1 SkMatrix Reference 2 === 3 4 # <a name="Matrix"></a> Matrix 5 6 ## <a name="Overview"></a> Overview 7 8 ## <a name="Overview_Subtopic"></a> Overview Subtopic 9 10 | name | description | 11 | --- | --- | 12 | Constant | enum and enum class, const values | 13 | <a href="#Constructor">Constructor</a> | functions that construct <a href="#SkMatrix">SkMatrix</a> | 14 | <a href="#Member_Function">Member Function</a> | static functions and member methods | 15 | <a href="#Operator">Operator</a> | operator overloading methods | 16 | <a href="#Related_Function">Related Function</a> | similar methods grouped together | 17 18 # <a name="SkMatrix"></a> Class SkMatrix 19 <a href="#Matrix">Matrix</a> holds a 3x3 matrix for transforming coordinates. This allows mapping 20 <a href="SkPoint_Reference#Point">Points</a> and <a href="SkPoint_Reference#Vector">Vectors</a> with translation, scaling, skewing, rotation, and 21 perspective. 22 23 <a href="#Matrix">Matrix</a> elements are in row major order. <a href="#Matrix">Matrix</a> does not have a constructor, 24 so it must be explicitly initialized. <a href="#SkMatrix_setIdentity">setIdentity</a> initializes <a href="#Matrix">Matrix</a> 25 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> 26 initializes all <a href="#Matrix">Matrix</a> elements with the corresponding mapping. 27 28 <a href="#Matrix">Matrix</a> includes a hidden variable that classifies the type of matrix to 29 improve performance. <a href="#Matrix">Matrix</a> is not thread safe unless <a href="#SkMatrix_getType">getType</a> is called first. 30 31 ## <a name="Member_Function"></a> Member Function 32 33 | name | description | 34 | --- | --- | 35 | <a href="#SkMatrix_Concat">Concat</a> | returns the concatenation of <a href="#Matrix">Matrix</a> pair | 36 | I | returns a reference to a const identity <a href="#Matrix">Matrix</a> | 37 | <a href="#SkMatrix_InvalidMatrix">InvalidMatrix</a> | returns a reference to a const invalid <a href="#Matrix">Matrix</a> | 38 | <a href="#SkMatrix_MakeAll">MakeAll</a> | constructs all nine values | 39 | <a href="#SkMatrix_MakeRectToRect">MakeRectToRect</a> | constructs from source <a href="SkRect_Reference#Rect">Rect</a> to destination <a href="SkRect_Reference#Rect">Rect</a> | 40 | <a href="#SkMatrix_MakeScale">MakeScale</a> | constructs from scale in x and y | 41 | <a href="#SkMatrix_MakeTrans">MakeTrans</a> | constructs from translate in x and y | 42 | <a href="#SkMatrix_SetAffineIdentity">SetAffineIdentity</a> | sets 3x2 array to identity | 43 | <a href="#SkMatrix_asAffine">asAffine</a> | copies to 3x2 array | 44 | <a href="#SkMatrix_cheapEqualTo">cheapEqualTo</a> | compares <a href="#Matrix">Matrix</a> pair using memcmp() | 45 | <a href="#SkMatrix_decomposeScale">decomposeScale</a> | separates scale if possible | 46 | <a href="#SkMatrix_dirtyMatrixTypeCache">dirtyMatrixTypeCache</a> | sets internal cache to unknown state | 47 | <a href="#SkMatrix_dump">dump</a> | sends text representation using floats to standard output | 48 | <a href="#SkMatrix_fixedStepInX">fixedStepInX</a> | returns step in x for a position in y | 49 | <a href="#SkMatrix_get">get</a> | returns one of nine <a href="#Matrix">Matrix</a> values | 50 | <a href="#SkMatrix_get9">get9</a> | returns all nine <a href="#Matrix">Matrix</a> values | 51 | <a href="#SkMatrix_getMaxScale">getMaxScale</a> | returns maximum scaling, if possible | 52 | <a href="#SkMatrix_getMinMaxScales">getMinMaxScales</a> | returns minimum and maximum scaling, if possible | 53 | <a href="#SkMatrix_getMinScale">getMinScale</a> | returns minimum scaling, if possible | 54 | <a href="#SkMatrix_getPerspX">getPerspX</a> | returns input x perspective factor | 55 | <a href="#SkMatrix_getPerspY">getPerspY</a> | returns input y perspective factor | 56 | <a href="#SkMatrix_getScaleX">getScaleX</a> | returns horizontal scale factor | 57 | <a href="#SkMatrix_getScaleY">getScaleY</a> | returns vertical scale factor | 58 | <a href="#SkMatrix_getSkewX">getSkewX</a> | returns horizontal skew factor | 59 | <a href="#SkMatrix_getSkewY">getSkewY</a> | returns vertical skew factor | 60 | <a href="#SkMatrix_getTranslateX">getTranslateX</a> | returns horizontal translation | 61 | <a href="#SkMatrix_getTranslateY">getTranslateY</a> | returns vertical translation | 62 | <a href="#SkMatrix_getType">getType</a> | returns transform complexity | 63 | <a href="#SkMatrix_hasPerspective">hasPerspective</a> | returns if transform includes perspective | 64 | <a href="#SkMatrix_invert">invert</a> | returns inverse, if possible | 65 | <a href="#SkMatrix_isFinite">isFinite</a> | returns if all <a href="#Matrix">Matrix</a> values are not infinity, NaN | 66 | <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> | returns if transformation supports fixed step in x | 67 | <a href="#SkMatrix_isIdentity">isIdentity</a> | returns if matrix equals the identity <a href="#Matrix">Matrix</a> | 68 | <a href="#SkMatrix_isScaleTranslate">isScaleTranslate</a> | returns if transform is limited to scale and translate | 69 | <a href="#SkMatrix_isSimilarity">isSimilarity</a> | returns if transform is limited to square scale and rotation | 70 | <a href="#SkMatrix_isTranslate">isTranslate</a> | returns if transform is limited to translate | 71 | <a href="#SkMatrix_mapHomogeneousPoints">mapHomogeneousPoints</a> | maps <a href="undocumented#Point3">Point3</a> array | 72 | <a href="#SkMatrix_mapPoints">mapPoints</a> | maps <a href="SkPoint_Reference#Point">Point</a> array | 73 | <a href="#SkMatrix_mapRadius">mapRadius</a> | returns mean radius of mapped <a href="undocumented#Circle">Circle</a> | 74 | <a href="#SkMatrix_mapRect">mapRect</a> | returns bounds of mapped <a href="SkRect_Reference#Rect">Rect</a> | 75 | <a href="#SkMatrix_mapRectScaleTranslate">mapRectScaleTranslate</a> | returns bounds of mapped <a href="SkRect_Reference#Rect">Rect</a> | 76 | <a href="#SkMatrix_mapRectToQuad">mapRectToQuad</a> | maps <a href="SkRect_Reference#Rect">Rect</a> to <a href="SkPoint_Reference#Point">Point</a> array | 77 | <a href="#SkMatrix_mapVector">mapVector</a> | maps <a href="SkPoint_Reference#Vector">Vector</a> | 78 | <a href="#SkMatrix_mapVectors">mapVectors</a> | maps <a href="SkPoint_Reference#Vector">Vector</a> array | 79 | <a href="#SkMatrix_mapXY">mapXY</a> | maps <a href="SkPoint_Reference#Point">Point</a> | 80 | <a href="#SkMatrix_postConcat">postConcat</a> | post-multiplies <a href="#Matrix">Matrix</a> by <a href="#Matrix">Matrix</a> parameter | 81 | <a href="#SkMatrix_postIDiv">postIDiv</a> | post-multiplies <a href="#Matrix">Matrix</a> by inverse scale | 82 | <a href="#SkMatrix_postRotate">postRotate</a> | post-multiplies <a href="#Matrix">Matrix</a> by rotation | 83 | <a href="#SkMatrix_postScale">postScale</a> | post-multiplies <a href="#Matrix">Matrix</a> by scale | 84 | <a href="#SkMatrix_postSkew">postSkew</a> | post-multiplies <a href="#Matrix">Matrix</a> by skew | 85 | <a href="#SkMatrix_postTranslate">postTranslate</a> | post-multiplies <a href="#Matrix">Matrix</a> by translation | 86 | <a href="#SkMatrix_preConcat">preConcat</a> | pre-multiplies <a href="#Matrix">Matrix</a> by <a href="#Matrix">Matrix</a> parameter | 87 | <a href="#SkMatrix_preRotate">preRotate</a> | pre-multiplies <a href="#Matrix">Matrix</a> by rotation | 88 | <a href="#SkMatrix_preScale">preScale</a> | pre-multiplies <a href="#Matrix">Matrix</a> by scale | 89 | <a href="#SkMatrix_preSkew">preSkew</a> | pre-multiplies <a href="#Matrix">Matrix</a> by skew | 90 | <a href="#SkMatrix_preTranslate">preTranslate</a> | pre-multiplies <a href="#Matrix">Matrix</a> by translation | 91 | <a href="#SkMatrix_preservesAxisAlignment">preservesAxisAlignment</a> | returns if mapping restricts to 90 degree multiples and mirroring | 92 | <a href="#SkMatrix_preservesRightAngles">preservesRightAngles</a> | returns if mapped 90 angle remains 90 degrees | 93 | <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> | returns if mapped <a href="SkRect_Reference#Rect">Rect</a> can be represented by another <a href="SkRect_Reference#Rect">Rect</a> | 94 | <a href="#SkMatrix_reset">reset</a> | sets <a href="#Matrix">Matrix</a> to identity | 95 | <a href="#SkMatrix_set">set</a> | sets one value | 96 | <a href="#SkMatrix_set9">set9</a> | sets all values from <a href="undocumented#Scalar">Scalar</a> array | 97 | <a href="#SkMatrix_setAffine">setAffine</a> | sets left two columns | 98 | <a href="#SkMatrix_setAll">setAll</a> | sets all values from parameters | 99 | <a href="#SkMatrix_setConcat">setConcat</a> | sets to <a href="#Matrix">Matrix</a> parameter multiplied by <a href="#Matrix">Matrix</a> parameter | 100 | <a href="#SkMatrix_setIdentity">setIdentity</a> | sets <a href="#Matrix">Matrix</a> to identity | 101 | <a href="#SkMatrix_setPerspX">setPerspX</a> | sets input x perspective factor | 102 | <a href="#SkMatrix_setPerspY">setPerspY</a> | sets input y perspective factor | 103 | <a href="#SkMatrix_setPolyToPoly">setPolyToPoly</a> | sets to map one to four points to an equal array of points | 104 | <a href="#SkMatrix_setRSXform">setRSXform</a> | sets to rotate, scale, and translate | 105 | <a href="#SkMatrix_setRectToRect">setRectToRect</a> | sets to map one <a href="SkRect_Reference#Rect">Rect</a> to another | 106 | <a href="#SkMatrix_setRotate">setRotate</a> | sets to rotate about a point | 107 | <a href="#SkMatrix_setScale">setScale</a> | sets to scale about a point | 108 | <a href="#SkMatrix_setScaleTranslate">setScaleTranslate</a> | sets to scale and translate | 109 | <a href="#SkMatrix_setScaleX">setScaleX</a> | sets horizontal scale factor | 110 | <a href="#SkMatrix_setScaleY">setScaleY</a> | sets vertical scale factor | 111 | <a href="#SkMatrix_setSinCos">setSinCos</a> | sets to rotate and scale about a point | 112 | <a href="#SkMatrix_setSkew">setSkew</a> | sets to skew about a point | 113 | <a href="#SkMatrix_setSkewX">setSkewX</a> | sets horizontal skew factor | 114 | <a href="#SkMatrix_setSkewY">setSkewY</a> | sets vertical skew factor | 115 | <a href="#SkMatrix_setTranslate">setTranslate</a> | sets to translate in x and y | 116 | <a href="#SkMatrix_setTranslateX">setTranslateX</a> | sets horizontal translation | 117 | <a href="#SkMatrix_setTranslateY">setTranslateY</a> | sets vertical translation | 118 | <a href="#SkMatrix_toString">toString</a> | converts <a href="#Matrix">Matrix</a> to machine readable form | 119 120 ## <a name="Related_Function"></a> Related Function 121 122 | name | description | 123 | --- | --- | 124 | <a href="#Property">Property</a> | values and attributes | 125 | <a href="#Set">Set</a> | set one or more matrix values | 126 | <a href="#Transform">Transform</a> | map points with <a href="#Matrix">Matrix</a> | 127 | <a href="#Utility">Utility</a> | rarely called management functions | 128 129 ## <a name="Constructor"></a> Constructor 130 131 | name | description | 132 | --- | --- | 133 | I | returns a reference to a const identity <a href="#Matrix">Matrix</a> | 134 | <a href="#SkMatrix_InvalidMatrix">InvalidMatrix</a> | returns a reference to a const invalid <a href="#Matrix">Matrix</a> | 135 | <a href="#SkMatrix_MakeAll">MakeAll</a> | constructs all nine values | 136 | <a href="#SkMatrix_MakeRectToRect">MakeRectToRect</a> | constructs from source <a href="SkRect_Reference#Rect">Rect</a> to destination <a href="SkRect_Reference#Rect">Rect</a> | 137 | <a href="#SkMatrix_MakeScale">MakeScale</a> | constructs from scale in x and y | 138 | | <a href="#SkMatrix_MakeScale">MakeScale(SkScalar sx, SkScalar sy)</a> | 139 | | <a href="#SkMatrix_MakeScale_2">MakeScale(SkScalar scale)</a> | 140 | <a href="#SkMatrix_MakeTrans">MakeTrans</a> | constructs from translate in x and y | 141 | <a href="#SkMatrix_SetAffineIdentity">SetAffineIdentity</a> | sets 3x2 array to identity | 142 | <a href="#SkMatrix_asAffine">asAffine</a> | copies to 3x2 array | 143 | <a href="#SkMatrix_reset">reset</a> | sets <a href="#Matrix">Matrix</a> to identity | 144 | <a href="#SkMatrix_setAffine">setAffine</a> | sets left two columns | 145 | <a href="#SkMatrix_setConcat">setConcat</a> | sets to <a href="#Matrix">Matrix</a> parameter multiplied by <a href="#Matrix">Matrix</a> parameter | 146 | <a href="#SkMatrix_setIdentity">setIdentity</a> | sets <a href="#Matrix">Matrix</a> to identity | 147 | <a href="#SkMatrix_setRSXform">setRSXform</a> | sets to rotate, scale, and translate | 148 | <a href="#SkMatrix_setRotate">setRotate</a> | sets to rotate about a point | 149 | | <a href="#SkMatrix_setRotate">setRotate(SkScalar degrees, SkScalar px, SkScalar py)</a> | 150 | | <a href="#SkMatrix_setRotate_2">setRotate(SkScalar degrees)</a> | 151 | <a href="#SkMatrix_setScale">setScale</a> | sets to scale about a point | 152 | | <a href="#SkMatrix_setScale">setScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a> | 153 | | <a href="#SkMatrix_setScale_2">setScale(SkScalar sx, SkScalar sy)</a> | 154 | <a href="#SkMatrix_setScaleTranslate">setScaleTranslate</a> | sets to scale and translate | 155 | <a href="#SkMatrix_setSinCos">setSinCos</a> | sets to rotate and scale about a point | 156 | | <a href="#SkMatrix_setSinCos">setSinCos(SkScalar sinValue, SkScalar cosValue, SkScalar px, SkScalar py)</a> | 157 | | <a href="#SkMatrix_setSinCos_2">setSinCos(SkScalar sinValue, SkScalar cosValue)</a> | 158 | <a href="#SkMatrix_setSkew">setSkew</a> | sets to skew about a point | 159 | | <a href="#SkMatrix_setSkew">setSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a> | 160 | | <a href="#SkMatrix_setSkew_2">setSkew(SkScalar kx, SkScalar ky)</a> | 161 | <a href="#SkMatrix_setTranslate">setTranslate</a> | sets to translate in x and y | 162 | | <a href="#SkMatrix_setTranslate">setTranslate(SkScalar dx, SkScalar dy)</a> | 163 | | <a href="#SkMatrix_setTranslate_2">setTranslate(const SkVector& v)</a> | 164 165 <a name="SkMatrix_MakeScale"></a> 166 ## MakeScale 167 168 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 169 static SkMatrix SK_WARN_UNUSED_RESULT MakeScale(SkScalar sx, SkScalar sy) 170 </pre> 171 172 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: 173 174 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 175 | sx 0 0 | 176 | 0 sy 0 | 177 | 0 0 1 |</pre> 178 179 ### Parameters 180 181 <table> <tr> <td><a name="SkMatrix_MakeScale_sx"> <code><strong>sx </strong></code> </a></td> <td> 182 horizontal scale factor</td> 183 </tr> <tr> <td><a name="SkMatrix_MakeScale_sy"> <code><strong>sy </strong></code> </a></td> <td> 184 vertical scale factor</td> 185 </tr> 186 </table> 187 188 ### Return Value 189 190 <a href="#Matrix">Matrix</a> with scale 191 192 ### Example 193 194 <div><fiddle-embed name="7ff17718111df6d6f95381d8a8f1b389"></fiddle-embed></div> 195 196 ### See Also 197 198 <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> 199 200 --- 201 202 <a name="SkMatrix_MakeScale_2"></a> 203 204 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 205 static SkMatrix SK_WARN_UNUSED_RESULT MakeScale(SkScalar scale) 206 </pre> 207 208 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: 209 210 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 211 | scale 0 0 | 212 | 0 scale 0 | 213 | 0 0 1 |</pre> 214 215 ### Parameters 216 217 <table> <tr> <td><a name="SkMatrix_MakeScale_2_scale"> <code><strong>scale </strong></code> </a></td> <td> 218 horizontal and vertical <a href="#SkMatrix_MakeScale_2_scale">scale</a> factor</td> 219 </tr> 220 </table> 221 222 ### Return Value 223 224 <a href="#Matrix">Matrix</a> with <a href="#SkMatrix_MakeScale_2_scale">scale</a> 225 226 ### Example 227 228 <div><fiddle-embed name="2956aeb50fa862cdb13995e1e56a4bc8"></fiddle-embed></div> 229 230 ### See Also 231 232 <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> 233 234 --- 235 236 <a name="SkMatrix_MakeTrans"></a> 237 ## MakeTrans 238 239 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 240 static SkMatrix SK_WARN_UNUSED_RESULT MakeTrans(SkScalar dx, SkScalar dy) 241 </pre> 242 243 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: 244 245 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 246 | 1 0 dx | 247 | 0 1 dy | 248 | 0 0 1 |</pre> 249 250 ### Parameters 251 252 <table> <tr> <td><a name="SkMatrix_MakeTrans_dx"> <code><strong>dx </strong></code> </a></td> <td> 253 horizontal translation</td> 254 </tr> <tr> <td><a name="SkMatrix_MakeTrans_dy"> <code><strong>dy </strong></code> </a></td> <td> 255 vertical translation</td> 256 </tr> 257 </table> 258 259 ### Return Value 260 261 <a href="#Matrix">Matrix</a> with translation 262 263 ### Example 264 265 <div><fiddle-embed name="b2479df0d9cf296ff64ac31e36684557"></fiddle-embed></div> 266 267 ### See Also 268 269 <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> 270 271 --- 272 273 <a name="SkMatrix_MakeAll"></a> 274 ## MakeAll 275 276 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 277 static SkMatrix SK_WARN_UNUSED_RESULT MakeAll(SkScalar scaleX, SkScalar skewX, SkScalar transX, 278 SkScalar skewY, SkScalar scaleY, SkScalar transY, 279 SkScalar pers0, SkScalar pers1, SkScalar pers2) 280 </pre> 281 282 Sets <a href="#Matrix">Matrix</a> to: 283 284 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 285 | scaleX skewX transX | 286 | skewY scaleY transY | 287 | pers0 pers1 pers2 |</pre> 288 289 ### Parameters 290 291 <table> <tr> <td><a name="SkMatrix_MakeAll_scaleX"> <code><strong>scaleX </strong></code> </a></td> <td> 292 horizontal scale factor</td> 293 </tr> <tr> <td><a name="SkMatrix_MakeAll_skewX"> <code><strong>skewX </strong></code> </a></td> <td> 294 horizontal skew factor</td> 295 </tr> <tr> <td><a name="SkMatrix_MakeAll_transX"> <code><strong>transX </strong></code> </a></td> <td> 296 horizontal translation</td> 297 </tr> <tr> <td><a name="SkMatrix_MakeAll_skewY"> <code><strong>skewY </strong></code> </a></td> <td> 298 vertical skew factor</td> 299 </tr> <tr> <td><a name="SkMatrix_MakeAll_scaleY"> <code><strong>scaleY </strong></code> </a></td> <td> 300 vertical scale factor</td> 301 </tr> <tr> <td><a name="SkMatrix_MakeAll_transY"> <code><strong>transY </strong></code> </a></td> <td> 302 vertical translation</td> 303 </tr> <tr> <td><a name="SkMatrix_MakeAll_pers0"> <code><strong>pers0 </strong></code> </a></td> <td> 304 input x perspective factor</td> 305 </tr> <tr> <td><a name="SkMatrix_MakeAll_pers1"> <code><strong>pers1 </strong></code> </a></td> <td> 306 input y perspective factor</td> 307 </tr> <tr> <td><a name="SkMatrix_MakeAll_pers2"> <code><strong>pers2 </strong></code> </a></td> <td> 308 perspective scale factor</td> 309 </tr> 310 </table> 311 312 ### Return Value 313 314 <a href="#Matrix">Matrix</a> constructed from parameters 315 316 ### Example 317 318 <div><fiddle-embed name="6bad83b64de9266e323c29d550e04188"></fiddle-embed></div> 319 320 ### See Also 321 322 <a href="#SkMatrix_setAll">setAll</a> <a href="#SkMatrix_set9">set9</a> <a href="#SkMatrix_postConcat">postConcat</a> <a href="#SkMatrix_preConcat">preConcat</a> 323 324 --- 325 326 ## <a name="SkMatrix_TypeMask"></a> Enum SkMatrix::TypeMask 327 328 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 329 enum <a href="#SkMatrix_TypeMask">TypeMask</a> { 330 <a href="#SkMatrix_kIdentity_Mask">kIdentity Mask</a> = 0, 331 <a href="#SkMatrix_kTranslate_Mask">kTranslate Mask</a> = 0x01, 332 <a href="#SkMatrix_kScale_Mask">kScale Mask</a> = 0x02, 333 <a href="#SkMatrix_kAffine_Mask">kAffine Mask</a> = 0x04, 334 <a href="#SkMatrix_kPerspective_Mask">kPerspective Mask</a> = 0x08, 335 };</pre> 336 337 Enum of bit fields for mask returned by <a href="#SkMatrix_getType">getType</a>. 338 Used to identify the complexity of <a href="#Matrix">Matrix</a>, to optimize performance. 339 340 ### Constants 341 342 <table> 343 <tr> 344 <td><a name="SkMatrix_kIdentity_Mask"> <code><strong>SkMatrix::kIdentity_Mask </strong></code> </a></td><td>0</td><td>all bits clear if <a href="#Matrix">Matrix</a> is identity</td> 345 </tr> 346 <tr> 347 <td><a name="SkMatrix_kTranslate_Mask"> <code><strong>SkMatrix::kTranslate_Mask </strong></code> </a></td><td>1</td><td>set if <a href="#Matrix">Matrix</a> has translation</td> 348 </tr> 349 <tr> 350 <td><a name="SkMatrix_kScale_Mask"> <code><strong>SkMatrix::kScale_Mask </strong></code> </a></td><td>2</td><td>set if <a href="#Matrix">Matrix</a> has x or y scale</td> 351 </tr> 352 <tr> 353 <td><a name="SkMatrix_kAffine_Mask"> <code><strong>SkMatrix::kAffine_Mask </strong></code> </a></td><td>4</td><td>set if <a href="#Matrix">Matrix</a> skews or rotates</td> 354 </tr> 355 <tr> 356 <td><a name="SkMatrix_kPerspective_Mask"> <code><strong>SkMatrix::kPerspective_Mask </strong></code> </a></td><td>8</td><td>set if <a href="#Matrix">Matrix</a> has perspective</td> 357 </tr> 358 </table> 359 360 ### Example 361 362 <div><fiddle-embed name="ba19b36df8cd78586f3dff54e2d4c093"> 363 364 #### Example Output 365 366 ~~~~ 367 after reset: kIdentity_Mask 368 after postTranslate: kTranslate_Mask 369 after postScale: kTranslate_Mask kScale_Mask 370 after postScale: kTranslate_Mask kScale_Mask kAffine_Mask 371 after setPolyToPoly: kTranslate_Mask kScale_Mask kAffine_Mask kPerspective_Mask 372 ~~~~ 373 374 </fiddle-embed></div> 375 376 ### See Also 377 378 <a href="#SkMatrix_getType">getType</a> 379 380 381 382 ## <a name="Property"></a> Property 383 384 | name | description | 385 | --- | --- | 386 | <a href="#SkMatrix_decomposeScale">decomposeScale</a> | separates scale if possible | 387 | <a href="#SkMatrix_fixedStepInX">fixedStepInX</a> | returns step in x for a position in y | 388 | <a href="#SkMatrix_get">get</a> | returns one of nine <a href="#Matrix">Matrix</a> values | 389 | <a href="#SkMatrix_get9">get9</a> | returns all nine <a href="#Matrix">Matrix</a> values | 390 | <a href="#SkMatrix_getMaxScale">getMaxScale</a> | returns maximum scaling, if possible | 391 | <a href="#SkMatrix_getMinMaxScales">getMinMaxScales</a> | returns minimum and maximum scaling, if possible | 392 | <a href="#SkMatrix_getMinScale">getMinScale</a> | returns minimum scaling, if possible | 393 | <a href="#SkMatrix_getPerspX">getPerspX</a> | returns input x perspective factor | 394 | <a href="#SkMatrix_getPerspY">getPerspY</a> | returns input y perspective factor | 395 | <a href="#SkMatrix_getScaleX">getScaleX</a> | returns horizontal scale factor | 396 | <a href="#SkMatrix_getScaleY">getScaleY</a> | returns vertical scale factor | 397 | <a href="#SkMatrix_getSkewX">getSkewX</a> | returns horizontal skew factor | 398 | <a href="#SkMatrix_getSkewY">getSkewY</a> | returns vertical skew factor | 399 | <a href="#SkMatrix_getTranslateX">getTranslateX</a> | returns horizontal translation | 400 | <a href="#SkMatrix_getTranslateY">getTranslateY</a> | returns vertical translation | 401 | <a href="#SkMatrix_getType">getType</a> | returns transform complexity | 402 | <a href="#SkMatrix_hasPerspective">hasPerspective</a> | returns if transform includes perspective | 403 | <a href="#SkMatrix_isFinite">isFinite</a> | returns if all <a href="#Matrix">Matrix</a> values are not infinity, NaN | 404 | <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> | returns if transformation supports fixed step in x | 405 | <a href="#SkMatrix_isIdentity">isIdentity</a> | returns if matrix equals the identity <a href="#Matrix">Matrix</a> | 406 | <a href="#SkMatrix_isScaleTranslate">isScaleTranslate</a> | returns if transform is limited to scale and translate | 407 | <a href="#SkMatrix_isSimilarity">isSimilarity</a> | returns if transform is limited to square scale and rotation | 408 | <a href="#SkMatrix_isTranslate">isTranslate</a> | returns if transform is limited to translate | 409 | <a href="#SkMatrix_preservesAxisAlignment">preservesAxisAlignment</a> | returns if mapping restricts to 90 degree multiples and mirroring | 410 | <a href="#SkMatrix_preservesRightAngles">preservesRightAngles</a> | returns if mapped 90 angle remains 90 degrees | 411 | <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> | returns if mapped <a href="SkRect_Reference#Rect">Rect</a> can be represented by another <a href="SkRect_Reference#Rect">Rect</a> | 412 413 <a name="SkMatrix_getType"></a> 414 ## getType 415 416 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 417 TypeMask getType() const 418 </pre> 419 420 Returns a bit field describing the transformations the matrix may 421 perform. The bit field is computed conservatively, so it may include 422 false