SkMatrix holds a 3x3 matrix for transforming coordinates. More...

#include <SkMatrix.h>

Public Types
enum	ScaleToFit { kFill_ScaleToFit , kStart_ScaleToFit , kCenter_ScaleToFit , kEnd_ScaleToFit }

enum	TypeMask { kIdentity_Mask = 0 , kTranslate_Mask = 0x01 , kScale_Mask = 0x02 , kAffine_Mask = 0x04 , kPerspective_Mask = 0x08 }

Public Member Functions
constexpr	SkMatrix ()
	Creates an identity SkMatrix: More...

TypeMask	getType () const
	Returns a bit field describing the transformations the matrix may perform. More...

bool	isIdentity () const
	Returns true if SkMatrix is identity. More...

bool	isScaleTranslate () const
	Returns true if SkMatrix at most scales and translates. More...

bool	isTranslate () const
	Returns true if SkMatrix is identity, or translates. More...

bool	rectStaysRect () const
	Returns true SkMatrix maps SkRect to another SkRect. More...

bool	preservesAxisAlignment () const
	Returns true SkMatrix maps SkRect to another SkRect. More...

bool	hasPerspective () const
	Returns true if the matrix contains perspective elements. More...

bool	isSimilarity (SkScalar tol=SK_ScalarNearlyZero) const
	Returns true if SkMatrix contains only translation, rotation, reflection, and uniform scale. More...

bool	preservesRightAngles (SkScalar tol=SK_ScalarNearlyZero) const
	Returns true if SkMatrix contains only translation, rotation, reflection, and scale. More...

SkScalar	operator[] (int index) const
	Returns one matrix value. More...

SkScalar	get (int index) const
	Returns one matrix value. More...

SkScalar	rc (int r, int c) const
	Returns one matrix value from a particular row/column. More...

SkScalar	getScaleX () const
	Returns scale factor multiplied by x-axis input, contributing to x-axis output. More...

SkScalar	getScaleY () const
	Returns scale factor multiplied by y-axis input, contributing to y-axis output. More...

SkScalar	getSkewY () const
	Returns scale factor multiplied by x-axis input, contributing to y-axis output. More...

SkScalar	getSkewX () const
	Returns scale factor multiplied by y-axis input, contributing to x-axis output. More...

SkScalar	getTranslateX () const
	Returns translation contributing to x-axis output. More...

SkScalar	getTranslateY () const
	Returns translation contributing to y-axis output. More...

SkScalar	getPerspX () const
	Returns factor scaling input x-axis relative to input y-axis. More...

SkScalar	getPerspY () const
	Returns factor scaling input y-axis relative to input x-axis. More...

SkScalar &	operator[] (int index)
	Returns writable SkMatrix value. More...

SkMatrix &	set (int index, SkScalar value)
	Sets SkMatrix value. More...

SkMatrix &	setScaleX (SkScalar v)
	Sets horizontal scale factor. More...

SkMatrix &	setScaleY (SkScalar v)
	Sets vertical scale factor. More...

SkMatrix &	setSkewY (SkScalar v)
	Sets vertical skew factor. More...

SkMatrix &	setSkewX (SkScalar v)
	Sets horizontal skew factor. More...

SkMatrix &	setTranslateX (SkScalar v)
	Sets horizontal translation. More...

SkMatrix &	setTranslateY (SkScalar v)
	Sets vertical translation. More...

SkMatrix &	setPerspX (SkScalar v)
	Sets input x-axis perspective factor, which causes mapXY() to vary input x-axis values inversely proportional to input y-axis values. More...

SkMatrix &	setPerspY (SkScalar v)
	Sets input y-axis perspective factor, which causes mapXY() to vary input y-axis values inversely proportional to input x-axis values. More...

SkMatrix &	setAll (SkScalar scaleX, SkScalar skewX, SkScalar transX, SkScalar skewY, SkScalar scaleY, SkScalar transY, SkScalar persp0, SkScalar persp1, SkScalar persp2)
	Sets all values from parameters. More...

void	get9 (SkScalar buffer[9]) const
	Copies nine scalar values contained by SkMatrix into buffer, in member value ascending order: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2. More...

SkMatrix &	set9 (const SkScalar buffer[9])
	Sets SkMatrix to nine scalar values in buffer, in member value ascending order: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2. More...

SkMatrix &	reset ()
	Sets SkMatrix to identity; which has no effect on mapped SkPoint. More...

SkMatrix &	setIdentity ()
	Sets SkMatrix to identity; which has no effect on mapped SkPoint. More...

SkMatrix &	setTranslate (SkScalar dx, SkScalar dy)
	Sets SkMatrix to translate by (dx, dy). More...

SkMatrix &	setTranslate (const SkVector &v)
	Sets SkMatrix to translate by (v.fX, v.fY). More...

SkMatrix &	setScale (SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)
	Sets SkMatrix to scale by sx and sy, about a pivot point at (px, py). More...

SkMatrix &	setScale (SkScalar sx, SkScalar sy)
	Sets SkMatrix to scale by sx and sy about at pivot point at (0, 0). More...

SkMatrix &	setRotate (SkScalar degrees, SkScalar px, SkScalar py)
	Sets SkMatrix to rotate by degrees about a pivot point at (px, py). More...

SkMatrix &	setRotate (SkScalar degrees)
	Sets SkMatrix to rotate by degrees about a pivot point at (0, 0). More...

SkMatrix &	setSinCos (SkScalar sinValue, SkScalar cosValue, SkScalar px, SkScalar py)
	Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (px, py). More...

SkMatrix &	setSinCos (SkScalar sinValue, SkScalar cosValue)
	Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (0, 0). More...

SkMatrix &	setRSXform (const SkRSXform &rsxForm)
	Sets SkMatrix to rotate, scale, and translate using a compressed matrix form. More...

SkMatrix &	setSkew (SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)
	Sets SkMatrix to skew by kx and ky, about a pivot point at (px, py). More...

SkMatrix &	setSkew (SkScalar kx, SkScalar ky)
	Sets SkMatrix to skew by kx and ky, about a pivot point at (0, 0). More...

SkMatrix &	setConcat (const SkMatrix &a, const SkMatrix &b)
	Sets SkMatrix to SkMatrix a multiplied by SkMatrix b. More...

SkMatrix &	preTranslate (SkScalar dx, SkScalar dy)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from translation (dx, dy). More...

SkMatrix &	preScale (SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from scaling by (sx, sy) about pivot point (px, py). More...

SkMatrix &	preScale (SkScalar sx, SkScalar sy)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0). More...

SkMatrix &	preRotate (SkScalar degrees, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (px, py). More...

SkMatrix &	preRotate (SkScalar degrees)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (0, 0). More...

SkMatrix &	preSkew (SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from skewing by (kx, ky) about pivot point (px, py). More...

SkMatrix &	preSkew (SkScalar kx, SkScalar ky)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0). More...

SkMatrix &	preConcat (const SkMatrix &other)
	Sets SkMatrix to SkMatrix multiplied by SkMatrix other. More...

SkMatrix &	postTranslate (SkScalar dx, SkScalar dy)
	Sets SkMatrix to SkMatrix constructed from translation (dx, dy) multiplied by SkMatrix. More...

SkMatrix &	postScale (SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix constructed from scaling by (sx, sy) about pivot point (px, py), multiplied by SkMatrix. More...

SkMatrix &	postScale (SkScalar sx, SkScalar sy)
	Sets SkMatrix to SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0), multiplied by SkMatrix. More...

SkMatrix &	postRotate (SkScalar degrees, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (px, py), multiplied by SkMatrix. More...

SkMatrix &	postRotate (SkScalar degrees)
	Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (0, 0), multiplied by SkMatrix. More...

SkMatrix &	postSkew (SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)
	Sets SkMatrix to SkMatrix constructed from skewing by (kx, ky) about pivot point (px, py), multiplied by SkMatrix. More...

SkMatrix &	postSkew (SkScalar kx, SkScalar ky)
	Sets SkMatrix to SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0), multiplied by SkMatrix. More...

SkMatrix &	postConcat (const SkMatrix &other)
	Sets SkMatrix to SkMatrix other multiplied by SkMatrix. More...

bool	setRectToRect (const SkRect &src, const SkRect &dst, ScaleToFit stf)
	Sets SkMatrix to scale and translate src SkRect to dst SkRect. More...

bool	setPolyToPoly (const SkPoint src[], const SkPoint dst[], int count)
	Sets SkMatrix to map src to dst. More...

bool	invert (SkMatrix *inverse) const
	Sets inverse to reciprocal matrix, returning true if SkMatrix can be inverted. More...

bool	asAffine (SkScalar affine[6]) const
	Fills affine in column major order. More...

SkMatrix &	setAffine (const SkScalar affine[6])
	Sets SkMatrix to affine values, passed in column major order. More...

void	normalizePerspective ()
	A matrix is categorized as 'perspective' if the bottom row is not [0, 0, 1]. More...

void	mapPoints (SkPoint dst[], const SkPoint src[], int count) const
	Maps src SkPoint array of length count to dst SkPoint array of equal or greater length. More...

void	mapPoints (SkPoint pts[], int count) const
	Maps pts SkPoint array of length count in place. More...

void	mapHomogeneousPoints (SkPoint3 dst[], const SkPoint3 src[], int count) const
	Maps src SkPoint3 array of length count to dst SkPoint3 array, which must of length count or greater. More...

void	mapHomogeneousPoints (SkPoint3 dst[], const SkPoint src[], int count) const
	Returns homogeneous points, starting with 2D src points (with implied w = 1). More...

