Skia
2D Graphics Library
SkMatrix Class Reference

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

#include <SkMatrix.h>

Public Types

enum  TypeMask {
  kIdentity_Mask = 0, kTranslate_Mask = 0x01, kScale_Mask = 0x02, kAffine_Mask = 0x04,
  kPerspective_Mask = 0x08
}
 
enum  ScaleToFit { kFill_ScaleToFit, kStart_ScaleToFit, kCenter_ScaleToFit, kEnd_ScaleToFit }
 

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 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...
 
SkScalaroperator[] (int index)
 Returns writable SkMatrix value. More...
 
SkMatrixset (int index, SkScalar value)
 Sets SkMatrix value. More...
 
SkMatrixsetScaleX (SkScalar v)
 Sets horizontal scale factor. More...
 
SkMatrixsetScaleY (SkScalar v)
 Sets vertical scale factor. More...
 
SkMatrixsetSkewY (SkScalar v)
 Sets vertical skew factor. More...
 
SkMatrixsetSkewX (SkScalar v)
 Sets horizontal skew factor. More...
 
SkMatrixsetTranslateX (SkScalar v)
 Sets horizontal translation. More...
 
SkMatrixsetTranslateY (SkScalar v)
 Sets vertical translation. More...
 
SkMatrixsetPerspX (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...
 
SkMatrixsetPerspY (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...
 
SkMatrixsetAll (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...
 
SkMatrixset9 (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...
 
SkMatrixreset ()
 Sets SkMatrix to identity; which has no effect on mapped SkPoint. More...
 
SkMatrixsetIdentity ()
 Sets SkMatrix to identity; which has no effect on mapped SkPoint. More...
 
SkMatrixsetTranslate (SkScalar dx, SkScalar dy)
 Sets SkMatrix to translate by (dx, dy). More...
 
SkMatrixsetTranslate (const SkVector &v)
 Sets SkMatrix to translate by (v.fX, v.fY). More...
 
SkMatrixsetScale (SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)
 Sets SkMatrix to scale by sx and sy, about a pivot point at (px, py). More...
 
SkMatrixsetScale (SkScalar sx, SkScalar sy)
 Sets SkMatrix to scale by sx and sy about at pivot point at (0, 0). More...
 
SkMatrixsetRotate (SkScalar degrees, SkScalar px, SkScalar py)
 Sets SkMatrix to rotate by degrees about a pivot point at (px, py). More...
 
SkMatrixsetRotate (SkScalar degrees)
 Sets SkMatrix to rotate by degrees about a pivot point at (0, 0). More...
 
SkMatrixsetSinCos (SkScalar sinValue, SkScalar cosValue, SkScalar px, SkScalar py)
 Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (px, py). More...
 
SkMatrixsetSinCos (SkScalar sinValue, SkScalar cosValue)
 Sets SkMatrix to rotate by sinValue and cosValue, about a pivot point at (0, 0). More...
 
SkMatrixsetRSXform (const SkRSXform &rsxForm)
 Sets SkMatrix to rotate, scale, and translate using a compressed matrix form. More...
 
SkMatrixsetSkew (SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)
 Sets SkMatrix to skew by kx and ky, about a pivot point at (px, py). More...
 
SkMatrixsetSkew (SkScalar kx, SkScalar ky)
 Sets SkMatrix to skew by kx and ky, about a pivot point at (0, 0). More...
 
SkMatrixsetConcat (const SkMatrix &a, const SkMatrix &b)
 Sets SkMatrix to SkMatrix a multiplied by SkMatrix b. More...
 
SkMatrixpreTranslate (SkScalar dx, SkScalar dy)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from translation (dx, dy). More...
 
SkMatrixpreScale (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...
 
SkMatrixpreScale (SkScalar sx, SkScalar sy)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0). More...
 
SkMatrixpreRotate (SkScalar degrees, SkScalar px, SkScalar py)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (px, py). More...
 
SkMatrixpreRotate (SkScalar degrees)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from rotating by degrees about pivot point (0, 0). More...
 
SkMatrixpreSkew (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...
 
SkMatrixpreSkew (SkScalar kx, SkScalar ky)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0). More...
 
SkMatrixpreConcat (const SkMatrix &other)
 Sets SkMatrix to SkMatrix multiplied by SkMatrix other. More...
 
SkMatrixpostTranslate (SkScalar dx, SkScalar dy)
 Sets SkMatrix to SkMatrix constructed from translation (dx, dy) multiplied by SkMatrix. More...
 