positives. For example, when <a href="#SkMatrix_kPerspective_Mask">kPerspective Mask</a> is set, all 423 other bits are set. 424 425 ### Return Value 426 427 <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>, 428 <a href="#SkMatrix_kAffine_Mask">kAffine Mask</a>, <a href="#SkMatrix_kPerspective_Mask">kPerspective Mask</a> 429 430 ### Example 431 432 <div><fiddle-embed name="8e45fe2dd52731bb2d4318686257e1d7"> 433 434 #### Example Output 435 436 ~~~~ 437 identity flags hex: 0 decimal: 0 438 set all flags hex: f decimal: 15 439 ~~~~ 440 441 </fiddle-embed></div> 442 443 ### See Also 444 445 <a href="#SkMatrix_TypeMask">TypeMask</a> 446 447 --- 448 449 <a name="SkMatrix_isIdentity"></a> 450 ## isIdentity 451 452 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 453 bool isIdentity() const 454 </pre> 455 456 Returns true if <a href="#Matrix">Matrix</a> is identity. Identity matrix is: 457 458 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 459 | 1 0 0 | 460 | 0 1 0 | 461 | 0 0 1 |</pre> 462 463 ### Return Value 464 465 true if <a href="#Matrix">Matrix</a> has no effect 466 467 ### Example 468 469 <div><fiddle-embed name="780ab376325b3cfa889ea26c0769ec11"> 470 471 #### Example Output 472 473 ~~~~ 474 is identity: true 475 is identity: false 476 ~~~~ 477 478 </fiddle-embed></div> 479 480 ### See Also 481 482 <a href="#SkMatrix_reset">reset</a> <a href="#SkMatrix_setIdentity">setIdentity</a> <a href="#SkMatrix_getType">getType</a> 483 484 --- 485 486 <a name="SkMatrix_isScaleTranslate"></a> 487 ## isScaleTranslate 488 489 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 490 bool isScaleTranslate() const 491 </pre> 492 493 Returns true if <a href="#Matrix">Matrix</a> at most scales and translates. <a href="#Matrix">Matrix</a> may be identity, 494 contain only scale elements, only translate elements, or both. <a href="#Matrix">Matrix</a> form is: 495 496 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 497 | scale-x 0 translate-x | 498 | 0 scale-y translate-y | 499 | 0 0 1 |</pre> 500 501 ### Return Value 502 503 true if <a href="#Matrix">Matrix</a> is identity; or scales, translates, or both 504 505 ### Example 506 507 <div><fiddle-embed name="6287e29674a487eb94174992d45b9a34"> 508 509 #### Example Output 510 511 ~~~~ 512 is scale-translate: true 513 is scale-translate: true 514 is scale-translate: true 515 is scale-translate: true 516 ~~~~ 517 518 </fiddle-embed></div> 519 520 ### See Also 521 522 <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> 523 524 --- 525 526 <a name="SkMatrix_isTranslate"></a> 527 ## isTranslate 528 529 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 530 bool isTranslate() const 531 </pre> 532 533 Returns true if <a href="#Matrix">Matrix</a> is identity, or translates. <a href="#Matrix">Matrix</a> form is: 534 535 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 536 | 1 0 translate-x | 537 | 0 1 translate-y | 538 | 0 0 1 |</pre> 539 540 ### Return Value 541 542 true if <a href="#Matrix">Matrix</a> is identity, or translates 543 544 ### Example 545 546 <div><fiddle-embed name="73ac71a8a30841873577c11c6c9b38ee"> 547 548 #### Example Output 549 550 ~~~~ 551 is translate: true 552 is translate: true 553 is translate: false 554 is translate: false 555 ~~~~ 556 557 </fiddle-embed></div> 558 559 ### See Also 560 561 <a href="#SkMatrix_setTranslate">setTranslate</a><sup><a href="#SkMatrix_setTranslate_2">[2]</a></sup> <a href="#SkMatrix_getType">getType</a> 562 563 --- 564 565 <a name="SkMatrix_rectStaysRect"></a> 566 ## rectStaysRect 567 568 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 569 bool rectStaysRect() const 570 </pre> 571 572 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, 573 or scales, or rotates a multiple of 90 degrees, or mirrors in x or y. In all 574 cases, <a href="#Matrix">Matrix</a> may also have translation. <a href="#Matrix">Matrix</a> form is either: 575 576 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 577 | scale-x 0 translate-x | 578 | 0 scale-y translate-y | 579 | 0 0 1 |</pre> 580 581 or 582 583 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 584 | 0 rotate-x translate-x | 585 | rotate-y 0 translate-y | 586 | 0 0 1 |</pre> 587 588 for non-zero values of scale-x, scale-y, rotate-x, and rotate-y. 589 590 Also called <a href="#SkMatrix_preservesAxisAlignment">preservesAxisAlignment</a>; use the one that provides better inline 591 documentation. 592 593 ### Return Value 594 595 true if <a href="#Matrix">Matrix</a> maps one <a href="SkRect_Reference#Rect">Rect</a> into another 596 597 ### Example 598 599 <div><fiddle-embed name="ce5319c036c9b5086da8a0009fe409f8"> 600 601 #### Example Output 602 603 ~~~~ 604 rectStaysRect: true 605 rectStaysRect: true 606 rectStaysRect: true 607 rectStaysRect: true 608 ~~~~ 609 610 </fiddle-embed></div> 611 612 ### See Also 613 614 <a href="#SkMatrix_preservesAxisAlignment">preservesAxisAlignment</a> <a href="#SkMatrix_preservesRightAngles">preservesRightAngles</a> 615 616 --- 617 618 <a name="SkMatrix_preservesAxisAlignment"></a> 619 ## preservesAxisAlignment 620 621 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 622 bool preservesAxisAlignment() const 623 </pre> 624 625 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, 626 or scales, or rotates a multiple of 90 degrees, or mirrors in x or y. In all 627 cases, <a href="#Matrix">Matrix</a> may also have translation. <a href="#Matrix">Matrix</a> form is either: 628 629 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 630 | scale-x 0 translate-x | 631 | 0 scale-y translate-y | 632 | 0 0 1 |</pre> 633 634 or 635 636 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 637 | 0 rotate-x translate-x | 638 | rotate-y 0 translate-y | 639 | 0 0 1 |</pre> 640 641 for non-zero values of scale-x, scale-y, rotate-x, and rotate-y. 642 643 Also called <a href="#SkMatrix_rectStaysRect">rectStaysRect</a>; use the one that provides better inline 644 documentation. 645 646 ### Return Value 647 648 true if <a href="#Matrix">Matrix</a> maps one <a href="SkRect_Reference#Rect">Rect</a> into another 649 650 ### Example 651 652 <div><fiddle-embed name="7a234c96608fb7cb8135b9940b0b15f7"> 653 654 #### Example Output 655 656 ~~~~ 657 preservesAxisAlignment: true 658 preservesAxisAlignment: true 659 preservesAxisAlignment: true 660 preservesAxisAlignment: true 661 ~~~~ 662 663 </fiddle-embed></div> 664 665 ### See Also 666 667 <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> <a href="#SkMatrix_preservesRightAngles">preservesRightAngles</a> 668 669 --- 670 671 <a name="SkMatrix_hasPerspective"></a> 672 ## hasPerspective 673 674 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 675 bool hasPerspective() const 676 </pre> 677 678 Returns true if the matrix contains perspective elements. <a href="#Matrix">Matrix</a> form is: 679 680 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 681 | -- -- -- | 682 | -- -- -- | 683 | perspective-x perspective-y perspective-scale |</pre> 684 685 where perspective-x or perspective-y is non-zero, or perspective-scale is 686 not one. All other elements may have any value. 687 688 ### Return Value 689 690 true if <a href="#Matrix">Matrix</a> is in most general form 691 692 ### Example 693 694 <div><fiddle-embed name="688123908c733169bbbfaf11f41ecff6"></fiddle-embed></div> 695 696 ### See Also 697 698 <a href="#SkMatrix_setAll">setAll</a> <a href="#SkMatrix_set9">set9</a> <a href="#SkMatrix_MakeAll">MakeAll</a> 699 700 --- 701 702 <a name="SkMatrix_isSimilarity"></a> 703 ## isSimilarity 704 705 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 706 bool isSimilarity(SkScalar tol = SK_ScalarNearlyZero) const 707 </pre> 708 709 Returns true if <a href="#Matrix">Matrix</a> contains only translation, rotation, reflection, and 710 uniform scale. 711 Returns false if <a href="#Matrix">Matrix</a> contains different scales, skewing, perspective, or 712 degenerate forms that collapse to a line or point. 713 714 Describes that the <a href="#Matrix">Matrix</a> makes rendering with and without the matrix are 715 visually alike; a transformed circle remains a circle. Mathematically, this is 716 referred to as similarity of a Euclidean_Space, or a similarity transformation. 717 718 Preserves right angles, keeping the arms of the angle equal lengths. 719 720 ### Parameters 721 722 <table> <tr> <td><a name="SkMatrix_isSimilarity_tol"> <code><strong>tol </strong></code> </a></td> <td> 723 to be deprecated</td> 724 </tr> 725 </table> 726 727 ### Return Value 728 729 true if <a href="#Matrix">Matrix</a> only rotates, uniformly scales, translates 730 731 ### Example 732 733 <div><fiddle-embed name="98d60230ad633ae74d851de3a65d72d6"><div><a href="undocumented#String">String</a> is drawn four times through but only two are visible. Drawing the pair 734 with <a href="#SkMatrix_isSimilarity">isSimilarity</a> false reveals the pair not visible through the matrix.</div></fiddle-embed></div> 735 736 ### See Also 737 738 <a href="#SkMatrix_isScaleTranslate">isScaleTranslate</a> <a href="#SkMatrix_preservesRightAngles">preservesRightAngles</a> <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> 739 740 --- 741 742 <a name="SkMatrix_preservesRightAngles"></a> 743 ## preservesRightAngles 744 745 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 746 bool preservesRightAngles(SkScalar tol = SK_ScalarNearlyZero) const 747 </pre> 748 749 Returns true if <a href="#Matrix">Matrix</a> contains only translation, rotation, reflection, and 750 scale. Scale may differ along rotated axes. 751 Returns false if <a href="#Matrix">Matrix</a> skewing, perspective, or degenerate forms that collapse 752 to a line or point. 753 754 Preserves right angles, but not requiring that the arms of the angle 755 retain equal lengths. 756 757 ### Parameters 758 759 <table> <tr> <td><a name="SkMatrix_preservesRightAngles_tol"> <code><strong>tol </strong></code> </a></td> <td> 760 to be deprecated</td> 761 </tr> 762 </table> 763 764 ### Return Value 765 766 true if <a href="#Matrix">Matrix</a> only rotates, scales, translates 767 768 ### Example 769 770 <div><fiddle-embed name="a3d5bfebc1c3423fb983d30aaf4ac5f4"><div>Equal scale is both similar and preserves right angles. 771 Unequal scale is not similar but preserves right angles. 772 Skews are not similar and do not preserve right angles.</div></fiddle-embed></div> 773 774 ### See Also 775 776 <a href="#SkMatrix_isScaleTranslate">isScaleTranslate</a> <a href="#SkMatrix_isSimilarity">isSimilarity</a> <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> 777 778 --- 779 780 ## <a name="SkMatrix__anonymous"></a> Enum SkMatrix::_anonymous 781 782 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 783 enum { 784 <a href="#SkMatrix_kMScaleX">kMScaleX</a>, 785 <a href="#SkMatrix_kMSkewX">kMSkewX</a>, 786 <a href="#SkMatrix_kMTransX">kMTransX</a>, 787 <a href="#SkMatrix_kMSkewY">kMSkewY</a>, 788 <a href="#SkMatrix_kMScaleY">kMScaleY</a>, 789 <a href="#SkMatrix_kMTransY">kMTransY</a>, 790 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, 791 <a href="#SkMatrix_kMPersp1">kMPersp1</a>, 792 <a href="#SkMatrix_kMPersp2">kMPersp2</a>, 793 };</pre> 794 795 <a href="#Matrix">Matrix</a> organizes its values in row order. These members correspond to 796 each value in <a href="#Matrix">Matrix</a>. 