [relatedView.sourcePoint.clone() ].concat( vertices, [relatedView.targetPoint.clone()]);
	        var indexOffset = 0;

	        // check if vertex before handle vertex exists
	        if (handleIndex - 1 >= 0) {
	            var v1 = vertexPoints[handleIndex - 1];
	            var v2 = vertexPoints[handleIndex];

	            var theta = new Line(v1, v2).vector().theta();

	            // check only non-orthogonal segments
	            if (theta % 90 !== 0) {
	                vertices.splice(handleIndex - 1, 0, data.originalVertices[handleIndex - 1]);
	                indexOffset++;
	                this.shiftHandleIndexes(1);
	            }
	        }

	        var vertex = vertices[index$1 + indexOffset];
	        var nextVertex = vertices[index$1 + 1 + indexOffset];

	        // check if vertex after handle vertex exists
	        if (handleIndex + 2 < vertexPoints.length) {
	            var v1$1 = vertexPoints[handleIndex + 1];
	            var v2$1 = vertexPoints[handleIndex + 2];

	            var theta$1 = new Line(v1$1, v2$1).vector().theta();

	            // check only non-orthogonal segments
	            if (theta$1 % 90 !== 0) {
	                var isSingleVertex = data.originalVertices.length === 1;
	                var origVIndex = isSingleVertex ? 0 : handleIndex;
	                var additionalOffset = data.firstHandleShifted && !isSingleVertex ? 1 : 0;
	                var nextVIndex = 1 + indexOffset;
	                vertices.splice(handleIndex + nextVIndex, 0, data.originalVertices[origVIndex - additionalOffset]);
	            }
	        }

	        // First Segment
	        var sourceView = relatedView.sourceView;
	        var sourceBBox = relatedView.sourceBBox;
	        var changeSourceAnchor = false;
	        var deleteSourceAnchor = false;
	        if (!vertex) {
	            vertex = relatedView.sourceAnchor.toJSON();
	            vertex[axis] = position[axis];
	            if (sourceBBox.containsPoint(vertex)) {
	                vertex[axis] = position[axis];
	                changeSourceAnchor = true;
	            } else {
	                // we left the area of the source magnet for the first time
	                vertices.unshift(vertex);
	                this.shiftHandleIndexes(1);
	                data.firstHandleShifted = true;
	                deleteSourceAnchor = true;
	            }
	        } else if (index$1 === 0) {
	            if (sourceBBox.containsPoint(vertex)) {
	                vertices.shift();
	                this.shiftHandleIndexes(-1);
	                changeSourceAnchor = true;
	            } else {
	                vertex[axis] = position[axis];
	                deleteSourceAnchor = true;
	            }
	        } else {
	            vertex[axis] = position[axis];
	        }

	        if (anchorFn && sourceView) {
	            if (changeSourceAnchor) {
	                var sourceAnchorPosition = data.sourceAnchor.clone();
	                sourceAnchorPosition[axis] = position[axis];
	                var sourceAnchor = anchorFn.call(relatedView, sourceAnchorPosition, sourceView, relatedView.sourceMagnet || sourceView.el, 'source', relatedView);
	                this.resetAnchor('source', sourceAnchor);
	            }
	            if (deleteSourceAnchor) {
	                this.resetAnchor('source', data.sourceAnchorDef);
	            }
	        }

	        // Last segment
	        var targetView = relatedView.targetView;
	        var targetBBox = relatedView.targetBBox;
	        var changeTargetAnchor = false;
	        var deleteTargetAnchor = false;
	        if (!nextVertex) {
	            nextVertex = relatedView.targetAnchor.toJSON();
	            nextVertex[axis] = position[axis];
	            if (targetBBox.containsPoint(nextVertex)) {
	                changeTargetAnchor = true;
	            } else {
	                // we left the area of the target magnet for the first time
	                vertices.push(nextVertex);
	                deleteTargetAnchor = true;
	            }
	        } else if (index$1 === vertices.length - 2) {
	            if (targetBBox.containsPoint(nextVertex)) {
	                vertices.pop();
	                changeTargetAnchor = true;
	            } else {
	                nextVertex[axis] = position[axis];
	                deleteTargetAnchor = true;
	            }
	        } else {
	            nextVertex[axis] = position[axis];
	        }