SkMatrixpostScale (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...
 
SkMatrixpostScale (SkScalar sx, SkScalar sy)
 Sets SkMatrix to SkMatrix constructed from scaling by (sx, sy) about pivot point (0, 0), multiplied by SkMatrix. More...
 
SkMatrixpostRotate (SkScalar degrees, SkScalar px, SkScalar py)
 Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (px, py), multiplied by SkMatrix. More...
 
SkMatrixpostRotate (SkScalar degrees)
 Sets SkMatrix to SkMatrix constructed from rotating by degrees about pivot point (0, 0), multiplied by SkMatrix. More...
 
SkMatrixpostSkew (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...
 
SkMatrixpostSkew (SkScalar kx, SkScalar ky)
 Sets SkMatrix to SkMatrix constructed from skewing by (kx, ky) about pivot point (0, 0), multiplied by SkMatrix. More...
 
SkMatrixpostConcat (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 SK_WARN_UNUSED_RESULT invert (SkMatrix *inverse) const
 Sets inverse to reciprocal matrix, returning true if SkMatrix can be inverted. More...
 
bool SK_WARN_UNUSED_RESULT asAffine (SkScalar affine[6]) const
 Fills affine in column major order. More...
 
SkMatrixsetAffine (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...
 
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...
 
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 SK_WARN_UNUSED_RESULT 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 SK_WARN_UNUSED_RESULT Scale (SkScalar sx, SkScalar sy)
 Sets SkMatrix to scale by (sx, sy). More...
 
static SkMatrix SK_WARN_UNUSED_RESULT Translate (SkScalar dx, SkScalar dy)
 Sets SkMatrix to translate by (dx, dy). More...
 
static SkMatrix SK_WARN_UNUSED_RESULT Translate (SkVector t)
 
static SkMatrix SK_WARN_UNUSED_RESULT Translate (SkIVector t)
 
static SkMatrix SK_WARN_UNUSED_RESULT RotateDeg (SkScalar deg)
 Sets SkMatrix to rotate by |deg| about a pivot point at (0, 0). More...
 
static SkMatrix SK_WARN_UNUSED_RESULT RotateRad (SkScalar rad)
 
static SkMatrix SK_WARN_UNUSED_RESULT 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 SkMatrixI ()
 Returns reference to const identity SkMatrix. More...
 
static const SkMatrixInvalidMatrix ()
 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 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 does not have a constructor, so it must be explicitly initialized. setIdentity() initializes SkMatrix so it has no effect. setTranslate(), setScale(), setSkew(), setRotate(), set9 and setAll() initializes all SkMatrix elements with the corresponding mapping.

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

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

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 ( )
inline

Creates an identity SkMatrix:

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

Member Function Documentation

◆ asAffine()

bool SK_WARN_UNUSED_RESULT 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
affinestorage 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
aSkMatrix on left side of multiply expression
bSkMatrix 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
scaleaxes scaling factors; may be nullptr
remainingSkMatrix 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
indexone 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
bufferstorage 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 SK_WARN_UNUSED_RESULT 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
scaleFactorsstorage 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 SK_WARN_UNUSED_RESULT 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
inversestorage 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
tolto 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 SK_WARN_UNUSED_RESULT 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
scaleXhorizontal scale factor
skewXhorizontal skew factor
transXhorizontal translation
skewYvertical skew factor
scaleYvertical scale factor
transYvertical translation
pers0input x-axis perspective factor
pers1input y-axis perspective factor
pers2perspective 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
srcSkRect to map from
dstSkRect to map to
Returns
SkMatrix mapping src to dst

◆ mapHomogeneousPoints() [1/2]

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
dststorage for mapped SkPoint3 array
srcSkPoint3 array to transform
countitems in SkPoint3 array to transform

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

◆ mapHomogeneousPoints() [2/2]

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

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

◆ 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
dststorage for mapped SkPoint
srcSkPoint to transform
countnumber 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
ptsstorage for mapped SkPoint
countnumber 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
radiuscircle size to map
Returns
average mapped radius

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

◆ mapRect() [1/3]

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
dststorage for bounds of mapped SkPoint
srcSkRect to map
pcwhether to apply perspective clipping
Returns
true if dst is equivalent to mapped src

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

◆ mapRect() [2/3]

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
rectrectangle to map, and storage for bounds of mapped corners
pcwhether to apply perspective clipping
Returns
true if result is equivalent to mapped rect

◆ mapRect() [3/3]

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

Returns bounds of src corners mapped by SkMatrix.

