AffineTransform Class Reference

Represents a 2D affine-transformation matrix. More...

#include <juce_AffineTransform.h>

Public Member Functions
	AffineTransform ()=default
	Creates an identity transform.
	AffineTransform (const AffineTransform &)=default
	Creates a copy of another transform.
	AffineTransform (float mat00, float mat01, float mat02, float mat10, float mat11, float mat12) noexcept
	Creates a transform from a set of raw matrix values.
AffineTransform &	operator= (const AffineTransform &)=default
	Copies from another AffineTransform object.
bool	operator== (const AffineTransform &other) const noexcept
	Compares two transforms.
bool	operator!= (const AffineTransform &other) const noexcept
	Compares two transforms.
template<typename ValueType >
void	transformPoint (ValueType &x, ValueType &y) const noexcept
	Transforms a 2D coordinate using this matrix.
template<typename ValueType >
void	transformPoints (ValueType &x1, ValueType &y1, ValueType &x2, ValueType &y2) const noexcept
	Transforms two 2D coordinates using this matrix.
template<typename ValueType >
void	transformPoints (ValueType &x1, ValueType &y1, ValueType &x2, ValueType &y2, ValueType &x3, ValueType &y3) const noexcept
	Transforms three 2D coordinates using this matrix.
AffineTransform	translated (float deltaX, float deltaY) const noexcept
	Returns a new transform which is the same as this one followed by a translation.
template<typename PointType >
AffineTransform	translated (PointType delta) const noexcept
	Returns a new transform which is the same as this one followed by a translation.
AffineTransform	withAbsoluteTranslation (float translationX, float translationY) const noexcept
	Returns a copy of this transform with the specified translation matrix values.
AffineTransform	rotated (float angleInRadians) const noexcept
	Returns a transform which is the same as this one followed by a rotation.
AffineTransform	rotated (float angleInRadians, float pivotX, float pivotY) const noexcept
	Returns a transform which is the same as this one followed by a rotation about a given point.
AffineTransform	scaled (float factorX, float factorY) const noexcept
	Returns a transform which is the same as this one followed by a re-scaling.
AffineTransform	scaled (float factor) const noexcept
	Returns a transform which is the same as this one followed by a re-scaling.
AffineTransform	scaled (float factorX, float factorY, float pivotX, float pivotY) const noexcept
	Returns a transform which is the same as this one followed by a re-scaling.
AffineTransform	sheared (float shearX, float shearY) const noexcept
	Returns a transform which is the same as this one followed by a shear.
AffineTransform	inverted () const noexcept
	Returns a matrix which is the inverse operation of this one.
AffineTransform	followedBy (const AffineTransform &other) const noexcept
	Returns the result of concatenating another transformation after this one.
bool	isIdentity () const noexcept
	Returns true if this transform has no effect on points.
bool	isSingularity () const noexcept
	Returns true if this transform maps to a singularity - i.e.
bool	isOnlyTranslation () const noexcept
	Returns true if the transform only translates, and doesn't scale or rotate the points.
float	getTranslationX () const noexcept
	If this transform is only a translation, this returns the X offset.
float	getTranslationY () const noexcept
	If this transform is only a translation, this returns the X offset.
float	getDeterminant () const noexcept
	Returns the determinant of the transform.

Static Public Member Functions
static AffineTransform	translation (float deltaX, float deltaY) noexcept
	Returns a new transform which is a translation.
template<typename PointType >
static AffineTransform	translation (PointType delta) noexcept
	Returns a new transform which is a translation.
static AffineTransform	rotation (float angleInRadians) noexcept
	Returns a new transform which is a rotation about (0, 0).
static AffineTransform	rotation (float angleInRadians, float pivotX, float pivotY) noexcept
	Returns a new transform which is a rotation about a given point.
static AffineTransform	scale (float factorX, float factorY) noexcept
	Returns a new transform which is a re-scale about the origin.
static AffineTransform	scale (float factor) noexcept
	Returns a new transform which is a re-scale about the origin.
static AffineTransform	scale (float factorX, float factorY, float pivotX, float pivotY) noexcept
	Returns a new transform which is a re-scale centred around the point provided.
static AffineTransform	shear (float shearX, float shearY) noexcept
	Returns a shear transform, centred around the origin (0, 0).
static AffineTransform	verticalFlip (float height) noexcept
	Returns a transform that will flip coordinates vertically within a window of the given height.
static AffineTransform	fromTargetPoints (float x00, float y00, float x10, float y10, float x01, float y01) noexcept
	Returns the transform that will map three known points onto three coordinates that are supplied.
static AffineTransform	fromTargetPoints (float sourceX1, float sourceY1, float targetX1, float targetY1, float sourceX2, float sourceY2, float targetX2, float targetY2, float sourceX3, float sourceY3, float targetX3, float targetY3) noexcept
	Returns the transform that will map three specified points onto three target points.
template<typename PointType >
static AffineTransform	fromTargetPoints (PointType source1, PointType target1, PointType source2, PointType target2, PointType source3, PointType target3) noexcept
	Returns the transform that will map three specified points onto three target points.