SkPoint	mapPoint (SkPoint pt) const
	Returns SkPoint pt multiplied by SkMatrix. More...

void	mapXY (SkScalar x, SkScalar y, SkPoint *result) const
	Maps SkPoint (x, y) to result. More...

SkPoint	mapXY (SkScalar x, SkScalar y) const
	Returns SkPoint (x, y) multiplied by SkMatrix. More...

SkPoint	mapOrigin () const
	Returns (0, 0) multiplied by SkMatrix. More...

void	mapVectors (SkVector dst[], const SkVector src[], int count) const
	Maps src vector array of length count to vector SkPoint array of equal or greater length. More...

void	mapVectors (SkVector vecs[], int count) const
	Maps vecs vector array of length count in place, multiplying each vector by SkMatrix, treating SkMatrix translation as zero. More...

void	mapVector (SkScalar dx, SkScalar dy, SkVector *result) const
	Maps vector (dx, dy) to result. More...

SkVector	mapVector (SkScalar dx, SkScalar dy) const
	Returns vector (dx, dy) multiplied by SkMatrix, treating SkMatrix translation as zero. More...

bool	mapRect (SkRect *dst, const SkRect &src, SkApplyPerspectiveClip pc=SkApplyPerspectiveClip::kYes) const
	Sets dst to bounds of src corners mapped by SkMatrix. More...

bool	mapRect (SkRect *rect, SkApplyPerspectiveClip pc=SkApplyPerspectiveClip::kYes) const
	Sets rect to bounds of rect corners mapped by SkMatrix. More...

SkRect	mapRect (const SkRect &src, SkApplyPerspectiveClip pc=SkApplyPerspectiveClip::kYes) const
	Returns bounds of src corners mapped by SkMatrix. More...

void	mapRectToQuad (SkPoint dst[4], const SkRect &rect) const
	Maps four corners of rect to dst. More...

void	mapRectScaleTranslate (SkRect *dst, const SkRect &src) const
	Sets dst to bounds of src corners mapped by SkMatrix. More...

SkScalar	mapRadius (SkScalar radius) const
	Returns geometric mean radius of ellipse formed by constructing circle of size radius, and mapping constructed circle with SkMatrix. More...

void	dump () const
	Writes text representation of SkMatrix to standard output. More...

SkScalar	getMinScale () const
	Returns the minimum scaling factor of SkMatrix by decomposing the scaling and skewing elements. More...

SkScalar	getMaxScale () const
	Returns the maximum scaling factor of SkMatrix by decomposing the scaling and skewing elements. More...

bool	getMinMaxScales (SkScalar scaleFactors[2]) const
	Sets scaleFactors[0] to the minimum scaling factor, and scaleFactors[1] to the maximum scaling factor. More...

bool	decomposeScale (SkSize scale, SkMatrix remaining=nullptr) const
	Decomposes SkMatrix into scale components and whatever remains. More...

void	dirtyMatrixTypeCache ()
	Sets internal cache to unknown state. More...

void	setScaleTranslate (SkScalar sx, SkScalar sy, SkScalar tx, SkScalar ty)
	Initializes SkMatrix with scale and translate elements. More...

bool	isFinite () const
	Returns true if all elements of the matrix are finite. More...

Static Public Member Functions
static SkMatrix	Scale (SkScalar sx, SkScalar sy)
	Sets SkMatrix to scale by (sx, sy). More...

static SkMatrix	Translate (SkScalar dx, SkScalar dy)
	Sets SkMatrix to translate by (dx, dy). More...

static SkMatrix	Translate (SkVector t)

static SkMatrix	Translate (SkIVector t)

static SkMatrix	RotateDeg (SkScalar deg)
	Sets SkMatrix to rotate by \|deg\| about a pivot point at (0, 0). More...

static SkMatrix	RotateDeg (SkScalar deg, SkPoint pt)

static SkMatrix	RotateRad (SkScalar rad)

static SkMatrix	Skew (SkScalar kx, SkScalar ky)
	Sets SkMatrix to skew by (kx, ky) about pivot point (0, 0). More...

static SkMatrix	RectToRect (const SkRect &src, const SkRect &dst, ScaleToFit mode=kFill_ScaleToFit)
	Returns SkMatrix set to scale and translate src to dst. More...

static SkMatrix	MakeAll (SkScalar scaleX, SkScalar skewX, SkScalar transX, SkScalar skewY, SkScalar scaleY, SkScalar transY, SkScalar pers0, SkScalar pers1, SkScalar pers2)
	Sets SkMatrix to: More...

static SkMatrix	MakeRectToRect (const SkRect &src, const SkRect &dst, ScaleToFit stf)
	Returns SkMatrix set to scale and translate src SkRect to dst SkRect. More...

static void	SetAffineIdentity (SkScalar affine[6])
	Fills affine with identity values in column major order. More...

static const SkMatrix &	I ()
	Returns reference to const identity SkMatrix. More...

static const SkMatrix &	InvalidMatrix ()
	Returns reference to a const SkMatrix with invalid values. More...

static SkMatrix	Concat (const SkMatrix &a, const SkMatrix &b)
	Returns SkMatrix a multiplied by SkMatrix b. More...

Static Public Attributes
static constexpr int	kMScaleX = 0
	SkMatrix organizes its values in row-major order. More...

static constexpr int	kMSkewX = 1
	horizontal skew factor More...

static constexpr int	kMTransX = 2
	horizontal translation More...

static constexpr int	kMSkewY = 3
	vertical skew factor More...

static constexpr int	kMScaleY = 4
	vertical scale factor More...

static constexpr int	kMTransY = 5
	vertical translation More...

static constexpr int	kMPersp0 = 6
	input x perspective factor More...

static constexpr int	kMPersp1 = 7
	input y perspective factor More...

static constexpr int	kMPersp2 = 8
	perspective bias More...

static constexpr int	kAScaleX = 0
	Affine arrays are in column-major order to match the matrix used by PDF and XPS. More...

static constexpr int	kASkewY = 1
	vertical skew factor More...

static constexpr int	kASkewX = 2
	horizontal skew factor More...

static constexpr int	kAScaleY = 3
	vertical scale factor More...

static constexpr int	kATransX = 4
	horizontal translation More...

static constexpr int	kATransY = 5
	vertical translation More...

Friends
class	SkPerspIter

class	SkMatrixPriv

class	SerializationTest

SK_API bool	operator== (const SkMatrix &a, const SkMatrix &b)
	Compares a and b; returns true if a and b are numerically equal. More...

SK_API bool	operator!= (const SkMatrix &a, const SkMatrix &b)
	Compares a and b; returns true if a and b are not numerically equal. More...

SkMatrix	operator* (const SkMatrix &a, const SkMatrix &b)

Detailed Description

SkMatrix holds a 3x3 matrix for transforming coordinates.

This allows mapping SkPoint and vectors with translation, scaling, skewing, rotation, and perspective.

SkMatrix elements are in row major order. SkMatrix constexpr default constructs to identity.

SkMatrix includes a hidden variable that classifies the type of matrix to improve performance. SkMatrix is not thread safe unless getType() is called first.

example: https://fiddle.skia.org/c/@Matrix_063

Member Enumeration Documentation

◆ ScaleToFit

enum SkMatrix::ScaleToFit

Enumerator
kFill_ScaleToFit	scales in x and y to fill destination SkRect
kStart_ScaleToFit	scales and aligns to left and top
kCenter_ScaleToFit	scales and aligns to center
kEnd_ScaleToFit	scales and aligns to right and bottom

◆ TypeMask

enum SkMatrix::TypeMask

Enumerator
kIdentity_Mask	identity SkMatrix; all bits clear
kTranslate_Mask	translation SkMatrix
kScale_Mask	scale SkMatrix
kAffine_Mask	skew or rotate SkMatrix
kPerspective_Mask	perspective SkMatrix

Constructor & Destructor Documentation

◆ SkMatrix()

constexpr SkMatrix::SkMatrix ( )

inlineconstexpr

Creates an identity SkMatrix:

| 1 0 0 |
| 0 1 0 |
| 0 0 1 |

Member Function Documentation

◆ asAffine()

bool SkMatrix::asAffine ( SkScalar affine[6] ) const

Fills affine in column major order.

Sets affine to:

| scale-x  skew-x translate-x |
| skew-y  scale-y translate-y |

If SkMatrix contains perspective, returns false and leaves affine unchanged.

Parameters

affine storage for 3 by 2 affine matrix; may be nullptr

Returns: true if SkMatrix does not contain perspective

◆ Concat()

static SkMatrix SkMatrix::Concat	(	const SkMatrix &	a,
		const SkMatrix &	b
	)

inlinestatic

Returns SkMatrix a multiplied by SkMatrix b.

Given:

    | A B C |      | J K L |
a = | D E F |, b = | M N O |
    | G H I |      | P Q R |

sets SkMatrix to:

        | A B C |   | J K L |   | AJ+BM+CP AK+BN+CQ AL+BO+CR |
a * b = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR |
        | G H I |   | P Q R |   | GJ+HM+IP GK+HN+IQ GL+HO+IR |

Parameters

a	SkMatrix on left side of multiply expression
b	SkMatrix on right side of multiply expression

Returns: SkMatrix computed from a times b

◆ decomposeScale()

bool SkMatrix::decomposeScale	(	SkSize *	scale,
		SkMatrix *	remaining = `nullptr`
	)		const

Decomposes SkMatrix into scale components and whatever remains.

Returns false if SkMatrix could not be decomposed.

Sets scale to portion of SkMatrix that scale axes. Sets remaining to SkMatrix with scaling factored out. remaining may be passed as nullptr to determine if SkMatrix can be decomposed without computing remainder.