Parameters
srcrectangle to map
Returns
mapped bounds

◆ 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
dststorage for bounds of mapped SkPoint
srcSkRect 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
dststorage for mapped corner SkPoint
rectSkRect 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]

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
dxx-axis value of vector to map
dyy-axis value of vector to map
resultstorage for mapped vector

◆ mapVector() [2/2]

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
dxx-axis value of vector to map
dyy-axis value of vector to map
Returns
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
dststorage for mapped vectors
srcvectors to transform
countnumber 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
vecsvectors to transform, and storage for mapped vectors
countnumber of vectors to transform

◆ mapXY() [1/2]

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
xx-axis value of SkPoint to map
yy-axis value of SkPoint to map
resultstorage for mapped SkPoint

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

◆ mapXY() [2/2]

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
xx-axis value of SkPoint to map
yy-axis value of SkPoint to map
Returns
mapped SkPoint

◆ 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) const
inline

Returns one matrix value.

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

Parameters
indexone of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2
Returns
value corresponding to index

◆ operator[]() [2/2]

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
indexone of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2
Returns
writable 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
otherSkMatrix on left side of multiply expression

◆ postRotate() [1/2]

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
degreesangle of axes relative to upright axes
pxpivot on x-axis
pypivot on y-axis

◆ postRotate() [2/2]

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
degreesangle of axes relative to upright axes

◆ postScale() [1/2]

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
sxhorizontal scale factor
syvertical scale factor
pxpivot on x-axis
pypivot on y-axis

◆ postScale() [2/2]

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
sxhorizontal scale factor
syvertical scale factor

◆ postSkew() [1/2]

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
kxhorizontal skew factor
kyvertical skew factor
pxpivot on x-axis
pypivot on y-axis

◆ postSkew() [2/2]

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
kxhorizontal skew factor
kyvertical skew factor

◆ 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
dxx-axis translation after applying SkMatrix
dyy-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
otherSkMatrix on right side of multiply expression

◆ preRotate() [1/2]

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
degreesangle of axes relative to upright axes
pxpivot on x-axis
pypivot on y-axis

◆ preRotate() [2/2]

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
degreesangle of axes relative to upright axes

◆ preScale() [1/2]

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
sxhorizontal scale factor
syvertical scale factor
pxpivot on x-axis
pypivot on y-axis

◆ preScale() [2/2]

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
sxhorizontal scale factor
syvertical scale factor

◆ 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
tolto 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,
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
kxhorizontal skew factor
kyvertical skew factor
pxpivot on x-axis
pypivot on y-axis

◆ preSkew() [2/2]

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
kxhorizontal skew factor
kyvertical skew factor

◆ 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
dxx-axis translation before applying SkMatrix
dyy-axis translation before applying SkMatrix

◆ 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

◆ 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()

static SkMatrix SK_WARN_UNUSED_RESULT SkMatrix::RotateDeg ( SkScalar  deg)
inlinestatic

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

Parameters
degrotation angle in degrees (positive rotates clockwise)
Returns
SkMatrix with rotation

◆ RotateRad()

static SkMatrix SK_WARN_UNUSED_RESULT SkMatrix::RotateRad ( SkScalar  rad)
inlinestatic

◆ Scale()

static SkMatrix SK_WARN_UNUSED_RESULT 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
sxhorizontal scale factor
syvertical 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
indexone of: kMScaleX, kMSkewX, kMTransX, kMSkewY, kMScaleY, kMTransY, kMPersp0, kMPersp1, kMPersp2
valuescalar 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
buffernine 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
affine3 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
affinestorage 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
scaleXhorizontal scale factor to store
skewXhorizontal skew factor to store
transXhorizontal translation to store
skewYvertical skew factor to store
scaleYvertical scale factor to store
transYvertical translation to store
persp0input x-axis values perspective factor to store
persp1input y-axis values perspective factor to store
persp2perspective 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
aSkMatrix on left side of multiply expression
bSkMatrix 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
vperspective 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
vperspective 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
srcSkPoint to map from
dstSkPoint to map to
countnumber 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
srcSkRect to map from
dstSkRect 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,
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
degreesangle of axes relative to upright axes
pxpivot on x-axis
pypivot on y-axis

◆ setRotate() [2/2]

SkMatrix& SkMatrix::setRotate ( SkScalar  degrees)

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

Positive degrees rotates clockwise.