	        if (anchorFn && targetView) {
	            if (changeTargetAnchor) {
	                var targetAnchorPosition = data.targetAnchor.clone();
	                targetAnchorPosition[axis] = position[axis];
	                var targetAnchor = anchorFn.call(relatedView, targetAnchorPosition, targetView, relatedView.targetMagnet || targetView.el, 'target', relatedView);
	                this.resetAnchor('target', targetAnchor);
	            }
	            if (deleteTargetAnchor) {
	                this.resetAnchor('target', data.targetAnchorDef);
	            }
	        }
	        if (vertices.some(function (v) { return !v; })) {
	            // This can happen when the link is using a smart routing and the number of
	            // vertices is not the same as the number of route points.
	            throw new Error('Segments: incompatible router in use');
	        }
	        link.vertices(vertices, { ui: true, tool: this.cid });
	        this.updateHandle(handle, vertex, nextVertex, offset);
	        if (!options.stopPropagation) { relatedView.notifyPointermove(normalizedEvent, coords.x, coords.y); }
	    },
	    onHandleChangeStart: function(handle, evt) {
	        var ref = this;
	        var options = ref.options;
	        var handles = ref.handles;
	        var linkView = ref.relatedView;
	        var model = linkView.model;
	        var paper = linkView.paper;
	        var index$1 = handle.options.index;
	        if (!Array.isArray(handles)) { return; }
	        for (var i = 0, n = handles.length; i < n; i++) {
	            if (i !== index$1) { handles[i].hide(); }
	        }
	        this.focus();
	        this.eventData(evt, {
	            sourceAnchor: linkView.sourceAnchor.clone(),
	            targetAnchor: linkView.targetAnchor.clone(),
	            sourceAnchorDef: clone(model.prop(['source', 'anchor'])),
	            targetAnchorDef: clone(model.prop(['target', 'anchor'])),
	            originalVertices: cloneDeep(model.vertices()),
	            firstHandleShifted: false
	        });
	        model.startBatch('segment-move', { ui: true, tool: this.cid });
	        if (!options.stopPropagation) { linkView.notifyPointerdown.apply(linkView, paper.getPointerArgs(evt)); }
	    },
	    onHandleChangeEnd: function(_handle, evt) {
	        var ref= this;
	        var options = ref.options;
	        var linkView = ref.relatedView;
	        var paper = linkView.paper;
	        var model = linkView.model;
	        if (options.redundancyRemoval) {
	            linkView.removeRedundantLinearVertices({ ui: true, tool: this.cid });
	        }
	        var normalizedEvent = normalizeEvent(evt);
	        var coords = paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        this.render();
	        this.blur();
	        model.stopBatch('segment-move', { ui: true, tool: this.cid });
	        if (!options.stopPropagation) { linkView.notifyPointerup(normalizedEvent, coords.x, coords.y); }
	        linkView.checkMouseleave(normalizedEvent);
	    },
	    updateHandle: function(handle, vertex, nextVertex, offset) {
	        var vertical = Math.abs(vertex.x - nextVertex.x) < this.precision;
	        var horizontal = Math.abs(vertex.y - nextVertex.y) < this.precision;
	        if (vertical || horizontal) {
	            var segmentLine = new Line(vertex, nextVertex);
	            var length = segmentLine.length();
	            if (length < this.options.segmentLengthThreshold) {
	                handle.hide();
	            } else {
	                var position = segmentLine.midpoint();
	                var axis = (vertical) ? 'x' : 'y';
	                position[axis] += offset || 0;
	                var angle = segmentLine.vector().vectorAngle(new Point(1, 0));
	                handle.position(position.x, position.y, angle, this.relatedView);
	                handle.show();
	                handle.options.axis = axis;
	            }
	        } else {
	            handle.hide();
	        }
	    },
	    onRemove: function() {
	        this.resetHandles();
	    }
	}, {
	    SegmentHandle: SegmentHandle // keep as class property
	});

	// End Markers
	var Arrowhead = ToolView.extend({
	    tagName: 'path',
	    xAxisVector: new Point(1, 0),
	    events: {
	        mousedown: 'onPointerDown',
	        touchstart: 'onPointerDown'
	    },
	    documentEvents: {
	        mousemove: 'onPointerMove',
	        touchmove: 'onPointerMove',
	        mouseup: 'onPointerUp',
	        touchend: 'onPointerUp',
	        touchcancel: 'onPointerUp'
	    },
	    options: {
	        scale: null
	    },
	    onRender: function() {
	        this.update();
	    },
	    update: function() {
	        var ratio = this.ratio;
	        var view = this.relatedView;
	        var tangent = view.getTangentAtRatio(ratio);
	        var position, angle;
	        if (tangent) {
	            position = tangent.start;
	            angle = tangent.vector().vectorAngle(this.xAxisVector) || 0;
	        } else {
	            position = view.getPointAtRatio(ratio);
	            angle = 0;
	        }
	        if (!position) { return this; }
	        var matrix = V.createSVGMatrix().translate(position.x, position.y).rotate(angle);
	        var ref = this.options;
	        var scale = ref.scale;
	        if (scale) { matrix = matrix.scale(scale); }
	        this.vel.transform(matrix, { absolute: true });
	        return this;
	    },
	    onPointerDown: function(evt) {
	        if (this.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        var relatedView = this.relatedView;
	        relatedView.model.startBatch('arrowhead-move', { ui: true, tool: this.cid });
	        relatedView.startArrowheadMove(this.arrowheadType);
	        this.delegateDocumentEvents();
	        relatedView.paper.undelegateEvents();
	        this.focus();
	        this.el.style.pointerEvents = 'none';
	    },
	    onPointerMove: function(evt) {
	        var normalizedEvent = normalizeEvent(evt);
	        var coords = this.paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        this.relatedView.pointermove(normalizedEvent, coords.x, coords.y);
	    },
	    onPointerUp: function(evt) {
	        this.undelegateDocumentEvents();
	        var relatedView = this.relatedView;
	        var paper = relatedView.paper;
	        var normalizedEvent = normalizeEvent(evt);
	        var coords = paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        relatedView.pointerup(normalizedEvent, coords.x, coords.y);
	        paper.delegateEvents();
	        this.blur();
	        this.el.style.pointerEvents = '';
	        relatedView.model.stopBatch('arrowhead-move', { ui: true, tool: this.cid });
	    }
	});