Returns true if scale components are found. scale and remaining are unchanged if SkMatrix contains perspective; scale factors are not finite, or are nearly zero.

On success: Matrix = Remaining * scale.

Parameters

scale	axes scaling factors; may be nullptr
remaining	SkMatrix without scaling; may be nullptr

Returns: true if scale can be computed

example: https://fiddle.skia.org/c/@Matrix_decomposeScale

◆ dirtyMatrixTypeCache()

void SkMatrix::dirtyMatrixTypeCache ( )

inline

Sets internal cache to unknown state.

Use to force update after repeated modifications to SkMatrix element reference returned by operator[](int index).

◆ dump()

void SkMatrix::dump ( ) const

Writes text representation of SkMatrix to standard output.

Floating point values are written with limited precision; it may not be possible to reconstruct original SkMatrix from output.

example: https://fiddle.skia.org/c/@Matrix_dump

◆ get()

SkScalar SkMatrix::get ( int index ) const

inline

Returns one matrix value.

Asserts if index is out of range and SK_DEBUG is defined.

Parameters

index one of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2

Returns: value corresponding to index

◆ get9()

void SkMatrix::get9 ( SkScalar buffer[9] ) const

inline

Copies nine scalar values contained by SkMatrix into buffer, in member value ascending order: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2.

Parameters

buffer storage for nine scalar values

◆ getMaxScale()

SkScalar SkMatrix::getMaxScale ( ) const

Returns the maximum scaling factor of SkMatrix by decomposing the scaling and skewing elements.

Returns -1 if scale factor overflows or SkMatrix contains perspective.

Returns: maximum scale factor

example: https://fiddle.skia.org/c/@Matrix_getMaxScale

◆ getMinMaxScales()

bool SkMatrix::getMinMaxScales ( SkScalar scaleFactors[2] ) const

Sets scaleFactors[0] to the minimum scaling factor, and scaleFactors[1] to the maximum scaling factor.

Scaling factors are computed by decomposing the SkMatrix scaling and skewing elements.

Returns true if scaleFactors are found; otherwise, returns false and sets scaleFactors to undefined values.

Parameters

scaleFactors storage for minimum and maximum scale factors

Returns: true if scale factors were computed correctly

◆ getMinScale()

SkScalar SkMatrix::getMinScale ( ) const

Returns the minimum scaling factor of SkMatrix by decomposing the scaling and skewing elements.

Returns -1 if scale factor overflows or SkMatrix contains perspective.

Returns: minimum scale factor

example: https://fiddle.skia.org/c/@Matrix_getMinScale

◆ getPerspX()

SkScalar SkMatrix::getPerspX ( ) const

inline

Returns factor scaling input x-axis relative to input y-axis.

Returns: input x-axis perspective factor

◆ getPerspY()

SkScalar SkMatrix::getPerspY ( ) const

inline

Returns factor scaling input y-axis relative to input x-axis.

Returns: input y-axis perspective factor

◆ getScaleX()

SkScalar SkMatrix::getScaleX ( ) const

inline

Returns scale factor multiplied by x-axis input, contributing to x-axis output.

With mapPoints(), scales SkPoint along the x-axis.

Returns: horizontal scale factor

◆ getScaleY()

SkScalar SkMatrix::getScaleY ( ) const

inline

Returns scale factor multiplied by y-axis input, contributing to y-axis output.

With mapPoints(), scales SkPoint along the y-axis.

Returns: vertical scale factor

◆ getSkewX()

SkScalar SkMatrix::getSkewX ( ) const

inline

Returns scale factor multiplied by y-axis input, contributing to x-axis output.

With mapPoints(), skews SkPoint along the x-axis. Skewing both axes can rotate SkPoint.

Returns: horizontal scale factor

◆ getSkewY()

SkScalar SkMatrix::getSkewY ( ) const

inline

Returns scale factor multiplied by x-axis input, contributing to y-axis output.

With mapPoints(), skews SkPoint along the y-axis. Skewing both axes can rotate SkPoint.

Returns: vertical skew factor

◆ getTranslateX()

SkScalar SkMatrix::getTranslateX ( ) const

inline

Returns translation contributing to x-axis output.

With mapPoints(), moves SkPoint along the x-axis.

Returns: horizontal translation factor

◆ getTranslateY()

SkScalar SkMatrix::getTranslateY ( ) const

inline

Returns translation contributing to y-axis output.

With mapPoints(), moves SkPoint along the y-axis.

Returns: vertical translation factor

◆ getType()

TypeMask SkMatrix::getType ( ) const

inline

Returns a bit field describing the transformations the matrix may perform.

The bit field is computed conservatively, so it may include false positives. For example, when kPerspective_Mask is set, all other bits are set.

Returns: kIdentity_Mask, or combinations of: kTranslate_Mask, kScale_Mask, kAffine_Mask, kPerspective_Mask

◆ hasPerspective()

bool SkMatrix::hasPerspective ( ) const

inline

Returns true if the matrix contains perspective elements.

SkMatrix form is:

|       --            --              --          |
|       --            --              --          |
| perspective-x  perspective-y  perspective-scale |

where perspective-x or perspective-y is non-zero, or perspective-scale is not one. All other elements may have any value.

Returns: true if SkMatrix is in most general form

◆ I()

static const SkMatrix& SkMatrix::I ( )

static

Returns reference to const identity SkMatrix.

Returned SkMatrix is set to:

| 1 0 0 |
| 0 1 0 |
| 0 0 1 |

Returns: const identity SkMatrix

example: https://fiddle.skia.org/c/@Matrix_I

◆ InvalidMatrix()

static const SkMatrix& SkMatrix::InvalidMatrix ( )

static

Returns reference to a const SkMatrix with invalid values.

Returned SkMatrix is set to:

| SK_ScalarMax SK_ScalarMax SK_ScalarMax |
| SK_ScalarMax SK_ScalarMax SK_ScalarMax |
| SK_ScalarMax SK_ScalarMax SK_ScalarMax |

Returns: const invalid SkMatrix

example: https://fiddle.skia.org/c/@Matrix_InvalidMatrix

◆ invert()

bool SkMatrix::invert ( SkMatrix * inverse ) const

inline

Sets inverse to reciprocal matrix, returning true if SkMatrix can be inverted.

Geometrically, if SkMatrix maps from source to destination, inverse SkMatrix maps from destination to source. If SkMatrix can not be inverted, inverse is unchanged.

Parameters

inverse storage for inverted SkMatrix; may be nullptr

Returns: true if SkMatrix can be inverted

◆ isFinite()

bool SkMatrix::isFinite ( ) const

inline

Returns true if all elements of the matrix are finite.

Returns false if any element is infinity, or NaN.

Returns: true if matrix has only finite elements

◆ isIdentity()

bool SkMatrix::isIdentity ( ) const

inline

Returns true if SkMatrix is identity.

Identity matrix is:

| 1 0 0 |
| 0 1 0 |
| 0 0 1 |

Returns: true if SkMatrix has no effect

◆ isScaleTranslate()

bool SkMatrix::isScaleTranslate ( ) const

inline

Returns true if SkMatrix at most scales and translates.

SkMatrix may be identity, contain only scale elements, only translate elements, or both. SkMatrix form is:

| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |

Returns: true if SkMatrix is identity; or scales, translates, or both

◆ isSimilarity()

bool SkMatrix::isSimilarity ( SkScalar tol = SK_ScalarNearlyZero ) const

Returns true if SkMatrix contains only translation, rotation, reflection, and uniform scale.

Returns false if SkMatrix contains different scales, skewing, perspective, or degenerate forms that collapse to a line or point.

Describes that the SkMatrix makes rendering with and without the matrix are visually alike; a transformed circle remains a circle. Mathematically, this is referred to as similarity of a Euclidean space, or a similarity transformation.

Preserves right angles, keeping the arms of the angle equal lengths.

Parameters

tol	to be deprecated

Returns: true if SkMatrix only rotates, uniformly scales, translates

example: https://fiddle.skia.org/c/@Matrix_isSimilarity

◆ isTranslate()

bool SkMatrix::isTranslate ( ) const

inline

Returns true if SkMatrix is identity, or translates.

SkMatrix form is:

| 1 0 translate-x |
| 0 1 translate-y |
| 0 0      1      |

Returns: true if SkMatrix is identity, or translates

◆ MakeAll()

static SkMatrix SkMatrix::MakeAll	(	SkScalar	scaleX,
		SkScalar	skewX,
		SkScalar	transX,
		SkScalar	skewY,
		SkScalar	scaleY,
		SkScalar	transY,
		SkScalar	pers0,
		SkScalar	pers1,
		SkScalar	pers2
	)

inlinestatic

Sets SkMatrix to:

| scaleX  skewX transX |
|  skewY scaleY transY |
|  pers0  pers1  pers2 |

Parameters

scaleX	horizontal scale factor
skewX	horizontal skew factor
transX	horizontal translation
skewY	vertical skew factor
scaleY	vertical scale factor
transY	vertical translation
pers0	input x-axis perspective factor
pers1	input y-axis perspective factor
pers2	perspective scale factor

Returns: SkMatrix constructed from parameters

◆ MakeRectToRect()

static SkMatrix SkMatrix::MakeRectToRect	(	const SkRect &	src,
		const SkRect &	dst,
		ScaleToFit	stf
	)

inlinestatic

Returns SkMatrix set to scale and translate src SkRect to dst SkRect.

stf selects whether mapping completely fills dst or preserves the aspect ratio, and how to align src within dst. Returns the identity SkMatrix if src is empty. If dst is empty, returns SkMatrix set to:

| 0 0 0 |
| 0 0 0 |
| 0 0 1 |

Parameters

src	SkRect to map from
dst	SkRect to map to

Returns: SkMatrix mapping src to dst

◆ mapHomogeneousPoints() [1/2]

void SkMatrix::mapHomogeneousPoints	(	SkPoint3	dst[],
		const SkPoint	src[],
		int	count
	)		const

Returns homogeneous points, starting with 2D src points (with implied w = 1).