797 798 ### Constants 799 800 <table> 801 <tr> 802 <td><a name="SkMatrix_kMScaleX"> <code><strong>SkMatrix::kMScaleX </strong></code> </a></td><td>0</td><td>horizontal scale factor</td> 803 </tr> 804 <tr> 805 <td><a name="SkMatrix_kMSkewX"> <code><strong>SkMatrix::kMSkewX </strong></code> </a></td><td>1</td><td>horizontal skew factor</td> 806 </tr> 807 <tr> 808 <td><a name="SkMatrix_kMTransX"> <code><strong>SkMatrix::kMTransX </strong></code> </a></td><td>2</td><td>horizontal translation</td> 809 </tr> 810 <tr> 811 <td><a name="SkMatrix_kMSkewY"> <code><strong>SkMatrix::kMSkewY </strong></code> </a></td><td>3</td><td>vertical skew factor</td> 812 </tr> 813 <tr> 814 <td><a name="SkMatrix_kMScaleY"> <code><strong>SkMatrix::kMScaleY </strong></code> </a></td><td>4</td><td>vertical scale factor</td> 815 </tr> 816 <tr> 817 <td><a name="SkMatrix_kMTransY"> <code><strong>SkMatrix::kMTransY </strong></code> </a></td><td>5</td><td>vertical translation</td> 818 </tr> 819 <tr> 820 <td><a name="SkMatrix_kMPersp0"> <code><strong>SkMatrix::kMPersp0 </strong></code> </a></td><td>6</td><td>input x perspective factor</td> 821 </tr> 822 <tr> 823 <td><a name="SkMatrix_kMPersp1"> <code><strong>SkMatrix::kMPersp1 </strong></code> </a></td><td>7</td><td>input y perspective factor</td> 824 </tr> 825 <tr> 826 <td><a name="SkMatrix_kMPersp2"> <code><strong>SkMatrix::kMPersp2 </strong></code> </a></td><td>8</td><td>perspective bias</td> 827 </tr> 828 </table> 829 830 ### Example 831 832 <div><fiddle-embed name="3bbf75f4748420810aa2586e3c8548d9"></fiddle-embed></div> 833 834 ### See Also 835 836 <a href="#SkMatrix_get">get</a> <a href="#SkMatrix_set">set</a> 837 838 839 840 ## <a name="SkMatrix__anonymous_2"></a> Enum SkMatrix::_anonymous_2 841 842 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 843 enum { 844 <a href="#SkMatrix_kAScaleX">kAScaleX</a>, 845 <a href="#SkMatrix_kASkewY">kASkewY</a>, 846 <a href="#SkMatrix_kASkewX">kASkewX</a>, 847 <a href="#SkMatrix_kAScaleY">kAScaleY</a>, 848 <a href="#SkMatrix_kATransX">kATransX</a>, 849 <a href="#SkMatrix_kATransY">kATransY</a>, 850 };</pre> 851 852 Affine arrays are in column major order to match the matrix used by 853 PDF and XPS. 854 855 ### Constants 856 857 <table> 858 <tr> 859 <td><a name="SkMatrix_kAScaleX"> <code><strong>SkMatrix::kAScaleX </strong></code> </a></td><td>0</td><td>horizontal scale factor</td> 860 </tr> 861 <tr> 862 <td><a name="SkMatrix_kASkewY"> <code><strong>SkMatrix::kASkewY </strong></code> </a></td><td>1</td><td>vertical skew factor</td> 863 </tr> 864 <tr> 865 <td><a name="SkMatrix_kASkewX"> <code><strong>SkMatrix::kASkewX </strong></code> </a></td><td>2</td><td>horizontal skew factor</td> 866 </tr> 867 <tr> 868 <td><a name="SkMatrix_kAScaleY"> <code><strong>SkMatrix::kAScaleY </strong></code> </a></td><td>3</td><td>vertical scale factor</td> 869 </tr> 870 <tr> 871 <td><a name="SkMatrix_kATransX"> <code><strong>SkMatrix::kATransX </strong></code> </a></td><td>4</td><td>horizontal translation</td> 872 </tr> 873 <tr> 874 <td><a name="SkMatrix_kATransY"> <code><strong>SkMatrix::kATransY </strong></code> </a></td><td>5</td><td>vertical translation</td> 875 </tr> 876 </table> 877 878 ### See Also 879 880 <a href="#SkMatrix_SetAffineIdentity">SetAffineIdentity</a> <a href="#SkMatrix_asAffine">asAffine</a> <a href="#SkMatrix_setAffine">setAffine</a> 881 882 883 884 ## <a name="Operator"></a> Operator 885 886 | name | description | 887 | --- | --- | 888 | <a href="#SkMatrix_Concat">Concat</a> | returns the concatenation of <a href="#Matrix">Matrix</a> pair | 889 | <a href="#SkMatrix_cheapEqualTo">cheapEqualTo</a> | compares <a href="#Matrix">Matrix</a> pair using memcmp() | 890 | <a href="#SkMatrix_invert">invert</a> | returns inverse, if possible | 891 | <a href="#SkMatrix_notequal_operator">operator!=(const SkMatrix& a, const SkMatrix& b)</a> | returns true if members are unequal | 892 | <a href="#SkMatrix_equal_operator">operator==(const SkMatrix& a, const SkMatrix& b)</a> | returns true if members are equal | 893 | <a href="#SkMatrix_array1_operator">operator[](int index)</a> | returns writable reference to <a href="#Matrix">Matrix</a> value | 894 | <a href="#SkMatrix_array_operator">operator[](int index) const</a> | returns <a href="#Matrix">Matrix</a> value | 895 896 <a name="SkMatrix_array_operator"></a> 897 ## operator[] 898 899 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 900 SkScalar operator[](int index) _const 901 </pre> 902 903 Returns one matrix value. Asserts if <a href="#SkMatrix_array_operator_index">index</a> is out of range and SK_DEBUG is 904 defined. 905 906 ### Parameters 907 908 <table> <tr> <td><a name="SkMatrix_array_operator_index"> <code><strong>index </strong></code> </a></td> <td> 909 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>, 910 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, <a href="#SkMatrix_kMPersp1">kMPersp1</a>, <a href="#SkMatrix_kMPersp2">kMPersp2</a></td> 911 </tr> 912 </table> 913 914 ### Return Value 915 916 value corresponding to <a href="#SkMatrix_array_operator_index">index</a> 917 918 ### Example 919 920 <div><fiddle-embed name="e8740493abdf0c6341762db9cee56b89"> 921 922 #### Example Output 923 924 ~~~~ 925 matrix[SkMatrix::kMScaleX] == 42 926 matrix[SkMatrix::kMScaleY] == 24 927 ~~~~ 928 929 </fiddle-embed></div> 930 931 ### See Also 932 933 <a href="#SkMatrix_get">get</a> <a href="#SkMatrix_set">set</a> 934 935 --- 936 937 <a name="SkMatrix_get"></a> 938 ## get 939 940 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 941 SkScalar get(int index) const 942 </pre> 943 944 Returns one matrix value. Asserts if <a href="#SkMatrix_get_index">index</a> is out of range and SK_DEBUG is 945 defined. 946 947 ### Parameters 948 949 <table> <tr> <td><a name="SkMatrix_get_index"> <code><strong>index </strong></code> </a></td> <td> 950 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>, 951 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, <a href="#SkMatrix_kMPersp1">kMPersp1</a>, <a href="#SkMatrix_kMPersp2">kMPersp2</a></td> 952 </tr> 953 </table> 954 955 ### Return Value 956 957 value corresponding to <a href="#SkMatrix_get_index">index</a> 958 959 ### Example 960 961 <div><fiddle-embed name="f5ed382bd04fa7d50b2398cce2fca23a"> 962 963 #### Example Output 964 965 ~~~~ 966 matrix.get(SkMatrix::kMSkewX) == 42 967 matrix.get(SkMatrix::kMSkewY) == 24 968 ~~~~ 969 970 </fiddle-embed></div> 971 972 ### See Also 973 974 <a href="#SkMatrix_array1_operator">operator[](int index)</a> <a href="#SkMatrix_set">set</a> 975 976 --- 977 978 <a name="SkMatrix_getScaleX"></a> 979 ## getScaleX 980 981 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 982 SkScalar getScaleX() const 983 </pre> 984 985 Returns scale factor multiplied by x input, contributing to x output. 986 With <a href="#SkMatrix_mapPoints">mapPoints</a>, scales <a href="SkPoint_Reference#Point">Points</a> along the x-axis. 987 988 ### Return Value 989 990 horizontal scale factor 991 992 ### Example 993 994 <div><fiddle-embed name="ab746d9be63975041ae8e50cba84dc3d"> 995 996 #### Example Output 997 998 ~~~~ 999 matrix.getScaleX() == 42 1000 ~~~~ 1001 1002 </fiddle-embed></div> 1003 1004 ### See Also 1005 1006 <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> 1007 1008 --- 1009 1010 <a name="SkMatrix_getScaleY"></a> 1011 ## getScaleY 1012 1013 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1014 SkScalar getScaleY() const 1015 </pre> 1016 1017 Returns scale factor multiplied by y input, contributing to y output. 1018 With <a href="#SkMatrix_mapPoints">mapPoints</a>, scales <a href="SkPoint_Reference#Point">Points</a> along the y-axis. 1019 1020 ### Return Value 1021 1022 vertical scale factor 1023 1024 ### Example 1025 1026 <div><fiddle-embed name="708b1a548a2f8661b2ab570782fbc751"> 1027 1028 #### Example Output 1029 1030 ~~~~ 1031 matrix.getScaleY() == 24 1032 ~~~~ 1033 1034 </fiddle-embed></div> 1035 1036 ### See Also 1037 1038 <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> 1039 1040 --- 1041 1042 <a name="SkMatrix_getSkewY"></a> 1043 ## getSkewY 1044 1045 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1046 SkScalar getSkewY() const 1047 </pre> 1048 1049 Returns scale factor multiplied by x input, contributing to y output. 1050 With <a href="#SkMatrix_mapPoints">mapPoints</a>, skews <a href="SkPoint_Reference#Point">Points</a> along the y-axis. 1051 Skew x and y together can rotate <a href="SkPoint_Reference#Point">Points</a>. 1052 1053 ### Return Value 1054 1055 vertical skew factor 1056 1057 ### Example 1058 1059 <div><fiddle-embed name="6be5704506d029ffc91ba03b1d3e674b"> 1060 1061 #### Example Output 1062 1063 ~~~~ 1064 matrix.getSkewY() == 24 1065 ~~~~ 1066 1067 </fiddle-embed></div> 1068 1069 ### See Also 1070 1071 <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> 1072 1073 --- 1074 1075 <a name="SkMatrix_getSkewX"></a> 1076 ## getSkewX 1077 1078 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1079 SkScalar getSkewX() const 1080 </pre> 1081 1082 Returns scale factor multiplied by y input, contributing to x output. 1083 With <a href="#SkMatrix_mapPoints">mapPoints</a>, skews <a href="SkPoint_Reference#Point">Points</a> along the x-axis. 1084 Skew x and y together can rotate <a href="SkPoint_Reference#Point">Points</a>. 1085 1086 ### Return Value 1087 1088 horizontal scale factor 1089 1090 ### Example 1091 1092 <div><fiddle-embed name="df3a5d3c688e7597eae1e4e07bf91ae6"> 1093 1094 #### Example Output 1095 1096 ~~~~ 1097 matrix.getSkewX() == 42 1098 ~~~~ 1099 1100 </fiddle-embed></div> 1101 1102 ### See Also 1103 1104 <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> 1105 1106 --- 1107 1108 <a name="SkMatrix_getTranslateX"></a> 1109 ## getTranslateX 1110 1111 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1112 SkScalar getTranslateX() const 1113 </pre> 1114 1115 Returns translation contributing to x output. 1116 With <a href="#SkMatrix_mapPoints">mapPoints</a>, moves <a href="SkPoint_Reference#Point">Points</a> along the x-axis. 1117 1118 ### Return Value 1119 1120 horizontal translation factor 1121 1122 ### Example 1123 1124 <div><fiddle-embed name="6236f7f2b91aff977a66ba2ee2558ca4"> 1125 1126 #### Example Output 1127 1128 ~~~~ 1129 matrix.getTranslateX() == 42 1130 ~~~~ 1131 1132 </fiddle-embed></div> 1133 1134 ### See Also 1135 1136 <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> 1137 1138 --- 1139 1140 <a name="SkMatrix_getTranslateY"></a> 1141 ## getTranslateY 1142 1143 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1144 SkScalar getTranslateY() const 1145 </pre> 1146 1147 Returns translation contributing to y output. 1148 With <a href="#SkMatrix_mapPoints">mapPoints</a>, moves <a href="SkPoint_Reference#Point">Points</a> along the y-axis. 1149 1150 ### Return Value 1151 1152 vertical translation factor 1153 1154 ### Example 1155 1156 <div><fiddle-embed name="08464e32d22421d2b254c71a84545ef5"> 1157 1158 #### Example Output 1159 1160 ~~~~ 1161 matrix.getTranslateY() == 24 1162 ~~~~ 1163 1164 </fiddle-embed></div> 1165 1166 ### See Also 1167 1168 <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> 1169 1170 --- 1171 1172 <a name="SkMatrix_getPerspX"></a> 1173 ## getPerspX 1174 1175 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1176 SkScalar getPerspX() const 1177 </pre> 1178 1179 Returns factor scaling input x relative to input y. 1180 1181 ### Return Value 1182 1183 input x perspective factor 1184 1185 ### Example 1186 1187 <div><fiddle-embed name="a0f5bf4b55e8c33bfda29bf67e34306f"></fiddle-embed></div> 1188 1189 ### See Also 1190 1191 <a href="#SkMatrix_kMPersp0">kMPersp0</a> <a href="#SkMatrix_getPerspY">getPerspY</a> 1192 1193 --- 1194 1195 <a name="SkMatrix_getPerspY"></a> 1196 ## getPerspY 1197 1198 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1199 SkScalar getPerspY() const 1200 </pre> 1201 1202 Returns factor scaling input y relative to input x. 1203 1204 ### Return Value 1205 1206 input y perspective factor 1207 1208 ### Example 1209 1210 <div><fiddle-embed name="424a00a73675dbd99ad20feb0267442b"></fiddle-embed></div> 1211 1212 ### See Also 1213 1214 <a href="#SkMatrix_kMPersp1">kMPersp1</a> <a href="#SkMatrix_getPerspX">getPerspX</a> 1215 1216 --- 1217 1218 <a name="SkMatrix_array1_operator"></a> 1219 ## operator[] 1220 1221 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1222 SkScalar& operator[](int index) 1223 </pre> 1224 1225 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 1226 defined. Clears internal cache anticipating that caller will change <a href="#Matrix">Matrix</a> value. 1227 1228 Next call to read <a href="#Matrix">Matrix</a> state may recompute cache; subsequent writes to <a href="#Matrix">Matrix</a> 1229 value must be followed by <a href="#SkMatrix_dirtyMatrixTypeCache">dirtyMatrixTypeCache</a>. 