SFML 2.5.1

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sf::Transform Class Reference
Graphics module

Define a 3x3 transform matrix. More...

`#include <Transform.hpp>`

## Public Member Functions
| Transform ()
| Default constructor. More...
| Transform (float a00, float a01, float a02, float a10, float a11, float a12, float a20, float a21, float a22)
| Construct a transform from a 3x3 matrix. More...
const float * | getMatrix () const
| Return the transform as a 4x4 matrix. More...
Transform | getInverse () const
| Return the inverse of the transform. More...
Vector2f | transformPoint (float x, float y) const
| Transform a 2D point. More...
Vector2f | transformPoint (const Vector2f &point) const
| Transform a 2D point. More...
FloatRect | transformRect (const FloatRect &rectangle) const
| Transform a rectangle. More...
Transform & | combine (const Transform &transform)
| Combine the current transform with another one. More...
Transform & | translate (float x, float y)
| Combine the current transform with a translation. More...
Transform & | translate (const Vector2f &offset)
| Combine the current transform with a translation. More...
Transform & | rotate (float angle)
| Combine the current transform with a rotation. More...
Transform & | rotate (float angle, float centerX, float centerY)
| Combine the current transform with a rotation. More...
Transform & | rotate (float angle, const Vector2f &center)
| Combine the current transform with a rotation. More...
Transform & | scale (float scaleX, float scaleY)
| Combine the current transform with a scaling. More...
Transform & | scale (float scaleX, float scaleY, float centerX, float centerY)
| Combine the current transform with a scaling. More...
Transform & | scale (const Vector2f &factors)
| Combine the current transform with a scaling. More...
Transform & | scale (const Vector2f &factors, const Vector2f &center)
| Combine the current transform with a scaling. More...

## Static Public Attributes
static const Transform | Identity
| The identity transform (does nothing) More...

## Related Functions
(Note that these are not member functions.)
Transform | operator* (const Transform &left, const Transform &right)
| Overload of binary operator * to combine two transforms. More...
Transform & | operator*= (Transform &left, const Transform &right)
| Overload of binary operator *= to combine two transforms. More...
Vector2f | operator* (const Transform &left, const Vector2f &right)
| Overload of binary operator * to transform a point. More...
bool | operator== (const Transform &left, const Transform &right)
| Overload of binary operator == to compare two transforms. More...
bool | operator!= (const Transform &left, const Transform &right)
| Overload of binary operator != to compare two transforms. More...

## Detailed Description

Define a 3x3 transform matrix.

A sf::Transform specifies how to translate, rotate, scale, shear, project, whatever things.

In mathematical terms, it defines how to transform a coordinate system into another.

For example, if you apply a rotation transform to a sprite, the result will be a rotated sprite. And anything that is transformed by this rotation transform will be rotated the same way, according to its initial position.

Transforms are typically used for drawing. But they can also be used for any computation that requires to transform points between the local and global coordinate systems of an entity (like collision detection).

Example:

// define a translation transform
sf::Transform translation;
translation.translate(20, 50);
// define a rotation transform
sf::Transform rotation;
rotation.rotate(45);
// combine them
sf::Transform transform = translation * rotation;
// use the result to transform stuff...
sf::Vector2f point = transform.transformPoint(10, 20);
sf::FloatRect rect = transform.transformRect(sf::FloatRect(0, 0, 10, 100));

See also
  sf::Transformable, sf::RenderStates

Definition at line 42 of file Transform.hpp.

## Constructor & Destructor Documentation

## ◆ Transform() [1/2]

sf::Transform::Transform | ( |  | ) |

Default constructor.

Creates an identity transform (a transform that does nothing).

## ◆ Transform() [2/2]

sf::Transform::Transform | ( | float | a00,
|  | float | a01,
|  | float | a02,
|  | float | a10,
|  | float | a11,
|  | float | a12,
|  | float | a20,
|  | float | a21,
|  | float | a22
| ) |  |

Construct a transform from a 3x3 matrix.