◆ mapHomogeneousPoints() [2/2]

void SkMatrix::mapHomogeneousPoints	(	SkPoint3	dst[],
		const SkPoint3	src[],
		int	count
	)		const

Maps src SkPoint3 array of length count to dst SkPoint3 array, which must of length count or greater.

SkPoint3 array is mapped by multiplying each SkPoint3 by SkMatrix. Given:

         | A B C |         | x |
Matrix = | D E F |,  src = | y |
         | G H I |         | z |

each resulting dst SkPoint is computed as:

               |A B C| |x|
Matrix * src = |D E F| |y| = |Ax+By+Cz Dx+Ey+Fz Gx+Hy+Iz|
               |G H I| |z|

Parameters

dst	storage for mapped SkPoint3 array
src	SkPoint3 array to transform
count	items in SkPoint3 array to transform

example: https://fiddle.skia.org/c/@Matrix_mapHomogeneousPoints

◆ mapOrigin()

SkPoint SkMatrix::mapOrigin ( ) const

inline

Returns (0, 0) multiplied by SkMatrix.

Given:

         | A B C |        | 0 |
Matrix = | D E F |,  pt = | 0 |
         | G H I |        | 1 |

result is computed as:

              |A B C| |0|             C    F
Matrix * pt = |D E F| |0| = |C F I| = -  , -
              |G H I| |1|             I    I

Returns: mapped (0, 0)

◆ mapPoint()

SkPoint SkMatrix::mapPoint ( SkPoint pt ) const

inline

Returns SkPoint pt multiplied by SkMatrix.

Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

result is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

Parameters

p	SkPoint to map

Returns: mapped SkPoint

◆ mapPoints() [1/2]

void SkMatrix::mapPoints	(	SkPoint	dst[],
		const SkPoint	src[],
		int	count
	)		const

Maps src SkPoint array of length count to dst SkPoint array of equal or greater length.

SkPoint are mapped by multiplying each SkPoint by SkMatrix. Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

where

for (i = 0; i < count; ++i) {
    x = src[i].fX
    y = src[i].fY
}

each dst SkPoint is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

src and dst may point to the same storage.

Parameters

dst	storage for mapped SkPoint
src	SkPoint to transform
count	number of SkPoint to transform

example: https://fiddle.skia.org/c/@Matrix_mapPoints

◆ mapPoints() [2/2]

void SkMatrix::mapPoints	(	SkPoint	pts[],
		int	count
	)		const

inline

Maps pts SkPoint array of length count in place.

SkPoint are mapped by multiplying each SkPoint by SkMatrix. Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

where

for (i = 0; i < count; ++i) {
    x = pts[i].fX
    y = pts[i].fY
}

each resulting pts SkPoint is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

Parameters

pts	storage for mapped SkPoint
count	number of SkPoint to transform

◆ mapRadius()

SkScalar SkMatrix::mapRadius ( SkScalar radius ) const

Returns geometric mean radius of ellipse formed by constructing circle of size radius, and mapping constructed circle with SkMatrix.

The result squared is equal to the major axis length times the minor axis length. Result is not meaningful if SkMatrix contains perspective elements.

Parameters

radius circle size to map

Returns: average mapped radius

example: https://fiddle.skia.org/c/@Matrix_mapRadius

◆ mapRect() [1/3]

SkRect SkMatrix::mapRect	(	const SkRect &	src,
		SkApplyPerspectiveClip	pc = `SkApplyPerspectiveClip::kYes`
	)		const

inline

Returns bounds of src corners mapped by SkMatrix.

Parameters

src	rectangle to map

Returns: mapped bounds

◆ mapRect() [2/3]

bool SkMatrix::mapRect	(	SkRect *	dst,
		const SkRect &	src,
		SkApplyPerspectiveClip	pc = `SkApplyPerspectiveClip::kYes`
	)		const

Sets dst to bounds of src corners mapped by SkMatrix.

Returns true if mapped corners are dst corners.

Returned value is the same as calling rectStaysRect().

Parameters

dst	storage for bounds of mapped SkPoint
src	SkRect to map
pc	whether to apply perspective clipping

Returns: true if dst is equivalent to mapped src

example: https://fiddle.skia.org/c/@Matrix_mapRect

◆ mapRect() [3/3]

bool SkMatrix::mapRect	(	SkRect *	rect,
		SkApplyPerspectiveClip	pc = `SkApplyPerspectiveClip::kYes`
	)		const

inline

Sets rect to bounds of rect corners mapped by SkMatrix.

Returns true if mapped corners are computed rect corners.

Returned value is the same as calling rectStaysRect().

Parameters

rect	rectangle to map, and storage for bounds of mapped corners
pc	whether to apply perspective clipping

Returns: true if result is equivalent to mapped rect

◆ mapRectScaleTranslate()

void SkMatrix::mapRectScaleTranslate	(	SkRect *	dst,
		const SkRect &	src
	)		const

Sets dst to bounds of src corners mapped by SkMatrix.

If matrix contains elements other than scale or translate: asserts if SK_DEBUG is defined; otherwise, results are undefined.

Parameters

dst	storage for bounds of mapped SkPoint
src	SkRect to map

example: https://fiddle.skia.org/c/@Matrix_mapRectScaleTranslate

◆ mapRectToQuad()

void SkMatrix::mapRectToQuad	(	SkPoint	dst[4],
		const SkRect &	rect
	)		const

inline

Maps four corners of rect to dst.

SkPoint are mapped by multiplying each rect corner by SkMatrix. rect corner is processed in this order: (rect.fLeft, rect.fTop), (rect.fRight, rect.fTop), (rect.fRight, rect.fBottom), (rect.fLeft, rect.fBottom).

rect may be empty: rect.fLeft may be greater than or equal to rect.fRight; rect.fTop may be greater than or equal to rect.fBottom.

Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

where pt is initialized from each of (rect.fLeft, rect.fTop), (rect.fRight, rect.fTop), (rect.fRight, rect.fBottom), (rect.fLeft, rect.fBottom), each dst SkPoint is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

Parameters

dst	storage for mapped corner SkPoint
rect	SkRect to map

Note: this does not perform perspective clipping (as that might result in more than 4 points, so results are suspect if the matrix contains perspective.

◆ mapVector() [1/2]

SkVector SkMatrix::mapVector	(	SkScalar	dx,
		SkScalar	dy
	)		const

inline

Returns vector (dx, dy) multiplied by SkMatrix, treating SkMatrix translation as zero.

Given:

         | A B 0 |         | dx |
Matrix = | D E 0 |,  vec = | dy |
         | G H I |         |  1 |

each result vector is computed as:

           |A B 0| |dx|                                        A*dx+B*dy     D*dx+E*dy

Matrix * vec = |D E 0| |dy| = |A*dx+B*dy D*dx+E*dy G*dx+H*dy+I| = --------— , --------— |G H I| | 1| G*dx+H*dy+I G*dx+*dHy+I

Parameters

dx	x-axis value of vector to map
dy	y-axis value of vector to map

Returns: mapped vector

◆ mapVector() [2/2]

void SkMatrix::mapVector	(	SkScalar	dx,
		SkScalar	dy,
		SkVector *	result
	)		const

inline

Maps vector (dx, dy) to result.

Vector is mapped by multiplying by SkMatrix, treating SkMatrix translation as zero. Given:

         | A B 0 |         | dx |
Matrix = | D E 0 |,  vec = | dy |
         | G H I |         |  1 |

each result vector is computed as:

           |A B 0| |dx|                                        A*dx+B*dy     D*dx+E*dy

Matrix * vec = |D E 0| |dy| = |A*dx+B*dy D*dx+E*dy G*dx+H*dy+I| = --------— , --------— |G H I| | 1| G*dx+H*dy+I G*dx+*dHy+I

Parameters

dx	x-axis value of vector to map
dy	y-axis value of vector to map
result	storage for mapped vector

◆ mapVectors() [1/2]

void SkMatrix::mapVectors	(	SkVector	dst[],
		const SkVector	src[],
		int	count
	)		const

Maps src vector array of length count to vector SkPoint array of equal or greater length.

Vectors are mapped by multiplying each vector by SkMatrix, treating SkMatrix translation as zero. Given:

         | A B 0 |         | x |
Matrix = | D E 0 |,  src = | y |
         | G H I |         | 1 |

where

for (i = 0; i < count; ++i) {
    x = src[i].fX
    y = src[i].fY
}

each dst vector is computed as:

               |A B 0| |x|                            Ax+By     Dx+Ey
Matrix * src = |D E 0| |y| = |Ax+By Dx+Ey Gx+Hy+I| = ------- , -------
               |G H I| |1|                           Gx+Hy+I   Gx+Hy+I

src and dst may point to the same storage.

Parameters

dst	storage for mapped vectors
src	vectors to transform
count	number of vectors to transform

example: https://fiddle.skia.org/c/@Matrix_mapVectors

◆ mapVectors() [2/2]

void SkMatrix::mapVectors	(	SkVector	vecs[],
		int	count
	)		const

inline

Maps vecs vector array of length count in place, multiplying each vector by SkMatrix, treating SkMatrix translation as zero.