Parameters
degreesangle of axes relative to upright axes

◆ 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
rsxFormcompressed SkRSXform matrix
Returns
reference to SkMatrix

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

◆ setScale() [1/2]

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
sxhorizontal scale factor
syvertical scale factor
pxpivot on x-axis
pypivot on y-axis

◆ setScale() [2/2]

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

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

Parameters
sxhorizontal scale factor
syvertical scale factor

◆ 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
sxhorizontal scale factor to store
syvertical scale factor to store
txhorizontal translation to store
tyvertical translation to store

◆ setScaleX()

SkMatrix& SkMatrix::setScaleX ( SkScalar  v)
inline

Sets horizontal scale factor.

Parameters
vhorizontal scale factor to store

◆ setScaleY()

SkMatrix& SkMatrix::setScaleY ( SkScalar  v)
inline

Sets vertical scale factor.

Parameters
vvertical scale factor to store

◆ setSinCos() [1/2]

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
sinValuerotation vector x-axis component
cosValuerotation vector y-axis component
pxpivot on x-axis
pypivot on y-axis

◆ setSinCos() [2/2]

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
sinValuerotation vector x-axis component
cosValuerotation vector y-axis component

◆ setSkew() [1/2]

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
kxhorizontal skew factor
kyvertical skew factor
pxpivot on x-axis
pypivot on y-axis

◆ setSkew() [2/2]

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

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

Parameters
kxhorizontal skew factor
kyvertical skew factor

◆ setSkewX()

SkMatrix& SkMatrix::setSkewX ( SkScalar  v)
inline

Sets horizontal skew factor.

Parameters
vhorizontal skew factor to store

◆ setSkewY()

SkMatrix& SkMatrix::setSkewY ( SkScalar  v)
inline

Sets vertical skew factor.

Parameters
vvertical skew factor to store

◆ setTranslate() [1/2]

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

Sets SkMatrix to translate by (dx, dy).

Parameters
dxhorizontal translation
dyvertical translation

◆ setTranslate() [2/2]

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

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

Parameters
vvector containing horizontal and vertical translation

◆ setTranslateX()

SkMatrix& SkMatrix::setTranslateX ( SkScalar  v)
inline

Sets horizontal translation.

Parameters
vhorizontal translation to store

◆ setTranslateY()

SkMatrix& SkMatrix::setTranslateY ( SkScalar  v)
inline

Sets vertical translation.

Parameters
vvertical translation to store

◆ Translate() [1/3]

static SkMatrix SK_WARN_UNUSED_RESULT 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
dxhorizontal translation
dyvertical translation
Returns
SkMatrix with translation

◆ Translate() [2/3]

static SkMatrix SK_WARN_UNUSED_RESULT SkMatrix::Translate ( SkVector  t)
inlinestatic

◆ Translate() [3/3]

static SkMatrix SK_WARN_UNUSED_RESULT SkMatrix::Translate ( SkIVector  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
aSkMatrix to compare
bSkMatrix 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
aSkMatrix to compare
bSkMatrix 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
static

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
static

vertical scale factor

◆ kASkewX

constexpr int SkMatrix::kASkewX = 2
static

horizontal skew factor

◆ kASkewY

constexpr int SkMatrix::kASkewY = 1
static

vertical skew factor

◆ kATransX

constexpr int SkMatrix::kATransX = 4
static

horizontal translation

◆ kATransY

constexpr int SkMatrix::kATransY = 5
static

vertical translation

◆ kMPersp0

constexpr int SkMatrix::kMPersp0 = 6
static

input x perspective factor

◆ kMPersp1

constexpr int SkMatrix::kMPersp1 = 7
static

input y perspective factor

◆ kMPersp2

constexpr int SkMatrix::kMPersp2 = 8
static

perspective bias

◆ kMScaleX

constexpr int SkMatrix::kMScaleX = 0
static

SkMatrix organizes its values in row order.

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

◆ kMScaleY

constexpr int SkMatrix::kMScaleY = 4
static

vertical scale factor

◆ kMSkewX

constexpr int SkMatrix::kMSkewX = 1
static

horizontal skew factor

◆ kMSkewY

constexpr int SkMatrix::kMSkewY = 3
static

vertical skew factor

◆ kMTransX

constexpr int SkMatrix::kMTransX = 2
static

horizontal translation

◆ kMTransY

constexpr int SkMatrix::kMTransY = 5
static

vertical translation


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