Parameters

  a00 | Element (0, 0) of the matrix
  a01 | Element (0, 1) of the matrix
  a02 | Element (0, 2) of the matrix
  a10 | Element (1, 0) of the matrix
  a11 | Element (1, 1) of the matrix
  a12 | Element (1, 2) of the matrix
  a20 | Element (2, 0) of the matrix
  a21 | Element (2, 1) of the matrix
  a22 | Element (2, 2) of the matrix

## Member Function Documentation

## ◆ combine()

Transform& sf::Transform::combine | ( | const Transform & | transform | ) |

Combine the current transform with another one.

The result is a transform that is equivalent to applying *this followed by transform. Mathematically, it is equivalent to a matrix multiplication.

Parameters

  transform | Transform to combine with this transform

Returns
  Reference to *this

## ◆ getInverse()

Transform sf::Transform::getInverse | ( |  | ) | const

Return the inverse of the transform.

If the inverse cannot be computed, an identity transform is returned.

Returns
  A new transform which is the inverse of self

## ◆ getMatrix()

const float* sf::Transform::getMatrix | ( |  | ) | const

Return the transform as a 4x4 matrix.

This function returns a pointer to an array of 16 floats containing the transform elements as a 4x4 matrix, which is directly compatible with OpenGL functions.

sf::Transform transform = ...;
glLoadMatrixf(transform.getMatrix());

Returns
  Pointer to a 4x4 matrix

## ◆ rotate() [1/3]

Transform& sf::Transform::rotate | ( | float | angle | ) |

Combine the current transform with a rotation.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.rotate(90).translate(50, 20);

Parameters

  angle | Rotation angle, in degrees

Returns
  Reference to *this

See also
  translate, scale

## ◆ rotate() [2/3]

Transform& sf::Transform::rotate | ( | float | angle,
|  | float | centerX,
|  | float | centerY
| ) |  |

Combine the current transform with a rotation.

The center of rotation is provided for convenience as a second argument, so that you can build rotations around arbitrary points more easily (and efficiently) than the usual translate(-center).rotate(angle).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.rotate(90, 8, 3).translate(50, 20);

Parameters

  angle | Rotation angle, in degrees
  centerX | X coordinate of the center of rotation
  centerY | Y coordinate of the center of rotation

Returns
  Reference to *this

See also
  translate, scale

## ◆ rotate() [3/3]

Transform& sf::Transform::rotate | ( | float | angle,
|  | const Vector2f & | center
| ) |  |

Combine the current transform with a rotation.

The center of rotation is provided for convenience as a second argument, so that you can build rotations around arbitrary points more easily (and efficiently) than the usual translate(-center).rotate(angle).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.rotate(90, sf::Vector2f(8, 3)).translate(sf::Vector2f(50, 20));

Parameters

  angle | Rotation angle, in degrees
  center | Center of rotation

Returns
  Reference to *this

See also
  translate, scale

## ◆ scale() [1/4]

Transform& sf::Transform::scale | ( | float | scaleX,
|  | float | scaleY
| ) |  |

Combine the current transform with a scaling.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.scale(2, 1).rotate(45);

Parameters

  scaleX | Scaling factor on the X axis
  scaleY | Scaling factor on the Y axis

Returns
  Reference to *this

See also
  translate, rotate

## ◆ scale() [2/4]

Transform& sf::Transform::scale | ( | float | scaleX,
|  | float | scaleY,
|  | float | centerX,
|  | float | centerY
| ) |  |

Combine the current transform with a scaling.

The center of scaling is provided for convenience as a second argument, so that you can build scaling around arbitrary points more easily (and efficiently) than the usual translate(-center).scale(factors).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.scale(2, 1, 8, 3).rotate(45);

Parameters

  scaleX | Scaling factor on X axis
  scaleY | Scaling factor on Y axis
  centerX | X coordinate of the center of scaling
  centerY | Y coordinate of the center of scaling

Returns
  Reference to *this

See also
  translate, rotate

## ◆ scale() [3/4]

Transform& sf::Transform::scale | ( | const Vector2f & | factors | ) |

Combine the current transform with a scaling.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.scale(sf::Vector2f(2, 1)).rotate(45);

Parameters

  factors | Scaling factors

Returns
  Reference to *this

See also
  translate, rotate

## ◆ scale() [4/4]

Transform& sf::Transform::scale | ( | const Vector2f & | factors,
|  | const Vector2f & | center
| ) |  |

Combine the current transform with a scaling.

