AffineTransform Class Reference

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

List of all members.

Public Member Functions
	AffineTransform () noexcept
	Creates an identity transform.
	AffineTransform (const AffineTransform &other) noexcept
	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 &other) noexcept
	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 co-ordinate using this matrix.
template<typename ValueType >
void	transformPoints (ValueType &x1, ValueType &y1, ValueType &x2, ValueType &y2) const noexcept
	Transforms two 2D co-ordinates 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 co-ordinates 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.
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 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	getScaleFactor () const noexcept
	Returns the approximate scale factor by which lengths will be transformed.
Static Public Member Functions
static AffineTransform	translation (float deltaX, float deltaY) 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 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	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.
Public Attributes
float	mat00
float	mat01
float	mat02
float	mat10
float	mat11
float	mat12
Static Public Attributes
static const AffineTransform	identity
	A ready-to-use identity transform, which you can use to append other transformations to.

---

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::AffineTransform

(

)

Creates an identity transform.

AffineTransform::AffineTransform

(

const AffineTransform &

other )

Creates a copy of another transform.

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

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

AffineTransform& AffineTransform::operator=

(

const AffineTransform &

other )

Copies from another AffineTransform object.

bool AffineTransform::operator==

(

const AffineTransform &

other )

const

Compares two transforms.

bool AffineTransform::operator!=

(

const AffineTransform &

other )

const

Compares two transforms.

template<typename ValueType >

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

Transforms a 2D co-ordinate using this matrix.

template<typename ValueType >

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

Transforms two 2D co-ordinates 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).

template<typename ValueType >

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

Transforms three 2D co-ordinates 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).

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

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

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

Returns a new transform which is a translation.

AffineTransform AffineTransform::rotated

(

float

angleInRadians )

const

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).

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

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 co-ordinates passed in.

static AffineTransform AffineTransform::rotation

(

float

angleInRadians )

[static]

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

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

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

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

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

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

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

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

The scaling is centred around the origin provided.

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

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

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

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

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

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

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

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

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

AffineTransform AffineTransform::inverted

(

)

const

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.

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

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).

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
	)		[static]

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

AffineTransform AffineTransform::followedBy

(

const AffineTransform &

other )

const

Returns the result of concatenating another transformation after this one.

bool AffineTransform::isIdentity

(

)

const

Returns true if this transform has no effect on points.

bool AffineTransform::isSingularity

(

)

const

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

if it has no inverse.

bool AffineTransform::isOnlyTranslation

(

)

const

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

float AffineTransform::getTranslationX

(

)

const

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

See also:

isOnlyTranslation

float AffineTransform::getTranslationY

(

)

const

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

See also:

isOnlyTranslation

float AffineTransform::getScaleFactor

(

)

const

Returns the approximate scale factor by which lengths will be transformed.

Obviously a length may be scaled by entirely different amounts depending on its direction, so this is only appropriate as a rough guide.

---

Member Data Documentation

const AffineTransform AffineTransform::identity [static]

A ready-to-use identity transform, which you can use to append other transformations to.

e.g.

        AffineTransform myTransform = AffineTransform::identity.rotated (.5f)
                                                               .scaled (2.0f);

float AffineTransform::mat00

float AffineTransform::mat01

float AffineTransform::mat02

float AffineTransform::mat10

float AffineTransform::mat11

float AffineTransform::mat12

---

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

• juce_AffineTransform.h