Given:

         | A B 0 |         | x |
Matrix = | D E 0 |,  vec = | y |
         | G H I |         | 1 |

where

for (i = 0; i < count; ++i) {
    x = vecs[i].fX
    y = vecs[i].fY
}

each result vector is computed as:

               |A B 0| |x|                            Ax+By     Dx+Ey
Matrix * vec = |D E 0| |y| = |Ax+By Dx+Ey Gx+Hy+I| = ------- , -------
               |G H I| |1|                           Gx+Hy+I   Gx+Hy+I

Parameters

vecs	vectors to transform, and storage for mapped vectors
count	number of vectors to transform

◆ mapXY() [1/2]

SkPoint SkMatrix::mapXY	(	SkScalar	x,
		SkScalar	y
	)		const

inline

Returns SkPoint (x, y) multiplied by SkMatrix.

Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

result is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

Parameters

x	x-axis value of SkPoint to map
y	y-axis value of SkPoint to map

Returns: mapped SkPoint

◆ mapXY() [2/2]

void SkMatrix::mapXY	(	SkScalar	x,
		SkScalar	y,
		SkPoint *	result
	)		const

Maps SkPoint (x, y) to result.

SkPoint is mapped by multiplying by SkMatrix. Given:

         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |

result is computed as:

              |A B C| |x|                               Ax+By+C   Dx+Ey+F
Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , -------
              |G H I| |1|                               Gx+Hy+I   Gx+Hy+I

Parameters

x	x-axis value of SkPoint to map
y	y-axis value of SkPoint to map
result	storage for mapped SkPoint

example: https://fiddle.skia.org/c/@Matrix_mapXY

◆ normalizePerspective()

void SkMatrix::normalizePerspective ( )

inline

A matrix is categorized as 'perspective' if the bottom row is not [0, 0, 1].

However, for most uses (e.g. mapPoints) a bottom row of [0, 0, X] behaves like a non-perspective matrix, though it will be categorized as perspective. Calling normalizePerspective() will change the matrix such that, if its bottom row was [0, 0, X], it will be changed to [0, 0, 1] by scaling the rest of the matrix by 1/X.

| A B C | | A/X B/X C/X | | D E F | -> | D/X E/X F/X | for X != 0 | 0 0 X | | 0 0 1 |

◆ operator[]() [1/2]

SkScalar& SkMatrix::operator[] ( int index )

inline

Returns writable SkMatrix value.

Asserts if index is out of range and SK_DEBUG is defined. Clears internal cache anticipating that caller will change SkMatrix value.

Next call to read SkMatrix state may recompute cache; subsequent writes to SkMatrix value must be followed by dirtyMatrixTypeCache().

Parameters

index one of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2

Returns: writable value corresponding to index

◆ operator[]() [2/2]

SkScalar SkMatrix::operator[] ( int index ) const

inline

Returns one matrix value.

Asserts if index is out of range and SK_DEBUG is defined.

Parameters

index one of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2

Returns: value corresponding to index

◆ postConcat()

SkMatrix& SkMatrix::postConcat ( const SkMatrix & other )

Sets SkMatrix to SkMatrix other multiplied by SkMatrix.

This can be thought of mapping by other after applying SkMatrix.

Given:

         | J K L |           | A B C |
Matrix = | M N O |,  other = | D E F |
         | P Q R |           | G H I |

sets SkMatrix to:

                 | A B C |   | J K L |   | AJ+BM+CP AK+BN+CQ AL+BO+CR |
other * Matrix = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR |
                 | G H I |   | P Q R |   | GJ+HM+IP GK+HN+IQ GL+HO+IR |

Parameters

other SkMatrix on left side of multiply expression

◆ postRotate() [1/2]

SkMatrix& SkMatrix::postRotate ( SkScalar degrees )

Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (0, 0), multiplied by SkMatrix.

This can be thought of as rotating about the origin after applying SkMatrix.

Positive degrees rotates clockwise.

Given:

         | J K L |                        | c -s 0 |
Matrix = | M N O |,  R(degrees, px, py) = | s  c 0 |
         | P Q R |                        | 0  0 1 |

where

c  = cos(degrees)
s  = sin(degrees)

sets SkMatrix to:

                              | c -s dx | | J K L |   | cJ-sM cK-sN cL-sO |
R(degrees, px, py) * Matrix = | s  c dy | | M N O | = | sJ+cM sK+cN sL+cO |
                              | 0  0  1 | | P Q R |   |     P     Q     R |

Parameters

degrees angle of axes relative to upright axes

◆ postRotate() [2/2]

SkMatrix& SkMatrix::postRotate	(	SkScalar	degrees,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (px, py), multiplied by SkMatrix.

This can be thought of as rotating about a pivot point after applying SkMatrix.

Positive degrees rotates clockwise.

Given:

         | J K L |                        | c -s dx |
Matrix = | M N O |,  R(degrees, px, py) = | s  c dy |
         | P Q R |                        | 0  0  1 |

where

c  = cos(degrees)
s  = sin(degrees)
dx =  s * py + (1 - c) * px
dy = -s * px + (1 - c) * py

sets SkMatrix to:

                              |c -s dx| |J K L|   |cJ-sM+dx*P cK-sN+dx*Q cL-sO+dx+R|
R(degrees, px, py) * Matrix = |s  c dy| |M N O| = |sJ+cM+dy*P sK+cN+dy*Q sL+cO+dy*R|
                              |0  0  1| |P Q R|   |         P          Q          R|

Parameters

degrees	angle of axes relative to upright axes
px	pivot on x-axis
py	pivot on y-axis

◆ postScale() [1/2]

SkMatrix& SkMatrix::postScale	(	SkScalar	sx,
		SkScalar	sy
	)

Sets SkMatrix to SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0), multiplied by SkMatrix.

This can be thought of as scaling about the origin after applying SkMatrix.

Given:

         | J K L |               | sx  0  0 |
Matrix = | M N O |,  S(sx, sy) = |  0 sy  0 |
         | P Q R |               |  0  0  1 |

sets SkMatrix to:

                     | sx  0  0 | | J K L |   | sx*J sx*K sx*L |
S(sx, sy) * Matrix = |  0 sy  0 | | M N O | = | sy*M sy*N sy*O |
                     |  0  0  1 | | P Q R |   |    P    Q    R |

Parameters

sx	horizontal scale factor
sy	vertical scale factor

◆ postScale() [2/2]

SkMatrix& SkMatrix::postScale	(	SkScalar	sx,
		SkScalar	sy,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix constructed from scaling by (sx, sy) about pivot point (px, py), multiplied by SkMatrix.

This can be thought of as scaling about a pivot point after applying SkMatrix.

Given:

         | J K L |                       | sx  0 dx |
Matrix = | M N O |,  S(sx, sy, px, py) = |  0 sy dy |
         | P Q R |                       |  0  0  1 |

where

dx = px - sx * px
dy = py - sy * py

sets SkMatrix to:

                             | sx  0 dx | | J K L |   | sx*J+dx*P sx*K+dx*Q sx*L+dx+R |
S(sx, sy, px, py) * Matrix = |  0 sy dy | | M N O | = | sy*M+dy*P sy*N+dy*Q sy*O+dy*R |
                             |  0  0  1 | | P Q R |   |         P         Q         R |

Parameters

sx	horizontal scale factor
sy	vertical scale factor
px	pivot on x-axis
py	pivot on y-axis

◆ postSkew() [1/2]

SkMatrix& SkMatrix::postSkew	(	SkScalar	kx,
		SkScalar	ky
	)

Sets SkMatrix to SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0), multiplied by SkMatrix.

This can be thought of as skewing about the origin after applying SkMatrix.

Given:

         | J K L |               |  1 kx 0 |
Matrix = | M N O |,  K(kx, ky) = | ky  1 0 |
         | P Q R |               |  0  0 1 |

sets SkMatrix to:

                     |  1 kx 0 | | J K L |   | J+kx*M K+kx*N L+kx*O |
K(kx, ky) * Matrix = | ky  1 0 | | M N O | = | ky*J+M ky*K+N ky*L+O |
                     |  0  0 1 | | P Q R |   |      P      Q      R |

Parameters

kx	horizontal skew factor
ky	vertical skew factor

◆ postSkew() [2/2]

SkMatrix& SkMatrix::postSkew	(	SkScalar	kx,
		SkScalar	ky,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix constructed from skewing by (kx, ky) about pivot point (px, py), multiplied by SkMatrix.

This can be thought of as skewing about a pivot point after applying SkMatrix.

Given:

         | J K L |                       |  1 kx dx |
Matrix = | M N O |,  K(kx, ky, px, py) = | ky  1 dy |
         | P Q R |                       |  0  0  1 |

where

dx = -kx * py
dy = -ky * px

sets SkMatrix to:

                             | 1 kx dx| |J K L|   |J+kx*M+dx*P K+kx*N+dx*Q L+kx*O+dx+R|
K(kx, ky, px, py) * Matrix = |ky  1 dy| |M N O| = |ky*J+M+dy*P ky*K+N+dy*Q ky*L+O+dy*R|
                             | 0  0  1| |P Q R|   |          P           Q           R|

Parameters

kx	horizontal skew factor
ky	vertical skew factor
px	pivot on x-axis
py	pivot on y-axis

◆ postTranslate()

SkMatrix& SkMatrix::postTranslate	(	SkScalar	dx,
		SkScalar	dy
	)

Sets SkMatrix to SkMatrix constructed from translation (dx, dy) multiplied by SkMatrix.

This can be thought of as moving the point to be mapped after applying SkMatrix.