1230 1231 ### Parameters 1232 1233 <table> <tr> <td><a name="SkMatrix_array1_operator_index"> <code><strong>index </strong></code> </a></td> <td> 1234 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>, 1235 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, <a href="#SkMatrix_kMPersp1">kMPersp1</a>, <a href="#SkMatrix_kMPersp2">kMPersp2</a></td> 1236 </tr> 1237 </table> 1238 1239 ### Return Value 1240 1241 writable value corresponding to <a href="#SkMatrix_array1_operator_index">index</a> 1242 1243 ### Example 1244 1245 <div><fiddle-embed name="f4365ef332f51f7fd25040e0771ba9a2"> 1246 1247 #### Example Output 1248 1249 ~~~~ 1250 with identity matrix: x = 24 1251 after skew x mod: x = 24 1252 after 2nd skew x mod: x = 24 1253 after dirty cache: x = 66 1254 ~~~~ 1255 1256 </fiddle-embed></div> 1257 1258 ### See Also 1259 1260 <a href="#SkMatrix_get">get</a> <a href="#SkMatrix_dirtyMatrixTypeCache">dirtyMatrixTypeCache</a> <a href="#SkMatrix_set">set</a> 1261 1262 --- 1263 1264 ## <a name="Set"></a> Set 1265 1266 | name | description | 1267 | --- | --- | 1268 | <a href="#SkMatrix_postConcat">postConcat</a> | post-multiplies <a href="#Matrix">Matrix</a> by <a href="#Matrix">Matrix</a> parameter | 1269 | <a href="#SkMatrix_postIDiv">postIDiv</a> | post-multiplies <a href="#Matrix">Matrix</a> by inverse scale | 1270 | <a href="#SkMatrix_postRotate">postRotate</a> | post-multiplies <a href="#Matrix">Matrix</a> by rotation | 1271 | | <a href="#SkMatrix_postRotate">postRotate(SkScalar degrees, SkScalar px, SkScalar py)</a> | 1272 | | <a href="#SkMatrix_postRotate_2">postRotate(SkScalar degrees)</a> | 1273 | <a href="#SkMatrix_postScale">postScale</a> | post-multiplies <a href="#Matrix">Matrix</a> by scale | 1274 | | <a href="#SkMatrix_postScale">postScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a> | 1275 | | <a href="#SkMatrix_postScale_2">postScale(SkScalar sx, SkScalar sy)</a> | 1276 | <a href="#SkMatrix_postSkew">postSkew</a> | post-multiplies <a href="#Matrix">Matrix</a> by skew | 1277 | | <a href="#SkMatrix_postSkew">postSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a> | 1278 | | <a href="#SkMatrix_postSkew_2">postSkew(SkScalar kx, SkScalar ky)</a> | 1279 | <a href="#SkMatrix_postTranslate">postTranslate</a> | post-multiplies <a href="#Matrix">Matrix</a> by translation | 1280 | <a href="#SkMatrix_preConcat">preConcat</a> | pre-multiplies <a href="#Matrix">Matrix</a> by <a href="#Matrix">Matrix</a> parameter | 1281 | <a href="#SkMatrix_preRotate">preRotate</a> | pre-multiplies <a href="#Matrix">Matrix</a> by rotation | 1282 | | <a href="#SkMatrix_preRotate">preRotate(SkScalar degrees, SkScalar px, SkScalar py)</a> | 1283 | | <a href="#SkMatrix_preRotate_2">preRotate(SkScalar degrees)</a> | 1284 | <a href="#SkMatrix_preScale">preScale</a> | pre-multiplies <a href="#Matrix">Matrix</a> by scale | 1285 | | <a href="#SkMatrix_preScale">preScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py)</a> | 1286 | | <a href="#SkMatrix_preScale_2">preScale(SkScalar sx, SkScalar sy)</a> | 1287 | <a href="#SkMatrix_preSkew">preSkew</a> | pre-multiplies <a href="#Matrix">Matrix</a> by skew | 1288 | | <a href="#SkMatrix_preSkew">preSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py)</a> | 1289 | | <a href="#SkMatrix_preSkew_2">preSkew(SkScalar kx, SkScalar ky)</a> | 1290 | <a href="#SkMatrix_preTranslate">preTranslate</a> | pre-multiplies <a href="#Matrix">Matrix</a> by translation | 1291 | <a href="#SkMatrix_set">set</a> | sets one value | 1292 | <a href="#SkMatrix_set9">set9</a> | sets all values from <a href="undocumented#Scalar">Scalar</a> array | 1293 | <a href="#SkMatrix_setAll">setAll</a> | sets all values from parameters | 1294 | <a href="#SkMatrix_setPerspX">setPerspX</a> | sets input x perspective factor | 1295 | <a href="#SkMatrix_setPerspY">setPerspY</a> | sets input y perspective factor | 1296 | <a href="#SkMatrix_setPolyToPoly">setPolyToPoly</a> | sets to map one to four points to an equal array of points | 1297 | <a href="#SkMatrix_setRectToRect">setRectToRect</a> | sets to map one <a href="SkRect_Reference#Rect">Rect</a> to another | 1298 | <a href="#SkMatrix_setScaleX">setScaleX</a> | sets horizontal scale factor | 1299 | <a href="#SkMatrix_setScaleY">setScaleY</a> | sets vertical scale factor | 1300 | <a href="#SkMatrix_setSkewX">setSkewX</a> | sets horizontal skew factor | 1301 | <a href="#SkMatrix_setSkewY">setSkewY</a> | sets vertical skew factor | 1302 | <a href="#SkMatrix_setTranslateX">setTranslateX</a> | sets horizontal translation | 1303 | <a href="#SkMatrix_setTranslateY">setTranslateY</a> | sets vertical translation | 1304 1305 <a name="SkMatrix_set"></a> 1306 ## set 1307 1308 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1309 void set(int index, SkScalar value) 1310 </pre> 1311 1312 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 1313 defined. Safer than operator[]; internal cache is always maintained. 1314 1315 ### Parameters 1316 1317 <table> <tr> <td><a name="SkMatrix_set_index"> <code><strong>index </strong></code> </a></td> <td> 1318 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>, 1319 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, <a href="#SkMatrix_kMPersp1">kMPersp1</a>, <a href="#SkMatrix_kMPersp2">kMPersp2</a></td> 1320 </tr> <tr> <td><a name="SkMatrix_set_value"> <code><strong>value </strong></code> </a></td> <td> 1321 <a href="undocumented#Scalar">Scalar</a> to store in <a href="#Matrix">Matrix</a></td> 1322 </tr> 1323 </table> 1324 1325 ### Example 1326 1327 <div><fiddle-embed name="1d400a92ca826cc89bcb88ea051f28c8"> 1328 1329 #### Example Output 1330 1331 ~~~~ 1332 with identity matrix: x = 24 1333 after skew x mod: x = 24 1334 after 2nd skew x mod: x = 66 1335 ~~~~ 1336 1337 </fiddle-embed></div> 1338 1339 ### See Also 1340 1341 operator[] <a href="#SkMatrix_get">get</a> 1342 1343 --- 1344 1345 <a name="SkMatrix_setScaleX"></a> 1346 ## setScaleX 1347 1348 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1349 void setScaleX(SkScalar v) 1350 </pre> 1351 1352 Sets horizontal scale factor. 1353 1354 ### Parameters 1355 1356 <table> <tr> <td><a name="SkMatrix_setScaleX_v"> <code><strong>v </strong></code> </a></td> <td> 1357 horizontal scale factor to store</td> 1358 </tr> 1359 </table> 1360 1361 ### Example 1362 1363 <div><fiddle-embed name="a39dfed98c3c3c3a56be9ad59fe4e21e"></fiddle-embed></div> 1364 1365 ### See Also 1366 1367 <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> 1368 1369 --- 1370 1371 <a name="SkMatrix_setScaleY"></a> 1372 ## setScaleY 1373 1374 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1375 void setScaleY(SkScalar v) 1376 </pre> 1377 1378 Sets vertical scale factor. 1379 1380 ### Parameters 1381 1382 <table> <tr> <td><a name="SkMatrix_setScaleY_v"> <code><strong>v </strong></code> </a></td> <td> 1383 vertical scale factor to store</td> 1384 </tr> 1385 </table> 1386 1387 ### Example 1388 1389 <div><fiddle-embed name="f040c6dd85a02e94eaca00d5c2832604"></fiddle-embed></div> 1390 1391 ### See Also 1392 1393 <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> 1394 1395 --- 1396 1397 <a name="SkMatrix_setSkewY"></a> 1398 ## setSkewY 1399 1400 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1401 void setSkewY(SkScalar v) 1402 </pre> 1403 1404 Sets vertical skew factor. 1405 1406 ### Parameters 1407 1408 <table> <tr> <td><a name="SkMatrix_setSkewY_v"> <code><strong>v </strong></code> </a></td> <td> 1409 vertical skew factor to store</td> 1410 </tr> 1411 </table> 1412 1413 ### Example 1414 1415 <div><fiddle-embed name="b418d15df9829aefcc6aca93a37428bb"></fiddle-embed></div> 1416 1417 ### See Also 1418 1419 <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> 1420 1421 --- 1422 1423 <a name="SkMatrix_setSkewX"></a> 1424 ## setSkewX 1425 1426 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1427 void setSkewX(SkScalar v) 1428 </pre> 1429 1430 Sets horizontal skew factor. 1431 1432 ### Parameters 1433 1434 <table> <tr> <td><a name="SkMatrix_setSkewX_v"> <code><strong>v </strong></code> </a></td> <td> 1435 horizontal skew factor to store</td> 1436 </tr> 1437 </table> 1438 1439 ### Example 1440 1441 <div><fiddle-embed name="c7177a6fbc1545be95a5ebca87e0cd0d"></fiddle-embed></div> 1442 1443 ### See Also 1444 1445 <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> 1446 1447 --- 1448 1449 <a name="SkMatrix_setTranslateX"></a> 1450 ## setTranslateX 1451 1452 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1453 void setTranslateX(SkScalar v) 1454 </pre> 1455 1456 Sets horizontal translation. 1457 1458 ### Parameters 1459 1460 <table> <tr> <td><a name="SkMatrix_setTranslateX_v"> <code><strong>v </strong></code> </a></td> <td> 1461 horizontal translation to store</td> 1462 </tr> 1463 </table> 1464 1465 ### Example 1466 1467 <div><fiddle-embed name="a18bc2e3607ac3a8e438bcb61fb13130"></fiddle-embed></div> 1468 1469 ### See Also 1470 1471 <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> 1472 1473 --- 1474 1475 <a name="SkMatrix_setTranslateY"></a> 1476 ## setTranslateY 1477 1478 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1479 void setTranslateY(SkScalar v) 1480 </pre> 1481 1482 Sets vertical translation. 1483 1484 ### Parameters 1485 1486 <table> <tr> <td><a name="SkMatrix_setTranslateY_v"> <code><strong>v </strong></code> </a></td> <td> 1487 vertical translation to store</td> 1488 </tr> 1489 </table> 1490 1491 ### Example 1492 1493 <div><fiddle-embed name="34e3c70a72b836abf7f4858d35eecc98"></fiddle-embed></div> 1494 1495 ### See Also 1496 1497 <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> 1498 1499 --- 1500 1501 <a name="SkMatrix_setPerspX"></a> 1502 ## setPerspX 1503 1504 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1505 void setPerspX(SkScalar v) 1506 </pre> 1507 1508 Sets input x perspective factor, which causes <a href="#SkMatrix_mapXY">mapXY</a> to vary input x inversely 1509 proportional to input y. 1510 1511 ### Parameters 1512 1513 <table> <tr> <td><a name="SkMatrix_setPerspX_v"> <code><strong>v </strong></code> </a></td> <td> 1514 perspective factor</td> 1515 </tr> 1516 </table> 1517 1518 ### Example 1519 1520 <div><fiddle-embed name="830a9e4e4bb93d25afd83b2fea63929e"></fiddle-embed></div> 1521 1522 ### See Also 1523 1524 <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> 1525 1526 --- 1527 1528 <a name="SkMatrix_setPerspY"></a> 1529 ## setPerspY 1530 1531 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1532 void setPerspY(SkScalar v) 1533 </pre> 1534 1535 Sets input y perspective factor, which causes <a href="#SkMatrix_mapXY">mapXY</a> to vary input y inversely 1536 proportional to input x. 1537 1538 ### Parameters 1539 1540 <table> <tr> <td><a name="SkMatrix_setPerspY_v"> <code><strong>v </strong></code> </a></td> <td> 1541 perspective factor</td> 1542 </tr> 1543 </table> 1544 1545 ### Example 1546 1547 <div><fiddle-embed name="aeb258b7922c1a11b698b00f562182ec"></fiddle-embed></div> 1548 1549 ### See Also 1550 1551 <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> 1552 1553 --- 1554 1555 <a name="SkMatrix_setAll"></a> 1556 ## setAll 1557 1558 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1559 void setAll(SkScalar scaleX, SkScalar skewX, SkScalar transX, SkScalar skewY, SkScalar scaleY, 1560 SkScalar transY, SkScalar persp0, SkScalar persp1, SkScalar persp2) 1561 </pre> 1562 1563 Sets all values from parameters. Sets matrix to: 1564 1565 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1566 | scaleX skewX transX | 1567 | skewY scaleY transY | 1568 | persp0 persp1 persp2 |</pre> 1569 1570 ### Parameters 1571 1572 <table> <tr> <td><a name="SkMatrix_setAll_scaleX"> <code><strong>scaleX </strong></code> </a></td> <td> 1573 horizontal scale factor to store</td> 1574 </tr> <tr> <td><a name="SkMatrix_setAll_skewX"> <code><strong>skewX </strong></code> </a></td> <td> 1575 horizontal skew factor to store</td> 1576 </tr> <tr> <td><a name="SkMatrix_setAll_transX"> <code><strong>transX </strong></code> </a></td> <td> 1577 horizontal translation to store</td> 1578 </tr> <tr> <td><a name="SkMatrix_setAll_skewY"> <code><strong>skewY </strong></code> </a></td> <td> 1579 vertical skew factor to store</td> 1580 </tr> <tr> <td><a name="SkMatrix_setAll_scaleY"> <code><strong>scaleY </strong></code> </a></td> <td> 1581 vertical scale factor to store</td> 1582 </tr> <tr> <td><a name="SkMatrix_setAll_transY"> <code><strong>transY </strong></code> </a></td> <td> 1583 vertical translation to store</td> 1584 </tr> <tr> <td><a name="SkMatrix_setAll_persp0"> <code><strong>persp0 </strong></code> </a></td> <td> 1585 input x perspective factor to store</td> 1586 </tr> <tr> <td><a name="SkMatrix_setAll_persp1"> <code><strong>persp1 </strong></code> </a></td> <td> 1587 input y perspective factor to store</td> 1588 </tr> <tr> <td><a name="SkMatrix_setAll_persp2"> <code><strong>persp2 </strong></code> </a></td> <td> 1589 perspective scale factor to store</td> 1590 </tr> 1591 </table> 1592 1593 ### Example 1594 1595 <div><fiddle-embed name="95ccfc2a89ce593e6b7a9f992a844bc0"></fiddle-embed></div> 1596 1597 ### See Also 1598 1599 <a href="#SkMatrix_set9">set9</a> <a href="#SkMatrix_MakeAll">MakeAll</a> 1600 1601 --- 1602 1603 <a name="SkMatrix_get9"></a> 1604 ## get9 1605 1606 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1607 void get9(SkScalar buffer[9]) const 1608 </pre> 1609 1610 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 1611 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>, 1612 <a href="#SkMatrix_kMPersp0">kMPersp0</a>, <a href="#SkMatrix_kMPersp1">kMPersp1</a>, <a href="#SkMatrix_kMPersp2">kMPersp2</a>. 