Public Attributes
float	mat00 { 1.0f }
float	mat01 { 0.0f }
float	mat02 { 0.0f }
float	mat10 { 0.0f }
float	mat11 { 1.0f }
float	mat12 { 0.0f }

Detailed Description

Represents a 2D affine-transformation matrix.

An affine transformation is a transformation such as a rotation, scale, shear, resize or translation.

These are used for various 2D transformation tasks, e.g. with Path objects.

See also

Path, Point, Line

Constructor & Destructor Documentation

AffineTransform() [1/3]

AffineTransform::AffineTransform ( )

default

Creates an identity transform.

AffineTransform() [2/3]

AffineTransform::AffineTransform ( const AffineTransform & )

default

Creates a copy of another transform.

AffineTransform() [3/3]

AffineTransform::AffineTransform ( float mat00, float mat01, float mat02, float mat10, float mat11, float mat12 )

noexcept

Creates a transform from a set of raw matrix values.

The resulting matrix is:

(mat00 mat01 mat02)
(mat10 mat11 mat12)
(  0     0     1  )

Member Function Documentation

operator=()

AffineTransform & AffineTransform::operator= ( const AffineTransform & )

default

Copies from another AffineTransform object.

operator==()

bool AffineTransform::operator== ( const AffineTransform & other ) const

noexcept

Compares two transforms.

operator!=()

bool AffineTransform::operator!= ( const AffineTransform & other ) const

noexcept

Compares two transforms.

transformPoint()

template<typename ValueType >

void AffineTransform::transformPoint ( ValueType & x, ValueType & y ) const

noexcept

Transforms a 2D coordinate using this matrix.

References x, and y.

transformPoints() [1/2]

template<typename ValueType >

void AffineTransform::transformPoints ( ValueType & x1, ValueType & y1, ValueType & x2, ValueType & y2 ) const

noexcept

Transforms two 2D coordinates using this matrix.

This is just a shortcut for calling transformPoint() on each of these pairs of coordinates in turn. (And putting all the calculations into one function hopefully also gives the compiler a bit more scope for pipelining it).

transformPoints() [2/2]

template<typename ValueType >

void AffineTransform::transformPoints ( ValueType & x1, ValueType & y1, ValueType & x2, ValueType & y2, ValueType & x3, ValueType & y3 ) const

noexcept

Transforms three 2D coordinates using this matrix.

This is just a shortcut for calling transformPoint() on each of these pairs of coordinates in turn. (And putting all the calculations into one function hopefully also gives the compiler a bit more scope for pipelining it).

translated() [1/2]

AffineTransform AffineTransform::translated ( float deltaX, float deltaY ) const

noexcept

Returns a new transform which is the same as this one followed by a translation.

translated() [2/2]

template<typename PointType >

AffineTransform AffineTransform::translated ( PointType delta ) const

noexcept

Returns a new transform which is the same as this one followed by a translation.

translation() [1/2]

static AffineTransform AffineTransform::translation ( float deltaX, float deltaY )

staticnoexcept

Returns a new transform which is a translation.

translation() [2/2]

template<typename PointType >

static AffineTransform AffineTransform::translation ( PointType delta )

staticnoexcept

Returns a new transform which is a translation.

withAbsoluteTranslation()

AffineTransform AffineTransform::withAbsoluteTranslation ( float translationX, float translationY ) const

noexcept

Returns a copy of this transform with the specified translation matrix values.

rotated() [1/2]

AffineTransform AffineTransform::rotated ( float angleInRadians ) const

noexcept

Returns a transform which is the same as this one followed by a rotation.

The rotation is specified by a number of radians to rotate clockwise, centred around the origin (0, 0).

rotated() [2/2]

AffineTransform AffineTransform::rotated ( float angleInRadians, float pivotX, float pivotY ) const

noexcept

Returns a transform which is the same as this one followed by a rotation about a given point.

The rotation is specified by a number of radians to rotate clockwise, centred around the coordinates passed in.

rotation() [1/2]

static AffineTransform AffineTransform::rotation ( float angleInRadians )

staticnoexcept

Returns a new transform which is a rotation about (0, 0).

rotation() [2/2]

static AffineTransform AffineTransform::rotation ( float angleInRadians, float pivotX, float pivotY )

staticnoexcept

Returns a new transform which is a rotation about a given point.

scaled() [1/3]

AffineTransform AffineTransform::scaled ( float factorX, float factorY ) const

noexcept

Returns a transform which is the same as this one followed by a re-scaling.

