skia2/site/user/api/SkMatrix_Reference.md

SkMatrix Reference
===

# <a name='Matrix'>Matrix</a>

# <a name='SkMatrix'>Class SkMatrix</a>

## <a name='Constant'>Constant</a>


SkMatrix related constants are defined by <code>enum</code>, <code>enum class</code>,  <code>#define</code>, <code>const</code>, and <code>constexpr</code>.
<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_ScaleToFit'>ScaleToFit</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>options to map <a href='SkRect_Reference#Rect'>Rects</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_TypeMask'>TypeMask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>bit field for <a href='#Matrix'>Matrix</a> complexity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kAScaleX'>kAScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kAScaleY'>kAScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kASkewX'>kASkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kASkewY'>kASkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kATransX'>kATransX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kATransY'>kATransY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kAffine_Mask'>kAffine Mask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>skew or rotate <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kCenter_ScaleToFit'>kCenter ScaleToFit</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>scales and aligns to center</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kEnd_ScaleToFit'>kEnd ScaleToFit</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>scales and aligns to right and bottom</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kFill_ScaleToFit'>kFill ScaleToFit</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>scales in x and y to fill destination <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kIdentity_Mask'>kIdentity Mask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>identity <a href='#Matrix'>Matrix</a>; all bits clear</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp0'>kMPersp0</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>input x perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp1'>kMPersp1</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>input y perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp2'>kMPersp2</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>perspective bias</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMScaleX'>kMScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMScaleY'>kMScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMSkewX'>kMSkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMSkewY'>kMSkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMTransX'>kMTransX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMTransY'>kMTransY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kPerspective_Mask'>kPerspective Mask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>perspective <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kScale_Mask'>kScale Mask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>scale <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kStart_ScaleToFit'>kStart ScaleToFit</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>scales and aligns to left and top</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kTranslate_Mask'>kTranslate Mask</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>translation <a href='#Matrix'>Matrix</a></td>
  </tr>
</table>

<a href='#Matrix'>Matrix</a> holds a 3x3 matrix for transforming coordinates. This allows mapping
<a href='SkPoint_Reference#Point'>Points</a> and <a href='SkPoint_Reference#Vector'>Vectors</a> with translation, scaling, skewing, rotation, and
perspective.

<a href='#Matrix'>Matrix</a> elements are in row major order. <a href='#Matrix'>Matrix</a> does not have a constructor,
so it must be explicitly initialized. <a href='#SkMatrix_setIdentity'>setIdentity</a> initializes <a href='#Matrix'>Matrix</a>
so it has no effect. <a href='#SkMatrix_setTranslate'>setTranslate</a>, <a href='#SkMatrix_setScale'>setScale</a>, <a href='#SkMatrix_setSkew'>setSkew</a>, <a href='#SkMatrix_setRotate'>setRotate</a>, <a href='#SkMatrix_set9'>set9</a> and <a href='#SkMatrix_setAll'>setAll</a>
initializes all <a href='#Matrix'>Matrix</a> elements with the corresponding mapping.

<a href='#Matrix'>Matrix</a> includes a hidden variable that classifies the type of matrix to
improve performance. <a href='#Matrix'>Matrix</a> is not thread safe unless <a href='#SkMatrix_getType'>getType</a> is called first.

## Overview

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Constant'>Constants</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>enum and enum class, and their const values</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Constructor'>Constructors</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>functions that construct <a href='#SkMatrix'>SkMatrix</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Member_Function'>Functions</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>global and class member functions</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Operator'>Operators</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>operator overloading methods</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Related_Function'>Related Functions</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>similar member functions grouped together</td>
  </tr>
</table>


## <a name='Member_Function'>Member Function</a>


SkMatrix member functions read and modify the structure properties.
<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_Concat'>Concat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns the concatenation of <a href='#Matrix'>Matrix</a> pair</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>I</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns a reference to a const identity <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_InvalidMatrix'>InvalidMatrix</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns a reference to a const invalid <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeAll'>MakeAll</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs all nine values</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from source <a href='SkRect_Reference#Rect'>Rect</a> to destination <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeScale'>MakeScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from scale in x and y</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeTrans'>MakeTrans</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from translate in x and y</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets 3x2 array to identity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_asAffine'>asAffine</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>copies to 3x2 array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_cheapEqualTo'>cheapEqualTo</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>compares <a href='#Matrix'>Matrix</a> pair using memcmp()</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_decomposeScale'>decomposeScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>separates scale if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_dirtyMatrixTypeCache'>dirtyMatrixTypeCache</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets internal cache to unknown state</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_dump'>dump</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sends text representation using floats to standard output</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_fixedStepInX'>fixedStepInX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns step in x for a position in y</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_get'>get</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns one of nine <a href='#Matrix'>Matrix</a> values</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_get9'>get9</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns all nine <a href='#Matrix'>Matrix</a> values</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMaxScale'>getMaxScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns maximum scaling, if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMinMaxScales'>getMinMaxScales</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns minimum and maximum scaling, if possible</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMinScale'>getMinScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns minimum scaling, if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getPerspX'>getPerspX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns input x perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getPerspY'>getPerspY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns input y perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getScaleX'>getScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getScaleY'>getScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getSkewX'>getSkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getSkewY'>getSkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getTranslateX'>getTranslateX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getTranslateY'>getTranslateY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getType'>getType</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns transform complexity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_hasPerspective'>hasPerspective</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform includes perspective</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_invert'>invert</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns inverse, if possible</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isFinite'>isFinite</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if all <a href='#Matrix'>Matrix</a> values are not infinity, NaN</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transformation supports fixed step in x</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isIdentity'>isIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if matrix equals the identity <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to scale and translate</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isSimilarity'>isSimilarity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to square scale and rotation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isTranslate'>isTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to translate</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapHomogeneousPoints'>mapHomogeneousPoints</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='undocumented#Point3'>Point3</a> array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapPoints'>mapPoints</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Point'>Point</a> array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRadius'>mapRadius</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns mean radius of mapped <a href='undocumented#Circle'>Circle</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRect'>mapRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns bounds of mapped <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns bounds of mapped <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRectToQuad'>mapRectToQuad</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkRect_Reference#Rect'>Rect</a> to <a href='SkPoint_Reference#Point'>Point</a> array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVector'>mapVector</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Vector'>Vector</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVectors'>mapVectors</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Vector'>Vector</a> array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapXY'>mapXY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Point'>Point</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postConcat'>postConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postIDiv'>postIDiv</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by inverse scale</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postRotate'>postRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by rotation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postScale'>postScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by scale</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postSkew'>postSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by skew</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postTranslate'>postTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preConcat'>preConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preRotate'>preRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by rotation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preScale'>preScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by scale</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preSkew'>preSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by skew</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preTranslate'>preTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preservesAxisAlignment'>preservesAxisAlignment</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapping restricts to 90 degree multiples and mirroring</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapped 90 angle remains 90 degrees</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_rectStaysRect'>rectStaysRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapped <a href='SkRect_Reference#Rect'>Rect</a> can be represented by another <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_reset'>reset</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets <a href='#Matrix'>Matrix</a> to identity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_set'>set</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets one value</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_set9'>set9</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets all values from <a href='undocumented#Scalar'>Scalar</a> array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setAffine'>setAffine</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets left two columns</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setAll'>setAll</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets all values from parameters</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setConcat'>setConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to <a href='#Matrix'>Matrix</a> parameter multiplied by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setIdentity'>setIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets <a href='#Matrix'>Matrix</a> to identity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPerspX'>setPerspX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets input x perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPerspY'>setPerspY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets input y perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to map one to four points to an equal array of points</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRSXform'>setRSXform</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate, scale, and translate</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRectToRect'>setRectToRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to map one <a href='SkRect_Reference#Rect'>Rect</a> to another</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRotate'>setRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate about a point</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScale'>setScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to scale about a point</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleTranslate'>setScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to scale and translate</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleX'>setScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleY'>setScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSinCos'>setSinCos</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate and scale about a point</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkew'>setSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to skew about a point</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkewX'>setSkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkewY'>setSkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslate'>setTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to translate in x and y</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslateX'>setTranslateX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslateY'>setTranslateY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical translation</td>
  </tr>
</table>

## <a name='Related_Function'>Related Function</a>


SkMatrix global, <code>struct</code>, and <code>class</code> related member functions share a topic.
<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#AffineIndex'>AffineIndex</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>affine member indices</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#MemberIndex'>MemberIndex</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>member indices</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Property'>Property</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>values and attributes</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Set'>Set</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets one or more matrix values</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Transform'>Transform</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>map points with <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#Utility'>Utility</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>rarely called management functions</td>
  </tr>
</table>

## <a name='Constructor'>Constructor</a>


SkMatrix can be constructed or initialized by these functions, including C++ class constructors.
<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>I</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns a reference to a const identity <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_InvalidMatrix'>InvalidMatrix</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns a reference to a const invalid <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeAll'>MakeAll</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs all nine values</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from source <a href='SkRect_Reference#Rect'>Rect</a> to destination <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeScale'>MakeScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from scale in x and y</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeScale'>MakeScale(SkScalar sx, SkScalar sy)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeScale_2'>MakeScale(SkScalar scale)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_MakeTrans'>MakeTrans</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>constructs from translate in x and y</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets 3x2 array to identity</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_asAffine'>asAffine</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>copies to 3x2 array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_reset'>reset</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets <a href='#Matrix'>Matrix</a> to identity</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setAffine'>setAffine</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets left two columns</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setConcat'>setConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to <a href='#Matrix'>Matrix</a> parameter multiplied by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setIdentity'>setIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets <a href='#Matrix'>Matrix</a> to identity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRSXform'>setRSXform</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate, scale, and translate</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRotate'>setRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate about a point</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRotate'>setRotate(SkScalar degrees, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRotate_2'>setRotate(SkScalar degrees)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScale'>setScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to scale about a point</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScale'>setScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScale_2'>setScale(SkScalar sx, SkScalar sy)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleTranslate'>setScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to scale and translate</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSinCos'>setSinCos</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to rotate and scale about a point</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSinCos'>setSinCos(SkScalar sinValue, SkScalar cosValue, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSinCos_2'>setSinCos(SkScalar sinValue, SkScalar cosValue)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkew'>setSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to skew about a point</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkew'>setSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkew_2'>setSkew(SkScalar kx, SkScalar ky)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslate'>setTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to translate in x and y</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslate'>setTranslate(SkScalar dx, SkScalar dy)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslate_2'>setTranslate(const SkVector& v)</a></td>
  </tr>
</table>

<a name='SkMatrix_MakeScale'></a>
## MakeScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> SK_WARN_UNUSED_RESULT <a href='#SkMatrix_MakeScale'>MakeScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to scale by (<a href='#SkMatrix_MakeScale_sx'>sx</a>, <a href='#SkMatrix_MakeScale_sy'>sy</a>). Returned matrix is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| sx  0  0 |
|  0 sy  0 |
|  0  0  1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_MakeScale_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeScale_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> with scale

### Example

<div><fiddle-embed name="7ff17718111df6d6f95381d8a8f1b389"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup> <a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup>

---

<a name='SkMatrix_MakeScale_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> SK_WARN_UNUSED_RESULT <a href='#SkMatrix_MakeScale'>MakeScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> scale)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#SkMatrix_MakeScale_2_scale'>scale</a> by (<a href='#SkMatrix_MakeScale_2_scale'>scale</a>, <a href='#SkMatrix_MakeScale_2_scale'>scale</a>). Returned matrix is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale   0   0 |
|   0   scale 0 |
|   0     0   1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_MakeScale_2_scale'><code><strong>scale</strong></code></a></td>
    <td>horizontal and vertical <a href='#SkMatrix_MakeScale_2_scale'>scale</a> factor</td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> with <a href='#SkMatrix_MakeScale_2_scale'>scale</a>

### Example

<div><fiddle-embed name="2956aeb50fa862cdb13995e1e56a4bc8"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup> <a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup>

---

<a name='SkMatrix_MakeTrans'></a>
## MakeTrans

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> SK_WARN_UNUSED_RESULT <a href='#SkMatrix_MakeTrans'>MakeTrans</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to translate by (<a href='#SkMatrix_MakeTrans_dx'>dx</a>, <a href='#SkMatrix_MakeTrans_dy'>dy</a>). Returned matrix is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 dx |
| 0 1 dy |
| 0 0  1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_MakeTrans_dx'><code><strong>dx</strong></code></a></td>
    <td>horizontal translation</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeTrans_dy'><code><strong>dy</strong></code></a></td>
    <td>vertical translation</td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> with translation

### Example

<div><fiddle-embed name="b2479df0d9cf296ff64ac31e36684557"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_postTranslate'>postTranslate</a> <a href='#SkMatrix_preTranslate'>preTranslate</a>

---

<a name='SkMatrix_MakeAll'></a>
## MakeAll

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> SK_WARN_UNUSED_RESULT <a href='#SkMatrix_MakeAll'>MakeAll</a>(<a href='undocumented#SkScalar'>SkScalar</a> scaleX, <a href='undocumented#SkScalar'>SkScalar</a> skewX, <a href='undocumented#SkScalar'>SkScalar</a> transX,
                                              <a href='undocumented#SkScalar'>SkScalar</a> skewY, <a href='undocumented#SkScalar'>SkScalar</a> scaleY, <a href='undocumented#SkScalar'>SkScalar</a> transY,
                                              <a href='undocumented#SkScalar'>SkScalar</a> pers0, <a href='undocumented#SkScalar'>SkScalar</a> pers1, <a href='undocumented#SkScalar'>SkScalar</a> pers2)
</pre>

Sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scaleX  skewX transX |
|  skewY scaleY transY |
|  pers0  pers1  pers2 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_MakeAll_scaleX'><code><strong>scaleX</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_skewX'><code><strong>skewX</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_transX'><code><strong>transX</strong></code></a></td>
    <td>horizontal translation</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_skewY'><code><strong>skewY</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_scaleY'><code><strong>scaleY</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_transY'><code><strong>transY</strong></code></a></td>
    <td>vertical translation</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_pers0'><code><strong>pers0</strong></code></a></td>
    <td>input x-axis perspective factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_pers1'><code><strong>pers1</strong></code></a></td>
    <td>input y-axis perspective factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeAll_pers2'><code><strong>pers2</strong></code></a></td>
    <td>perspective scale factor</td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> constructed from parameters

### Example

<div><fiddle-embed name="6bad83b64de9266e323c29d550e04188"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setAll'>setAll</a> <a href='#SkMatrix_set9'>set9</a> <a href='#SkMatrix_postConcat'>postConcat</a> <a href='#SkMatrix_preConcat'>preConcat</a>

---

## <a name='SkMatrix_TypeMask'>Enum SkMatrix::TypeMask</a>

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    enum <a href='#SkMatrix_TypeMask'>TypeMask</a> {
        <a href='#SkMatrix_kIdentity_Mask'>kIdentity Mask</a> = 0,
        <a href='#SkMatrix_kTranslate_Mask'>kTranslate Mask</a> = 0x01,
        <a href='#SkMatrix_kScale_Mask'>kScale Mask</a> = 0x02,
        <a href='#SkMatrix_kAffine_Mask'>kAffine Mask</a> = 0x04,
        <a href='#SkMatrix_kPerspective_Mask'>kPerspective Mask</a> = 0x08,
    };
</pre>

Enum of bit fields for mask returned by <a href='#SkMatrix_getType'>getType</a>.
Used to identify the complexity of <a href='#Matrix'>Matrix</a>, to optimize performance.

### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kIdentity_Mask'><code>SkMatrix::kIdentity_Mask</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
all bits clear if <a href='#Matrix'>Matrix</a> is identity</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kTranslate_Mask'><code>SkMatrix::kTranslate_Mask</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
set if <a href='#Matrix'>Matrix</a> has translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kScale_Mask'><code>SkMatrix::kScale_Mask</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
set if <a href='#Matrix'>Matrix</a> has x or y scale</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kAffine_Mask'><code>SkMatrix::kAffine_Mask</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>4</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
set if <a href='#Matrix'>Matrix</a> skews or rotates</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kPerspective_Mask'><code>SkMatrix::kPerspective_Mask</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>8</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
set if <a href='#Matrix'>Matrix</a> has perspective</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="ba19b36df8cd78586f3dff54e2d4c093">

#### Example Output

~~~~
after reset: kIdentity_Mask
after postTranslate: kTranslate_Mask
after postScale: kTranslate_Mask kScale_Mask
after postScale: kTranslate_Mask kScale_Mask kAffine_Mask
after setPolyToPoly: kTranslate_Mask kScale_Mask kAffine_Mask kPerspective_Mask
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_getType'>getType</a>

## <a name='Property'>Property</a>


<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_decomposeScale'>decomposeScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>separates scale if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_fixedStepInX'>fixedStepInX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns step in x for a position in y</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_get'>get</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns one of nine <a href='#Matrix'>Matrix</a> values</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_get9'>get9</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns all nine <a href='#Matrix'>Matrix</a> values</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMaxScale'>getMaxScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns maximum scaling, if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMinMaxScales'>getMinMaxScales</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns minimum and maximum scaling, if possible</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getMinScale'>getMinScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns minimum scaling, if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getPerspX'>getPerspX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns input x perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getPerspY'>getPerspY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns input y perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getScaleX'>getScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getScaleY'>getScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getSkewX'>getSkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getSkewY'>getSkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getTranslateX'>getTranslateX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns horizontal translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getTranslateY'>getTranslateY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns vertical translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_getType'>getType</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns transform complexity</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_hasPerspective'>hasPerspective</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform includes perspective</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isFinite'>isFinite</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if all <a href='#Matrix'>Matrix</a> values are not infinity, NaN</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transformation supports fixed step in x</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isIdentity'>isIdentity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if matrix equals the identity <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to scale and translate</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isSimilarity'>isSimilarity</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to square scale and rotation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_isTranslate'>isTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if transform is limited to translate</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preservesAxisAlignment'>preservesAxisAlignment</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapping restricts to 90 degree multiples and mirroring</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapped 90 angle remains 90 degrees</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_rectStaysRect'>rectStaysRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns if mapped <a href='SkRect_Reference#Rect'>Rect</a> can be represented by another <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
</table>

<a name='SkMatrix_getType'></a>
## getType

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='#SkMatrix_TypeMask'>TypeMask</a> <a href='#SkMatrix_getType'>getType</a>() const
</pre>

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 <a href='#SkMatrix_kPerspective_Mask'>kPerspective Mask</a> is set, all
other bits are set.

### Return Value

<a href='#SkMatrix_kIdentity_Mask'>kIdentity Mask</a>, or combinations of: <a href='#SkMatrix_kTranslate_Mask'>kTranslate Mask</a>, <a href='#SkMatrix_kScale_Mask'>kScale Mask</a>,
<a href='#SkMatrix_kAffine_Mask'>kAffine Mask</a>, <a href='#SkMatrix_kPerspective_Mask'>kPerspective Mask</a>

### Example

<div><fiddle-embed name="8e45fe2dd52731bb2d4318686257e1d7">

#### Example Output

~~~~
identity flags hex: 0 decimal: 0
set all  flags hex: f decimal: 15
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_TypeMask'>TypeMask</a>

---

<a name='SkMatrix_isIdentity'></a>
## isIdentity

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isIdentity'>isIdentity</a>() const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> is identity.  Identity matrix is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |
</pre>

### Return Value

true if <a href='#Matrix'>Matrix</a> has no effect

### Example

<div><fiddle-embed name="780ab376325b3cfa889ea26c0769ec11">

#### Example Output

~~~~
is identity: true
is identity: false
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_reset'>reset</a> <a href='#SkMatrix_setIdentity'>setIdentity</a> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_isScaleTranslate'></a>
## isScaleTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a>() const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> at most scales and translates. <a href='#Matrix'>Matrix</a> may be identity,
contain only scale elements, only translate elements, or both. <a href='#Matrix'>Matrix</a> form is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |
</pre>

### Return Value

true if <a href='#Matrix'>Matrix</a> is identity; or scales, translates, or both

### Example

<div><fiddle-embed name="6287e29674a487eb94174992d45b9a34">

#### Example Output

~~~~
is scale-translate: true
is scale-translate: true
is scale-translate: true
is scale-translate: true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_isTranslate'>isTranslate</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_isTranslate'></a>
## isTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isTranslate'>isTranslate</a>() const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> is identity, or translates. <a href='#Matrix'>Matrix</a> form is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 translate-x |
| 0 1 translate-y |
| 0 0      1      |
</pre>

### Return Value

true if <a href='#Matrix'>Matrix</a> is identity, or translates

### Example

<div><fiddle-embed name="73ac71a8a30841873577c11c6c9b38ee">

#### Example Output

~~~~
is translate: true
is translate: true
is translate: false
is translate: false
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_rectStaysRect'></a>
## rectStaysRect

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>() const
</pre>

Returns true <a href='#Matrix'>Matrix</a> maps <a href='SkRect_Reference#Rect'>Rect</a> to another <a href='SkRect_Reference#Rect'>Rect</a>. If true, <a href='#Matrix'>Matrix</a> is identity,
or scales, or rotates a multiple of 90 degrees, or mirrors on axes. In all
cases, <a href='#Matrix'>Matrix</a> may also have translation. <a href='#Matrix'>Matrix</a> form is either:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |
</pre>

or

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
|    0     rotate-x translate-x |
| rotate-y    0     translate-y |
|    0        0          1      |
</pre>

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

Also called <a href='#SkMatrix_preservesAxisAlignment'>preservesAxisAlignment</a>; use the one that provides better inline
documentation.

### Return Value

true if <a href='#Matrix'>Matrix</a> maps one <a href='SkRect_Reference#Rect'>Rect</a> into another

### Example

<div><fiddle-embed name="ce5319c036c9b5086da8a0009fe409f8">

#### Example Output

~~~~
rectStaysRect: true
rectStaysRect: true
rectStaysRect: true
rectStaysRect: true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_preservesAxisAlignment'>preservesAxisAlignment</a> <a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a>

---

<a name='SkMatrix_preservesAxisAlignment'></a>
## preservesAxisAlignment

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_preservesAxisAlignment'>preservesAxisAlignment</a>() const
</pre>

Returns true <a href='#Matrix'>Matrix</a> maps <a href='SkRect_Reference#Rect'>Rect</a> to another <a href='SkRect_Reference#Rect'>Rect</a>. If true, <a href='#Matrix'>Matrix</a> is identity,
or scales, or rotates a multiple of 90 degrees, or mirrors on axes. In all
cases, <a href='#Matrix'>Matrix</a> may also have translation. <a href='#Matrix'>Matrix</a> form is either:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x    0    translate-x |
|    0    scale-y translate-y |
|    0       0         1      |
</pre>

or

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
|    0     rotate-x translate-x |
| rotate-y    0     translate-y |
|    0        0          1      |
</pre>

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

Also called <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>; use the one that provides better inline
documentation.

### Return Value

true if <a href='#Matrix'>Matrix</a> maps one <a href='SkRect_Reference#Rect'>Rect</a> into another

### Example

<div><fiddle-embed name="7a234c96608fb7cb8135b9940b0b15f7">

#### Example Output

~~~~
preservesAxisAlignment: true
preservesAxisAlignment: true
preservesAxisAlignment: true
preservesAxisAlignment: true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_rectStaysRect'>rectStaysRect</a> <a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a>

---

<a name='SkMatrix_hasPerspective'></a>
## hasPerspective

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_hasPerspective'>hasPerspective</a>() const
</pre>

Returns true if the matrix contains perspective elements. <a href='#Matrix'>Matrix</a> form is:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
|       --            --              --          |
|       --            --              --          |
| perspective-x  perspective-y  perspective-scale |
</pre>

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

### Return Value

true if <a href='#Matrix'>Matrix</a> is in most general form

### Example

<div><fiddle-embed name="688123908c733169bbbfaf11f41ecff6"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setAll'>setAll</a> <a href='#SkMatrix_set9'>set9</a> <a href='#SkMatrix_MakeAll'>MakeAll</a>

---

<a name='SkMatrix_isSimilarity'></a>
## isSimilarity

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isSimilarity'>isSimilarity</a>(<a href='undocumented#SkScalar'>SkScalar</a> tol = <a href='undocumented#SK_ScalarNearlyZero'>SK ScalarNearlyZero</a>) const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> contains only translation, rotation, reflection, and
uniform scale.
Returns false if <a href='#Matrix'>Matrix</a> contains different scales, skewing, perspective, or
degenerate forms that collapse to a line or point.

Describes that the <a href='#Matrix'>Matrix</a> 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 <a href='undocumented#Euclidean_Space'>Euclidean Space</a>, or a similarity transformation.

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

### Parameters

<table>  <tr>    <td><a name='SkMatrix_isSimilarity_tol'><code><strong>tol</strong></code></a></td>
    <td>to be deprecated</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> only rotates, uniformly scales, translates

### Example

<div><fiddle-embed name="8b37f4ae7fec1756433c0f984175fb14"><div><a href='undocumented#String'>String</a> is drawn four times through but only two are visible. Drawing the pair
with <a href='#SkMatrix_isSimilarity'>isSimilarity</a> false reveals the pair not visible through the matrix.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a> <a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a> <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a> <a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a>

---

<a name='SkMatrix_preservesRightAngles'></a>
## preservesRightAngles

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_preservesRightAngles'>preservesRightAngles</a>(<a href='undocumented#SkScalar'>SkScalar</a> tol = <a href='undocumented#SK_ScalarNearlyZero'>SK ScalarNearlyZero</a>) const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> contains only translation, rotation, reflection, and
scale. Scale may differ along rotated axes.
Returns false if <a href='#Matrix'>Matrix</a> 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

<table>  <tr>    <td><a name='SkMatrix_preservesRightAngles_tol'><code><strong>tol</strong></code></a></td>
    <td>to be deprecated</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> only rotates, scales, translates

### Example

<div><fiddle-embed name="b9becf0dc24a9f00726e24a81fb72f16"><div>Equal scale is both similar and preserves right angles.
Unequal scale is not similar but preserves right angles.
Skews are not similar and do not preserve right angles.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a> <a href='#SkMatrix_isSimilarity'>isSimilarity</a> <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a> <a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a>

---

## <a name='MemberIndex'>MemberIndex</a>



### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMScaleX'><code>SkMatrix::kMScaleX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMSkewX'><code>SkMatrix::kMSkewX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMTransX'><code>SkMatrix::kMTransX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMSkewY'><code>SkMatrix::kMSkewY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>3</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMScaleY'><code>SkMatrix::kMScaleY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>4</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMTransY'><code>SkMatrix::kMTransY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>5</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp0'><code>SkMatrix::kMPersp0</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>6</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>input x perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp1'><code>SkMatrix::kMPersp1</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>7</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>input y perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kMPersp2'><code>SkMatrix::kMPersp2</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>8</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>perspective bias</td>
  </tr>
</table>


<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    static constexpr int <a href='#SkMatrix_kMScaleX'>kMScaleX</a> = 0;
    static constexpr int <a href='#SkMatrix_kMSkewX'>kMSkewX</a>  = 1;
    static constexpr int <a href='#SkMatrix_kMTransX'>kMTransX</a> = 2;
    static constexpr int <a href='#SkMatrix_kMSkewY'>kMSkewY</a>  = 3;
    static constexpr int <a href='#SkMatrix_kMScaleY'>kMScaleY</a> = 4;
    static constexpr int <a href='#SkMatrix_kMTransY'>kMTransY</a> = 5;
    static constexpr int <a href='#SkMatrix_kMPersp0'>kMPersp0</a> = 6;
    static constexpr int <a href='#SkMatrix_kMPersp1'>kMPersp1</a> = 7;
    static constexpr int <a href='#SkMatrix_kMPersp2'>kMPersp2</a> = 8;
</pre>

<a href='#Matrix'>Matrix</a> organizes its values in row order. These members correspond to
each value in <a href='#Matrix'>Matrix</a>.

### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMScaleX'><code>SkMatrix::kMScaleX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMSkewX'><code>SkMatrix::kMSkewX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMTransX'><code>SkMatrix::kMTransX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMSkewY'><code>SkMatrix::kMSkewY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>3</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMScaleY'><code>SkMatrix::kMScaleY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>4</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMTransY'><code>SkMatrix::kMTransY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>5</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMPersp0'><code>SkMatrix::kMPersp0</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>6</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
input x perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMPersp1'><code>SkMatrix::kMPersp1</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>7</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
input y perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kMPersp2'><code>SkMatrix::kMPersp2</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>8</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
perspective bias</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="3bbf75f4748420810aa2586e3c8548d9"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_set'>set</a>

## <a name='AffineIndex'>AffineIndex</a>



### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kAScaleX'><code>SkMatrix::kAScaleX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kASkewY'><code>SkMatrix::kASkewY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kASkewX'><code>SkMatrix::kASkewX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kAScaleY'><code>SkMatrix::kAScaleY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>3</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kATransX'><code>SkMatrix::kATransX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>4</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_kATransY'><code>SkMatrix::kATransY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>5</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>vertical translation</td>
  </tr>
</table>


<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    static constexpr int <a href='#SkMatrix_kAScaleX'>kAScaleX</a> = 0;
    static constexpr int <a href='#SkMatrix_kASkewY'>kASkewY</a>  = 1;
    static constexpr int <a href='#SkMatrix_kASkewX'>kASkewX</a>  = 2;
    static constexpr int <a href='#SkMatrix_kAScaleY'>kAScaleY</a> = 3;
    static constexpr int <a href='#SkMatrix_kATransX'>kATransX</a> = 4;
    static constexpr int <a href='#SkMatrix_kATransY'>kATransY</a> = 5;
</pre>

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

### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kAScaleX'><code>SkMatrix::kAScaleX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kASkewY'><code>SkMatrix::kASkewY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kASkewX'><code>SkMatrix::kASkewX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kAScaleY'><code>SkMatrix::kAScaleY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>3</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kATransX'><code>SkMatrix::kATransX</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>4</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kATransY'><code>SkMatrix::kATransY</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>5</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
vertical translation</td>
  </tr>
</table>

### See Also

<a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a> <a href='#SkMatrix_asAffine'>asAffine</a> <a href='#SkMatrix_setAffine'>setAffine</a>

## <a name='Operator'>Operator</a>


SkMatrix operators inline class member functions with arithmetic equivalents.
<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_Concat'>Concat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns the concatenation of <a href='#Matrix'>Matrix</a> pair</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_cheapEqualTo'>cheapEqualTo</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>compares <a href='#Matrix'>Matrix</a> pair using memcmp()</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_invert'>invert</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns inverse, if possible</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_notequal_operator'>operator!=(const SkMatrix& a, const SkMatrix& b)</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns true if members are unequal</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_equal_operator'>operator==(const SkMatrix& a, const SkMatrix& b)</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns true if members are equal</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_array1_operator'>operator[](int index)</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns writable reference to <a href='#Matrix'>Matrix</a> value</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_array_operator'>operator[](int index) const</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns <a href='#Matrix'>Matrix</a> value</td>
  </tr>
</table>

<a name='SkMatrix_array_operator'></a>
## operator[]

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_array1_operator'>operator[](int index)</a> _const
</pre>

Returns one matrix value. Asserts if <a href='#SkMatrix_array_operator_index'>index</a> is out of range and SK_DEBUG is
defined.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_array_operator_index'><code><strong>index</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>,
<a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>, <a href='#SkMatrix_kMPersp2'>kMPersp2</a></td>
  </tr>
</table>

### Return Value

value corresponding to <a href='#SkMatrix_array_operator_index'>index</a>

### Example

<div><fiddle-embed name="e8740493abdf0c6341762db9cee56b89">

#### Example Output

~~~~
matrix[SkMatrix::kMScaleX] == 42
matrix[SkMatrix::kMScaleY] == 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_set'>set</a>

---

<a name='SkMatrix_get'></a>
## get

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_get'>get</a>(int index) const
</pre>

Returns one matrix value. Asserts if <a href='#SkMatrix_get_index'>index</a> is out of range and SK_DEBUG is
defined.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_get_index'><code><strong>index</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>,
<a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>, <a href='#SkMatrix_kMPersp2'>kMPersp2</a></td>
  </tr>
</table>

### Return Value

value corresponding to <a href='#SkMatrix_get_index'>index</a>

### Example

<div><fiddle-embed name="f5ed382bd04fa7d50b2398cce2fca23a">

#### Example Output

~~~~
matrix.get(SkMatrix::kMSkewX) == 42
matrix.get(SkMatrix::kMSkewY) == 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_array1_operator'>operator[](int index)</a> <a href='#SkMatrix_set'>set</a>

---

<a name='SkMatrix_getScaleX'></a>
## getScaleX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getScaleX'>getScaleX</a>() const
</pre>

Returns scale factor multiplied by x-axis input, contributing to x-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, scales <a href='SkPoint_Reference#Point'>Points</a> along the x-axis.

### Return Value

horizontal scale factor

### Example

<div><fiddle-embed name="ab746d9be63975041ae8e50cba84dc3d">

#### Example Output

~~~~
matrix.getScaleX() == 42
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getScaleY'>getScaleY</a> <a href='#SkMatrix_setScaleX'>setScaleX</a> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup>

---

<a name='SkMatrix_getScaleY'></a>
## getScaleY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getScaleY'>getScaleY</a>() const
</pre>

Returns scale factor multiplied by y-axis input, contributing to y-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, scales <a href='SkPoint_Reference#Point'>Points</a> along the y-axis.