1613 1614 ### Parameters 1615 1616 <table> <tr> <td><a name="SkMatrix_get9_buffer"> <code><strong>buffer </strong></code> </a></td> <td> 1617 storage for nine <a href="undocumented#Scalar">Scalar</a> values</td> 1618 </tr> 1619 </table> 1620 1621 ### Example 1622 1623 <div><fiddle-embed name="df509d73b47cb98b0475e4465db7b246"> 1624 1625 #### Example Output 1626 1627 ~~~~ 1628 {4, 0, 3}, 1629 {0, 5, 4}, 1630 {0, 0, 1} 1631 ~~~~ 1632 1633 </fiddle-embed></div> 1634 1635 ### See Also 1636 1637 <a href="#SkMatrix_set9">set9</a> 1638 1639 --- 1640 1641 <a name="SkMatrix_set9"></a> 1642 ## set9 1643 1644 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1645 void set9(const SkScalar buffer[9]) 1646 </pre> 1647 1648 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: 1649 <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>, 1650 <a href="#SkMatrix_kMPersp2">kMPersp2</a>. 1651 1652 Sets matrix to: 1653 1654 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1655 | buffer[0] buffer[1] buffer[2] | 1656 | buffer[3] buffer[4] buffer[5] | 1657 | buffer[6] buffer[7] buffer[8] |</pre> 1658 1659 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> 1660 maps non-homogeneous coordinates, scaling all nine values produces an equivalent 1661 transformation, possibly improving precision. 1662 1663 ### Parameters 1664 1665 <table> <tr> <td><a name="SkMatrix_set9_buffer"> <code><strong>buffer </strong></code> </a></td> <td> 1666 nine <a href="undocumented#Scalar">Scalar</a> values</td> 1667 </tr> 1668 </table> 1669 1670 ### Example 1671 1672 <div><fiddle-embed name="ec5de0d23e5fe28ba7628625d1402e85"></fiddle-embed></div> 1673 1674 ### See Also 1675 1676 <a href="#SkMatrix_setAll">setAll</a> <a href="#SkMatrix_get9">get9</a> <a href="#SkMatrix_MakeAll">MakeAll</a> 1677 1678 --- 1679 1680 <a name="SkMatrix_reset"></a> 1681 ## reset 1682 1683 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1684 void reset() 1685 </pre> 1686 1687 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: 1688 1689 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1690 | 1 0 0 | 1691 | 0 1 0 | 1692 | 0 0 1 |</pre> 1693 1694 Also called <a href="#SkMatrix_setIdentity">setIdentity</a>; use the one that provides better inline 1695 documentation. 1696 1697 ### Example 1698 1699 <div><fiddle-embed name="ca94f7922bc37ef03bbc51ad70536fcf"> 1700 1701 #### Example Output 1702 1703 ~~~~ 1704 m.isIdentity(): true 1705 ~~~~ 1706 1707 </fiddle-embed></div> 1708 1709 ### See Also 1710 1711 <a href="#SkMatrix_isIdentity">isIdentity</a> <a href="#SkMatrix_setIdentity">setIdentity</a> 1712 1713 --- 1714 1715 <a name="SkMatrix_setIdentity"></a> 1716 ## setIdentity 1717 1718 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1719 void setIdentity() 1720 </pre> 1721 1722 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: 1723 1724 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1725 | 1 0 0 | 1726 | 0 1 0 | 1727 | 0 0 1 |</pre> 1728 1729 Also called <a href="#SkMatrix_reset">reset</a>; use the one that provides better inline 1730 documentation. 1731 1732 ### Example 1733 1734 <div><fiddle-embed name="3979c865bb482e6ef1fafc71e56bbb91"> 1735 1736 #### Example Output 1737 1738 ~~~~ 1739 m.isIdentity(): true 1740 ~~~~ 1741 1742 </fiddle-embed></div> 1743 1744 ### See Also 1745 1746 <a href="#SkMatrix_isIdentity">isIdentity</a> <a href="#SkMatrix_reset">reset</a> 1747 1748 --- 1749 1750 <a name="SkMatrix_setTranslate"></a> 1751 ## setTranslate 1752 1753 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1754 void setTranslate(SkScalar dx, SkScalar dy) 1755 </pre> 1756 1757 Sets <a href="#Matrix">Matrix</a> to translate by (<a href="#SkMatrix_setTranslate_dx">dx</a>, <a href="#SkMatrix_setTranslate_dy">dy</a>). 1758 1759 ### Parameters 1760 1761 <table> <tr> <td><a name="SkMatrix_setTranslate_dx"> <code><strong>dx </strong></code> </a></td> <td> 1762 horizontal translation</td> 1763 </tr> <tr> <td><a name="SkMatrix_setTranslate_dy"> <code><strong>dy </strong></code> </a></td> <td> 1764 vertical translation</td> 1765 </tr> 1766 </table> 1767 1768 ### Example 1769 1770 <div><fiddle-embed name="63ca62985741b1bccb5e8b9cf734874e"></fiddle-embed></div> 1771 1772 ### See Also 1773 1774 <a href="#SkMatrix_setTranslateX">setTranslateX</a> <a href="#SkMatrix_setTranslateY">setTranslateY</a> 1775 1776 --- 1777 1778 <a name="SkMatrix_setTranslate_2"></a> 1779 1780 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1781 void setTranslate(const SkVector& v) 1782 </pre> 1783 1784 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). 1785 1786 ### Parameters 1787 1788 <table> <tr> <td><a name="SkMatrix_setTranslate_2_v"> <code><strong>v </strong></code> </a></td> <td> 1789 <a href="SkPoint_Reference#Vector">Vector</a> containing horizontal and vertical translation</td> 1790 </tr> 1791 </table> 1792 1793 ### Example 1794 1795 <div><fiddle-embed name="ccfc734aff2ddea0b097c83f5621de5e"></fiddle-embed></div> 1796 1797 ### See Also 1798 1799 <a href="#SkMatrix_setTranslateX">setTranslateX</a> <a href="#SkMatrix_setTranslateY">setTranslateY</a> <a href="#SkMatrix_MakeTrans">MakeTrans</a> 1800 1801 --- 1802 1803 <a name="SkMatrix_setScale"></a> 1804 ## setScale 1805 1806 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1807 void setScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py) 1808 </pre> 1809 1810 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>). 1811 The pivot point is unchanged when mapped with <a href="#Matrix">Matrix</a>. 1812 1813 ### Parameters 1814 1815 <table> <tr> <td><a name="SkMatrix_setScale_sx"> <code><strong>sx </strong></code> </a></td> <td> 1816 horizontal scale factor</td> 1817 </tr> <tr> <td><a name="SkMatrix_setScale_sy"> <code><strong>sy </strong></code> </a></td> <td> 1818 vertical scale factor</td> 1819 </tr> <tr> <td><a name="SkMatrix_setScale_px"> <code><strong>px </strong></code> </a></td> <td> 1820 pivot x</td> 1821 </tr> <tr> <td><a name="SkMatrix_setScale_py"> <code><strong>py </strong></code> </a></td> <td> 1822 pivot y</td> 1823 </tr> 1824 </table> 1825 1826 ### Example 1827 1828 <div><fiddle-embed name="4565a0792058178c88e0a129a87272d6"></fiddle-embed></div> 1829 1830 ### See Also 1831 1832 <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> 1833 1834 --- 1835 1836 <a name="SkMatrix_setScale_2"></a> 1837 1838 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1839 void setScale(SkScalar sx, SkScalar sy) 1840 </pre> 1841 1842 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). 1843 1844 ### Parameters 1845 1846 <table> <tr> <td><a name="SkMatrix_setScale_2_sx"> <code><strong>sx </strong></code> </a></td> <td> 1847 horizontal scale factor</td> 1848 </tr> <tr> <td><a name="SkMatrix_setScale_2_sy"> <code><strong>sy </strong></code> </a></td> <td> 1849 vertical scale factor</td> 1850 </tr> 1851 </table> 1852 1853 ### Example 1854 1855 <div><fiddle-embed name="1579d0cc109c26e69f66f73abd35fb0e"></fiddle-embed></div> 1856 1857 ### See Also 1858 1859 <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> 1860 1861 --- 1862 1863 <a name="SkMatrix_setRotate"></a> 1864 ## setRotate 1865 1866 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1867 void setRotate(SkScalar degrees, SkScalar px, SkScalar py) 1868 </pre> 1869 1870 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>). 1871 The pivot point is unchanged when mapped with <a href="#Matrix">Matrix</a>. 1872 1873 Positive <a href="#SkMatrix_setRotate_degrees">degrees</a> rotates clockwise. 1874 1875 ### Parameters 1876 1877 <table> <tr> <td><a name="SkMatrix_setRotate_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 1878 angle of axes relative to upright axes</td> 1879 </tr> <tr> <td><a name="SkMatrix_setRotate_px"> <code><strong>px </strong></code> </a></td> <td> 1880 pivot x</td> 1881 </tr> <tr> <td><a name="SkMatrix_setRotate_py"> <code><strong>py </strong></code> </a></td> <td> 1882 pivot y</td> 1883 </tr> 1884 </table> 1885 1886 ### Example 1887 1888 <div><fiddle-embed name="8c28db3add9cd0177225088f6df6bbb5"></fiddle-embed></div> 1889 1890 ### See Also 1891 1892 <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> 1893 1894 --- 1895 1896 <a name="SkMatrix_setRotate_2"></a> 1897 1898 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1899 void setRotate(SkScalar degrees) 1900 </pre> 1901 1902 Sets <a href="#Matrix">Matrix</a> to rotate by <a href="#SkMatrix_setRotate_2_degrees">degrees</a> about a pivot point at (0, 0). 1903 Positive <a href="#SkMatrix_setRotate_2_degrees">degrees</a> rotates clockwise. 1904 1905 ### Parameters 1906 1907 <table> <tr> <td><a name="SkMatrix_setRotate_2_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 1908 angle of axes relative to upright axes</td> 1909 </tr> 1910 </table> 1911 1912 ### Example 1913 1914 <div><fiddle-embed name="93efb9d191bf1b9710c173513e014d6c"></fiddle-embed></div> 1915 1916 ### See Also 1917 1918 <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> 1919 1920 --- 1921 1922 <a name="SkMatrix_setSinCos"></a> 1923 ## setSinCos 1924 1925 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1926 void setSinCos(SkScalar sinValue, SkScalar cosValue, SkScalar px, SkScalar py) 1927 </pre> 1928 1929 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>). 1930 The pivot point is unchanged when mapped with <a href="#Matrix">Matrix</a>. 1931 1932 <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). 1933 <a href="SkPoint_Reference#Vector">Vector</a> length specifies scale. 1934 1935 ### Parameters 1936 1937 <table> <tr> <td><a name="SkMatrix_setSinCos_sinValue"> <code><strong>sinValue </strong></code> </a></td> <td> 1938 rotation vector x component</td> 1939 </tr> <tr> <td><a name="SkMatrix_setSinCos_cosValue"> <code><strong>cosValue </strong></code> </a></td> <td> 1940 rotation vector y component</td> 1941 </tr> <tr> <td><a name="SkMatrix_setSinCos_px"> <code><strong>px </strong></code> </a></td> <td> 1942 pivot x</td> 1943 </tr> <tr> <td><a name="SkMatrix_setSinCos_py"> <code><strong>py </strong></code> </a></td> <td> 1944 pivot y</td> 1945 </tr> 1946 </table> 1947 1948 ### Example 1949 1950 <div><fiddle-embed name="187e1d9228e2e4341ef820bd77b6fda9"></fiddle-embed></div> 1951 1952 ### See Also 1953 1954 <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> 1955 1956 --- 1957 1958 <a name="SkMatrix_setSinCos_2"></a> 1959 1960 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1961 void setSinCos(SkScalar sinValue, SkScalar cosValue) 1962 </pre> 1963 1964 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). 1965 1966 <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). 1967 <a href="SkPoint_Reference#Vector">Vector</a> length specifies scale. 