	var TargetArrowhead = Arrowhead.extend({
	    name: 'target-arrowhead',
	    ratio: 1,
	    arrowheadType: 'target',
	    attributes: {
	        'd': 'M -10 -8 10 0 -10 8 Z',
	        'fill': '#33334F',
	        'stroke': '#FFFFFF',
	        'stroke-width': 2,
	        'cursor': 'move',
	        'class': 'target-arrowhead'
	    }
	});

	var SourceArrowhead = Arrowhead.extend({
	    name: 'source-arrowhead',
	    ratio: 0,
	    arrowheadType: 'source',
	    attributes: {
	        'd': 'M 10 -8 -10 0 10 8 Z',
	        'fill': '#33334F',
	        'stroke': '#FFFFFF',
	        'stroke-width': 2,
	        'cursor': 'move',
	        'class': 'source-arrowhead'
	    }
	});

	var Boundary = ToolView.extend({
	    name: 'boundary',
	    tagName: 'rect',
	    options: {
	        padding: 10,
	        useModelGeometry: false,
	    },
	    attributes: {
	        'fill': 'none',
	        'stroke': '#33334F',
	        'stroke-width': .5,
	        'stroke-dasharray': '5, 5',
	        'pointer-events': 'none'
	    },
	    onRender: function() {
	        this.update();
	    },
	    update: function() {
	        var ref = this;
	        var view = ref.relatedView;
	        var options = ref.options;
	        var vel = ref.vel;
	        var useModelGeometry = options.useModelGeometry;
	        var rotate = options.rotate;
	        var padding = normalizeSides(options.padding);
	        var bbox = getViewBBox(view, useModelGeometry).moveAndExpand({
	            x: -padding.left,
	            y: -padding.top,
	            width: padding.left + padding.right,
	            height: padding.top + padding.bottom
	        });
	        var model = view.model;
	        if (model.isElement()) {
	            var angle = model.angle();
	            if (angle) {
	                if (rotate) {
	                    var origin = model.getBBox().center();
	                    vel.rotate(angle, origin.x, origin.y, { absolute: true });
	                } else {
	                    bbox = bbox.bbox(angle);
	                }
	            }
	        }
	        vel.attr(bbox.toJSON());
	        return this;
	    }
	});

	var Anchor = ToolView.extend({
	    tagName: 'g',
	    type: null,
	    children: [{
	        tagName: 'circle',
	        selector: 'anchor',
	        attributes: {
	            'cursor': 'pointer'
	        }
	    }, {
	        tagName: 'rect',
	        selector: 'area',
	        attributes: {
	            'pointer-events': 'none',
	            'fill': 'none',
	            'stroke': '#33334F',
	            'stroke-dasharray': '2,4',
	            'rx': 5,
	            'ry': 5
	        }
	    }],
	    events: {
	        mousedown: 'onPointerDown',
	        touchstart: 'onPointerDown',
	        dblclick: 'onPointerDblClick',
	        dbltap: 'onPointerDblClick'
	    },
	    documentEvents: {
	        mousemove: 'onPointerMove',
	        touchmove: 'onPointerMove',
	        mouseup: 'onPointerUp',
	        touchend: 'onPointerUp',
	        touchcancel: 'onPointerUp'
	    },
	    options: {
	        snap: snapAnchor,
	        anchor: getAnchor,
	        scale: null,
	        resetAnchor: true,
	        customAnchorAttributes: {
	            'stroke-width': 4,
	            'stroke': '#33334F',
	            'fill': '#FFFFFF',
	            'r': 5
	        },
	        defaultAnchorAttributes: {
	            'stroke-width': 2,
	            'stroke': '#FFFFFF',
	            'fill': '#33334F',
	            'r': 6
	        },
	        areaPadding: 6,
	        snapRadius: 10,
	        restrictArea: true,
	        redundancyRemoval: true
	    },
	    onRender: function() {
	        this.renderChildren();
	        this.toggleArea(false);
	        this.update();
	    },
	    update: function() {
	        var type = this.type;
	        var relatedView = this.relatedView;
	        var view = relatedView.getEndView(type);
	        if (view) {
	            this.updateAnchor();
	            this.updateArea();
	            this.el.style.display = '';
	        } else {
	            this.el.style.display = 'none';
	        }
	        return this;
	    },
	    updateAnchor: function() {
	        var childNodes = this.childNodes;
	        if (!childNodes) { return; }
	        var anchorNode = childNodes.anchor;
	        if (!anchorNode) { return; }
	        var relatedView = this.relatedView;
	        var type = this.type;
	        var position = relatedView.getEndAnchor(type);
	        var options = this.options;
	        var customAnchor = relatedView.model.prop([type, 'anchor']);
	        var transformString =  "translate(" + (position.x) + "," + (position.y) + ")";
	        if (options.scale) {
	            transformString += " scale(" + (options.scale) + ")";
	        }
	        anchorNode.setAttribute('transform', transformString);
	        var anchorAttributes = (customAnchor) ? options.customAnchorAttributes : options.defaultAnchorAttributes;
	        for (var attrName in anchorAttributes) {
	            anchorNode.setAttribute(attrName, anchorAttributes[attrName]);
	        }
	    },
	    updateArea: function() {
	        var childNodes = this.childNodes;
	        if (!childNodes) { return; }
	        var areaNode = childNodes.area;
	        if (!areaNode) { return; }
	        var relatedView = this.relatedView;
	        var type = this.type;
	        var view = relatedView.getEndView(type);
	        var model = view.model;
	        var magnet = relatedView.getEndMagnet(type);
	        var padding = this.options.areaPadding;
	        if (!isFinite(padding)) { padding = 0; }
	        var bbox, angle, center;
	        if (view.isNodeConnection(magnet)) {
	            bbox = view.getNodeBBox(magnet);
	            angle = 0;
	            center = bbox.center();
	        } else {
	            bbox = view.getNodeUnrotatedBBox(magnet);
	            angle = model.angle();
	            center = bbox.center();
	            if (angle) { center.rotate(model.getBBox().center(), -angle); }
	            // TODO: get the link's magnet rotation into account
	        }
	        bbox.inflate(padding);
	        areaNode.setAttribute('x', -bbox.width / 2);
	        areaNode.setAttribute('y', -bbox.height / 2);
	        areaNode.setAttribute('width', bbox.width);
	        areaNode.setAttribute('height', bbox.height);
	        areaNode.setAttribute('transform', 'translate(' + center.x + ',' + center.y + ') rotate(' + angle + ')');
	    },
	    toggleArea: function(visible) {
	        var childNodes = this.childNodes;
	        if (!childNodes) { return; }
	        var areaNode = childNodes.area;
	        if (!areaNode) { return; }
	        areaNode.style.display = (visible) ? '' : 'none';
	    },
	    onPointerDown: function(evt) {
	        if (this.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        this.paper.undelegateEvents();
	        this.delegateDocumentEvents();
	        this.focus();
	        this.toggleArea(this.options.restrictArea);
	        this.relatedView.model.startBatch('anchor-move', { ui: true, tool: this.cid });
	    },
	    resetAnchor: function(anchor) {
	        var type = this.type;
	        var relatedModel = this.relatedView.model;
	        if (anchor) {
	            relatedModel.prop([type, 'anchor'], anchor, {
	                rewrite: true,
	                ui: true,
	                tool: this.cid
	            });
	        } else {
	            relatedModel.removeProp([type, 'anchor'], {
	                ui: true,
	                tool: this.cid
	            });
	        }
	    },
	    onPointerMove: function(evt) {