### Return Value

vertical scale factor

### Example

<div><fiddle-embed name="708b1a548a2f8661b2ab570782fbc751">

#### Example Output

~~~~
matrix.getScaleY() == 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getScaleX'>getScaleX</a> <a href='#SkMatrix_setScaleY'>setScaleY</a> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup>

---

<a name='SkMatrix_getSkewY'></a>
## getSkewY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getSkewY'>getSkewY</a>() const
</pre>

Returns scale factor multiplied by x-axis input, contributing to y-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, skews <a href='SkPoint_Reference#Point'>Points</a> along the y-axis.
Skewing both axes can rotate <a href='SkPoint_Reference#Point'>Points</a>.

### Return Value

vertical skew factor

### Example

<div><fiddle-embed name="6be5704506d029ffc91ba03b1d3e674b">

#### Example Output

~~~~
matrix.getSkewY() == 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getSkewX'>getSkewX</a> <a href='#SkMatrix_setSkewY'>setSkewY</a> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_getSkewX'></a>
## getSkewX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getSkewX'>getSkewX</a>() const
</pre>

Returns scale factor multiplied by y-axis input, contributing to x-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, skews <a href='SkPoint_Reference#Point'>Points</a> along the x-axis.
Skewing both axes can rotate <a href='SkPoint_Reference#Point'>Points</a>.

### Return Value

horizontal scale factor

### Example

<div><fiddle-embed name="df3a5d3c688e7597eae1e4e07bf91ae6">

#### Example Output

~~~~
matrix.getSkewX() == 42
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getSkewY'>getSkewY</a> <a href='#SkMatrix_setSkewX'>setSkewX</a> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_getTranslateX'></a>
## getTranslateX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getTranslateX'>getTranslateX</a>() const
</pre>

Returns translation contributing to x-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, moves <a href='SkPoint_Reference#Point'>Points</a> along the x-axis.

### Return Value

horizontal translation factor

### Example

<div><fiddle-embed name="6236f7f2b91aff977a66ba2ee2558ca4">

#### Example Output

~~~~
matrix.getTranslateX() == 42
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getTranslateY'>getTranslateY</a> <a href='#SkMatrix_setTranslateX'>setTranslateX</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup>

---

<a name='SkMatrix_getTranslateY'></a>
## getTranslateY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getTranslateY'>getTranslateY</a>() const
</pre>

Returns translation contributing to y-axis output.
With <a href='#SkMatrix_mapPoints'>mapPoints</a>, moves <a href='SkPoint_Reference#Point'>Points</a> along the y-axis.

### Return Value

vertical translation factor

### Example

<div><fiddle-embed name="08464e32d22421d2b254c71a84545ef5">

#### Example Output

~~~~
matrix.getTranslateY() == 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_getTranslateX'>getTranslateX</a> <a href='#SkMatrix_setTranslateY'>setTranslateY</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup>

---

<a name='SkMatrix_getPerspX'></a>
## getPerspX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getPerspX'>getPerspX</a>() const
</pre>

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

### Return Value

input x-axis perspective factor

### Example

<div><fiddle-embed name="a0f5bf4b55e8c33bfda29bf67e34306f"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_kMPersp0'>kMPersp0</a> <a href='#SkMatrix_getPerspY'>getPerspY</a>

---

<a name='SkMatrix_getPerspY'></a>
## getPerspY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getPerspY'>getPerspY</a>() const
</pre>

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

### Return Value

input y-axis perspective factor

### Example

<div><fiddle-embed name="424a00a73675dbd99ad20feb0267442b"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_kMPersp1'>kMPersp1</a> <a href='#SkMatrix_getPerspX'>getPerspX</a>

---

<a name='SkMatrix_array1_operator'></a>
## operator[]

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a>& <a href='#SkMatrix_array1_operator'>operator[](int index)</a>
</pre>

Returns writable <a href='#Matrix'>Matrix</a> value. Asserts if <a href='#SkMatrix_array1_operator_index'>index</a> is out of range and SK_DEBUG is
defined. Clears internal cache anticipating that caller will change <a href='#Matrix'>Matrix</a> value.

Next call to read <a href='#Matrix'>Matrix</a> state may recompute cache; subsequent writes to <a href='#Matrix'>Matrix</a>
value must be followed by <a href='#SkMatrix_dirtyMatrixTypeCache'>dirtyMatrixTypeCache</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_array1_operator_index'><code><strong>index</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>,
<a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>, <a href='#SkMatrix_kMPersp2'>kMPersp2</a></td>
  </tr>
</table>

### Return Value

writable value corresponding to <a href='#SkMatrix_array1_operator_index'>index</a>

### Example

<div><fiddle-embed name="f4365ef332f51f7fd25040e0771ba9a2">

#### Example Output

~~~~
with identity matrix: x = 24
after skew x mod:     x = 24
after 2nd skew x mod: x = 24
after dirty cache:    x = 66
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_get'>get</a> <a href='#SkMatrix_dirtyMatrixTypeCache'>dirtyMatrixTypeCache</a> <a href='#SkMatrix_set'>set</a>

---

## <a name='Set'>Set</a>


<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postConcat'>postConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postIDiv'>postIDiv</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by inverse scale</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postRotate'>postRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by rotation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postRotate'>postRotate(SkScalar degrees, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postRotate_2'>postRotate(SkScalar degrees)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postScale'>postScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by scale</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postScale'>postScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postScale_2'>postScale(SkScalar sx, SkScalar sy)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postSkew'>postSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by skew</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postSkew'>postSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postSkew_2'>postSkew(SkScalar kx, SkScalar ky)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_postTranslate'>postTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>post-multiplies <a href='#Matrix'>Matrix</a> by translation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preConcat'>preConcat</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by <a href='#Matrix'>Matrix</a> parameter</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preRotate'>preRotate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by rotation</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preRotate'>preRotate(SkScalar degrees, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preRotate_2'>preRotate(SkScalar degrees)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preScale'>preScale</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by scale</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preScale'>preScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preScale_2'>preScale(SkScalar sx, SkScalar sy)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preSkew'>preSkew</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by skew</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preSkew'>preSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preSkew_2'>preSkew(SkScalar kx, SkScalar ky)</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_preTranslate'>preTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>pre-multiplies <a href='#Matrix'>Matrix</a> by translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_set'>set</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets one value</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_set9'>set9</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets all values from <a href='undocumented#Scalar'>Scalar</a> array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setAll'>setAll</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets all values from parameters</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPerspX'>setPerspX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets input x perspective factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPerspY'>setPerspY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets input y perspective factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to map one to four points to an equal array of points</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setRectToRect'>setRectToRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets to map one <a href='SkRect_Reference#Rect'>Rect</a> to another</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleX'>setScaleX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal scale factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setScaleY'>setScaleY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical scale factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkewX'>setSkewX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal skew factor</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setSkewY'>setSkewY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical skew factor</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslateX'>setTranslateX</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets horizontal translation</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_setTranslateY'>setTranslateY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets vertical translation</td>
  </tr>
</table>

<a name='SkMatrix_set'></a>
## set

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_set'>set</a>(int index, <a href='undocumented#SkScalar'>SkScalar</a> value)
</pre>

Sets <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_set_value'>value</a>. Asserts if <a href='#SkMatrix_set_index'>index</a> is out of range and SK_DEBUG is
defined. Safer than operator[]; internal cache is always maintained.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_set_index'><code><strong>index</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>,
<a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>, <a href='#SkMatrix_kMPersp2'>kMPersp2</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_set_value'><code><strong>value</strong></code></a></td>
    <td><a href='undocumented#Scalar'>Scalar</a> to store in <a href='#Matrix'>Matrix</a></td>
  </tr>
</table>

### Example

<div><fiddle-embed name="1d400a92ca826cc89bcb88ea051f28c8">

#### Example Output

~~~~
with identity matrix: x = 24
after skew x mod:     x = 24
after 2nd skew x mod: x = 66
~~~~

</fiddle-embed></div>

### See Also

operator[] <a href='#SkMatrix_get'>get</a>

---

<a name='SkMatrix_setScaleX'></a>
## setScaleX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setScaleX'>setScaleX</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets horizontal scale factor.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setScaleX_v'><code><strong>v</strong></code></a></td>
    <td>horizontal scale factor to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="a39dfed98c3c3c3a56be9ad59fe4e21e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_setScaleY'>setScaleY</a>

---

<a name='SkMatrix_setScaleY'></a>
## setScaleY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setScaleY'>setScaleY</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets vertical scale factor.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setScaleY_v'><code><strong>v</strong></code></a></td>
    <td>vertical scale factor to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="f040c6dd85a02e94eaca00d5c2832604"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_setScaleX'>setScaleX</a>

---

<a name='SkMatrix_setSkewY'></a>
## setSkewY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSkewY'>setSkewY</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets vertical skew factor.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSkewY_v'><code><strong>v</strong></code></a></td>
    <td>vertical skew factor to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="b418d15df9829aefcc6aca93a37428bb"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkewX'>setSkewX</a>

---

<a name='SkMatrix_setSkewX'></a>
## setSkewX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSkewX'>setSkewX</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets horizontal skew factor.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSkewX_v'><code><strong>v</strong></code></a></td>
    <td>horizontal skew factor to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="c7177a6fbc1545be95a5ebca87e0cd0d"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkewX'>setSkewX</a>

---

<a name='SkMatrix_setTranslateX'></a>
## setTranslateX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setTranslateX'>setTranslateX</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets horizontal translation.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setTranslateX_v'><code><strong>v</strong></code></a></td>
    <td>horizontal translation to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="a18bc2e3607ac3a8e438bcb61fb13130"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_setTranslateY'>setTranslateY</a>

---

<a name='SkMatrix_setTranslateY'></a>
## setTranslateY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setTranslateY'>setTranslateY</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets vertical translation.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setTranslateY_v'><code><strong>v</strong></code></a></td>
    <td>vertical translation to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="34e3c70a72b836abf7f4858d35eecc98"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_setTranslateX'>setTranslateX</a>

---

<a name='SkMatrix_setPerspX'></a>
## setPerspX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setPerspX'>setPerspX</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets input x-axis perspective factor, which causes <a href='#SkMatrix_mapXY'>mapXY</a> to vary input x-axis values
inversely proportional to input y-axis values.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setPerspX_v'><code><strong>v</strong></code></a></td>
    <td>perspective factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="830a9e4e4bb93d25afd83b2fea63929e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_getPerspX'>getPerspX</a> <a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setAll'>setAll</a> <a href='#SkMatrix_set9'>set9</a> <a href='#SkMatrix_MakeAll'>MakeAll</a>

---

<a name='SkMatrix_setPerspY'></a>
## setPerspY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setPerspY'>setPerspY</a>(<a href='undocumented#SkScalar'>SkScalar</a> v)
</pre>

Sets input y-axis perspective factor, which causes <a href='#SkMatrix_mapXY'>mapXY</a> to vary input y-axis values
inversely proportional to input x-axis values.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setPerspY_v'><code><strong>v</strong></code></a></td>
    <td>perspective factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="aeb258b7922c1a11b698b00f562182ec"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_getPerspY'>getPerspY</a> <a href='#SkMatrix_set'>set</a> <a href='#SkMatrix_setAll'>setAll</a> <a href='#SkMatrix_set9'>set9</a> <a href='#SkMatrix_MakeAll'>MakeAll</a>

---

<a name='SkMatrix_setAll'></a>
## setAll

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setAll'>setAll</a>(<a href='undocumented#SkScalar'>SkScalar</a> scaleX, <a href='undocumented#SkScalar'>SkScalar</a> skewX, <a href='undocumented#SkScalar'>SkScalar</a> transX, <a href='undocumented#SkScalar'>SkScalar</a> skewY, <a href='undocumented#SkScalar'>SkScalar</a> scaleY,
            <a href='undocumented#SkScalar'>SkScalar</a> transY, <a href='undocumented#SkScalar'>SkScalar</a> persp0, <a href='undocumented#SkScalar'>SkScalar</a> persp1, <a href='undocumented#SkScalar'>SkScalar</a> persp2)
</pre>

Sets all values from parameters. Sets matrix to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scaleX  skewX transX |
|  skewY scaleY transY |
| persp0 persp1 persp2 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setAll_scaleX'><code><strong>scaleX</strong></code></a></td>
    <td>horizontal scale factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_skewX'><code><strong>skewX</strong></code></a></td>
    <td>horizontal skew factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_transX'><code><strong>transX</strong></code></a></td>
    <td>horizontal translation to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_skewY'><code><strong>skewY</strong></code></a></td>
    <td>vertical skew factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_scaleY'><code><strong>scaleY</strong></code></a></td>
    <td>vertical scale factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_transY'><code><strong>transY</strong></code></a></td>
    <td>vertical translation to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_persp0'><code><strong>persp0</strong></code></a></td>
    <td>input x-axis values perspective factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_persp1'><code><strong>persp1</strong></code></a></td>
    <td>input y-axis values perspective factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setAll_persp2'><code><strong>persp2</strong></code></a></td>
    <td>perspective scale factor to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="95ccfc2a89ce593e6b7a9f992a844bc0"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_set9'>set9</a> <a href='#SkMatrix_MakeAll'>MakeAll</a>

---

<a name='SkMatrix_get9'></a>
## get9

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_get9'>get9</a>(<a href='undocumented#SkScalar'>SkScalar</a> buffer[9]) const
</pre>

Copies nine <a href='undocumented#Scalar'>Scalar</a> values contained by <a href='#Matrix'>Matrix</a> into <a href='#SkMatrix_get9_buffer'>buffer</a>, in member value
ascending order: <a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>,
<a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>, <a href='#SkMatrix_kMPersp2'>kMPersp2</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_get9_buffer'><code><strong>buffer</strong></code></a></td>
    <td>storage for nine <a href='undocumented#Scalar'>Scalar</a> values</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="379fc375e011050b54ed9df83c0996a7">

#### Example Output

~~~~
{4, 0, 3},
{0, 5, 4},
{0, 0, 1}
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_set9'>set9</a>

---

<a name='SkMatrix_set9'></a>
## set9

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_set9'>set9</a>(const <a href='undocumented#SkScalar'>SkScalar</a> buffer[9])
</pre>

Sets <a href='#Matrix'>Matrix</a> to nine <a href='undocumented#Scalar'>Scalar</a> values in <a href='#SkMatrix_set9_buffer'>buffer</a>, in member value ascending order:
<a href='#SkMatrix_kMScaleX'>kMScaleX</a>, <a href='#SkMatrix_kMSkewX'>kMSkewX</a>, <a href='#SkMatrix_kMTransX'>kMTransX</a>, <a href='#SkMatrix_kMSkewY'>kMSkewY</a>, <a href='#SkMatrix_kMScaleY'>kMScaleY</a>, <a href='#SkMatrix_kMTransY'>kMTransY</a>, <a href='#SkMatrix_kMPersp0'>kMPersp0</a>, <a href='#SkMatrix_kMPersp1'>kMPersp1</a>,
<a href='#SkMatrix_kMPersp2'>kMPersp2</a>.

Sets matrix to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| buffer[0] buffer[1] buffer[2] |
| buffer[3] buffer[4] buffer[5] |
| buffer[6] buffer[7] buffer[8] |
</pre>

In the future, <a href='#SkMatrix_set9'>set9</a> followed by <a href='#SkMatrix_get9'>get9</a> may not return the same values. Since <a href='#Matrix'>Matrix</a>
maps non-homogeneous coordinates, scaling all nine values produces an equivalent
transformation, possibly improving precision.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_set9_buffer'><code><strong>buffer</strong></code></a></td>
    <td>nine <a href='undocumented#Scalar'>Scalar</a> values</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="ec5de0d23e5fe28ba7628625d1402e85"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setAll'>setAll</a> <a href='#SkMatrix_get9'>get9</a> <a href='#SkMatrix_MakeAll'>MakeAll</a>

---

<a name='SkMatrix_reset'></a>
## reset

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_reset'>reset</a>()
</pre>

Sets <a href='#Matrix'>Matrix</a> to identity; which has no effect on mapped <a href='SkPoint_Reference#Point'>Points</a>. Sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |
</pre>

Also called <a href='#SkMatrix_setIdentity'>setIdentity</a>; use the one that provides better inline
documentation.

### Example

<div><fiddle-embed name="ca94f7922bc37ef03bbc51ad70536fcf">

#### Example Output

~~~~
m.isIdentity(): true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_isIdentity'>isIdentity</a> <a href='#SkMatrix_setIdentity'>setIdentity</a>

---

<a name='SkMatrix_setIdentity'></a>
## setIdentity

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setIdentity'>setIdentity</a>()
</pre>

Sets <a href='#Matrix'>Matrix</a> to identity; which has no effect on mapped <a href='SkPoint_Reference#Point'>Points</a>. Sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |
</pre>

Also called <a href='#SkMatrix_reset'>reset</a>; use the one that provides better inline
documentation.