1968 1969 ### Parameters 1970 1971 <table> <tr> <td><a name="SkMatrix_setSinCos_2_sinValue"> <code><strong>sinValue </strong></code> </a></td> <td> 1972 rotation vector x component</td> 1973 </tr> <tr> <td><a name="SkMatrix_setSinCos_2_cosValue"> <code><strong>cosValue </strong></code> </a></td> <td> 1974 rotation vector y component</td> 1975 </tr> 1976 </table> 1977 1978 ### Example 1979 1980 <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> 1981 1982 ### See Also 1983 1984 <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> 1985 1986 --- 1987 1988 <a name="SkMatrix_setRSXform"></a> 1989 ## setRSXform 1990 1991 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 1992 SkMatrix& setRSXform(const SkRSXform& rsxForm) 1993 </pre> 1994 1995 Sets <a href="#Matrix">Matrix</a> to rotate, scale, and translate using a compressed matrix form. 1996 1997 <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 1998 to (0, 1). <a href="SkPoint_Reference#Vector">Vector</a> length specifies scale. Mapped point is rotated and scaled 1999 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). 2000 2001 ### Parameters 2002 2003 <table> <tr> <td><a name="SkMatrix_setRSXform_rsxForm"> <code><strong>rsxForm </strong></code> </a></td> <td> 2004 compressed <a href="undocumented#RSXform">RSXform</a> matrix</td> 2005 </tr> 2006 </table> 2007 2008 ### Return Value 2009 2010 reference to <a href="#Matrix">Matrix</a> 2011 2012 ### Example 2013 2014 <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> 2015 2016 ### See Also 2017 2018 <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> 2019 2020 --- 2021 2022 <a name="SkMatrix_setSkew"></a> 2023 ## setSkew 2024 2025 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2026 void setSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py) 2027 </pre> 2028 2029 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>). 2030 The pivot point is unchanged when mapped with <a href="#Matrix">Matrix</a>. 2031 2032 ### Parameters 2033 2034 <table> <tr> <td><a name="SkMatrix_setSkew_kx"> <code><strong>kx </strong></code> </a></td> <td> 2035 horizontal skew factor</td> 2036 </tr> <tr> <td><a name="SkMatrix_setSkew_ky"> <code><strong>ky </strong></code> </a></td> <td> 2037 vertical skew factor</td> 2038 </tr> <tr> <td><a name="SkMatrix_setSkew_px"> <code><strong>px </strong></code> </a></td> <td> 2039 pivot x</td> 2040 </tr> <tr> <td><a name="SkMatrix_setSkew_py"> <code><strong>py </strong></code> </a></td> <td> 2041 pivot y</td> 2042 </tr> 2043 </table> 2044 2045 ### Example 2046 2047 <div><fiddle-embed name="55e0431adc6c5b1987ebb8123cc10342"></fiddle-embed></div> 2048 2049 ### See Also 2050 2051 <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> 2052 2053 --- 2054 2055 <a name="SkMatrix_setSkew_2"></a> 2056 2057 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2058 void setSkew(SkScalar kx, SkScalar ky) 2059 </pre> 2060 2061 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). 2062 2063 ### Parameters 2064 2065 <table> <tr> <td><a name="SkMatrix_setSkew_2_kx"> <code><strong>kx </strong></code> </a></td> <td> 2066 horizontal skew factor</td> 2067 </tr> <tr> <td><a name="SkMatrix_setSkew_2_ky"> <code><strong>ky </strong></code> </a></td> <td> 2068 vertical skew factor</td> 2069 </tr> 2070 </table> 2071 2072 ### Example 2073 2074 <div><fiddle-embed name="05be7844e9afdd7b9bfc31c5423a70a2"></fiddle-embed></div> 2075 2076 ### See Also 2077 2078 <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> 2079 2080 --- 2081 2082 <a name="SkMatrix_setConcat"></a> 2083 ## setConcat 2084 2085 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2086 void setConcat(const SkMatrix& a, const SkMatrix& b) 2087 </pre> 2088 2089 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. 2090 2091 Given: 2092 2093 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2094 | A B C | | J K L | 2095 a = | D E F |, b = | M N O | 2096 | G H I | | P Q R |</pre> 2097 2098 sets <a href="#Matrix">Matrix</a> to: 2099 2100 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2101 | A B C | | J K L | | AJ+BM+CP AK+BN+CQ AL+BO+CR | 2102 a * b = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR | 2103 | G H I | | P Q R | | GJ+HM+IP GK+HN+IQ GL+HO+IR |</pre> 2104 2105 ### Parameters 2106 2107 <table> <tr> <td><a name="SkMatrix_setConcat_a"> <code><strong>a </strong></code> </a></td> <td> 2108 <a href="#Matrix">Matrix</a> on left side of multiply expression</td> 2109 </tr> <tr> <td><a name="SkMatrix_setConcat_b"> <code><strong>b </strong></code> </a></td> <td> 2110 <a href="#Matrix">Matrix</a> on right side of multiply expression</td> 2111 </tr> 2112 </table> 2113 2114 ### Example 2115 2116 <div><fiddle-embed name="0381a10ac69bdefdf9d15b47cbb9fefe"><div><a href="#SkMatrix_setPolyToPoly">setPolyToPoly</a> creates perspective matrices, one the inverse of the other. 2117 Multiplying the matrix by its inverse turns into an identity matrix.</div></fiddle-embed></div> 2118 2119 ### See Also 2120 2121 <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> 2122 2123 --- 2124 2125 <a name="SkMatrix_preTranslate"></a> 2126 ## preTranslate 2127 2128 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2129 void preTranslate(SkScalar dx, SkScalar dy) 2130 </pre> 2131 2132 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>). 2133 This can be thought of as moving the point to be mapped before applying <a href="#Matrix">Matrix</a>. 2134 2135 Given: 2136 2137 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2138 | A B C | | 1 0 dx | 2139 Matrix = | D E F |, T(dx, dy) = | 0 1 dy | 2140 | G H I | | 0 0 1 |</pre> 2141 2142 sets <a href="#Matrix">Matrix</a> to: 2143 2144 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2145 | A B C | | 1 0 dx | | A B A*dx+B*dy+C | 2146 Matrix * T(dx, dy) = | D E F | | 0 1 dy | = | D E D*dx+E*dy+F | 2147 | G H I | | 0 0 1 | | G H G*dx+H*dy+I |</pre> 2148 2149 ### Parameters 2150 2151 <table> <tr> <td><a name="SkMatrix_preTranslate_dx"> <code><strong>dx </strong></code> </a></td> <td> 2152 x translation before applying <a href="#Matrix">Matrix</a></td> 2153 </tr> <tr> <td><a name="SkMatrix_preTranslate_dy"> <code><strong>dy </strong></code> </a></td> <td> 2154 y translation before applying <a href="#Matrix">Matrix</a></td> 2155 </tr> 2156 </table> 2157 2158 ### Example 2159 2160 <div><fiddle-embed name="08f6749933f4ce541073077ab506fd9b"></fiddle-embed></div> 2161 2162 ### See Also 2163 2164 <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> 2165 2166 --- 2167 2168 <a name="SkMatrix_preScale"></a> 2169 ## preScale 2170 2171 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2172 void preScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py) 2173 </pre> 2174 2175 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>) 2176 about pivot point (<a href="#SkMatrix_preScale_px">px</a>, <a href="#SkMatrix_preScale_py">py</a>). 2177 This can be thought of as scaling about a pivot point before applying <a href="#Matrix">Matrix</a>. 2178 2179 Given: 2180 2181 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2182 | A B C | | sx 0 dx | 2183 Matrix = | D E F |, S(sx, sy, px, py) = | 0 sy dy | 2184 | G H I | | 0 0 1 |</pre> 2185 2186 where 2187 2188 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2189 dx = px - sx * px 2190 dy = py - sy * py</pre> 2191 2192 sets <a href="#Matrix">Matrix</a> to: 2193 2194 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2195 | A B C | | sx 0 dx | | A*sx B*sy A*dx+B*dy+C | 2196 Matrix * S(sx, sy, px, py) = | D E F | | 0 sy dy | = | D*sx E*sy D*dx+E*dy+F | 2197 | G H I | | 0 0 1 | | G*sx H*sy G*dx+H*dy+I |</pre> 2198 2199 ### Parameters 2200 2201 <table> <tr> <td><a name="SkMatrix_preScale_sx"> <code><strong>sx </strong></code> </a></td> <td> 2202 horizontal scale factor</td> 2203 </tr> <tr> <td><a name="SkMatrix_preScale_sy"> <code><strong>sy </strong></code> </a></td> <td> 2204 vertical scale factor</td> 2205 </tr> <tr> <td><a name="SkMatrix_preScale_px"> <code><strong>px </strong></code> </a></td> <td> 2206 pivot x</td> 2207 </tr> <tr> <td><a name="SkMatrix_preScale_py"> <code><strong>py </strong></code> </a></td> <td> 2208 pivot y</td> 2209 </tr> 2210 </table> 2211 2212 ### Example 2213 2214 <div><fiddle-embed name="2531f8d1e05d7b6dc22f3efcd2fb84e4"></fiddle-embed></div> 2215 2216 ### See Also 2217 2218 <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> 2219 2220 --- 2221 2222 <a name="SkMatrix_preScale_2"></a> 2223 2224 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2225 void preScale(SkScalar sx, SkScalar sy) 2226 </pre> 2227 2228 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>) 2229 about pivot point (0, 0). 2230 This can be thought of as scaling about the origin before applying <a href="#Matrix">Matrix</a>. 2231 2232 Given: 2233 2234 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2235 | A B C | | sx 0 0 | 2236 Matrix = | D E F |, S(sx, sy) = | 0 sy 0 | 2237 | G H I | | 0 0 1 |</pre> 2238 2239 sets <a href="#Matrix">Matrix</a> to: 2240 2241 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2242 | A B C | | sx 0 0 | | A*sx B*sy C | 2243 Matrix * S(sx, sy) = | D E F | | 0 sy 0 | = | D*sx E*sy F | 2244 | G H I | | 0 0 1 | | G*sx H*sy I |</pre> 2245 2246 ### Parameters 2247 2248 <table> <tr> <td><a name="SkMatrix_preScale_2_sx"> <code><strong>sx </strong></code> </a></td> <td> 2249 horizontal scale factor</td> 2250 </tr> <tr> <td><a name="SkMatrix_preScale_2_sy"> <code><strong>sy </strong></code> </a></td> <td> 2251 vertical scale factor</td> 2252 </tr> 2253 </table> 2254 2255 ### Example 2256 2257 <div><fiddle-embed name="3edbdea8e43d06086abf33ec4a9b415b"></fiddle-embed></div> 2258 2259 ### See Also 2260 2261 <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> 2262 2263 --- 2264 2265 <a name="SkMatrix_preRotate"></a> 2266 ## preRotate 2267 2268 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2269 void preRotate(SkScalar degrees, SkScalar px, SkScalar py) 2270 </pre> 2271 2272 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> 2273 about pivot point (<a href="#SkMatrix_preRotate_px">px</a>, <a href="#SkMatrix_preRotate_py">py</a>). 2274 This can be thought of as rotating about a pivot point before applying <a href="#Matrix">Matrix</a>. 2275 2276 Positive <a href="#SkMatrix_preRotate_degrees">degrees</a> rotates clockwise. 2277 2278 Given: 2279 2280 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2281 | A B C | | c -s dx | 2282 Matrix = | D E F |, R(degrees, px, py) = | s c dy | 2283 | G H I | | 0 0 1 |</pre> 2284 2285 where 2286 2287 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2288 c = cos(degrees) 2289 s = sin(degrees) 2290 dx = s * py + (1 - c) * px 2291 dy = -s * px + (1 - c) * py</pre> 2292 2293 sets <a href="#Matrix">Matrix</a> to: 2294 2295 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2296 | A B C | | c -s dx | | Ac+Bs -As+Bc A*dx+B*dy+C | 2297 Matrix * R(degrees, px, py) = | D E F | | s c dy | = | Dc+Es -Ds+Ec D*dx+E*dy+F | 2298 | G H I | | 0 0 1 | | Gc+Hs -Gs+Hc G*dx+H*dy+I |</pre> 2299 2300 ### Parameters 2301 2302 <table> <tr> <td><a name="SkMatrix_preRotate_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 2303 angle of axes relative to upright axes</td> 2304 </tr> <tr> <td><a name="SkMatrix_preRotate_px"> <code><strong>px </strong></code> </a></td> <td> 2305 pivot x</td> 2306 </tr> <tr> <td><a name="SkMatrix_preRotate_py"> <code><strong>py </strong></code> </a></td> <td> 2307 pivot y</td> 2308 </tr> 2309 </table> 2310 2311 ### Example 2312 2313 <div><fiddle-embed name="a70bb18d67c06a20ab514e7a47924e5a"></fiddle-embed></div> 2314 2315 ### See Also 2316 2317 <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> 2318 2319 --- 2320 2321 <a name="SkMatrix_preRotate_2"></a> 2322 2323 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2324 void preRotate(SkScalar degrees) 2325 </pre> 2326 2327 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> 2328 about pivot point (0, 0). 2329 This can be thought of as rotating about the origin before applying <a href="#Matrix">Matrix</a>. 2330 2331 Positive <a href="#SkMatrix_preRotate_2_degrees">degrees</a> rotates clockwise. 