	        var relatedView = this.relatedView;
	        var type = this.type;
	        var view = relatedView.getEndView(type);
	        var model = view.model;
	        var magnet = relatedView.getEndMagnet(type);
	        var normalizedEvent = normalizeEvent(evt);
	        var coords = this.paper.clientToLocalPoint(normalizedEvent.clientX, normalizedEvent.clientY);
	        var snapFn = this.options.snap;
	        if (typeof snapFn === 'function') {
	            coords = snapFn.call(relatedView, coords, view, magnet, type, relatedView, this);
	            coords = new Point(coords);
	        }

	        if (this.options.restrictArea) {
	            if (view.isNodeConnection(magnet)) {
	                // snap coords to the link's connection
	                var pointAtConnection = view.getClosestPoint(coords);
	                if (pointAtConnection) { coords = pointAtConnection; }
	            } else {
	                // snap coords within node bbox
	                var bbox = view.getNodeUnrotatedBBox(magnet);
	                var angle = model.angle();
	                var origin = model.getBBox().center();
	                var rotatedCoords = coords.clone().rotate(origin, angle);
	                if (!bbox.containsPoint(rotatedCoords)) {
	                    coords = bbox.pointNearestToPoint(rotatedCoords).rotate(origin, -angle);
	                }
	            }
	        }

	        var anchor;
	        var anchorFn = this.options.anchor;
	        if (typeof anchorFn === 'function') {
	            anchor = anchorFn.call(relatedView, coords, view, magnet, type, relatedView);
	        }

	        this.resetAnchor(anchor);
	        this.update();
	    },

	    onPointerUp: function(evt) {
	        var normalizedEvent = normalizeEvent(evt);
	        this.paper.delegateEvents();
	        this.undelegateDocumentEvents();
	        this.blur();
	        this.toggleArea(false);
	        var linkView = this.relatedView;
	        if (this.options.redundancyRemoval) { linkView.removeRedundantLinearVertices({ ui: true, tool: this.cid }); }
	        linkView.checkMouseleave(normalizedEvent);
	        linkView.model.stopBatch('anchor-move', { ui: true, tool: this.cid });
	    },

	    onPointerDblClick: function() {
	        var anchor = this.options.resetAnchor;
	        if (anchor === false) { return; } // reset anchor disabled
	        if (anchor === true) { anchor = null; } // remove the current anchor
	        this.resetAnchor(cloneDeep(anchor));
	        this.update();
	    }
	});

	var SourceAnchor = Anchor.extend({
	    name: 'source-anchor',
	    type: 'source'
	});

	var TargetAnchor = Anchor.extend({
	    name: 'target-anchor',
	    type: 'target'
	});