### Example

<div><fiddle-embed name="3979c865bb482e6ef1fafc71e56bbb91">

#### Example Output

~~~~
m.isIdentity(): true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_isIdentity'>isIdentity</a> <a href='#SkMatrix_reset'>reset</a>

---

<a name='SkMatrix_setTranslate'></a>
## setTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setTranslate'>setTranslate</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to translate by (<a href='#SkMatrix_setTranslate_dx'>dx</a>, <a href='#SkMatrix_setTranslate_dy'>dy</a>).

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setTranslate_dx'><code><strong>dx</strong></code></a></td>
    <td>horizontal translation</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setTranslate_dy'><code><strong>dy</strong></code></a></td>
    <td>vertical translation</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="63ca62985741b1bccb5e8b9cf734874e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setTranslateX'>setTranslateX</a> <a href='#SkMatrix_setTranslateY'>setTranslateY</a>

---

<a name='SkMatrix_setTranslate_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setTranslate'>setTranslate</a>(const <a href='SkPoint_Reference#SkVector'>SkVector</a>& v)
</pre>

Sets <a href='#Matrix'>Matrix</a> to translate by (<a href='#SkMatrix_setTranslate_2_v'>v</a>.fX, <a href='#SkMatrix_setTranslate_2_v'>v</a>.fY).

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setTranslate_2_v'><code><strong>v</strong></code></a></td>
    <td><a href='SkPoint_Reference#Vector'>Vector</a> containing horizontal and vertical translation</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="ccfc734aff2ddea0b097c83f5621de5e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setTranslateX'>setTranslateX</a> <a href='#SkMatrix_setTranslateY'>setTranslateY</a> <a href='#SkMatrix_MakeTrans'>MakeTrans</a>

---

<a name='SkMatrix_setScale'></a>
## setScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setScale'>setScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to scale by <a href='#SkMatrix_setScale_sx'>sx</a> and <a href='#SkMatrix_setScale_sy'>sy</a>, about a pivot point at (<a href='#SkMatrix_setScale_px'>px</a>, <a href='#SkMatrix_setScale_py'>py</a>).
The pivot point is unchanged when mapped with <a href='#Matrix'>Matrix</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setScale_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScale_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScale_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScale_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="4565a0792058178c88e0a129a87272d6"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScaleX'>setScaleX</a> <a href='#SkMatrix_setScaleY'>setScaleY</a> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup> <a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup> <a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup>

---

<a name='SkMatrix_setScale_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setScale'>setScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to scale by <a href='#SkMatrix_setScale_2_sx'>sx</a> and <a href='#SkMatrix_setScale_2_sy'>sy</a> about at pivot point at (0, 0).

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setScale_2_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScale_2_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="1579d0cc109c26e69f66f73abd35fb0e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScaleX'>setScaleX</a> <a href='#SkMatrix_setScaleY'>setScaleY</a> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup> <a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup> <a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup>

---

<a name='SkMatrix_setRotate'></a>
## setRotate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setRotate'>setRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to rotate by <a href='#SkMatrix_setRotate_degrees'>degrees</a> about a pivot point at (<a href='#SkMatrix_setRotate_px'>px</a>, <a href='#SkMatrix_setRotate_py'>py</a>).
The pivot point is unchanged when mapped with <a href='#Matrix'>Matrix</a>.

Positive <a href='#SkMatrix_setRotate_degrees'>degrees</a> rotates clockwise.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setRotate_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setRotate_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setRotate_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="8c28db3add9cd0177225088f6df6bbb5"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setSinCos'>setSinCos</a><sup><a href='#SkMatrix_setSinCos_2'>[2]</a></sup> <a href='#SkMatrix_preRotate'>preRotate</a><sup><a href='#SkMatrix_preRotate_2'>[2]</a></sup> <a href='#SkMatrix_postRotate'>postRotate</a><sup><a href='#SkMatrix_postRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_setRotate_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setRotate'>setRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees)
</pre>

Sets <a href='#Matrix'>Matrix</a> to rotate by <a href='#SkMatrix_setRotate_2_degrees'>degrees</a> about a pivot point at (0, 0).
Positive <a href='#SkMatrix_setRotate_2_degrees'>degrees</a> rotates clockwise.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setRotate_2_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="93efb9d191bf1b9710c173513e014d6c"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setSinCos'>setSinCos</a><sup><a href='#SkMatrix_setSinCos_2'>[2]</a></sup> <a href='#SkMatrix_preRotate'>preRotate</a><sup><a href='#SkMatrix_preRotate_2'>[2]</a></sup> <a href='#SkMatrix_postRotate'>postRotate</a><sup><a href='#SkMatrix_postRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_setSinCos'></a>
## setSinCos

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSinCos'>setSinCos</a>(<a href='undocumented#SkScalar'>SkScalar</a> sinValue, <a href='undocumented#SkScalar'>SkScalar</a> cosValue, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to rotate by <a href='#SkMatrix_setSinCos_sinValue'>sinValue</a> and <a href='#SkMatrix_setSinCos_cosValue'>cosValue</a>, about a pivot point at (<a href='#SkMatrix_setSinCos_px'>px</a>, <a href='#SkMatrix_setSinCos_py'>py</a>).
The pivot point is unchanged when mapped with <a href='#Matrix'>Matrix</a>.

<a href='SkPoint_Reference#Vector'>Vector</a> (<a href='#SkMatrix_setSinCos_sinValue'>sinValue</a>, <a href='#SkMatrix_setSinCos_cosValue'>cosValue</a>) describes the angle of rotation relative to (0, 1).
<a href='SkPoint_Reference#Vector'>Vector</a> length specifies scale.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSinCos_sinValue'><code><strong>sinValue</strong></code></a></td>
    <td>rotation vector x-axis component</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSinCos_cosValue'><code><strong>cosValue</strong></code></a></td>
    <td>rotation vector y-axis component</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSinCos_px'><code><strong>px</strong></code></a></td>
    <td>pivot x-axis</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSinCos_py'><code><strong>py</strong></code></a></td>
    <td>pivot y-axis</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="187e1d9228e2e4341ef820bd77b6fda9"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_setRSXform'>setRSXform</a>

---

<a name='SkMatrix_setSinCos_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSinCos'>setSinCos</a>(<a href='undocumented#SkScalar'>SkScalar</a> sinValue, <a href='undocumented#SkScalar'>SkScalar</a> cosValue)
</pre>

Sets <a href='#Matrix'>Matrix</a> to rotate by <a href='#SkMatrix_setSinCos_2_sinValue'>sinValue</a> and <a href='#SkMatrix_setSinCos_2_cosValue'>cosValue</a>, about a pivot point at (0, 0).

<a href='SkPoint_Reference#Vector'>Vector</a> (<a href='#SkMatrix_setSinCos_2_sinValue'>sinValue</a>, <a href='#SkMatrix_setSinCos_2_cosValue'>cosValue</a>) describes the angle of rotation relative to (0, 1).
<a href='SkPoint_Reference#Vector'>Vector</a> length specifies scale.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSinCos_2_sinValue'><code><strong>sinValue</strong></code></a></td>
    <td>rotation vector x-axis component</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSinCos_2_cosValue'><code><strong>cosValue</strong></code></a></td>
    <td>rotation vector y-axis component</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="e37a94a53c959951b059fcd624639ef6"><div><a href='SkCanvas_Reference#Canvas'>Canvas</a> needs offset after applying <a href='#Matrix'>Matrix</a> to pivot about <a href='SkRect_Reference#Rect'>Rect</a> center.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_setRSXform'>setRSXform</a>

---

<a name='SkMatrix_setRSXform'></a>
## setRSXform

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='#SkMatrix'>SkMatrix</a>& <a href='#SkMatrix_setRSXform'>setRSXform</a>(const <a href='undocumented#SkRSXform'>SkRSXform</a>& rsxForm)
</pre>

Sets <a href='#Matrix'>Matrix</a> to rotate, scale, and translate using a compressed matrix form.

<a href='SkPoint_Reference#Vector'>Vector</a> (<a href='#SkMatrix_setRSXform_rsxForm'>rsxForm</a>.fSSin, <a href='#SkMatrix_setRSXform_rsxForm'>rsxForm</a>.fSCos) describes the angle of rotation relative
to (0, 1). <a href='SkPoint_Reference#Vector'>Vector</a> length specifies scale. Mapped point is rotated and scaled
by <a href='SkPoint_Reference#Vector'>Vector</a>, then translated by (<a href='#SkMatrix_setRSXform_rsxForm'>rsxForm</a>.fTx, <a href='#SkMatrix_setRSXform_rsxForm'>rsxForm</a>.fTy).

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setRSXform_rsxForm'><code><strong>rsxForm</strong></code></a></td>
    <td>compressed <a href='undocumented#RSXform'>RSXform</a> matrix</td>
  </tr>
</table>

### Return Value

reference to <a href='#Matrix'>Matrix</a>

### Example

<div><fiddle-embed name="c3f5faddca466f78278b32b88fd5f5eb"><div><a href='SkCanvas_Reference#Canvas'>Canvas</a> needs offset after applying <a href='#Matrix'>Matrix</a> to pivot about <a href='SkRect_Reference#Rect'>Rect</a> center.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setSinCos'>setSinCos</a><sup><a href='#SkMatrix_setSinCos_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup>

---

<a name='SkMatrix_setSkew'></a>
## setSkew

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSkew'>setSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to skew by <a href='#SkMatrix_setSkew_kx'>kx</a> and <a href='#SkMatrix_setSkew_ky'>ky</a>, about a pivot point at (<a href='#SkMatrix_setSkew_px'>px</a>, <a href='#SkMatrix_setSkew_py'>py</a>).
The pivot point is unchanged when mapped with <a href='#Matrix'>Matrix</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSkew_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSkew_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSkew_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSkew_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="55e0431adc6c5b1987ebb8123cc10342"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setSkewX'>setSkewX</a> <a href='#SkMatrix_setSkewY'>setSkewY</a> <a href='#SkMatrix_preSkew'>preSkew</a><sup><a href='#SkMatrix_preSkew_2'>[2]</a></sup> <a href='#SkMatrix_postSkew'>postSkew</a><sup><a href='#SkMatrix_postSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_setSkew_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setSkew'>setSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky)
</pre>

Sets <a href='#Matrix'>Matrix</a> to skew by <a href='#SkMatrix_setSkew_2_kx'>kx</a> and <a href='#SkMatrix_setSkew_2_ky'>ky</a>, about a pivot point at (0, 0).

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setSkew_2_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setSkew_2_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="05be7844e9afdd7b9bfc31c5423a70a2"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setSkewX'>setSkewX</a> <a href='#SkMatrix_setSkewY'>setSkewY</a> <a href='#SkMatrix_preSkew'>preSkew</a><sup><a href='#SkMatrix_preSkew_2'>[2]</a></sup> <a href='#SkMatrix_postSkew'>postSkew</a><sup><a href='#SkMatrix_postSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_setConcat'></a>
## setConcat

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setConcat'>setConcat</a>(const <a href='#SkMatrix'>SkMatrix</a>& a, const <a href='#SkMatrix'>SkMatrix</a>& b)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_setConcat_a'>a</a> multiplied by <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_setConcat_b'>b</a>. Either <a href='#SkMatrix_setConcat_a'>a</a> or <a href='#SkMatrix_setConcat_b'>b</a> may be this.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    | A B C |      | J K L |
a = | D E F |, b = | M N O |
    | G H I |      | P Q R |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
        | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setConcat_a'><code><strong>a</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on left side of multiply expression</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setConcat_b'><code><strong>b</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on right side of multiply expression</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="0381a10ac69bdefdf9d15b47cbb9fefe"><div><a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a> creates perspective matrices, one the inverse of the other.
Multiplying the matrix by its inverse turns into an identity matrix.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_Concat'>Concat</a> <a href='#SkMatrix_preConcat'>preConcat</a> <a href='#SkMatrix_postConcat'>postConcat</a> <a href='SkCanvas_Reference#SkCanvas_concat'>SkCanvas::concat</a>

---

<a name='SkMatrix_preTranslate'></a>
## preTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preTranslate'>preTranslate</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from translation (<a href='#SkMatrix_preTranslate_dx'>dx</a>, <a href='#SkMatrix_preTranslate_dy'>dy</a>).
This can be thought of as moving the point to be mapped before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |               | 1 0 dx |
Matrix = | D E F |,  T(dx, dy) = | 0 1 dy |
         | G H I |               | 0 0  1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preTranslate_dx'><code><strong>dx</strong></code></a></td>
    <td>x-axis translation before applying <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_preTranslate_dy'><code><strong>dy</strong></code></a></td>
    <td>y-axis translation before applying <a href='#Matrix'>Matrix</a></td>
  </tr>
</table>

### Example

<div><fiddle-embed name="f75a9b629aa6c51ed888f8799b5ba5f7"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postTranslate'>postTranslate</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_MakeTrans'>MakeTrans</a>

---

<a name='SkMatrix_preScale'></a>
## preScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preScale'>preScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from scaling by (<a href='#SkMatrix_preScale_sx'>sx</a>, <a href='#SkMatrix_preScale_sy'>sy</a>)
about pivot point (<a href='#SkMatrix_preScale_px'>px</a>, <a href='#SkMatrix_preScale_py'>py</a>).
This can be thought of as scaling about a pivot point before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |                       | sx  0 dx |
Matrix = | D E F |,  S(sx, sy, px, py) = |  0 sy dy |
         | G H I |                       |  0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
dx = px - sx * px
dy = py - sy * py
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                             | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preScale_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preScale_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preScale_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preScale_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="2531f8d1e05d7b6dc22f3efcd2fb84e4"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_preScale_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preScale'>preScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from scaling by (<a href='#SkMatrix_preScale_2_sx'>sx</a>, <a href='#SkMatrix_preScale_2_sy'>sy</a>)
about pivot point (0, 0).
This can be thought of as scaling about the origin before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |               | sx  0  0 |
Matrix = | D E F |,  S(sx, sy) = |  0 sy  0 |
         | G H I |               |  0  0  1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preScale_2_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preScale_2_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="3edbdea8e43d06086abf33ec4a9b415b"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_preRotate'></a>
## preRotate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preRotate'>preRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from rotating by <a href='#SkMatrix_preRotate_degrees'>degrees</a>
about pivot point (<a href='#SkMatrix_preRotate_px'>px</a>, <a href='#SkMatrix_preRotate_py'>py</a>).
This can be thought of as rotating about a pivot point before applying <a href='#Matrix'>Matrix</a>.

Positive <a href='#SkMatrix_preRotate_degrees'>degrees</a> rotates clockwise.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |                        | c -s dx |
Matrix = | D E F |,  R(degrees, px, py) = | s  c dy |
         | G H I |                        | 0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
c  = cos(degrees)
s  = sin(degrees)
dx =  s * py + (1 - c) * px
dy = -s * px + (1 - c) * py
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                              | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preRotate_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preRotate_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preRotate_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="a70bb18d67c06a20ab514e7a47924e5a"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postRotate'>postRotate</a><sup><a href='#SkMatrix_postRotate_2'>[2]</a></sup> <a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_preRotate_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preRotate'>preRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from rotating by <a href='#SkMatrix_preRotate_2_degrees'>degrees</a>
about pivot point (0, 0).
This can be thought of as rotating about the origin before applying <a href='#Matrix'>Matrix</a>.

Positive <a href='#SkMatrix_preRotate_2_degrees'>degrees</a> rotates clockwise.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |                        | c -s 0 |
Matrix = | D E F |,  R(degrees, px, py) = | s  c 0 |
         | G H I |                        | 0  0 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
c  = cos(degrees)
s  = sin(degrees)
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                              | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preRotate_2_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="5acd49bd931c79a808dd6c7cc0e92f72"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postRotate'>postRotate</a><sup><a href='#SkMatrix_postRotate_2'>[2]</a></sup> <a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_preSkew'></a>
## preSkew

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preSkew'>preSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from skewing by (<a href='#SkMatrix_preSkew_kx'>kx</a>, <a href='#SkMatrix_preSkew_ky'>ky</a>)
about pivot point (<a href='#SkMatrix_preSkew_px'>px</a>, <a href='#SkMatrix_preSkew_py'>py</a>).
This can be thought of as skewing about a pivot point before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |                       |  1 kx dx |
Matrix = | D E F |,  K(kx, ky, px, py) = | ky  1 dy |
         | G H I |                       |  0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
dx = -kx * py
dy = -ky * px
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                             | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preSkew_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preSkew_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preSkew_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preSkew_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="199a18ad61d702664ce6df1d7037aa48"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postSkew'>postSkew</a><sup><a href='#SkMatrix_postSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_preSkew_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preSkew'>preSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> constructed from skewing by (<a href='#SkMatrix_preSkew_2_kx'>kx</a>, <a href='#SkMatrix_preSkew_2_ky'>ky</a>)
about pivot point (0, 0).
This can be thought of as skewing about the origin before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |               |  1 kx 0 |
Matrix = | D E F |,  K(kx, ky) = | ky  1 0 |
         | G H I |               |  0  0 1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preSkew_2_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_preSkew_2_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="e100c543869fe8fd516ba69de79444ba"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postSkew'>postSkew</a><sup><a href='#SkMatrix_postSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_preConcat'></a>
## preConcat

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_preConcat'>preConcat</a>(const <a href='#SkMatrix'>SkMatrix</a>& other)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> multiplied by <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_preConcat_other'>other</a>.
This can be thought of mapping by <a href='#SkMatrix_preConcat_other'>other</a> before applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |          | J K L |
Matrix = | D E F |, other = | M N O |
         | G H I |          | P Q R |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                 | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_preConcat_other'><code><strong>other</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on right side of multiply expression</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="b07e62298e7b0ab5683db199faffceb2"><div><a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a> creates perspective matrices, one the inverse of the <a href='#SkMatrix_preConcat_other'>other</a>.
Multiplying the matrix by its inverse turns into an identity matrix.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postConcat'>postConcat</a> <a href='#SkMatrix_setConcat'>setConcat</a> <a href='#SkMatrix_Concat'>Concat</a>

---

<a name='SkMatrix_postTranslate'></a>
## postTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postTranslate'>postTranslate</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from translation (<a href='#SkMatrix_postTranslate_dx'>dx</a>, <a href='#SkMatrix_postTranslate_dy'>dy</a>) multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as moving the point to be mapped after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |               | 1 0 dx |
Matrix = | M N O |,  T(dx, dy) = | 0 1 dy |
         | P Q R |               | 0 0  1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postTranslate_dx'><code><strong>dx</strong></code></a></td>
    <td>x-axis translation after applying <a href='#Matrix'>Matrix</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_postTranslate_dy'><code><strong>dy</strong></code></a></td>
    <td>y-axis translation after applying <a href='#Matrix'>Matrix</a></td>
  </tr>
</table>

### Example

<div><fiddle-embed name="f5144ef4bd7cea294fad2f756ed335af"><div>Compare with <a href='#SkMatrix_preTranslate'>preTranslate</a> example.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preTranslate'>preTranslate</a> <a href='#SkMatrix_setTranslate'>setTranslate</a><sup><a href='#SkMatrix_setTranslate_2'>[2]</a></sup> <a href='#SkMatrix_MakeTrans'>MakeTrans</a>

---

<a name='SkMatrix_postScale'></a>
## postScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postScale'>postScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from scaling by (<a href='#SkMatrix_postScale_sx'>sx</a>, <a href='#SkMatrix_postScale_sy'>sy</a>) about pivot point
(<a href='#SkMatrix_postScale_px'>px</a>, <a href='#SkMatrix_postScale_py'>py</a>), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as scaling about a pivot point after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |                       | sx  0 dx |
Matrix = | M N O |,  S(sx, sy, px, py) = |  0 sy dy |
         | P Q R |                       |  0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
dx = px - sx * px
dy = py - sy * py
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                             | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postScale_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postScale_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postScale_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postScale_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="ed3aa18ba0ea95c85cc49aa3829fe384"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_postScale_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postScale'>postScale</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from scaling by (<a href='#SkMatrix_postScale_2_sx'>sx</a>, <a href='#SkMatrix_postScale_2_sy'>sy</a>) about pivot point
(0, 0), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as scaling about the origin after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |               | sx  0  0 |
Matrix = | M N O |,  S(sx, sy) = |  0 sy  0 |
         | P Q R |               |  0  0  1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postScale_2_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postScale_2_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="1931017698766a67d3a26423453b8095"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preScale'>preScale</a><sup><a href='#SkMatrix_preScale_2'>[2]</a></sup> <a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_postIDiv'></a>
## postIDiv

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_postIDiv'>postIDiv</a>(int divx, int divy)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from scaling by(1/<a href='#SkMatrix_postIDiv_divx'>divx</a>, 1/<a href='#SkMatrix_postIDiv_divy'>divy</a>)
about pivot point (px, py), multiplied by <a href='#Matrix'>Matrix</a>.

Returns false if either <a href='#SkMatrix_postIDiv_divx'>divx</a> or <a href='#SkMatrix_postIDiv_divy'>divy</a> is zero.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |                   | sx  0  0 |
Matrix = | M N O |,  I(divx, divy) = |  0 sy  0 |
         | P Q R |                   |  0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
sx = 1 / divx
sy = 1 / divy
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                         | sx  0  0 | | J K L |   | sx*J sx*K sx*L |
I(divx, divy) * Matrix = |  0 sy  0 | | M N O | = | sy*M sy*N sy*O |
                         |  0  0  1 | | P Q R |   |    P    Q    R |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postIDiv_divx'><code><strong>divx</strong></code></a></td>
    <td>integer divisor for inverse scale in x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postIDiv_divy'><code><strong>divy</strong></code></a></td>
    <td>integer divisor for inverse scale in y</td>
  </tr>
</table>

### Return Value

true on successful scale

### Example

<div><fiddle-embed name="e6ad0bd2999613d9e4758b661d45070c"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_postScale'>postScale</a><sup><a href='#SkMatrix_postScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_postRotate'></a>
## postRotate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postRotate'>postRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from rotating by <a href='#SkMatrix_postRotate_degrees'>degrees</a> about pivot point
(<a href='#SkMatrix_postRotate_px'>px</a>, <a href='#SkMatrix_postRotate_py'>py</a>), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as rotating about a pivot point after applying <a href='#Matrix'>Matrix</a>.

Positive <a href='#SkMatrix_postRotate_degrees'>degrees</a> rotates clockwise.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |                        | c -s dx |
Matrix = | M N O |,  R(degrees, px, py) = | s  c dy |
         | P Q R |                        | 0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
c  = cos(degrees)
s  = sin(degrees)
dx =  s * py + (1 - c) * px
dy = -s * px + (1 - c) * py
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                              |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|
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postRotate_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postRotate_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postRotate_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="e09194ee48a81e7b375ade473d340f0d"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preRotate'>preRotate</a><sup><a href='#SkMatrix_preRotate_2'>[2]</a></sup> <a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_postRotate_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postRotate'>postRotate</a>(<a href='undocumented#SkScalar'>SkScalar</a> degrees)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from rotating by <a href='#SkMatrix_postRotate_2_degrees'>degrees</a> about pivot point
(0, 0), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as rotating about the origin after applying <a href='#Matrix'>Matrix</a>.

Positive <a href='#SkMatrix_postRotate_2_degrees'>degrees</a> rotates clockwise.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |                        | c -s 0 |
Matrix = | M N O |,  R(degrees, px, py) = | s  c 0 |
         | P Q R |                        | 0  0 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
c  = cos(degrees)
s  = sin(degrees)
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                              | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postRotate_2_degrees'><code><strong>degrees</strong></code></a></td>
    <td>angle of axes relative to upright axes</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="52e4c53e26971af5576b30de60fa70c2"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preRotate'>preRotate</a><sup><a href='#SkMatrix_preRotate_2'>[2]</a></sup> <a href='#SkMatrix_setRotate'>setRotate</a><sup><a href='#SkMatrix_setRotate_2'>[2]</a></sup>

---

<a name='SkMatrix_postSkew'></a>
## postSkew

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postSkew'>postSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky, <a href='undocumented#SkScalar'>SkScalar</a> px, <a href='undocumented#SkScalar'>SkScalar</a> py)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from skewing by (<a href='#SkMatrix_postSkew_kx'>kx</a>, <a href='#SkMatrix_postSkew_ky'>ky</a>) about pivot point
(<a href='#SkMatrix_postSkew_px'>px</a>, <a href='#SkMatrix_postSkew_py'>py</a>), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as skewing about a pivot point after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |                       |  1 kx dx |
Matrix = | M N O |,  K(kx, ky, px, py) = | ky  1 dy |
         | P Q R |                       |  0  0  1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
dx = -kx * py
dy = -ky * px
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                             | 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|
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postSkew_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postSkew_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postSkew_px'><code><strong>px</strong></code></a></td>
    <td>pivot x</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postSkew_py'><code><strong>py</strong></code></a></td>
    <td>pivot y</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="8c34ae3a2b7e2742bb969819737365ec"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preSkew'>preSkew</a><sup><a href='#SkMatrix_preSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_postSkew_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postSkew'>postSkew</a>(<a href='undocumented#SkScalar'>SkScalar</a> kx, <a href='undocumented#SkScalar'>SkScalar</a> ky)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> constructed from skewing by (<a href='#SkMatrix_postSkew_2_kx'>kx</a>, <a href='#SkMatrix_postSkew_2_ky'>ky</a>) about pivot point
(0, 0), multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of as skewing about the origin after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |               |  1 kx 0 |
Matrix = | M N O |,  K(kx, ky) = | ky  1 0 |
         | P Q R |               |  0  0 1 |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                     |  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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postSkew_2_kx'><code><strong>kx</strong></code></a></td>
    <td>horizontal skew factor</td>
  </tr>
  <tr>    <td><a name='SkMatrix_postSkew_2_ky'><code><strong>ky</strong></code></a></td>
    <td>vertical skew factor</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="3aa2603225dff72ac53dd359f897f494"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preSkew'>preSkew</a><sup><a href='#SkMatrix_preSkew_2'>[2]</a></sup> <a href='#SkMatrix_setSkew'>setSkew</a><sup><a href='#SkMatrix_setSkew_2'>[2]</a></sup>

---

<a name='SkMatrix_postConcat'></a>
## postConcat

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_postConcat'>postConcat</a>(const <a href='#SkMatrix'>SkMatrix</a>& other)
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_postConcat_other'>other</a> multiplied by <a href='#Matrix'>Matrix</a>.
This can be thought of mapping by <a href='#SkMatrix_postConcat_other'>other</a> after applying <a href='#Matrix'>Matrix</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | J K L |           | A B C |
Matrix = | M N O |,  other = | D E F |
         | P Q R |           | G H I |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
                 | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_postConcat_other'><code><strong>other</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on left side of multiply expression</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="e4226c55d9bdbc119264bd372b2b9835"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preConcat'>preConcat</a> <a href='#SkMatrix_setConcat'>setConcat</a> <a href='#SkMatrix_Concat'>Concat</a>

---

## <a name='SkMatrix_ScaleToFit'>Enum SkMatrix::ScaleToFit</a>

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    enum <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> {
        <a href='#SkMatrix_kFill_ScaleToFit'>kFill ScaleToFit</a>,
        <a href='#SkMatrix_kStart_ScaleToFit'>kStart ScaleToFit</a>,
        <a href='#SkMatrix_kCenter_ScaleToFit'>kCenter ScaleToFit</a>,
        <a href='#SkMatrix_kEnd_ScaleToFit'>kEnd ScaleToFit</a>,
    };
</pre>

<a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> describes how <a href='#Matrix'>Matrix</a> is constructed to map one <a href='SkRect_Reference#Rect'>Rect</a> to another.
<a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> may allow <a href='#Matrix'>Matrix</a> to have unequal horizontal and vertical scaling,
or may restrict <a href='#Matrix'>Matrix</a> to square scaling. If restricted, <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> specifies
how <a href='#Matrix'>Matrix</a> maps to the side or center of the destination <a href='SkRect_Reference#Rect'>Rect</a>.

### Constants

<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Const</th>
<th style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>Value</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kFill_ScaleToFit'><code>SkMatrix::kFill_ScaleToFit</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>0</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
Computes <a href='#Matrix'>Matrix</a> that scales in x and y independently, so that source <a href='SkRect_Reference#Rect'>Rect</a> is
mapped to completely fill destination <a href='SkRect_Reference#Rect'>Rect</a>. The aspect ratio of source <a href='SkRect_Reference#Rect'>Rect</a>
may change.
</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kStart_ScaleToFit'><code>SkMatrix::kStart_ScaleToFit</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>1</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
Computes <a href='#Matrix'>Matrix</a> that maintains source <a href='SkRect_Reference#Rect'>Rect</a> aspect ratio, mapping source <a href='SkRect_Reference#Rect'>Rect</a>
width or height to destination <a href='SkRect_Reference#Rect'>Rect</a>. Aligns mapping to left and top edges
of destination <a href='SkRect_Reference#Rect'>Rect</a>.
</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kCenter_ScaleToFit'><code>SkMatrix::kCenter_ScaleToFit</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>2</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
Computes <a href='#Matrix'>Matrix</a> that maintains source <a href='SkRect_Reference#Rect'>Rect</a> aspect ratio, mapping source <a href='SkRect_Reference#Rect'>Rect</a>
width or height to destination <a href='SkRect_Reference#Rect'>Rect</a>. Aligns mapping to center of destination
<a href='SkRect_Reference#Rect'>Rect</a>.
</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a name='SkMatrix_kEnd_ScaleToFit'><code>SkMatrix::kEnd_ScaleToFit</code></a></td>
    <td style='text-align: center; border: 2px solid #dddddd; padding: 8px; '>3</td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>
Computes <a href='#Matrix'>Matrix</a> that maintains source <a href='SkRect_Reference#Rect'>Rect</a> aspect ratio, mapping source <a href='SkRect_Reference#Rect'>Rect</a>
width or height to destination <a href='SkRect_Reference#Rect'>Rect</a>. Aligns mapping to right and bottom
edges of destination <a href='SkRect_Reference#Rect'>Rect</a>.
</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="17c3070b31b700ea8f52e48af9a66b6e"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setRectToRect'>setRectToRect</a> <a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a> <a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a>

<a name='SkMatrix_setRectToRect'></a>
## setRectToRect

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_setRectToRect'>setRectToRect</a>(const <a href='SkRect_Reference#SkRect'>SkRect</a>& src, const <a href='SkRect_Reference#SkRect'>SkRect</a>& dst, <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> stf)
</pre>

Sets <a href='#Matrix'>Matrix</a> to scale and translate <a href='#SkMatrix_setRectToRect_src'>src</a> <a href='SkRect_Reference#Rect'>Rect</a> to <a href='#SkMatrix_setRectToRect_dst'>dst</a> <a href='SkRect_Reference#Rect'>Rect</a>. <a href='#SkMatrix_setRectToRect_stf'>stf</a> selects whether
mapping completely fills <a href='#SkMatrix_setRectToRect_dst'>dst</a> or preserves the aspect ratio, and how to align
<a href='#SkMatrix_setRectToRect_src'>src</a> within <a href='#SkMatrix_setRectToRect_dst'>dst</a>. Returns false if <a href='#SkMatrix_setRectToRect_src'>src</a> is empty, and sets <a href='#Matrix'>Matrix</a> to identity.
Returns true if <a href='#SkMatrix_setRectToRect_dst'>dst</a> is empty, and sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 0 0 0 |
| 0 0 0 |
| 0 0 1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setRectToRect_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map from</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setRectToRect_dst'><code><strong>dst</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map to</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setRectToRect_stf'><code><strong>stf</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kFill_ScaleToFit'>kFill ScaleToFit</a>, <a href='#SkMatrix_kStart_ScaleToFit'>kStart ScaleToFit</a>,
<a href='#SkMatrix_kCenter_ScaleToFit'>kCenter ScaleToFit</a>, <a href='#SkMatrix_kEnd_ScaleToFit'>kEnd ScaleToFit</a></td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> can represent <a href='SkRect_Reference#Rect'>Rect</a> mapping

### Example

<div><fiddle-embed name="69cdea599dcaaec35efcb24403f4287b">

#### Example Output