The center of scaling is provided for convenience as a second argument, so that you can build scaling around arbitrary points more easily (and efficiently) than the usual translate(-center).scale(factors).translate(center).

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.scale(sf::Vector2f(2, 1), sf::Vector2f(8, 3)).rotate(45);

Parameters

  factors | Scaling factors
  center | Center of scaling

Returns
  Reference to *this

See also
  translate, rotate

## ◆ transformPoint() [1/2]

Vector2f sf::Transform::transformPoint | ( | float | x,
|  | float | y
| ) |  | const

Transform a 2D point.

Parameters

  x | X coordinate of the point to transform
  y | Y coordinate of the point to transform

Returns
  Transformed point

## ◆ transformPoint() [2/2]

Vector2f sf::Transform::transformPoint | ( | const Vector2f & | point | ) | const

Transform a 2D point.

Parameters

  point | Point to transform

Returns
  Transformed point

## ◆ transformRect()

FloatRect sf::Transform::transformRect | ( | const FloatRect & | rectangle | ) | const

Transform a rectangle.

Since SFML doesn't provide support for oriented rectangles, the result of this function is always an axis-aligned rectangle. Which means that if the transform contains a rotation, the bounding rectangle of the transformed rectangle is returned.

Parameters

  rectangle | Rectangle to transform

Returns
  Transformed rectangle

## ◆ translate() [1/2]

Transform& sf::Transform::translate | ( | float | x,
|  | float | y
| ) |  |

Combine the current transform with a translation.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.translate(100, 200).rotate(45);

Parameters

  x | Offset to apply on X axis
  y | Offset to apply on Y axis

Returns
  Reference to *this

See also
  rotate, scale

## ◆ translate() [2/2]

Transform& sf::Transform::translate | ( | const Vector2f & | offset | ) |

Combine the current transform with a translation.

This function returns a reference to *this, so that calls can be chained.

sf::Transform transform;
transform.translate(sf::Vector2f(100, 200)).rotate(45);

Parameters

  offset | Translation offset to apply

Returns
  Reference to *this

See also
  rotate, scale

## Friends And Related Function Documentation

## ◆ operator!=()

bool operator!= | ( | const Transform & | left,
|  | const Transform & | right
| ) |  |
| related

Overload of binary operator != to compare two transforms.

This call is equivalent to !(left == right).

Parameters

  left | Left operand (the first transform)
  right | Right operand (the second transform)

Returns
  true if the transforms are not equal, false otherwise

## ◆ operator*() [1/2]

Transform operator* | ( | const Transform & | left,
|  | const Transform & | right
| ) |  |
| related

Overload of binary operator * to combine two transforms.

This call is equivalent to calling Transform(left).combine(right).

Parameters

  left | Left operand (the first transform)
  right | Right operand (the second transform)

Returns
  New combined transform

## ◆ operator*() [2/2]

Vector2f operator* | ( | const Transform & | left,
|  | const Vector2f & | right
| ) |  |
| related

Overload of binary operator * to transform a point.

This call is equivalent to calling left.transformPoint(right).

Parameters

  left | Left operand (the transform)
  right | Right operand (the point to transform)

Returns
  New transformed point

## ◆ operator*=()

Transform & operator*= | ( | Transform & | left,
|  | const Transform & | right
| ) |  |
| related

Overload of binary operator *= to combine two transforms.

This call is equivalent to calling left.combine(right).

Parameters

  left | Left operand (the first transform)
  right | Right operand (the second transform)

Returns
  The combined transform

## ◆ operator==()

bool operator== | ( | const Transform & | left,
|  | const Transform & | right
| ) |  |
| related

Overload of binary operator == to compare two transforms.

Performs an element-wise comparison of the elements of the left transform with the elements of the right transform.

Parameters

  left | Left operand (the first transform)
  right | Right operand (the second transform)

Returns
  true if the transforms are equal, false otherwise

## Member Data Documentation

## ◆ Identity

const Transform sf::Transform::Identity
| static

The identity transform (does nothing)

Definition at line 354 of file Transform.hpp.

The documentation for this class was generated from the following file:

- Transform.hpp