	var Button = ToolView.extend({
	    name: 'button',
	    events: {
	        'mousedown': 'onPointerDown',
	        'touchstart': 'onPointerDown'
	    },
	    options: {
	        distance: 0,
	        offset: 0,
	        scale: null,
	        rotate: false
	    },
	    onRender: function() {
	        this.renderChildren(this.options.markup);
	        this.update();
	    },
	    update: function() {
	        this.position();
	        return this;
	    },
	    position: function() {
	        var ref = this;
	        var vel = ref.vel;
	        vel.transform(this.getCellMatrix(), { absolute: true });
	    },
	    getCellMatrix: function getCellMatrix() {
	        return this.relatedView.model.isLink() ? this.getLinkMatrix() : this.getElementMatrix();
	    },
	    getElementMatrix: function getElementMatrix() {
	        var ref = this;
	        var view = ref.relatedView;
	        var options = ref.options;
	        var x = options.x; if ( x === void 0 ) x = 0;
	        var y = options.y; if ( y === void 0 ) y = 0;
	        var offset = options.offset; if ( offset === void 0 ) offset = {};
	        var useModelGeometry = options.useModelGeometry;
	        var rotate = options.rotate;
	        var scale = options.scale;
	        var bbox = getViewBBox(view, useModelGeometry);
	        var angle = view.model.angle();
	        if (!rotate) { bbox = bbox.bbox(angle); }
	        var offsetX = offset.x; if ( offsetX === void 0 ) offsetX = 0;
	        var offsetY = offset.y; if ( offsetY === void 0 ) offsetY = 0;
	        if (isPercentage(x)) {
	            x = parseFloat(x) / 100 * bbox.width;
	        } else if (isCalcAttribute(x)) {
	            x = Number(evalCalcAttribute(x, bbox));
	        }
	        if (isPercentage(y)) {
	            y = parseFloat(y) / 100 * bbox.height;
	        } else if (isCalcAttribute(y)) {
	            y = Number(evalCalcAttribute(y, bbox));
	        }
	        var matrix = V.createSVGMatrix().translate(bbox.x + bbox.width / 2, bbox.y + bbox.height / 2);
	        if (rotate) { matrix = matrix.rotate(angle); }
	        matrix = matrix.translate(x + offsetX - bbox.width / 2, y + offsetY - bbox.height / 2);
	        if (scale) { matrix = matrix.scale(scale); }
	        return matrix;
	    },
	    getLinkMatrix: function getLinkMatrix() {
	        var ref = this;
	        var view = ref.relatedView;
	        var options = ref.options;
	        var offset = options.offset; if ( offset === void 0 ) offset = 0;
	        var distance = options.distance; if ( distance === void 0 ) distance = 0;
	        var rotate = options.rotate;
	        var scale = options.scale;
	        var tangent, position, angle;
	        if (isPercentage(distance)) {
	            tangent = view.getTangentAtRatio(parseFloat(distance) / 100);
	        } else {
	            tangent = view.getTangentAtLength(distance);
	        }
	        if (tangent) {
	            position = tangent.start;
	            angle = tangent.vector().vectorAngle(new Point(1, 0)) || 0;
	        } else {
	            position = view.getConnection().start;
	            angle = 0;
	        }
	        var matrix = V.createSVGMatrix()
	            .translate(position.x, position.y)
	            .rotate(angle)
	            .translate(0, offset);
	        if (!rotate) { matrix = matrix.rotate(-angle); }
	        if (scale) { matrix = matrix.scale(scale); }
	        return matrix;
	    },
	    onPointerDown: function(evt) {
	        if (this.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        var actionFn = this.options.action;
	        if (typeof actionFn === 'function') {
	            actionFn.call(this.relatedView, evt, this.relatedView, this);
	        }
	    }
	});

	var Remove = Button.extend({
	    name: 'remove',
	    children: [{
	        tagName: 'circle',
	        selector: 'button',
	        attributes: {
	            'r': 7,
	            'fill': '#FF1D00',
	            'cursor': 'pointer'
	        }
	    }, {
	        tagName: 'path',
	        selector: 'icon',
	        attributes: {
	            'd': 'M -3 -3 3 3 M -3 3 3 -3',
	            'fill': 'none',
	            'stroke': '#FFFFFF',
	            'stroke-width': 2,
	            'pointer-events': 'none'
	        }
	    }],
	    options: {
	        distance: 60,
	        offset: 0,
	        action: function(evt, view, tool) {
	            view.model.remove({ ui: true, tool: tool.cid });
	        }
	    }
	});