~~~~
src: 0, 0, 0, 0  dst: 0, 0, 0, 0  success: false
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
src: 0, 0, 0, 0  dst: 5, 6, 8, 9  success: false
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
src: 1, 2, 3, 4  dst: 0, 0, 0, 0  success: true
[  0.0000   0.0000   0.0000][  0.0000   0.0000   0.0000][  0.0000   0.0000   1.0000]
src: 1, 2, 3, 4  dst: 5, 6, 8, 9  success: true
[  1.5000   0.0000   3.5000][  0.0000   1.5000   3.0000][  0.0000   0.0000   1.0000]
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a> <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> <a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a> <a href='SkRect_Reference#SkRect_isEmpty'>SkRect::isEmpty</a>

---

<a name='SkMatrix_MakeRectToRect'></a>
## MakeRectToRect

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> <a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a>(const <a href='SkRect_Reference#SkRect'>SkRect</a>& src, const <a href='SkRect_Reference#SkRect'>SkRect</a>& dst, <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> stf)
</pre>

Returns <a href='#Matrix'>Matrix</a> set to scale and translate <a href='#SkMatrix_MakeRectToRect_src'>src</a> <a href='SkRect_Reference#Rect'>Rect</a> to <a href='#SkMatrix_MakeRectToRect_dst'>dst</a> <a href='SkRect_Reference#Rect'>Rect</a>. <a href='#SkMatrix_MakeRectToRect_stf'>stf</a> selects
whether mapping completely fills <a href='#SkMatrix_MakeRectToRect_dst'>dst</a> or preserves the aspect ratio, and how to
align <a href='#SkMatrix_MakeRectToRect_src'>src</a> within <a href='#SkMatrix_MakeRectToRect_dst'>dst</a>. Returns the identity <a href='#Matrix'>Matrix</a> if <a href='#SkMatrix_MakeRectToRect_src'>src</a> is empty. If <a href='#SkMatrix_MakeRectToRect_dst'>dst</a> is
empty, returns <a href='#Matrix'>Matrix</a> set to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 0 0 0 |
| 0 0 0 |
| 0 0 1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_MakeRectToRect_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map from</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeRectToRect_dst'><code><strong>dst</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map to</td>
  </tr>
  <tr>    <td><a name='SkMatrix_MakeRectToRect_stf'><code><strong>stf</strong></code></a></td>
    <td>one of: <a href='#SkMatrix_kFill_ScaleToFit'>kFill ScaleToFit</a>, <a href='#SkMatrix_kStart_ScaleToFit'>kStart ScaleToFit</a>,
<a href='#SkMatrix_kCenter_ScaleToFit'>kCenter ScaleToFit</a>, <a href='#SkMatrix_kEnd_ScaleToFit'>kEnd ScaleToFit</a></td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> mapping <a href='#SkMatrix_MakeRectToRect_src'>src</a> to <a href='#SkMatrix_MakeRectToRect_dst'>dst</a>