Given:

         | J K L |               | 1 0 dx |
Matrix = | M N O |,  T(dx, dy) = | 0 1 dy |
         | P Q R |               | 0 0  1 |

sets SkMatrix to:

                     | 1 0 dx | | J K L |   | J+dx*P K+dx*Q L+dx*R |
T(dx, dy) * Matrix = | 0 1 dy | | M N O | = | M+dy*P N+dy*Q O+dy*R |
                     | 0 0  1 | | P Q R |   |      P      Q      R |

Parameters

dx	x-axis translation after applying SkMatrix
dy	y-axis translation after applying SkMatrix

◆ preConcat()

SkMatrix& SkMatrix::preConcat ( const SkMatrix & other )

Sets SkMatrix to SkMatrix multiplied by SkMatrix other.

This can be thought of mapping by other before applying SkMatrix.

Given:

         | A B C |          | J K L |
Matrix = | D E F |, other = | M N O |
         | G H I |          | P Q R |

sets SkMatrix to:

                 | A B C |   | J K L |   | AJ+BM+CP AK+BN+CQ AL+BO+CR |
Matrix * other = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR |
                 | G H I |   | P Q R |   | GJ+HM+IP GK+HN+IQ GL+HO+IR |

Parameters

other SkMatrix on right side of multiply expression

◆ preRotate() [1/2]

SkMatrix& SkMatrix::preRotate ( SkScalar degrees )

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (0, 0).

This can be thought of as rotating about the origin before applying SkMatrix.

Positive degrees rotates clockwise.

Given:

         | A B C |                        | c -s 0 |
Matrix = | D E F |,  R(degrees, px, py) = | s  c 0 |
         | G H I |                        | 0  0 1 |

where

c  = cos(degrees)
s  = sin(degrees)

sets SkMatrix to:

                              | A B C | | c -s 0 |   | Ac+Bs -As+Bc C |
Matrix * R(degrees, px, py) = | D E F | | s  c 0 | = | Dc+Es -Ds+Ec F |
                              | G H I | | 0  0 1 |   | Gc+Hs -Gs+Hc I |

Parameters

degrees angle of axes relative to upright axes

◆ preRotate() [2/2]

SkMatrix& SkMatrix::preRotate	(	SkScalar	degrees,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (px, py).

This can be thought of as rotating about a pivot point before applying SkMatrix.

Positive degrees rotates clockwise.

Given:

         | A B C |                        | c -s dx |
Matrix = | D E F |,  R(degrees, px, py) = | s  c dy |
         | G H I |                        | 0  0  1 |

where

c  = cos(degrees)
s  = sin(degrees)
dx =  s * py + (1 - c) * px
dy = -s * px + (1 - c) * py

sets SkMatrix to:

                              | A B C | | c -s dx |   | Ac+Bs -As+Bc A*dx+B*dy+C |
Matrix * R(degrees, px, py) = | D E F | | s  c dy | = | Dc+Es -Ds+Ec D*dx+E*dy+F |
                              | G H I | | 0  0  1 |   | Gc+Hs -Gs+Hc G*dx+H*dy+I |

Parameters

degrees	angle of axes relative to upright axes
px	pivot on x-axis
py	pivot on y-axis

◆ preScale() [1/2]

SkMatrix& SkMatrix::preScale	(	SkScalar	sx,
		SkScalar	sy
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0).

This can be thought of as scaling about the origin before applying SkMatrix.

Given:

         | A B C |               | sx  0  0 |
Matrix = | D E F |,  S(sx, sy) = |  0 sy  0 |
         | G H I |               |  0  0  1 |

sets SkMatrix to:

                     | A B C | | sx  0  0 |   | A*sx B*sy C |
Matrix * S(sx, sy) = | D E F | |  0 sy  0 | = | D*sx E*sy F |
                     | G H I | |  0  0  1 |   | G*sx H*sy I |

Parameters

sx	horizontal scale factor
sy	vertical scale factor

◆ preScale() [2/2]

SkMatrix& SkMatrix::preScale	(	SkScalar	sx,
		SkScalar	sy,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from scaling by (sx, sy) about pivot point (px, py).

This can be thought of as scaling about a pivot point before applying SkMatrix.

Given:

         | A B C |                       | sx  0 dx |
Matrix = | D E F |,  S(sx, sy, px, py) = |  0 sy dy |
         | G H I |                       |  0  0  1 |

where

dx = px - sx * px
dy = py - sy * py

sets SkMatrix to:

                             | A B C | | sx  0 dx |   | A*sx B*sy A*dx+B*dy+C |
Matrix * S(sx, sy, px, py) = | D E F | |  0 sy dy | = | D*sx E*sy D*dx+E*dy+F |
                             | G H I | |  0  0  1 |   | G*sx H*sy G*dx+H*dy+I |

Parameters

sx	horizontal scale factor
sy	vertical scale factor
px	pivot on x-axis
py	pivot on y-axis

◆ preservesAxisAlignment()

bool SkMatrix::preservesAxisAlignment ( ) const

inline

Returns true SkMatrix maps SkRect to another SkRect.

If true, SkMatrix is identity, or scales, or rotates a multiple of 90 degrees, or mirrors on axes. In all cases, SkMatrix may also have translation. SkMatrix form is either:

| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |

or

|    0     rotate-x translate-x |
| rotate-y    0     translate-y |
|    0        0          1      |

for non-zero values of scale-x, scale-y, rotate-x, and rotate-y.

Also called rectStaysRect(); use the one that provides better inline documentation.

Returns: true if SkMatrix maps one SkRect into another

◆ preservesRightAngles()

bool SkMatrix::preservesRightAngles ( SkScalar tol = SK_ScalarNearlyZero ) const

Returns true if SkMatrix contains only translation, rotation, reflection, and scale.

Scale may differ along rotated axes. Returns false if SkMatrix skewing, perspective, or degenerate forms that collapse to a line or point.

Preserves right angles, but not requiring that the arms of the angle retain equal lengths.

Parameters

tol	to be deprecated

Returns: true if SkMatrix only rotates, scales, translates

example: https://fiddle.skia.org/c/@Matrix_preservesRightAngles

◆ preSkew() [1/2]

SkMatrix& SkMatrix::preSkew	(	SkScalar	kx,
		SkScalar	ky
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0).

This can be thought of as skewing about the origin before applying SkMatrix.

Given:

         | A B C |               |  1 kx 0 |
Matrix = | D E F |,  K(kx, ky) = | ky  1 0 |
         | G H I |               |  0  0 1 |

sets SkMatrix to:

                     | A B C | |  1 kx 0 |   | A+B*ky A*kx+B C |
Matrix * K(kx, ky) = | D E F | | ky  1 0 | = | D+E*ky D*kx+E F |
                     | G H I | |  0  0 1 |   | G+H*ky G*kx+H I |

Parameters

kx	horizontal skew factor
ky	vertical skew factor

◆ preSkew() [2/2]

SkMatrix& SkMatrix::preSkew	(	SkScalar	kx,
		SkScalar	ky,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from skewing by (kx, ky) about pivot point (px, py).

This can be thought of as skewing about a pivot point before applying SkMatrix.

Given:

         | A B C |                       |  1 kx dx |
Matrix = | D E F |,  K(kx, ky, px, py) = | ky  1 dy |
         | G H I |                       |  0  0  1 |

where

dx = -kx * py
dy = -ky * px

sets SkMatrix to:

                             | A B C | |  1 kx dx |   | A+B*ky A*kx+B A*dx+B*dy+C |
Matrix * K(kx, ky, px, py) = | D E F | | ky  1 dy | = | D+E*ky D*kx+E D*dx+E*dy+F |
                             | G H I | |  0  0  1 |   | G+H*ky G*kx+H G*dx+H*dy+I |

Parameters

kx	horizontal skew factor
ky	vertical skew factor
px	pivot on x-axis
py	pivot on y-axis

◆ preTranslate()

SkMatrix& SkMatrix::preTranslate	(	SkScalar	dx,
		SkScalar	dy
	)

Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from translation (dx, dy).

This can be thought of as moving the point to be mapped before applying SkMatrix.

Given:

         | A B C |               | 1 0 dx |
Matrix = | D E F |,  T(dx, dy) = | 0 1 dy |
         | G H I |               | 0 0  1 |

sets SkMatrix to:

                     | A B C | | 1 0 dx |   | A B A*dx+B*dy+C |
Matrix * T(dx, dy) = | D E F | | 0 1 dy | = | D E D*dx+E*dy+F |
                     | G H I | | 0 0  1 |   | G H G*dx+H*dy+I |

Parameters

dx	x-axis translation before applying SkMatrix
dy	y-axis translation before applying SkMatrix

◆ rc()

SkScalar SkMatrix::rc	(	int	r,
		int	c
	)		const

inline

Returns one matrix value from a particular row/column.

Asserts if index is out of range and SK_DEBUG is defined.

Parameters

r	matrix row to fetch
c	matrix column to fetch

Returns: value at the given matrix position

◆ rectStaysRect()

bool SkMatrix::rectStaysRect ( ) const

inline

Returns true SkMatrix maps SkRect to another SkRect.

If true, SkMatrix is identity, or scales, or rotates a multiple of 90 degrees, or mirrors on axes. In all cases, SkMatrix may also have translation. SkMatrix form is either:

| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |

or

|    0     rotate-x translate-x |
| rotate-y    0     translate-y |
|    0        0          1      |

for non-zero values of scale-x, scale-y, rotate-x, and rotate-y.

Also called preservesAxisAlignment(); use the one that provides better inline documentation.

Returns: true if SkMatrix maps one SkRect into another

◆ RectToRect()

static SkMatrix SkMatrix::RectToRect	(	const SkRect &	src,
		const SkRect &	dst,
		ScaleToFit	mode = `kFill_ScaleToFit`
	)

inlinestatic

Returns SkMatrix set to scale and translate src to dst.