	var Connect = Button.extend({
	    name: 'connect',
	    documentEvents: {
	        mousemove: 'drag',
	        touchmove: 'drag',
	        mouseup: 'dragend',
	        touchend: 'dragend',
	        touchcancel: 'dragend'
	    },
	    children: [{
	        tagName: 'circle',
	        selector: 'button',
	        attributes: {
	            'r': 7,
	            'fill': '#333333',
	            'cursor': 'pointer'
	        }
	    }, {
	        tagName: 'path',
	        selector: 'icon',
	        attributes: {
	            'd': 'M -4 -1 L 0 -1 L 0 -4 L 4 0 L 0 4 0 1 -4 1 z',
	            'fill': '#FFFFFF',
	            'stroke': 'none',
	            'stroke-width': 2,
	            'pointer-events': 'none'
	        }
	    }],
	    options: {
	        distance: 80,
	        offset: 0,
	        magnet: function (view) { return view.el; },
	        action: function (evt, _view, tool) { return tool.dragstart(evt); },
	    },
	    getMagnetNode: function() {
	        var ref = this;
	        var options = ref.options;
	        var relatedView = ref.relatedView;
	        var magnet = options.magnet;
	        var magnetNode;
	        switch (typeof magnet) {
	            case 'function': {
	                magnetNode = magnet.call(this, relatedView, this);
	                break;
	            }
	            case 'string': {
	                magnetNode = relatedView.findNode(magnet);
	                break;
	            }
	            default: {
	                magnetNode = magnet;
	                break;
	            }
	        }
	        if (!magnetNode) { magnetNode = relatedView.el; }
	        if (magnetNode instanceof SVGElement) { return magnetNode; }
	        throw new Error('Connect: magnet must be an SVGElement');
	    },
	    dragstart: function(evt) {
	        var ref = this;
	        var paper = ref.paper;
	        var relatedView = ref.relatedView;
	        var normalizedEvent = normalizeEvent(evt);
	        var ref$1 = paper.clientToLocalPoint(normalizedEvent.clientX, normalizedEvent.clientY);
	        var x = ref$1.x;
	        var y = ref$1.y;
	        relatedView.dragLinkStart(normalizedEvent, this.getMagnetNode(), x, y);
	        paper.undelegateEvents();
	        this.delegateDocumentEvents(null, normalizedEvent.data);
	        this.focus();
	    },
	    drag: function(evt) {
	        var ref = this;
	        var paper = ref.paper;
	        var relatedView = ref.relatedView;
	        var normalizedEvent = normalizeEvent(evt);
	        var ref$1 = paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        var x = ref$1.x;
	        var y = ref$1.y;
	        relatedView.dragLink(normalizedEvent, x, y);
	    },
	    dragend: function(evt) {
	        var ref = this;
	        var paper = ref.paper;
	        var relatedView = ref.relatedView;
	        var normalizedEvent = normalizeEvent(evt);
	        var ref$1 = paper.snapToGrid(normalizedEvent.clientX, normalizedEvent.clientY);
	        var x = ref$1.x;
	        var y = ref$1.y;
	        relatedView.dragLinkEnd(normalizedEvent, x, y);
	        this.undelegateDocumentEvents();
	        paper.delegateEvents();
	        this.blur();
	        relatedView.checkMouseleave(normalizedEvent);
	    }
	});

	var HoverConnect = Connect.extend({

	    name: 'hover-connect',

	    defaultMarkup: [
	        {
	            tagName: 'circle',
	            attributes: {
	                'r': 7,
	                'fill': '#333333',
	                'cursor': 'pointer'
	            }
	        },
	        {
	            tagName: 'path',
	            attributes: {
	                'd': 'M -4 -1 L 0 -1 L 0 -4 L 4 0 L 0 4 0 1 -4 1 z',
	                'fill': '#FFFFFF',
	                'stroke': 'none',
	                'stroke-width': 2
	            }
	        }
	    ],

	    children: function children() {
	        var ref = this;
	        var options = ref.options;
	        var defaultMarkup = ref.defaultMarkup;
	        return [
	            {
	                tagName: 'path',
	                selector: 'track',
	                attributes: {
	                    'fill': 'none',
	                    'stroke': 'transparent',
	                    'stroke-width': options.trackWidth || 15,
	                    'cursor': 'pointer'
	                }
	            },
	            {
	                tagName: 'g',
	                selector: 'button',
	                attributes: {
	                    'pointer-events': 'none',
	                    'display': 'none'
	                },
	                children: options.markup || defaultMarkup
	            }
	        ];
	    },

	    events: Object.assign({
	        mousemove: 'onMousemove',
	        mouseenter: 'onMouseenter',
	        mouseleave: 'onMouseleave'
	    }, Connect.prototype.events),

	    onRender: function() {
	        this.renderChildren();
	        this.update();
	    },

	    trackPath: null,

	    update: function update() {
	        var ref = this;
	        var childNodes = ref.childNodes;
	        this.trackPath = this.getTrackPath();
	        Connect.prototype.update.apply(this, arguments);
	        childNodes.track.setAttribute(
	            'd',
	            this.trackPath.serialize()
	        );
	    },

	    position: function position() {
	        var ref = this;
	        var el = ref.el;
	        var childNodes = ref.childNodes;
	        childNodes.button.setAttribute(
	            'transform',
	            V.matrixToTransformString(this.getButtonMatrix())
	        );
	        el.setAttribute(
	            'transform',
	            V.matrixToTransformString(this.getTrackMatrix())
	        );
	    },

	    getButtonMatrix: function getButtonMatrix() {
	        var ref = this;
	        var options = ref.options;
	        var trackPath = ref.trackPath;
	        var offset = options.offset; if ( offset === void 0 ) offset = 0;
	        var distance = options.distance; if ( distance === void 0 ) distance = 0;
	        var rotate = options.rotate;
	        var scale = options.scale;
	        var tangent, position, angle;
	        if (isPercentage(distance)) {
	            tangent = trackPath.tangentAtRatio(parseFloat(distance) / 100);
	        } else {
	            tangent = trackPath.tangentAtLength(distance);
	        }
	        if (tangent) {
	            position = tangent.start;
	            angle = tangent.vector().vectorAngle(new Point(1, 0)) || 0;
	        } else {
	            position = trackPath.start;
	            angle = 0;
	        }
	        var matrix = V.createSVGMatrix()
	            .translate(position.x, position.y)
	            .rotate(angle)
	            .translate(0, offset);
	        if (!rotate) { matrix = matrix.rotate(-angle); }
	        if (scale) { matrix = matrix.scale(scale); }
	        return matrix;
	    },