### Example

<div><fiddle-embed name="a1d6a6721b39350f81021f71a1b93208">

#### Example Output

~~~~
src: 0, 0, 0, 0  dst: 0, 0, 0, 0
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
src: 0, 0, 0, 0  dst: 5, 6, 8, 9
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
src: 1, 2, 3, 4  dst: 0, 0, 0, 0
[  0.0000   0.0000   0.0000][  0.0000   0.0000   0.0000][  0.0000   0.0000   1.0000]
src: 1, 2, 3, 4  dst: 5, 6, 8, 9
[  1.5000   0.0000   3.5000][  0.0000   1.5000   3.0000][  0.0000   0.0000   1.0000]
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setRectToRect'>setRectToRect</a> <a href='#SkMatrix_ScaleToFit'>ScaleToFit</a> <a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a> <a href='SkRect_Reference#SkRect_isEmpty'>SkRect::isEmpty</a>

---

<a name='SkMatrix_setPolyToPoly'></a>
## setPolyToPoly

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a>(const <a href='SkPoint_Reference#SkPoint'>SkPoint</a> src[], const <a href='SkPoint_Reference#SkPoint'>SkPoint</a> dst[], int count)
</pre>

Sets <a href='#Matrix'>Matrix</a> to map <a href='#SkMatrix_setPolyToPoly_src'>src</a> to <a href='#SkMatrix_setPolyToPoly_dst'>dst</a>. <a href='#SkMatrix_setPolyToPoly_count'>count</a> must be zero or greater, and four or less.

If <a href='#SkMatrix_setPolyToPoly_count'>count</a> is zero, sets <a href='#Matrix'>Matrix</a> to identity and returns true.
If <a href='#SkMatrix_setPolyToPoly_count'>count</a> is one, sets <a href='#Matrix'>Matrix</a> to translate and returns true.
If <a href='#SkMatrix_setPolyToPoly_count'>count</a> is two or more, sets <a href='#Matrix'>Matrix</a> to map <a href='SkPoint_Reference#Point'>Points</a> if possible; returns false
if <a href='#Matrix'>Matrix</a> cannot be constructed. If <a href='#SkMatrix_setPolyToPoly_count'>count</a> is four, <a href='#Matrix'>Matrix</a> may include
perspective.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setPolyToPoly_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkPoint_Reference#Point'>Points</a> to map from</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setPolyToPoly_dst'><code><strong>dst</strong></code></a></td>
    <td><a href='SkPoint_Reference#Point'>Points</a> to map to</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setPolyToPoly_count'><code><strong>count</strong></code></a></td>
    <td>number of <a href='SkPoint_Reference#Point'>Points</a> in <a href='#SkMatrix_setPolyToPoly_src'>src</a> and <a href='#SkMatrix_setPolyToPoly_dst'>dst</a></td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> was constructed successfully

### Example

<div><fiddle-embed name="c851d1313e8909aaea4f0591699fdb7b"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_setRectToRect'>setRectToRect</a> <a href='#SkMatrix_MakeRectToRect'>MakeRectToRect</a>

---

<a name='SkMatrix_invert'></a>
## invert

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool SK_WARN_UNUSED_RESULT <a href='#SkMatrix_invert'>invert</a>(<a href='#SkMatrix'>SkMatrix</a>* inverse) const
</pre>

Sets <a href='#SkMatrix_invert_inverse'>inverse</a> to reciprocal matrix, returning true if <a href='#Matrix'>Matrix</a> can be inverted.
Geometrically, if <a href='#Matrix'>Matrix</a> maps from source to destination, <a href='#SkMatrix_invert_inverse'>inverse</a> <a href='#Matrix'>Matrix</a>
maps from destination to source. If <a href='#Matrix'>Matrix</a> can not be inverted, <a href='#SkMatrix_invert_inverse'>inverse</a> is
unchanged.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_invert_inverse'><code><strong>inverse</strong></code></a></td>
    <td>storage for inverted <a href='#Matrix'>Matrix</a>; may be nullptr</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> can be inverted

### Example

<div><fiddle-embed name="0e03cd9f154603ed4b21ca56d69dae44"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_Concat'>Concat</a>

---

<a name='SkMatrix_SetAffineIdentity'></a>
## SetAffineIdentity

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static void <a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a>(<a href='undocumented#SkScalar'>SkScalar</a> affine[6])
</pre>

Fills <a href='#SkMatrix_SetAffineIdentity_affine'>affine</a> with identity values in column major order.
Sets <a href='#SkMatrix_SetAffineIdentity_affine'>affine</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 0 |
| 0 1 0 |
</pre>

Affine 3x2 matrices in column major order are used by OpenGL and XPS.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_SetAffineIdentity_affine'><code><strong>affine</strong></code></a></td>
    <td>storage for 3x2 <a href='#SkMatrix_SetAffineIdentity_affine'>affine</a> matrix</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="e10adbd0bcc940c5d4d872db0e78e892">

#### Example Output

~~~~
ScaleX: 1 SkewY: 0 SkewX: 0 ScaleY: 1 TransX: 0 TransY: 0
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setAffine'>setAffine</a> <a href='#SkMatrix_asAffine'>asAffine</a>

---

<a name='SkMatrix_asAffine'></a>
## asAffine

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool SK_WARN_UNUSED_RESULT <a href='#SkMatrix_asAffine'>asAffine</a>(<a href='undocumented#SkScalar'>SkScalar</a> affine[6]) const
</pre>

Fills <a href='#SkMatrix_asAffine_affine'>affine</a> in column major order. Sets <a href='#SkMatrix_asAffine_affine'>affine</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x  skew-x translate-x |
| skew-y  scale-y translate-y |
</pre>

If <a href='#Matrix'>Matrix</a> contains perspective, returns false and leaves <a href='#SkMatrix_asAffine_affine'>affine</a> unchanged.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_asAffine_affine'><code><strong>affine</strong></code></a></td>
    <td>storage for 3x2 <a href='#SkMatrix_asAffine_affine'>affine</a> matrix; may be nullptr</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> does not contain perspective

### Example

<div><fiddle-embed name="3325bdf82bd86d9fbc4199f248afa82c">

#### Example Output

~~~~
ScaleX: 2 SkewY: 5 SkewX: 3 ScaleY: 6 TransX: 4 TransY: 7
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setAffine'>setAffine</a> <a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a>

---

<a name='SkMatrix_setAffine'></a>
## setAffine

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setAffine'>setAffine</a>(const <a href='undocumented#SkScalar'>SkScalar</a> affine[6])
</pre>

Sets <a href='#Matrix'>Matrix</a> to <a href='#SkMatrix_setAffine_affine'>affine</a> values, passed in column major order. Given <a href='#SkMatrix_setAffine_affine'>affine</a>,
column, then row, as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x  skew-x translate-x |
|  skew-y scale-y translate-y |
</pre>

<a href='#Matrix'>Matrix</a> is set, row, then column, to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| scale-x  skew-x translate-x |
|  skew-y scale-y translate-y |
|       0       0           1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setAffine_affine'><code><strong>affine</strong></code></a></td>
    <td>3x2 <a href='#SkMatrix_setAffine_affine'>affine</a> matrix</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="f5b6d371c4d65e5b5ac6eebdd4b237d8">

#### Example Output

~~~~
ScaleX: 2 SkewY: 5 SkewX: 3 ScaleY: 6 TransX: 4 TransY: 7
[  2.0000   3.0000   4.0000][  5.0000   6.0000   7.0000][  0.0000   0.0000   1.0000]
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_asAffine'>asAffine</a> <a href='#SkMatrix_SetAffineIdentity'>SetAffineIdentity</a>

---

## <a name='Transform'>Transform</a>


<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapHomogeneousPoints'>mapHomogeneousPoints</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='undocumented#Point3'>Point3</a> array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapPoints'>mapPoints</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Point'>Point</a> array</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapPoints'>mapPoints(SkPoint dst[], const SkPoint src[], int count)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapPoints_2'>mapPoints(SkPoint pts[], int count)</a> const</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRadius'>mapRadius</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns mean radius of mapped <a href='undocumented#Circle'>Circle</a></td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRect'>mapRect</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns bounds of mapped <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRect'>mapRect(SkRect* dst, const SkRect& src)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRect_2'>mapRect(SkRect* rect)</a> const</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRect_3'>mapRect(const SkRect& src)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>returns bounds of mapped <a href='SkRect_Reference#Rect'>Rect</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapRectToQuad'>mapRectToQuad</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkRect_Reference#Rect'>Rect</a> to <a href='SkPoint_Reference#Point'>Point</a> array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVector'>mapVector</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Vector'>Vector</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVector'>mapVector(SkScalar dx, SkScalar dy, SkVector* result)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVector_2'>mapVector(SkScalar dx, SkScalar dy)</a> const</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVectors'>mapVectors</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Vector'>Vector</a> array</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVectors'>mapVectors(SkVector dst[], const SkVector src[], int count)</a> const</td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapVectors_2'>mapVectors(SkVector vecs[], int count)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapXY'>mapXY</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>maps <a href='SkPoint_Reference#Point'>Point</a></td>
  </tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapXY'>mapXY(SkScalar x, SkScalar y, SkPoint* result)</a> const</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_mapXY_2'>mapXY(SkScalar x, SkScalar y)</a> const</td>
  </tr>
</table>

<a name='SkMatrix_mapPoints'></a>
## mapPoints

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapPoints'>mapPoints</a>(<a href='SkPoint_Reference#SkPoint'>SkPoint</a> dst[], const <a href='SkPoint_Reference#SkPoint'>SkPoint</a> src[], int count) const
</pre>

Maps <a href='#SkMatrix_mapPoints_src'>src</a> <a href='SkPoint_Reference#Point'>Point</a> array of length <a href='#SkMatrix_mapPoints_count'>count</a> to <a href='#SkMatrix_mapPoints_dst'>dst</a> <a href='SkPoint_Reference#Point'>Point</a> array of equal or greater
length. <a href='SkPoint_Reference#Point'>Points</a> are mapped by multiplying each <a href='SkPoint_Reference#Point'>Point</a> by <a href='#Matrix'>Matrix</a>. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
for (i = 0; i < count; ++i) {
    x = src[i].fX
    y = src[i].fY
}
</pre>

each <a href='#SkMatrix_mapPoints_dst'>dst</a> <a href='SkPoint_Reference#Point'>Point</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
              |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
</pre>

<a href='#SkMatrix_mapPoints_src'>src</a> and <a href='#SkMatrix_mapPoints_dst'>dst</a> may point to the same storage.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapPoints_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for mapped <a href='SkPoint_Reference#Point'>Points</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapPoints_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkPoint_Reference#Point'>Points</a> to transform</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapPoints_count'><code><strong>count</strong></code></a></td>
    <td>number of <a href='SkPoint_Reference#Point'>Points</a> to transform</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="f99dcb00296d0c56b6c0e178e94b3534"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup> <a href='#SkMatrix_mapHomogeneousPoints'>mapHomogeneousPoints</a> <a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup>

---

<a name='SkMatrix_mapPoints_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapPoints'>mapPoints</a>(<a href='SkPoint_Reference#SkPoint'>SkPoint</a> pts[], int count) const
</pre>

Maps <a href='#SkMatrix_mapPoints_2_pts'>pts</a> <a href='SkPoint_Reference#Point'>Point</a> array of length <a href='#SkMatrix_mapPoints_2_count'>count</a> in place. <a href='SkPoint_Reference#Point'>Points</a> are mapped by multiplying
each <a href='SkPoint_Reference#Point'>Point</a> by <a href='#Matrix'>Matrix</a>. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
for (i = 0; i < count; ++i) {
    x = pts[i].fX
    y = pts[i].fY
}
</pre>

each resulting <a href='#SkMatrix_mapPoints_2_pts'>pts</a> <a href='SkPoint_Reference#Point'>Point</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
              |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapPoints_2_pts'><code><strong>pts</strong></code></a></td>
    <td>storage for mapped <a href='SkPoint_Reference#Point'>Points</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapPoints_2_count'><code><strong>count</strong></code></a></td>
    <td>number of <a href='SkPoint_Reference#Point'>Points</a> to transform</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="428ca171ae3bd0d3f992458ac598b97b"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup> <a href='#SkMatrix_mapHomogeneousPoints'>mapHomogeneousPoints</a> <a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup>

---

<a name='SkMatrix_mapHomogeneousPoints'></a>
## mapHomogeneousPoints

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapHomogeneousPoints'>mapHomogeneousPoints</a>(<a href='undocumented#SkPoint3'>SkPoint3</a> dst[], const <a href='undocumented#SkPoint3'>SkPoint3</a> src[], int count) const
</pre>

Maps <a href='#SkMatrix_mapHomogeneousPoints_src'>src</a> <a href='undocumented#Point3'>Point3</a> array of length <a href='#SkMatrix_mapHomogeneousPoints_count'>count</a> to <a href='#SkMatrix_mapHomogeneousPoints_dst'>dst</a> <a href='undocumented#Point3'>Point3</a> array, which must of length <a href='#SkMatrix_mapHomogeneousPoints_count'>count</a> or
greater. <a href='undocumented#Point3'>Point3</a> array is mapped by multiplying each <a href='undocumented#Point3'>Point3</a> by <a href='#Matrix'>Matrix</a>. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |         | x |
Matrix = | D E F |,  src = | y |
         | G H I |         | z |
</pre>

each resulting <a href='#SkMatrix_mapHomogeneousPoints_dst'>dst</a> <a href='SkPoint_Reference#Point'>Point</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
               |A B C| |x|
Matrix * src = |D E F| |y| = |Ax+By+Cz Dx+Ey+Fz Gx+Hy+Iz|
               |G H I| |z|
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapHomogeneousPoints_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for mapped <a href='undocumented#Point3'>Point3</a> array</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapHomogeneousPoints_src'><code><strong>src</strong></code></a></td>
    <td><a href='undocumented#Point3'>Point3</a> array to transform</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapHomogeneousPoints_count'><code><strong>count</strong></code></a></td>
    <td>items in <a href='undocumented#Point3'>Point3</a> array to transform</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="d56f93e4bc763c7ba4914321ed07a8b5"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup> <a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup>

---

<a name='SkMatrix_mapXY'></a>
## mapXY

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapXY'>mapXY</a>(<a href='undocumented#SkScalar'>SkScalar</a> x, <a href='undocumented#SkScalar'>SkScalar</a> y, <a href='SkPoint_Reference#SkPoint'>SkPoint</a>* result) const
</pre>

Maps <a href='SkPoint_Reference#Point'>Point</a> (<a href='#SkMatrix_mapXY_x'>x</a>, <a href='#SkMatrix_mapXY_y'>y</a>) to <a href='#SkMatrix_mapXY_result'>result</a>. <a href='SkPoint_Reference#Point'>Point</a> is mapped by multiplying by <a href='#Matrix'>Matrix</a>. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |
</pre>

<a href='#SkMatrix_mapXY_result'>result</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
              |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapXY_x'><code><strong>x</strong></code></a></td>
    <td><a href='#SkMatrix_mapXY_x'>x</a>-axis value of <a href='SkPoint_Reference#Point'>Point</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapXY_y'><code><strong>y</strong></code></a></td>
    <td><a href='#SkMatrix_mapXY_y'>y</a>-axis value of <a href='SkPoint_Reference#Point'>Point</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapXY_result'><code><strong>result</strong></code></a></td>
    <td>storage for mapped <a href='SkPoint_Reference#Point'>Point</a></td>
  </tr>
</table>

### Example

<div><fiddle-embed name="9e50185d502dc6903783679a84106089"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup>

---

<a name='SkMatrix_mapXY_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='SkPoint_Reference#SkPoint'>SkPoint</a> <a href='#SkMatrix_mapXY'>mapXY</a>(<a href='undocumented#SkScalar'>SkScalar</a> x, <a href='undocumented#SkScalar'>SkScalar</a> y) const
</pre>

Returns <a href='SkPoint_Reference#Point'>Point</a> (<a href='#SkMatrix_mapXY_2_x'>x</a>, <a href='#SkMatrix_mapXY_2_y'>y</a>) multiplied by <a href='#Matrix'>Matrix</a>. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |
</pre>

result is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
              |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapXY_2_x'><code><strong>x</strong></code></a></td>
    <td><a href='#SkMatrix_mapXY_2_x'>x</a>-axis value of <a href='SkPoint_Reference#Point'>Point</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapXY_2_y'><code><strong>y</strong></code></a></td>
    <td><a href='#SkMatrix_mapXY_2_y'>y</a>-axis value of <a href='SkPoint_Reference#Point'>Point</a> to map</td>
  </tr>
</table>

### Return Value

mapped <a href='SkPoint_Reference#Point'>Point</a>

### Example

<div><fiddle-embed name="b1ead09c67a177ab8eace12b061610a7"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup>

---

<a name='SkMatrix_mapVectors'></a>
## mapVectors

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapVectors'>mapVectors</a>(<a href='SkPoint_Reference#SkVector'>SkVector</a> dst[], const <a href='SkPoint_Reference#SkVector'>SkVector</a> src[], int count) const
</pre>