ScaleToFit selects whether mapping completely fills dst or preserves the aspect ratio, and how to align src within dst. Returns the identity SkMatrix if src is empty. If dst is empty, returns SkMatrix set to:

| 0 0 0 |
| 0 0 0 |
| 0 0 1 |

Parameters

src	SkRect to map from
dst	SkRect to map to
mode	How to handle the mapping

Returns: SkMatrix mapping src to dst

◆ reset()

SkMatrix& SkMatrix::reset ( )

Sets SkMatrix to identity; which has no effect on mapped SkPoint.

Sets SkMatrix to:

| 1 0 0 |
| 0 1 0 |
| 0 0 1 |

Also called setIdentity(); use the one that provides better inline documentation.

◆ RotateDeg() [1/2]

static SkMatrix SkMatrix::RotateDeg ( SkScalar deg )

inlinestatic

Sets SkMatrix to rotate by |deg| about a pivot point at (0, 0).

Parameters

deg	rotation angle in degrees (positive rotates clockwise)

Returns: SkMatrix with rotation

◆ RotateDeg() [2/2]

static SkMatrix SkMatrix::RotateDeg	(	SkScalar	deg,
		SkPoint	pt
	)

inlinestatic

◆ RotateRad()

static SkMatrix SkMatrix::RotateRad ( SkScalar rad )

inlinestatic

◆ Scale()

static SkMatrix SkMatrix::Scale	(	SkScalar	sx,
		SkScalar	sy
	)

inlinestatic

Sets SkMatrix to scale by (sx, sy).

Returned matrix is:

| sx  0  0 |
|  0 sy  0 |
|  0  0  1 |

Parameters

sx	horizontal scale factor
sy	vertical scale factor

Returns: SkMatrix with scale

◆ set()

SkMatrix& SkMatrix::set	(	int	index,
		SkScalar	value
	)

inline

Sets SkMatrix value.

Asserts if index is out of range and SK_DEBUG is defined. Safer than operator[]; internal cache is always maintained.

Parameters

index	one of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2
value	scalar to store in SkMatrix

◆ set9()

SkMatrix& SkMatrix::set9 ( const SkScalar buffer[9] )

Sets SkMatrix to nine scalar values in buffer, in member value ascending order: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2.

Sets matrix to:

| buffer[0] buffer[1] buffer[2] |
| buffer[3] buffer[4] buffer[5] |
| buffer[6] buffer[7] buffer[8] |

In the future, set9 followed by get9 may not return the same values. Since SkMatrix maps non-homogeneous coordinates, scaling all nine values produces an equivalent transformation, possibly improving precision.

Parameters

buffer nine scalar values

◆ setAffine()

SkMatrix& SkMatrix::setAffine ( const SkScalar affine[6] )

Sets SkMatrix to affine values, passed in column major order.

Given affine, column, then row, as:

| scale-x  skew-x translate-x |
|  skew-y scale-y translate-y |

SkMatrix is set, row, then column, to:

| scale-x  skew-x translate-x |
|  skew-y scale-y translate-y |
|       0       0           1 |

Parameters

affine 3 by 2 affine matrix

◆ SetAffineIdentity()

static void SkMatrix::SetAffineIdentity ( SkScalar affine[6] )

static

Fills affine with identity values in column major order.

Sets affine to:

| 1 0 0 |
| 0 1 0 |

Affine 3 by 2 matrices in column major order are used by OpenGL and XPS.

Parameters

affine storage for 3 by 2 affine matrix

example: https://fiddle.skia.org/c/@Matrix_SetAffineIdentity

◆ setAll()

SkMatrix& SkMatrix::setAll	(	SkScalar	scaleX,
		SkScalar	skewX,
		SkScalar	transX,
		SkScalar	skewY,
		SkScalar	scaleY,
		SkScalar	transY,
		SkScalar	persp0,
		SkScalar	persp1,
		SkScalar	persp2
	)

inline

Sets all values from parameters.

Sets matrix to:

| scaleX  skewX transX |
|  skewY scaleY transY |
| persp0 persp1 persp2 |

Parameters

scaleX	horizontal scale factor to store
skewX	horizontal skew factor to store
transX	horizontal translation to store
skewY	vertical skew factor to store
scaleY	vertical scale factor to store
transY	vertical translation to store
persp0	input x-axis values perspective factor to store
persp1	input y-axis values perspective factor to store
persp2	perspective scale factor to store

◆ setConcat()

SkMatrix& SkMatrix::setConcat	(	const SkMatrix &	a,
		const SkMatrix &	b
	)

Sets SkMatrix to SkMatrix a multiplied by SkMatrix b.

Either a or b may be this.

Given:

    | A B C |      | J K L |
a = | D E F |, b = | M N O |
    | G H I |      | P Q R |

sets SkMatrix to:

        | A B C |   | J K L |   | AJ+BM+CP AK+BN+CQ AL+BO+CR |
a * b = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR |
        | G H I |   | P Q R |   | GJ+HM+IP GK+HN+IQ GL+HO+IR |

Parameters

a	SkMatrix on left side of multiply expression
b	SkMatrix on right side of multiply expression

◆ setIdentity()

SkMatrix& SkMatrix::setIdentity ( )

inline

Sets SkMatrix to identity; which has no effect on mapped SkPoint.

Sets SkMatrix to:

| 1 0 0 |
| 0 1 0 |
| 0 0 1 |

Also called reset(); use the one that provides better inline documentation.

◆ setPerspX()

SkMatrix& SkMatrix::setPerspX ( SkScalar v )

inline

Sets input x-axis perspective factor, which causes mapXY() to vary input x-axis values inversely proportional to input y-axis values.

Parameters

v	perspective factor

◆ setPerspY()

SkMatrix& SkMatrix::setPerspY ( SkScalar v )

inline

Sets input y-axis perspective factor, which causes mapXY() to vary input y-axis values inversely proportional to input x-axis values.

Parameters

v	perspective factor

◆ setPolyToPoly()

bool SkMatrix::setPolyToPoly	(	const SkPoint	src[],
		const SkPoint	dst[],
		int	count
	)

Sets SkMatrix to map src to dst.

count must be zero or greater, and four or less.

If count is zero, sets SkMatrix to identity and returns true. If count is one, sets SkMatrix to translate and returns true. If count is two or more, sets SkMatrix to map SkPoint if possible; returns false if SkMatrix cannot be constructed. If count is four, SkMatrix may include perspective.

Parameters

src	SkPoint to map from
dst	SkPoint to map to
count	number of SkPoint in src and dst

Returns: true if SkMatrix was constructed successfully

example: https://fiddle.skia.org/c/@Matrix_setPolyToPoly

◆ setRectToRect()

bool SkMatrix::setRectToRect	(	const SkRect &	src,
		const SkRect &	dst,
		ScaleToFit	stf
	)

Sets SkMatrix to scale and translate src SkRect to dst SkRect.

stf selects whether mapping completely fills dst or preserves the aspect ratio, and how to align src within dst. Returns false if src is empty, and sets SkMatrix to identity. Returns true if dst is empty, and sets SkMatrix to:

| 0 0 0 |
| 0 0 0 |
| 0 0 1 |

Parameters

src	SkRect to map from
dst	SkRect to map to

Returns: true if SkMatrix can represent SkRect mapping

example: https://fiddle.skia.org/c/@Matrix_setRectToRect

◆ setRotate() [1/2]

SkMatrix& SkMatrix::setRotate ( SkScalar degrees )

Sets SkMatrix to rotate by degrees about a pivot point at (0, 0).

Positive degrees rotates clockwise.

Parameters

degrees angle of axes relative to upright axes

◆ setRotate() [2/2]

SkMatrix& SkMatrix::setRotate	(	SkScalar	degrees,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to rotate by degrees about a pivot point at (px, py).

The pivot point is unchanged when mapped with SkMatrix.

Positive degrees rotates clockwise.

Parameters

degrees	angle of axes relative to upright axes
px	pivot on x-axis
py	pivot on y-axis

◆ setRSXform()

SkMatrix& SkMatrix::setRSXform ( const SkRSXform & rsxForm )

Sets SkMatrix to rotate, scale, and translate using a compressed matrix form.

Vector (rsxForm.fSSin, rsxForm.fSCos) describes the angle of rotation relative to (0, 1). Vector length specifies scale. Mapped point is rotated and scaled by vector, then translated by (rsxForm.fTx, rsxForm.fTy).

Parameters

rsxForm compressed SkRSXform matrix

Returns: reference to SkMatrix

example: https://fiddle.skia.org/c/@Matrix_setRSXform

◆ setScale() [1/2]

SkMatrix& SkMatrix::setScale	(	SkScalar	sx,
		SkScalar	sy
	)

Sets SkMatrix to scale by sx and sy about at pivot point at (0, 0).

Parameters

sx	horizontal scale factor
sy	vertical scale factor

◆ setScale() [2/2]

SkMatrix& SkMatrix::setScale	(	SkScalar	sx,
		SkScalar	sy,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to scale by sx and sy, about a pivot point at (px, py).

The pivot point is unchanged when mapped with SkMatrix.

Parameters

sx	horizontal scale factor
sy	vertical scale factor
px	pivot on x-axis
py	pivot on y-axis

◆ setScaleTranslate()

void SkMatrix::setScaleTranslate	(	SkScalar	sx,
		SkScalar	sy,
		SkScalar	tx,
		SkScalar	ty
	)

inline

Initializes SkMatrix with scale and translate elements.

| sx  0 tx |
|  0 sy ty |
|  0  0  1 |

Parameters

sx	horizontal scale factor to store
sy	vertical scale factor to store
tx	horizontal translation to store
ty	vertical translation to store

◆ setScaleX()

SkMatrix& SkMatrix::setScaleX ( SkScalar v )

inline

Sets horizontal scale factor.