	    getTrackPath: function getTrackPath() {
	        return this.relatedView.getConnection();
	    },

	    getTrackMatrix: function getTrackMatrix() {
	        return V.createSVGMatrix();
	    },

	    getTrackRatioFromEvent: function getTrackRatioFromEvent(evt) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var trackPath = ref.trackPath;
	        var localPoint = relatedView.paper.clientToLocalPoint(evt.clientX, evt.clientY);
	        var trackPoint = V.transformPoint(localPoint, this.getTrackMatrix().inverse());
	        return trackPath.closestPointLength(trackPoint);
	    },

	    canShowButton: function canShowButton() {
	        // Has been the paper events undelegated? If so, we can't show the button.
	        // TODO: add a method to the paper to check if the events are delegated.
	        return $.event.has(this.paper.el);
	    },

	    showButton: function showButton() {
	        this.childNodes.button.style.display = 'block';
	    },

	    hideButton: function hideButton() {
	        this.childNodes.button.style.display = '';
	    },

	    onMousemove: function onMousemove(evt) {
	        var ref = this;
	        var trackPath = ref.trackPath;
	        if (!trackPath) { return; }
	        var ref$1 = this;
	        var options = ref$1.options;
	        options.distance = this.getTrackRatioFromEvent(evt);
	        this.position();
	    },

	    onMouseenter: function onMouseenter() {
	        if (!this.canShowButton()) { return; }
	        this.showButton();
	    },

	    onMouseleave: function onMouseleave() {
	        this.hideButton();
	    }
	});



	var index$5 = ({
		Vertices: Vertices,
		Segments: Segments,
		TargetArrowhead: TargetArrowhead,
		SourceArrowhead: SourceArrowhead,
		Boundary: Boundary,
		SourceAnchor: SourceAnchor,
		TargetAnchor: TargetAnchor,
		Button: Button,
		Remove: Remove,
		Connect: Connect,
		HoverConnect: HoverConnect
	});

	var Control = ToolView.extend({
	    tagName: 'g',
	    children: [{
	        tagName: 'circle',
	        selector: 'handle',
	        attributes: {
	            'cursor': 'pointer',
	            'stroke-width': 2,
	            'stroke': '#FFFFFF',
	            'fill': '#33334F',
	            'r': 6
	        }
	    }, {
	        tagName: 'rect',
	        selector: 'extras',
	        attributes: {
	            'pointer-events': 'none',
	            'fill': 'none',
	            'stroke': '#33334F',
	            'stroke-dasharray': '2,4',
	            'rx': 5,
	            'ry': 5
	        }
	    }],
	    events: {
	        mousedown: 'onPointerDown',
	        touchstart: 'onPointerDown',
	        dblclick: 'onPointerDblClick',
	        dbltap: 'onPointerDblClick'
	    },
	    documentEvents: {
	        mousemove: 'onPointerMove',
	        touchmove: 'onPointerMove',
	        mouseup: 'onPointerUp',
	        touchend: 'onPointerUp',
	        touchcancel: 'onPointerUp'
	    },
	    options: {
	        handleAttributes: null,
	        selector: 'root',
	        padding: 6,
	        scale: null
	    },