Maps <a href='#SkMatrix_mapVectors_src'>src</a> <a href='SkPoint_Reference#Vector'>Vector</a> array of length <a href='#SkMatrix_mapVectors_count'>count</a> to <a href='SkPoint_Reference#Vector'>Vector</a> <a href='SkPoint_Reference#Point'>Point</a> array of equal or greater
length. <a href='SkPoint_Reference#Vector'>Vectors</a> are mapped by multiplying each <a href='SkPoint_Reference#Vector'>Vector</a> by <a href='#Matrix'>Matrix</a>, treating
<a href='#Matrix'>Matrix</a> translation as zero. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B 0 |         | x |
Matrix = | D E 0 |,  src = | y |
         | G H I |         | 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
for (i = 0; i < count; ++i) {
    x = src[i].fX
    y = src[i].fY
}
</pre>

each <a href='#SkMatrix_mapVectors_dst'>dst</a> <a href='SkPoint_Reference#Vector'>Vector</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
               |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
</pre>

<a href='#SkMatrix_mapVectors_src'>src</a> and <a href='#SkMatrix_mapVectors_dst'>dst</a> may point to the same storage.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapVectors_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for mapped <a href='SkPoint_Reference#Vector'>Vectors</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVectors_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkPoint_Reference#Vector'>Vectors</a> to transform</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVectors_count'><code><strong>count</strong></code></a></td>
    <td>number of <a href='SkPoint_Reference#Vector'>Vectors</a> to transform</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="918a9778c3d7d5cb306692784399f6dc"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapVector'>mapVector</a><sup><a href='#SkMatrix_mapVector_2'>[2]</a></sup> <a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup>

---

<a name='SkMatrix_mapVectors_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapVectors'>mapVectors</a>(<a href='SkPoint_Reference#SkVector'>SkVector</a> vecs[], int count) const
</pre>

Maps <a href='#SkMatrix_mapVectors_2_vecs'>vecs</a> <a href='SkPoint_Reference#Vector'>Vector</a> array of length <a href='#SkMatrix_mapVectors_2_count'>count</a> in place, multiplying each <a href='SkPoint_Reference#Vector'>Vector</a> by
<a href='#Matrix'>Matrix</a>, treating <a href='#Matrix'>Matrix</a> translation as zero. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B 0 |         | x |
Matrix = | D E 0 |,  vec = | y |
         | G H I |         | 1 |
</pre>

where

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
for (i = 0; i < count; ++i) {
    x = vecs[i].fX
    y = vecs[i].fY
}
</pre>

each result <a href='SkPoint_Reference#Vector'>Vector</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
               |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapVectors_2_vecs'><code><strong>vecs</strong></code></a></td>
    <td><a href='SkPoint_Reference#Vector'>Vectors</a> to transform, and storage for mapped <a href='SkPoint_Reference#Vector'>Vectors</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVectors_2_count'><code><strong>count</strong></code></a></td>
    <td>number of <a href='SkPoint_Reference#Vector'>Vectors</a> to transform</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="5754501a00a1323e76353fb53153e939"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapVector'>mapVector</a><sup><a href='#SkMatrix_mapVector_2'>[2]</a></sup> <a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup>

---

<a name='SkMatrix_mapVector'></a>
## mapVector

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapVector'>mapVector</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy, <a href='SkPoint_Reference#SkVector'>SkVector</a>* result) const
</pre>

Maps <a href='SkPoint_Reference#Vector'>Vector</a> (x, y) to <a href='#SkMatrix_mapVector_result'>result</a>. <a href='SkPoint_Reference#Vector'>Vector</a> is mapped by multiplying by <a href='#Matrix'>Matrix</a>,
treating <a href='#Matrix'>Matrix</a> translation as zero. Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B 0 |         | dx |
Matrix = | D E 0 |,  vec = | dy |
         | G H I |         |  1 |
</pre>

each <a href='#SkMatrix_mapVector_result'>result</a> <a href='SkPoint_Reference#Vector'>Vector</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
               |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapVector_dx'><code><strong>dx</strong></code></a></td>
    <td>x-axis value of <a href='SkPoint_Reference#Vector'>Vector</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVector_dy'><code><strong>dy</strong></code></a></td>
    <td>y-axis value of <a href='SkPoint_Reference#Vector'>Vector</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVector_result'><code><strong>result</strong></code></a></td>
    <td>storage for mapped <a href='SkPoint_Reference#Vector'>Vector</a></td>
  </tr>
</table>

### Example

<div><fiddle-embed name="aed143fc6cd0bce4ed029b98d1e61f2d"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup> <a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup>

---

<a name='SkMatrix_mapVector_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='SkPoint_Reference#SkVector'>SkVector</a> <a href='#SkMatrix_mapVector'>mapVector</a>(<a href='undocumented#SkScalar'>SkScalar</a> dx, <a href='undocumented#SkScalar'>SkScalar</a> dy) const
</pre>

Returns <a href='SkPoint_Reference#Vector'>Vector</a> (x, y) multiplied by <a href='#Matrix'>Matrix</a>, treating <a href='#Matrix'>Matrix</a> translation as zero.
Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B 0 |         | dx |
Matrix = | D E 0 |,  vec = | dy |
         | G H I |         |  1 |
</pre>

each result <a href='SkPoint_Reference#Vector'>Vector</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
               |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapVector_2_dx'><code><strong>dx</strong></code></a></td>
    <td>x-axis value of <a href='SkPoint_Reference#Vector'>Vector</a> to map</td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapVector_2_dy'><code><strong>dy</strong></code></a></td>
    <td>y-axis value of <a href='SkPoint_Reference#Vector'>Vector</a> to map</td>
  </tr>
</table>

### Return Value

mapped <a href='SkPoint_Reference#Vector'>Vector</a>

### Example

<div><fiddle-embed name="8bf1518db3f369696cd3065b541a8bd7"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapVectors'>mapVectors</a><sup><a href='#SkMatrix_mapVectors_2'>[2]</a></sup> <a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_mapXY'>mapXY</a><sup><a href='#SkMatrix_mapXY_2'>[2]</a></sup>

---

<a name='SkMatrix_mapRect'></a>
## mapRect

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_mapRect'>mapRect</a>(<a href='SkRect_Reference#SkRect'>SkRect</a>* dst, const <a href='SkRect_Reference#SkRect'>SkRect</a>& src) const
</pre>

Sets <a href='#SkMatrix_mapRect_dst'>dst</a> to bounds of <a href='#SkMatrix_mapRect_src'>src</a> corners mapped by <a href='#Matrix'>Matrix</a>.
Returns true if mapped corners are <a href='#SkMatrix_mapRect_dst'>dst</a> corners.

Returned value is the same as calling <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRect_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for bounds of mapped <a href='SkPoint_Reference#Point'>Points</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapRect_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map</td>
  </tr>
</table>

### Return Value

true if <a href='#SkMatrix_mapRect_dst'>dst</a> is equivalent to mapped <a href='#SkMatrix_mapRect_src'>src</a>

### Example

<div><fiddle-embed name="dbcf928b035a31ca69c99392e2e2cca9"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>

---

<a name='SkMatrix_mapRect_2'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_mapRect'>mapRect</a>(<a href='SkRect_Reference#SkRect'>SkRect</a>* rect) const
</pre>

Sets <a href='#SkMatrix_mapRect_2_rect'>rect</a> to bounds of <a href='#SkMatrix_mapRect_2_rect'>rect</a> corners mapped by <a href='#Matrix'>Matrix</a>.
Returns true if mapped corners are computed <a href='#SkMatrix_mapRect_2_rect'>rect</a> corners.

Returned value is the same as calling <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRect_2_rect'><code><strong>rect</strong></code></a></td>
    <td>rectangle to map, and storage for bounds of mapped corners</td>
  </tr>
</table>

### Return Value

true if result is equivalent to mapped src

### Example

<div><fiddle-embed name="5fafd0bd23d1ed37425b970b4a3c6cc9"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a> <a href='#SkMatrix_mapPoints'>mapPoints</a><sup><a href='#SkMatrix_mapPoints_2'>[2]</a></sup> <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>

---

<a name='SkMatrix_mapRect_3'></a>

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='SkRect_Reference#SkRect'>SkRect</a> <a href='#SkMatrix_mapRect'>mapRect</a>(const <a href='SkRect_Reference#SkRect'>SkRect</a>& src) const
</pre>

Returns bounds of <a href='#SkMatrix_mapRect_3_src'>src</a> corners mapped by <a href='#Matrix'>Matrix</a>.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRect_3_src'><code><strong>src</strong></code></a></td>
    <td>rectangle to map</td>
  </tr>
</table>

### Return Value

mapped bounds

### Example

<div><fiddle-embed name="3b7b1f884437ab450f986234e4aec27f"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapRectToQuad'>mapRectToQuad</a> <a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a>

---

<a name='SkMatrix_mapRectToQuad'></a>
## mapRectToQuad

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapRectToQuad'>mapRectToQuad</a>(<a href='SkPoint_Reference#SkPoint'>SkPoint</a> dst[4], const <a href='SkRect_Reference#SkRect'>SkRect</a>& rect) const
</pre>

Maps four corners of <a href='#SkMatrix_mapRectToQuad_rect'>rect</a> to <a href='#SkMatrix_mapRectToQuad_dst'>dst</a>. <a href='SkPoint_Reference#Point'>Points</a> are mapped by multiplying each
<a href='#SkMatrix_mapRectToQuad_rect'>rect</a> corner by <a href='#Matrix'>Matrix</a>. <a href='#SkMatrix_mapRectToQuad_rect'>rect</a> corner is processed in this order:
(<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fLeft, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fTop), (<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fRight, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fTop), (<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fRight, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fBottom),
(<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fLeft, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fBottom).

<a href='#SkMatrix_mapRectToQuad_rect'>rect</a> may be empty: <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fLeft may be greater than or equal to <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fRight;
<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fTop may be greater than or equal to <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fBottom.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
         | A B C |        | x |
Matrix = | D E F |,  pt = | y |
         | G H I |        | 1 |
</pre>

where pt is initialized from each of (<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fLeft, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fTop),
(<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fRight, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fTop), (<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fRight, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fBottom), (<a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fLeft, <a href='#SkMatrix_mapRectToQuad_rect'>rect</a>.fBottom),
each <a href='#SkMatrix_mapRectToQuad_dst'>dst</a> <a href='SkPoint_Reference#Point'>Point</a> is computed as:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
              |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
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRectToQuad_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for mapped corner <a href='SkPoint_Reference#Point'>Points</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapRectToQuad_rect'><code><strong>rect</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="c69cd2a590b5733c3cbc92cb9ceed3f5"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapRect'>mapRect</a><sup><a href='#SkMatrix_mapRect_2'>[2]</a></sup><sup><a href='#SkMatrix_mapRect_3'>[3]</a></sup> <a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a>

---

<a name='SkMatrix_mapRectScaleTranslate'></a>
## mapRectScaleTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_mapRectScaleTranslate'>mapRectScaleTranslate</a>(<a href='SkRect_Reference#SkRect'>SkRect</a>* dst, const <a href='SkRect_Reference#SkRect'>SkRect</a>& src) const
</pre>

Sets <a href='#SkMatrix_mapRectScaleTranslate_dst'>dst</a> to bounds of <a href='#SkMatrix_mapRectScaleTranslate_src'>src</a> corners mapped by <a href='#Matrix'>Matrix</a>. If matrix contains
elements other than scale or translate: asserts if SK_DEBUG is defined;
otherwise, results are undefined.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRectScaleTranslate_dst'><code><strong>dst</strong></code></a></td>
    <td>storage for bounds of mapped <a href='SkPoint_Reference#Point'>Points</a></td>
  </tr>
  <tr>    <td><a name='SkMatrix_mapRectScaleTranslate_src'><code><strong>src</strong></code></a></td>
    <td><a href='SkRect_Reference#Rect'>Rect</a> to map</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="62bc26989c2b4c2a54d516596a71dd97"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapRect'>mapRect</a><sup><a href='#SkMatrix_mapRect_2'>[2]</a></sup><sup><a href='#SkMatrix_mapRect_3'>[3]</a></sup> <a href='#SkMatrix_mapRectToQuad'>mapRectToQuad</a> <a href='#SkMatrix_isScaleTranslate'>isScaleTranslate</a> <a href='#SkMatrix_rectStaysRect'>rectStaysRect</a>

---

<a name='SkMatrix_mapRadius'></a>
## mapRadius

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_mapRadius'>mapRadius</a>(<a href='undocumented#SkScalar'>SkScalar</a> radius) const
</pre>

Returns geometric mean <a href='#SkMatrix_mapRadius_radius'>radius</a> of ellipse formed by constructing <a href='undocumented#Circle'>Circle</a> of
size <a href='#SkMatrix_mapRadius_radius'>radius</a>, and mapping constructed <a href='undocumented#Circle'>Circle</a> with <a href='#Matrix'>Matrix</a>. The result squared is
equal to the major axis length times the minor axis length.
Result is not meaningful if <a href='#Matrix'>Matrix</a> contains perspective elements.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_mapRadius_radius'><code><strong>radius</strong></code></a></td>
    <td><a href='undocumented#Circle'>Circle</a> size to map</td>
  </tr>
</table>

### Return Value

average mapped <a href='#SkMatrix_mapRadius_radius'>radius</a>

### Example

<div><fiddle-embed name="6d6f2082fcf59d9f02bfb1758b87db69"><div>The area enclosed by a square with sides equal to mappedRadius is the same as
the area enclosed by the ellipse major and minor axes.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_mapVector'>mapVector</a><sup><a href='#SkMatrix_mapVector_2'>[2]</a></sup>

---

<a name='SkMatrix_isFixedStepInX'></a>
## isFixedStepInX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a>() const
</pre>

Returns true if a unit step on x-axis at some y-axis value mapped through <a href='#Matrix'>Matrix</a>
can be represented by a constant <a href='SkPoint_Reference#Vector'>Vector</a>. Returns true if <a href='#SkMatrix_getType'>getType</a> returns
<a href='#SkMatrix_kIdentity_Mask'>kIdentity Mask</a>, or combinations of: <a href='#SkMatrix_kTranslate_Mask'>kTranslate Mask</a>, <a href='#SkMatrix_kScale_Mask'>kScale Mask</a>, and <a href='#SkMatrix_kAffine_Mask'>kAffine Mask</a>.

May return true if <a href='#SkMatrix_getType'>getType</a> returns <a href='#SkMatrix_kPerspective_Mask'>kPerspective Mask</a>, but only when <a href='#Matrix'>Matrix</a>
does not include rotation or skewing along the y-axis.

### Return Value

true if <a href='#Matrix'>Matrix</a> does not have complex perspective

### Example

<div><fiddle-embed name="ab57b232acef69f26de9cb23d23c8a1a">

#### Example Output

~~~~
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
isFixedStepInX: true
[  1.0000   0.0000   0.0000][  0.0000   2.0000   0.0000][  0.0000   0.0000   1.0000]
isFixedStepInX: true
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.0000   0.1000   1.0000]
isFixedStepInX: true
[  1.0000   0.0000   0.0000][  0.0000   2.0000   0.0000][  0.0000   0.1000   1.0000]
isFixedStepInX: true
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.1000   0.0000   1.0000]
isFixedStepInX: false
[  1.0000   0.0000   0.0000][  0.0000   2.0000   0.0000][  0.1000   0.0000   1.0000]
isFixedStepInX: false
[  1.0000   0.0000   0.0000][  0.0000   1.0000   0.0000][  0.1000   0.1000   1.0000]
isFixedStepInX: false
[  1.0000   0.0000   0.0000][  0.0000   2.0000   0.0000][  0.1000   0.1000   1.0000]
isFixedStepInX: false
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_fixedStepInX'>fixedStepInX</a> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_fixedStepInX'></a>
## fixedStepInX

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='SkPoint_Reference#SkVector'>SkVector</a> <a href='#SkMatrix_fixedStepInX'>fixedStepInX</a>(<a href='undocumented#SkScalar'>SkScalar</a> y) const
</pre>

Returns <a href='SkPoint_Reference#Vector'>Vector</a> representing a unit step on x-axis at <a href='#SkMatrix_fixedStepInX_y'>y</a> mapped through <a href='#Matrix'>Matrix</a>.
If <a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a> is false, returned value is undefined.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_fixedStepInX_y'><code><strong>y</strong></code></a></td>
    <td>position of line parallel to x-axis</td>
  </tr>
</table>

### Return Value

<a href='SkPoint_Reference#Vector'>Vector</a> advance of mapped unit step on x-axis

### Example

<div><fiddle-embed name="fad6b92b21b1e1deeae61978cec2d232"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_isFixedStepInX'>isFixedStepInX</a> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_cheapEqualTo'></a>
## cheapEqualTo

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_cheapEqualTo'>cheapEqualTo</a>(const <a href='#SkMatrix'>SkMatrix</a>& m) const
</pre>

Returns true if <a href='#Matrix'>Matrix</a> equals <a href='#SkMatrix_cheapEqualTo_m'>m</a>, using an efficient comparison.

Returns false when the sign of zero values is the different; when one
matrix has positive zero value and the other has negative zero value.

Returns true even when both <a href='#Matrix'>Matrices</a> contain NaN.

NaN never equals any value, including itself. To improve performance, NaN values
are treated as bit patterns that are equal if their bit patterns are equal.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_cheapEqualTo_m'><code><strong>m</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> to compare</td>
  </tr>
</table>

### Return Value

true if <a href='#SkMatrix_cheapEqualTo_m'>m</a> and <a href='#Matrix'>Matrix</a> are represented by identical bit patterns

### Example

<div><fiddle-embed name="39016b3cfc6bbabb09348a53822ce508">

#### Example Output