The scaling is centred around the origin (0, 0).

scaled() [2/3]

AffineTransform AffineTransform::scaled ( float factor ) const

noexcept

Returns a transform which is the same as this one followed by a re-scaling.

The scaling is centred around the origin (0, 0).

scaled() [3/3]

AffineTransform AffineTransform::scaled ( float factorX, float factorY, float pivotX, float pivotY ) const

noexcept

Returns a transform which is the same as this one followed by a re-scaling.

The scaling is centred around the origin provided.

scale() [1/3]

static AffineTransform AffineTransform::scale ( float factorX, float factorY )

staticnoexcept

Returns a new transform which is a re-scale about the origin.

scale() [2/3]

static AffineTransform AffineTransform::scale ( float factor )

staticnoexcept

Returns a new transform which is a re-scale about the origin.

scale() [3/3]

static AffineTransform AffineTransform::scale ( float factorX, float factorY, float pivotX, float pivotY )

staticnoexcept

Returns a new transform which is a re-scale centred around the point provided.

sheared()

AffineTransform AffineTransform::sheared ( float shearX, float shearY ) const

noexcept

Returns a transform which is the same as this one followed by a shear.

The shear is centred around the origin (0, 0).

shear()

static AffineTransform AffineTransform::shear ( float shearX, float shearY )

staticnoexcept

Returns a shear transform, centred around the origin (0, 0).

verticalFlip()

static AffineTransform AffineTransform::verticalFlip ( float height )

staticnoexcept

Returns a transform that will flip coordinates vertically within a window of the given height.

This is handy for converting between upside-down coordinate systems such as OpenGL or CoreGraphics.

inverted()

AffineTransform AffineTransform::inverted ( ) const

noexcept

Returns a matrix which is the inverse operation of this one.

Some matrices don't have an inverse - in this case, the method will just return an identity transform.

fromTargetPoints() [1/3]

static AffineTransform AffineTransform::fromTargetPoints ( float x00, float y00, float x10, float y10, float x01, float y01 )

staticnoexcept

Returns the transform that will map three known points onto three coordinates that are supplied.

This returns the transform that will transform (0, 0) into (x00, y00), (1, 0) to (x10, y10), and (0, 1) to (x01, y01).

fromTargetPoints() [2/3]

static AffineTransform AffineTransform::fromTargetPoints ( float sourceX1, float sourceY1, float targetX1, float targetY1, float sourceX2, float sourceY2, float targetX2, float targetY2, float sourceX3, float sourceY3, float targetX3, float targetY3 )

staticnoexcept

Returns the transform that will map three specified points onto three target points.

fromTargetPoints() [3/3]

template<typename PointType >

static AffineTransform AffineTransform::fromTargetPoints ( PointType source1, PointType target1, PointType source2, PointType target2, PointType source3, PointType target3 )

staticnoexcept

Returns the transform that will map three specified points onto three target points.

followedBy()

AffineTransform AffineTransform::followedBy ( const AffineTransform & other ) const

noexcept

Returns the result of concatenating another transformation after this one.

isIdentity()

bool AffineTransform::isIdentity ( ) const

noexcept

Returns true if this transform has no effect on points.

isSingularity()

bool AffineTransform::isSingularity ( ) const

noexcept

Returns true if this transform maps to a singularity - i.e.

if it has no inverse.

isOnlyTranslation()

bool AffineTransform::isOnlyTranslation ( ) const

noexcept

Returns true if the transform only translates, and doesn't scale or rotate the points.

getTranslationX()

float AffineTransform::getTranslationX ( ) const

noexcept

If this transform is only a translation, this returns the X offset.

See also

isOnlyTranslation

getTranslationY()

float AffineTransform::getTranslationY ( ) const

noexcept

If this transform is only a translation, this returns the X offset.

See also

isOnlyTranslation

getDeterminant()

float AffineTransform::getDeterminant ( ) const

noexcept

Returns the determinant of the transform.

Member Data Documentation

mat00

float AffineTransform::mat00 { 1.0f }

mat01

float AffineTransform::mat01 { 0.0f }

mat02

float AffineTransform::mat02 { 0.0f }

mat10

float AffineTransform::mat10 { 0.0f }

mat11

float AffineTransform::mat11 { 1.0f }

mat12

float AffineTransform::mat12 { 0.0f }

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

• juce_AffineTransform.h