	    getPosition: function() {
	        // To be overridden
	    },
	    setPosition: function() {
	        // To be overridden
	    },
	    resetPosition: function() {
	        // To be overridden
	    },
	    onRender: function() {
	        this.renderChildren();
	        this.toggleExtras(false);
	        this.update();
	    },
	    update: function() {
	        var ref = this.childNodes;
	        var handle = ref.handle;
	        var extras = ref.extras;
	        if (handle) {
	            this.updateHandle(handle);
	        } else {
	            throw new Error('Control: markup selector `handle` is required');
	        }
	        if (extras) {
	            this.updateExtras(extras);
	        }
	        return this;
	    },
	    updateHandle: function(handleNode) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var options = ref.options;
	        var model = relatedView.model;
	        var relativePos = this.getPosition(relatedView, this);
	        var absolutePos = model.getAbsolutePointFromRelative(relativePos);
	        var handleAttributes = options.handleAttributes;
	        var scale = options.scale;
	        var transformString =  "translate(" + (absolutePos.x) + "," + (absolutePos.y) + ")";
	        if (scale) {
	            transformString += " scale(" + scale + ")";
	        }
	        handleNode.setAttribute('transform', transformString);
	        if (handleAttributes) {
	            for (var attrName in handleAttributes) {
	                handleNode.setAttribute(attrName, handleAttributes[attrName]);
	            }
	        }
	    },
	    updateExtras: function(extrasNode) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var options = ref.options;
	        var ref$1 = this.options;
	        var selector = ref$1.selector;
	        if (!selector) {
	            this.toggleExtras(false);
	            return;
	        }
	        var magnet = relatedView.findNode(selector);
	        if (!magnet) { throw new Error('Control: invalid selector.'); }
	        var padding = options.padding;
	        if (!isFinite(padding)) { padding = 0; }
	        var bbox = relatedView.getNodeUnrotatedBBox(magnet);
	        var model = relatedView.model;
	        var angle = model.angle();
	        var center = bbox.center();
	        if (angle) { center.rotate(model.getBBox().center(), -angle); }
	        bbox.inflate(padding);
	        extrasNode.setAttribute('x', -bbox.width / 2);
	        extrasNode.setAttribute('y', -bbox.height / 2);
	        extrasNode.setAttribute('width', bbox.width);
	        extrasNode.setAttribute('height', bbox.height);
	        extrasNode.setAttribute('transform', ("translate(" + (center.x) + "," + (center.y) + ") rotate(" + angle + ")"));
	    },
	    toggleExtras: function(visible) {
	        var ref = this.childNodes;
	        var extras = ref.extras;
	        if (!extras) { return; }
	        extras.style.display = (visible) ? '' : 'none';
	    },
	    onPointerDown: function(evt) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var paper = ref.paper;
	        if (this.guard(evt)) { return; }
	        evt.stopPropagation();
	        evt.preventDefault();
	        paper.undelegateEvents();
	        this.delegateDocumentEvents();
	        this.focus();
	        this.toggleExtras(true);
	        relatedView.model.startBatch('control-move', { ui: true, tool: this.cid });
	    },
	    onPointerMove: function(evt) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var paper = ref.paper;
	        var model = relatedView.model;
	        var ref$1 = normalizeEvent(evt);
	        var clientX = ref$1.clientX;
	        var clientY = ref$1.clientY;
	        var coords = paper.clientToLocalPoint(clientX, clientY);
	        var relativeCoords = model.getRelativePointFromAbsolute(coords);
	        this.setPosition(relatedView, relativeCoords, this);
	        this.update();
	    },
	    onPointerUp: function(_evt) {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        var paper = ref.paper;
	        paper.delegateEvents();
	        this.undelegateDocumentEvents();
	        this.blur();
	        this.toggleExtras(false);
	        relatedView.model.stopBatch('control-move', { ui: true, tool: this.cid });
	    },
	    onPointerDblClick: function() {
	        var ref = this;
	        var relatedView = ref.relatedView;
	        this.resetPosition(relatedView, this);
	        this.update();
	    }

	});

	var HoverConnect$1 = HoverConnect.extend({

	    getTrackPath: function getTrackPath() {
	        var ref = this;
	        var view = ref.relatedView;
	        var options = ref.options;
	        var useModelGeometry = options.useModelGeometry;
	        var trackPath = options.trackPath; if ( trackPath === void 0 ) trackPath = 'M 0 0 H calc(w) V calc(h) H 0 Z';
	        if (typeof trackPath === 'function') {
	            trackPath = trackPath.call(this, view);
	        }
	        if (isCalcAttribute(trackPath)) {
	            var bbox = getViewBBox(view, useModelGeometry);
	            trackPath = evalCalcAttribute(trackPath, bbox);
	        }
	        return new Path(V.normalizePathData(trackPath));
	    },

	    getTrackMatrix: function getTrackMatrix() {
	        var ref = this;
	        var view = ref.relatedView;
	        var options = ref.options;
	        var useModelGeometry = options.useModelGeometry;
	        var rotate = options.rotate;
	        var bbox = getViewBBox(view, useModelGeometry);
	        var angle = view.model.angle();
	        if (!rotate) { bbox = bbox.bbox(angle); }
	        var matrix = V.createSVGMatrix().translate(bbox.x + bbox.width / 2, bbox.y + bbox.height / 2);
	        if (rotate) { matrix = matrix.rotate(angle); }
	        matrix = matrix.translate(- bbox.width / 2, - bbox.height / 2);
	        return matrix;
	    }

	});



	var index$6 = ({
		Button: Button,
		Remove: Remove,
		Connect: Connect,
		Boundary: Boundary,
		HoverConnect: HoverConnect$1,
		Control: Control
	});

	var version = "4.0.1";

	var Vectorizer = V;
	var layout = { PortLabel: PortLabel, Port: Port };
	var setTheme = function(theme, opt) {

	    opt = opt || {};

	    invoke(views, 'setTheme', theme, opt);

	    // Update the default theme on the view prototype.
	    View.prototype.defaultTheme = theme;
	};

	var layout$1 = { PortLabel: PortLabel, Port: Port };

	// export empty namespaces - backward compatibility
	var format$1 = {};
	var ui = {};

	exports.V = V;
	exports.Vectorizer = Vectorizer;
	exports.anchors = anchors;
	exports.config = config;
	exports.connectionPoints = connectionPoints;
	exports.connectionStrategies = index$3;
	exports.connectors = connectors;
	exports.dia = index$4;
	exports.elementTools = index$6;
	exports.env = env;
	exports.format = format$1;
	exports.g = g;
	exports.highlighters = highlighters;
	exports.layout = layout$1;
	exports.linkAnchors = linkAnchors;
	exports.linkTools = index$5;
	exports.mvc = index$2;
	exports.routers = routers;
	exports.setTheme = setTheme;
	exports.shapes = index$1;
	exports.ui = ui;
	exports.util = index;
	exports.version = version;

	Object.defineProperty(exports, '__esModule', { value: true });

}));
if (typeof joint !== 'undefined') { var g = joint.g, V = joint.V, Vectorizer = joint.V; }