~~~~
identity: a == b a.cheapEqualTo(b): true
neg zero: a == b a.cheapEqualTo(b): false
one NaN: a != b a.cheapEqualTo(b): false
both NaN: a != b a.cheapEqualTo(b): true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_equal_operator'>operator==(const SkMatrix& a, const SkMatrix& b)</a>

---

<a name='SkMatrix_equal_operator'></a>
## operator==

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_equal_operator'>operator==(const SkMatrix& a, const SkMatrix& b)</a>
</pre>

Compares <a href='#SkMatrix_equal_operator_a'>a</a> and <a href='#SkMatrix_equal_operator_b'>b</a>; returns true if <a href='#SkMatrix_equal_operator_a'>a</a> and <a href='#SkMatrix_equal_operator_b'>b</a> are numerically equal. Returns true
even if sign of zero values are different. Returns false if either <a href='#Matrix'>Matrix</a>
contains NaN, even if the other <a href='#Matrix'>Matrix</a> also contains NaN.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_equal_operator_a'><code><strong>a</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> to compare</td>
  </tr>
  <tr>    <td><a name='SkMatrix_equal_operator_b'><code><strong>b</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> to compare</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_equal_operator_a'>a</a> and <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_equal_operator_b'>b</a> are numerically equal

### Example

<div><fiddle-embed name="3902859150b0f0c4aeb1f25d00434baa">

#### Example Output

~~~~
identity: a == b a.cheapEqualTo(b): true
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_cheapEqualTo'>cheapEqualTo</a> <a href='#SkMatrix_notequal_operator'>operator!=(const SkMatrix& a, const SkMatrix& b)</a>

---

<a name='SkMatrix_notequal_operator'></a>
## operator!=

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_notequal_operator'>operator!=(const SkMatrix& a, const SkMatrix& b)</a>
</pre>

Compares <a href='#SkMatrix_notequal_operator_a'>a</a> and <a href='#SkMatrix_notequal_operator_b'>b</a>; returns true if <a href='#SkMatrix_notequal_operator_a'>a</a> and <a href='#SkMatrix_notequal_operator_b'>b</a> are not numerically equal. Returns false
even if sign of zero values are different. Returns true if either <a href='#Matrix'>Matrix</a>
contains NaN, even if the other <a href='#Matrix'>Matrix</a> also contains NaN.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_notequal_operator_a'><code><strong>a</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> to compare</td>
  </tr>
  <tr>    <td><a name='SkMatrix_notequal_operator_b'><code><strong>b</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> to compare</td>
  </tr>
</table>

### Return Value

true if <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_notequal_operator_a'>a</a> and <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_notequal_operator_b'>b</a> are numerically not equal

### Example

<div><fiddle-embed name="088ab41f877599f980a99523749b0afd"></fiddle-embed></div>

### See Also

<a href='#SkMatrix_cheapEqualTo'>cheapEqualTo</a> <a href='#SkMatrix_equal_operator'>operator==(const SkMatrix& a, const SkMatrix& b)</a>

---

## <a name='Utility'>Utility</a>


<table style='border-collapse: collapse; width: 62.5em'>
  <tr><th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Topic</th>
<th style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>Description</th></tr>
  <tr style='background-color: #f0f0f0; '>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_dirtyMatrixTypeCache'>dirtyMatrixTypeCache</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sets internal cache to unknown state</td>
  </tr>
  <tr>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '><a href='#SkMatrix_dump'>dump</a></td>
    <td style='text-align: left; border: 2px solid #dddddd; padding: 8px; '>sends text representation using floats to standard output</td>
  </tr>
</table>

<a name='SkMatrix_dump'></a>
## dump

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_dump'>dump</a>() const
</pre>

Writes text representation of <a href='#Matrix'>Matrix</a> to standard output. Floating point values
are written with limited precision; it may not be possible to reconstruct
original <a href='#Matrix'>Matrix</a> from output.

### Example

<div><fiddle-embed name="8d72a4818e5a9188348f6c08ab5d8a40">

#### Example Output

~~~~
[  0.7071  -0.7071   0.0000][  0.7071   0.7071   0.0000][  0.0000   0.0000   1.0000]
[  0.7071  -0.7071   0.0000][  0.7071   0.7071   0.0000][  0.0000   0.0000   1.0000]
matrix != nearlyEqual
~~~~

</fiddle-embed></div>

### See Also

<a href='SkPath_Reference#SkPath_dump'>SkPath::dump</a><sup><a href='SkPath_Reference#SkPath_dump_2'>[2]</a></sup>

---

<a name='SkMatrix_getMinScale'></a>
## getMinScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getMinScale'>getMinScale</a>() const
</pre>

Returns the minimum scaling factor of <a href='#Matrix'>Matrix</a> by decomposing the scaling and
skewing elements.
Returns -1 if scale factor overflows or <a href='#Matrix'>Matrix</a> contains perspective.

### Return Value

minimum scale factor

### Example

<div><fiddle-embed name="1d6f67904c88a806c3731879e9af4ae5">

#### Example Output

~~~~
matrix.getMinScale() 24
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_getMaxScale'>getMaxScale</a> <a href='#SkMatrix_getMinMaxScales'>getMinMaxScales</a>

---

<a name='SkMatrix_getMaxScale'></a>
## getMaxScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
<a href='undocumented#SkScalar'>SkScalar</a> <a href='#SkMatrix_getMaxScale'>getMaxScale</a>() const
</pre>

Returns the maximum scaling factor of <a href='#Matrix'>Matrix</a> by decomposing the scaling and
skewing elements.
Returns -1 if scale factor overflows or <a href='#Matrix'>Matrix</a> contains perspective.

### Return Value

maximum scale factor

### Example

<div><fiddle-embed name="3fee4364929899649cf9efc37897e964">

#### Example Output

~~~~
matrix.getMaxScale() 42
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_getMinScale'>getMinScale</a> <a href='#SkMatrix_getMinMaxScales'>getMinMaxScales</a>

---

<a name='SkMatrix_getMinMaxScales'></a>
## getMinMaxScales

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool SK_WARN_UNUSED_RESULT <a href='#SkMatrix_getMinMaxScales'>getMinMaxScales</a>(<a href='undocumented#SkScalar'>SkScalar</a> scaleFactors[2]) const
</pre>

Sets <a href='#SkMatrix_getMinMaxScales_scaleFactors'>scaleFactors</a>[0] to the minimum scaling factor, and <a href='#SkMatrix_getMinMaxScales_scaleFactors'>scaleFactors</a>[1] to the
maximum scaling factor. Scaling factors are computed by decomposing
the <a href='#Matrix'>Matrix</a> scaling and skewing elements.

Returns true if <a href='#SkMatrix_getMinMaxScales_scaleFactors'>scaleFactors</a> are found; otherwise, returns false and sets
<a href='#SkMatrix_getMinMaxScales_scaleFactors'>scaleFactors</a> to undefined values.

### Parameters

<table>  <tr>    <td><a name='SkMatrix_getMinMaxScales_scaleFactors'><code><strong>scaleFactors</strong></code></a></td>
    <td>storage for minimum and maximum scale factors</td>
  </tr>
</table>

### Return Value

true if scale factors were computed correctly

### Example

<div><fiddle-embed name="13adba0ecf5f82247cf051b4fa4d8a9c">

#### Example Output

~~~~
matrix.getMinMaxScales() false 2 2
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_getMinScale'>getMinScale</a> <a href='#SkMatrix_getMaxScale'>getMaxScale</a>

---

<a name='SkMatrix_decomposeScale'></a>
## decomposeScale

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_decomposeScale'>decomposeScale</a>(<a href='undocumented#SkSize'>SkSize</a>* scale, <a href='#SkMatrix'>SkMatrix</a>* remaining = nullptr) const
</pre>

Decomposes <a href='#Matrix'>Matrix</a> into <a href='#SkMatrix_decomposeScale_scale'>scale</a> components and whatever remains. Returns false if
<a href='#Matrix'>Matrix</a> could not be decomposed.

Sets <a href='#SkMatrix_decomposeScale_scale'>scale</a> to portion of <a href='#Matrix'>Matrix</a> that <a href='#SkMatrix_decomposeScale_scale'>scale</a> axes. Sets <a href='#SkMatrix_decomposeScale_remaining'>remaining</a> to <a href='#Matrix'>Matrix</a>
with scaling factored out. <a href='#SkMatrix_decomposeScale_remaining'>remaining</a> may be passed as nullptr
to determine if <a href='#Matrix'>Matrix</a> can be decomposed without computing remainder.

Returns true if <a href='#SkMatrix_decomposeScale_scale'>scale</a> components are found. <a href='#SkMatrix_decomposeScale_scale'>scale</a> and <a href='#SkMatrix_decomposeScale_remaining'>remaining</a> are
unchanged if <a href='#Matrix'>Matrix</a> contains perspective; <a href='#SkMatrix_decomposeScale_scale'>scale</a> factors are not finite, or
are nearly zero.

On success<a href='#Matrix'>Matrix</a> = <a href='#SkMatrix_decomposeScale_scale'>scale</a> * Remaining

### Parameters

<table>  <tr>    <td><a name='SkMatrix_decomposeScale_scale'><code><strong>scale</strong></code></a></td>
    <td>axes scaling factors; may be nullptr</td>
  </tr>
  <tr>    <td><a name='SkMatrix_decomposeScale_remaining'><code><strong>remaining</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> without scaling; may be nullptr</td>
  </tr>
</table>

### Return Value

true if <a href='#SkMatrix_decomposeScale_scale'>scale</a> can be computed

### Example

<div><fiddle-embed name="139b874da0a3ede1f3df88119085c0aa">

#### Example Output

~~~~
[  0.0000  -0.2500   0.0000][  0.5000   0.0000   0.0000][  0.0000   0.0000   1.0000]
success: true  scale: 0.5, 0.25
[  0.0000  -0.5000   0.0000][  2.0000   0.0000   0.0000][  0.0000   0.0000   1.0000]
[  0.0000  -0.2500   0.0000][  0.5000   0.0000   0.0000][  0.0000   0.0000   1.0000]
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_MakeScale'>MakeScale</a><sup><a href='#SkMatrix_MakeScale_2'>[2]</a></sup>

---

<a name='SkMatrix_I'></a>
## I

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static const <a href='#SkMatrix'>SkMatrix</a>& I()
</pre>

Returns reference to const identity <a href='#Matrix'>Matrix</a>. Returned <a href='#Matrix'>Matrix</a> is set to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| 1 0 0 |
| 0 1 0 |
| 0 0 1 |
</pre>

### Return Value

const identity <a href='#Matrix'>Matrix</a>

### Example

<div><fiddle-embed name="d961d91020f19037204a8c3fd8cb1060">

#### Example Output

~~~~
m1 == m2
m2 == m3
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_reset'>reset</a> <a href='#SkMatrix_setIdentity'>setIdentity</a>

---

<a name='SkMatrix_InvalidMatrix'></a>
## InvalidMatrix

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static const <a href='#SkMatrix'>SkMatrix</a>& <a href='#SkMatrix_InvalidMatrix'>InvalidMatrix</a>()
</pre>

Returns reference to a const <a href='#Matrix'>Matrix</a> with invalid values. Returned <a href='#Matrix'>Matrix</a> is set
to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| SK_ScalarMax SK_ScalarMax SK_ScalarMax |
| SK_ScalarMax SK_ScalarMax SK_ScalarMax |
| SK_ScalarMax SK_ScalarMax SK_ScalarMax |
</pre>

### Return Value

const invalid <a href='#Matrix'>Matrix</a>

### Example

<div><fiddle-embed name="af0b72360c1c7a25b4754bfa47011dd5">

#### Example Output

~~~~
scaleX 3.40282e+38
~~~~

</fiddle-embed></div>

### See Also

SeeAlso <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_Concat'></a>
## Concat

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
static <a href='#SkMatrix'>SkMatrix</a> <a href='#SkMatrix_Concat'>Concat</a>(const <a href='#SkMatrix'>SkMatrix</a>& a, const <a href='#SkMatrix'>SkMatrix</a>& b)
</pre>

Returns <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_Concat_a'>a</a> multiplied by <a href='#Matrix'>Matrix</a> <a href='#SkMatrix_Concat_b'>b</a>.

Given:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
    | A B C |      | J K L |
a = | D E F |, b = | M N O |
    | G H I |      | P Q R |
</pre>

sets <a href='#Matrix'>Matrix</a> to:

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
        | 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 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_Concat_a'><code><strong>a</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on left side of multiply expression</td>
  </tr>
  <tr>    <td><a name='SkMatrix_Concat_b'><code><strong>b</strong></code></a></td>
    <td><a href='#Matrix'>Matrix</a> on right side of multiply expression</td>
  </tr>
</table>

### Return Value

<a href='#Matrix'>Matrix</a> computed from <a href='#SkMatrix_Concat_a'>a</a> times <a href='#SkMatrix_Concat_b'>b</a>

### Example

<div><fiddle-embed name="6b4562c7052da94f3d5b2412dca41946"><div><a href='#SkMatrix_setPolyToPoly'>setPolyToPoly</a> creates perspective matrices, one the inverse of the other.
Multiplying the matrix by its inverse turns into an identity matrix.
</div></fiddle-embed></div>

### See Also

<a href='#SkMatrix_preConcat'>preConcat</a> <a href='#SkMatrix_postConcat'>postConcat</a>

---

<a name='SkMatrix_dirtyMatrixTypeCache'></a>
## dirtyMatrixTypeCache

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_dirtyMatrixTypeCache'>dirtyMatrixTypeCache</a>()
</pre>

Sets internal cache to unknown state. Use to force update after repeated
modifications to <a href='#Matrix'>Matrix</a> element reference returned by <a href='#SkMatrix_array1_operator'>operator[](int index)</a>.

### Example

<div><fiddle-embed name="f4365ef332f51f7fd25040e0771ba9a2">

#### Example Output

~~~~
with identity matrix: x = 24
after skew x mod:     x = 24
after 2nd skew x mod: x = 24
after dirty cache:    x = 66
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_array1_operator'>operator[](int index)</a> <a href='#SkMatrix_getType'>getType</a>

---

<a name='SkMatrix_setScaleTranslate'></a>
## setScaleTranslate

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
void <a href='#SkMatrix_setScaleTranslate'>setScaleTranslate</a>(<a href='undocumented#SkScalar'>SkScalar</a> sx, <a href='undocumented#SkScalar'>SkScalar</a> sy, <a href='undocumented#SkScalar'>SkScalar</a> tx, <a href='undocumented#SkScalar'>SkScalar</a> ty)
</pre>

Initializes <a href='#Matrix'>Matrix</a> with scale and translate elements.

<pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0">
| sx  0 tx |
|  0 sy ty |
|  0  0  1 |
</pre>

### Parameters

<table>  <tr>    <td><a name='SkMatrix_setScaleTranslate_sx'><code><strong>sx</strong></code></a></td>
    <td>horizontal scale factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScaleTranslate_sy'><code><strong>sy</strong></code></a></td>
    <td>vertical scale factor to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScaleTranslate_tx'><code><strong>tx</strong></code></a></td>
    <td>horizontal translation to store</td>
  </tr>
  <tr>    <td><a name='SkMatrix_setScaleTranslate_ty'><code><strong>ty</strong></code></a></td>
    <td>vertical translation to store</td>
  </tr>
</table>

### Example

<div><fiddle-embed name="fed43797f13796529cb6731385d6f8f3">

#### Example Output

~~~~
[  1.0000   0.0000   3.0000][  0.0000   2.0000   4.0000][  0.0000   0.0000   1.0000]
~~~~

</fiddle-embed></div>

### See Also

<a href='#SkMatrix_setScale'>setScale</a><sup><a href='#SkMatrix_setScale_2'>[2]</a></sup> <a href='#SkMatrix_preTranslate'>preTranslate</a> <a href='#SkMatrix_postTranslate'>postTranslate</a>

---

<a name='SkMatrix_isFinite'></a>
## isFinite

<pre style="padding: 1em 1em 1em 1em; width: 62.5em;background-color: #f0f0f0">
bool <a href='#SkMatrix_isFinite'>isFinite</a>() const
</pre>

Returns true if all elements of the matrix are finite. Returns false if any
element is infinity, or NaN.

### Return Value

true if matrix has only finite elements

### Example

<div><fiddle-embed name="bc6c6f6a5df770287120d87f81b922eb">

#### Example Output

~~~~
[  1.0000   0.0000      nan][  0.0000   1.0000   0.0000][  0.0000   0.0000   1.0000]
matrix is finite: false
matrix != matrix
~~~~

</fiddle-embed></div>

### See Also

operator==

---