Parameters

v	horizontal scale factor to store

◆ setScaleY()

SkMatrix& SkMatrix::setScaleY ( SkScalar v )

inline

Sets vertical scale factor.

Parameters

v	vertical scale factor to store

◆ setSinCos() [1/2]

SkMatrix& SkMatrix::setSinCos	(	SkScalar	sinValue,
		SkScalar	cosValue
	)

Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (0, 0).

Vector (sinValue, cosValue) describes the angle of rotation relative to (0, 1). Vector length specifies scale.

Parameters

sinValue	rotation vector x-axis component
cosValue	rotation vector y-axis component

◆ setSinCos() [2/2]

SkMatrix& SkMatrix::setSinCos	(	SkScalar	sinValue,
		SkScalar	cosValue,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (px, py).

The pivot point is unchanged when mapped with SkMatrix.

Vector (sinValue, cosValue) describes the angle of rotation relative to (0, 1). Vector length specifies scale.

Parameters

sinValue	rotation vector x-axis component
cosValue	rotation vector y-axis component
px	pivot on x-axis
py	pivot on y-axis

◆ setSkew() [1/2]

SkMatrix& SkMatrix::setSkew	(	SkScalar	kx,
		SkScalar	ky
	)

Sets SkMatrix to skew by kx and ky, about a pivot point at (0, 0).

Parameters

kx	horizontal skew factor
ky	vertical skew factor

◆ setSkew() [2/2]

SkMatrix& SkMatrix::setSkew	(	SkScalar	kx,
		SkScalar	ky,
		SkScalar	px,
		SkScalar	py
	)

Sets SkMatrix to skew by kx and ky, about a pivot point at (px, py).

The pivot point is unchanged when mapped with SkMatrix.

Parameters

kx	horizontal skew factor
ky	vertical skew factor
px	pivot on x-axis
py	pivot on y-axis

◆ setSkewX()

SkMatrix& SkMatrix::setSkewX ( SkScalar v )

inline

Sets horizontal skew factor.

Parameters

v	horizontal skew factor to store

◆ setSkewY()

SkMatrix& SkMatrix::setSkewY ( SkScalar v )

inline

Sets vertical skew factor.

Parameters

v	vertical skew factor to store

◆ setTranslate() [1/2]

SkMatrix& SkMatrix::setTranslate ( const SkVector & v )

inline

Sets SkMatrix to translate by (v.fX, v.fY).

Parameters

v	vector containing horizontal and vertical translation

◆ setTranslate() [2/2]

SkMatrix& SkMatrix::setTranslate	(	SkScalar	dx,
		SkScalar	dy
	)

Sets SkMatrix to translate by (dx, dy).

Parameters

dx	horizontal translation
dy	vertical translation

◆ setTranslateX()

SkMatrix& SkMatrix::setTranslateX ( SkScalar v )

inline

Sets horizontal translation.

Parameters

v	horizontal translation to store

◆ setTranslateY()

SkMatrix& SkMatrix::setTranslateY ( SkScalar v )

inline

Sets vertical translation.

Parameters

v	vertical translation to store

◆ Skew()

static SkMatrix SkMatrix::Skew	(	SkScalar	kx,
		SkScalar	ky
	)

inlinestatic

Sets SkMatrix to skew by (kx, ky) about pivot point (0, 0).

Parameters

kx	horizontal skew factor
ky	vertical skew factor

Returns: SkMatrix with skew

◆ Translate() [1/3]

static SkMatrix SkMatrix::Translate ( SkIVector t )

inlinestatic

◆ Translate() [2/3]

static SkMatrix SkMatrix::Translate	(	SkScalar	dx,
		SkScalar	dy
	)

inlinestatic

Sets SkMatrix to translate by (dx, dy).

Returned matrix is:

| 1 0 dx |
| 0 1 dy |
| 0 0  1 |

Parameters

dx	horizontal translation
dy	vertical translation

Returns: SkMatrix with translation

◆ Translate() [3/3]

static SkMatrix SkMatrix::Translate ( SkVector t )

inlinestatic

Friends And Related Function Documentation

◆ operator!=

SK_API bool operator!=	(	const SkMatrix &	a,
		const SkMatrix &	b
	)

friend

Compares a and b; returns true if a and b are not numerically equal.

Returns false even if sign of zero values are different. Returns true if either SkMatrix contains NaN, even if the other SkMatrix also contains NaN.

Parameters

a	SkMatrix to compare
b	SkMatrix to compare

Returns: true if SkMatrix a and SkMatrix b are numerically not equal

◆ operator*

SkMatrix operator*	(	const SkMatrix &	a,
		const SkMatrix &	b
	)

friend

◆ operator==

SK_API bool operator==	(	const SkMatrix &	a,
		const SkMatrix &	b
	)

friend

Compares a and b; returns true if a and b are numerically equal.

Returns true even if sign of zero values are different. Returns false if either SkMatrix contains NaN, even if the other SkMatrix also contains NaN.

Parameters

a	SkMatrix to compare
b	SkMatrix to compare

Returns: true if SkMatrix a and SkMatrix b are numerically equal

◆ SerializationTest

friend class SerializationTest

friend

◆ SkMatrixPriv

friend class SkMatrixPriv

friend

◆ SkPerspIter

friend class SkPerspIter

friend

Member Data Documentation

◆ kAScaleX

constexpr int SkMatrix::kAScaleX = 0

staticconstexpr

Affine arrays are in column-major order to match the matrix used by PDF and XPS.

horizontal scale factor

◆ kAScaleY

constexpr int SkMatrix::kAScaleY = 3

staticconstexpr

vertical scale factor

◆ kASkewX

constexpr int SkMatrix::kASkewX = 2

staticconstexpr

horizontal skew factor

◆ kASkewY

constexpr int SkMatrix::kASkewY = 1

staticconstexpr

vertical skew factor

◆ kATransX

constexpr int SkMatrix::kATransX = 4

staticconstexpr

horizontal translation

◆ kATransY

constexpr int SkMatrix::kATransY = 5

staticconstexpr

vertical translation

◆ kMPersp0

constexpr int SkMatrix::kMPersp0 = 6

staticconstexpr

input x perspective factor

◆ kMPersp1

constexpr int SkMatrix::kMPersp1 = 7

staticconstexpr

input y perspective factor

◆ kMPersp2

constexpr int SkMatrix::kMPersp2 = 8

staticconstexpr

perspective bias

◆ kMScaleX

constexpr int SkMatrix::kMScaleX = 0

staticconstexpr

SkMatrix organizes its values in row-major order.

These members correspond to each value in SkMatrix. horizontal scale factor

◆ kMScaleY

constexpr int SkMatrix::kMScaleY = 4

staticconstexpr

vertical scale factor

◆ kMSkewX

constexpr int SkMatrix::kMSkewX = 1

staticconstexpr

horizontal skew factor

◆ kMSkewY

constexpr int SkMatrix::kMSkewY = 3

staticconstexpr

vertical skew factor

◆ kMTransX

constexpr int SkMatrix::kMTransX = 2

staticconstexpr

horizontal translation

◆ kMTransY

constexpr int SkMatrix::kMTransY = 5

staticconstexpr

vertical translation

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

/CHECKOUT/include/core/SkMatrix.h

Public Types

Public Member Functions

Static Public Member Functions

Static Public Attributes

Friends

Detailed Description

Member Enumeration Documentation

◆ ScaleToFit

◆ TypeMask

Constructor & Destructor Documentation

◆ SkMatrix()

Member Function Documentation

◆ asAffine()

◆ Concat()

◆ decomposeScale()

◆ dirtyMatrixTypeCache()

◆ dump()

◆ get()

◆ get9()

◆ getMaxScale()

◆ getMinMaxScales()

◆ getMinScale()

◆ getPerspX()

◆ getPerspY()

◆ getScaleX()

◆ getScaleY()

◆ getSkewX()

◆ getSkewY()

◆ getTranslateX()

◆ getTranslateY()

◆ getType()

◆ hasPerspective()

◆ I()

◆ InvalidMatrix()

◆ invert()

◆ isFinite()

◆ isIdentity()

◆ isScaleTranslate()

◆ isSimilarity()

◆ isTranslate()

◆ MakeAll()

◆ MakeRectToRect()

◆ mapHomogeneousPoints() [1/2]

◆ mapHomogeneousPoints() [2/2]

◆ mapOrigin()

◆ mapPoint()

◆ mapPoints() [1/2]

◆ mapPoints() [2/2]

◆ mapRadius()

◆ mapRect() [1/3]

◆ mapRect() [2/3]

◆ mapRect() [3/3]

◆ mapRectScaleTranslate()

◆ mapRectToQuad()

◆ mapVector() [1/2]

◆ mapVector() [2/2]

◆ mapVectors() [1/2]

◆ mapVectors() [2/2]

◆ mapXY() [1/2]

◆ mapXY() [2/2]

◆ normalizePerspective()

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ postConcat()

◆ postRotate() [1/2]

◆ postRotate() [2/2]

◆ postScale() [1/2]

◆ postScale() [2/2]

◆ postSkew() [1/2]

◆ postSkew() [2/2]

◆ postTranslate()

◆ preConcat()

◆ preRotate() [1/2]

◆ preRotate() [2/2]

◆ preScale() [1/2]

◆ preScale() [2/2]

◆ preservesAxisAlignment()

◆ preservesRightAngles()

◆ preSkew() [1/2]

◆ preSkew() [2/2]