2332 2333 Given: 2334 2335 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2336 | A B C | | c -s 0 | 2337 Matrix = | D E F |, R(degrees, px, py) = | s c 0 | 2338 | G H I | | 0 0 1 |</pre> 2339 2340 where 2341 2342 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2343 c = cos(degrees) 2344 s = sin(degrees)</pre> 2345 2346 sets <a href="#Matrix">Matrix</a> to: 2347 2348 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2349 | A B C | | c -s 0 | | Ac+Bs -As+Bc C | 2350 Matrix * R(degrees, px, py) = | D E F | | s c 0 | = | Dc+Es -Ds+Ec F | 2351 | G H I | | 0 0 1 | | Gc+Hs -Gs+Hc I |</pre> 2352 2353 ### Parameters 2354 2355 <table> <tr> <td><a name="SkMatrix_preRotate_2_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 2356 angle of axes relative to upright axes</td> 2357 </tr> 2358 </table> 2359 2360 ### Example 2361 2362 <div><fiddle-embed name="5acd49bd931c79a808dd6c7cc0e92f72"></fiddle-embed></div> 2363 2364 ### See Also 2365 2366 <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> 2367 2368 --- 2369 2370 <a name="SkMatrix_preSkew"></a> 2371 ## preSkew 2372 2373 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2374 void preSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py) 2375 </pre> 2376 2377 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>) 2378 about pivot point (<a href="#SkMatrix_preSkew_px">px</a>, <a href="#SkMatrix_preSkew_py">py</a>). 2379 This can be thought of as skewing about a pivot point before applying <a href="#Matrix">Matrix</a>. 2380 2381 Given: 2382 2383 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2384 | A B C | | 1 kx dx | 2385 Matrix = | D E F |, K(kx, ky, px, py) = | ky 1 dy | 2386 | G H I | | 0 0 1 |</pre> 2387 2388 where 2389 2390 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2391 dx = -kx * py 2392 dy = -ky * px</pre> 2393 2394 sets <a href="#Matrix">Matrix</a> to: 2395 2396 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2397 | A B C | | 1 kx dx | | A+B*ky A*kx+B A*dx+B*dy+C | 2398 Matrix * K(kx, ky, px, py) = | D E F | | ky 1 dy | = | D+E*ky D*kx+E D*dx+E*dy+F | 2399 | G H I | | 0 0 1 | | G+H*ky G*kx+H G*dx+H*dy+I |</pre> 2400 2401 ### Parameters 2402 2403 <table> <tr> <td><a name="SkMatrix_preSkew_kx"> <code><strong>kx </strong></code> </a></td> <td> 2404 horizontal skew factor</td> 2405 </tr> <tr> <td><a name="SkMatrix_preSkew_ky"> <code><strong>ky </strong></code> </a></td> <td> 2406 vertical skew factor</td> 2407 </tr> <tr> <td><a name="SkMatrix_preSkew_px"> <code><strong>px </strong></code> </a></td> <td> 2408 pivot x</td> 2409 </tr> <tr> <td><a name="SkMatrix_preSkew_py"> <code><strong>py </strong></code> </a></td> <td> 2410 pivot y</td> 2411 </tr> 2412 </table> 2413 2414 ### Example 2415 2416 <div><fiddle-embed name="199a18ad61d702664ce6df1d7037aa48"></fiddle-embed></div> 2417 2418 ### See Also 2419 2420 <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> 2421 2422 --- 2423 2424 <a name="SkMatrix_preSkew_2"></a> 2425 2426 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2427 void preSkew(SkScalar kx, SkScalar ky) 2428 </pre> 2429 2430 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>) 2431 about pivot point (0, 0). 2432 This can be thought of as skewing about the origin before applying <a href="#Matrix">Matrix</a>. 2433 2434 Given: 2435 2436 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2437 | A B C | | 1 kx 0 | 2438 Matrix = | D E F |, K(kx, ky) = | ky 1 0 | 2439 | G H I | | 0 0 1 |</pre> 2440 2441 sets <a href="#Matrix">Matrix</a> to: 2442 2443 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2444 | A B C | | 1 kx 0 | | A+B*ky A*kx+B C | 2445 Matrix * K(kx, ky) = | D E F | | ky 1 0 | = | D+E*ky D*kx+E F | 2446 | G H I | | 0 0 1 | | G+H*ky G*kx+H I |</pre> 2447 2448 ### Parameters 2449 2450 <table> <tr> <td><a name="SkMatrix_preSkew_2_kx"> <code><strong>kx </strong></code> </a></td> <td> 2451 horizontal skew factor</td> 2452 </tr> <tr> <td><a name="SkMatrix_preSkew_2_ky"> <code><strong>ky </strong></code> </a></td> <td> 2453 vertical skew factor</td> 2454 </tr> 2455 </table> 2456 2457 ### Example 2458 2459 <div><fiddle-embed name="e100c543869fe8fd516ba69de79444ba"></fiddle-embed></div> 2460 2461 ### See Also 2462 2463 <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> 2464 2465 --- 2466 2467 <a name="SkMatrix_preConcat"></a> 2468 ## preConcat 2469 2470 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2471 void preConcat(const SkMatrix& other) 2472 </pre> 2473 2474 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>. 2475 This can be thought of mapping by <a href="#SkMatrix_preConcat_other">other</a> before applying <a href="#Matrix">Matrix</a>. 2476 2477 Given: 2478 2479 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2480 | A B C | | J K L | 2481 Matrix = | D E F |, other = | M N O | 2482 | G H I | | P Q R |</pre> 2483 2484 sets <a href="#Matrix">Matrix</a> to: 2485 2486 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2487 | A B C | | J K L | | AJ+BM+CP AK+BN+CQ AL+BO+CR | 2488 Matrix * other = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR | 2489 | G H I | | P Q R | | GJ+HM+IP GK+HN+IQ GL+HO+IR |</pre> 2490 2491 ### Parameters 2492 2493 <table> <tr> <td><a name="SkMatrix_preConcat_other"> <code><strong>other </strong></code> </a></td> <td> 2494 <a href="#Matrix">Matrix</a> on right side of multiply expression</td> 2495 </tr> 2496 </table> 2497 2498 ### Example 2499 2500 <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>. 2501 Multiplying the matrix by its inverse turns into an identity matrix.</div></fiddle-embed></div> 2502 2503 ### See Also 2504 2505 <a href="#SkMatrix_postConcat">postConcat</a> <a href="#SkMatrix_setConcat">setConcat</a> <a href="#SkMatrix_Concat">Concat</a> 2506 2507 --- 2508 2509 <a name="SkMatrix_postTranslate"></a> 2510 ## postTranslate 2511 2512 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2513 void postTranslate(SkScalar dx, SkScalar dy) 2514 </pre> 2515 2516 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>. 2517 This can be thought of as moving the point to be mapped after applying <a href="#Matrix">Matrix</a>. 2518 2519 Given: 2520 2521 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2522 | J K L | | 1 0 dx | 2523 Matrix = | M N O |, T(dx, dy) = | 0 1 dy | 2524 | P Q R | | 0 0 1 |</pre> 2525 2526 sets <a href="#Matrix">Matrix</a> to: 2527 2528 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2529 | 1 0 dx | | J K L | | J+dx*P K+dx*Q L+dx*R | 2530 T(dx, dy) * Matrix = | 0 1 dy | | M N O | = | M+dy*P N+dy*Q O+dy*R | 2531 | 0 0 1 | | P Q R | | P Q R |</pre> 2532 2533 ### Parameters 2534 2535 <table> <tr> <td><a name="SkMatrix_postTranslate_dx"> <code><strong>dx </strong></code> </a></td> <td> 2536 x translation after applying <a href="#Matrix">Matrix</a></td> 2537 </tr> <tr> <td><a name="SkMatrix_postTranslate_dy"> <code><strong>dy </strong></code> </a></td> <td> 2538 y translation after applying <a href="#Matrix">Matrix</a></td> 2539 </tr> 2540 </table> 2541 2542 ### Example 2543 2544 <div><fiddle-embed name="57e4cff302c0d754ac6c66050d741772"><div>Compare with <a href="#SkMatrix_preTranslate">preTranslate</a> example.</div></fiddle-embed></div> 2545 2546 ### See Also 2547 2548 <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> 2549 2550 --- 2551 2552 <a name="SkMatrix_postScale"></a> 2553 ## postScale 2554 2555 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2556 void postScale(SkScalar sx, SkScalar sy, SkScalar px, SkScalar py) 2557 </pre> 2558 2559 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 2560 (<a href="#SkMatrix_postScale_px">px</a>, <a href="#SkMatrix_postScale_py">py</a>), multiplied by <a href="#Matrix">Matrix</a>. 2561 This can be thought of as scaling about a pivot point after applying <a href="#Matrix">Matrix</a>. 2562 2563 Given: 2564 2565 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2566 | J K L | | sx 0 dx | 2567 Matrix = | M N O |, S(sx, sy, px, py) = | 0 sy dy | 2568 | P Q R | | 0 0 1 |</pre> 2569 2570 where 2571 2572 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2573 dx = px - sx * px 2574 dy = py - sy * py</pre> 2575 2576 sets <a href="#Matrix">Matrix</a> to: 2577 2578 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2579 | sx 0 dx | | J K L | | sx*J+dx*P sx*K+dx*Q sx*L+dx+R | 2580 S(sx, sy, px, py) * Matrix = | 0 sy dy | | M N O | = | sy*M+dy*P sy*N+dy*Q sy*O+dy*R | 2581 | 0 0 1 | | P Q R | | P Q R |</pre> 2582 2583 ### Parameters 2584 2585 <table> <tr> <td><a name="SkMatrix_postScale_sx"> <code><strong>sx </strong></code> </a></td> <td> 2586 horizontal scale factor</td> 2587 </tr> <tr> <td><a name="SkMatrix_postScale_sy"> <code><strong>sy </strong></code> </a></td> <td> 2588 vertical scale factor</td> 2589 </tr> <tr> <td><a name="SkMatrix_postScale_px"> <code><strong>px </strong></code> </a></td> <td> 2590 pivot x</td> 2591 </tr> <tr> <td><a name="SkMatrix_postScale_py"> <code><strong>py </strong></code> </a></td> <td> 2592 pivot y</td> 2593 </tr> 2594 </table> 2595 2596 ### Example 2597 2598 <div><fiddle-embed name="ed3aa18ba0ea95c85cc49aa3829fe384"></fiddle-embed></div> 2599 2600 ### See Also 2601 2602 <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> 2603 2604 --- 2605 2606 <a name="SkMatrix_postScale_2"></a> 2607 2608 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2609 void postScale(SkScalar sx, SkScalar sy) 2610 </pre> 2611 2612 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 2613 (0, 0), multiplied by <a href="#Matrix">Matrix</a>. 2614 This can be thought of as scaling about the origin after applying <a href="#Matrix">Matrix</a>. 2615 2616 Given: 2617 2618 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2619 | J K L | | sx 0 0 | 2620 Matrix = | M N O |, S(sx, sy) = | 0 sy 0 | 2621 | P Q R | | 0 0 1 |</pre> 2622 2623 sets <a href="#Matrix">Matrix</a> to: 2624 2625 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2626 | sx 0 0 | | J K L | | sx*J sx*K sx*L | 2627 S(sx, sy) * Matrix = | 0 sy 0 | | M N O | = | sy*M sy*N sy*O | 2628 | 0 0 1 | | P Q R | | P Q R |</pre> 2629 2630 ### Parameters 2631 2632 <table> <tr> <td><a name="SkMatrix_postScale_2_sx"> <code><strong>sx </strong></code> </a></td> <td> 2633 horizontal scale factor</td> 2634 </tr> <tr> <td><a name="SkMatrix_postScale_2_sy"> <code><strong>sy </strong></code> </a></td> <td> 2635 vertical scale factor</td> 2636 </tr> 2637 </table> 2638 2639 ### Example 2640 2641 <div><fiddle-embed name="1931017698766a67d3a26423453b8095"></fiddle-embed></div> 2642 2643 ### See Also 2644 2645 <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> 2646 2647 --- 2648 2649 <a name="SkMatrix_postIDiv"></a> 2650 ## postIDiv 2651 2652 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2653 bool postIDiv(int divx, int divy) 2654 </pre> 2655 2656 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>. 2657 2658 Returns false if either <a href="#SkMatrix_postIDiv_divx">divx</a> or <a href="#SkMatrix_postIDiv_divy">divy</a> is zero. 2659 2660 Given: 2661 2662 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2663 | J K L | | sx 0 0 | 2664 Matrix = | M N O |, I(divx, divy) = | 0 sy 0 | 2665 | P Q R | | 0 0 1 |</pre> 2666 2667 where 2668 2669 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2670 sx = 1 / divx 2671 sy = 1 / divy</pre> 2672 2673 sets <a href="#Matrix">Matrix</a> to: 2674 2675 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2676 | sx 0 0 | | J K L | | sx*J sx*K sx*L | 2677 I(divx, divy) * Matrix = | 0 sy 0 | | M N O | = | sy*M sy*N sy*O | 2678 | 0 0 1 | | P Q R | | P Q R |</pre> 2679 2680 ### Parameters 2681 2682 <table> <tr> <td><a name="SkMatrix_postIDiv_divx"> <code><strong>divx </strong></code> </a></td> <td> 2683 integer divisor for inverse scale in x</td> 2684 </tr> <tr> <td><a name="SkMatrix_postIDiv_divy"> <code><strong>divy </strong></code> </a></td> <td> 2685 integer divisor for inverse scale in y</td> 2686 </tr> 2687 </table> 2688 2689 ### Return Value 2690 2691 true on successful scale 2692 2693 ### Example 2694 2695 <div><fiddle-embed name="58c844b8f0c36acdbc8211e8c929c253"></fiddle-embed></div> 2696 2697 ### See Also 2698 2699 <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> 2700 2701 --- 2702 2703 <a name="SkMatrix_postRotate"></a> 2704 ## postRotate 2705 2706 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2707 void postRotate(SkScalar degrees, SkScalar px, SkScalar py) 2708 </pre> 2709 2710 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 2711 (<a href="#SkMatrix_postRotate_px">px</a>, <a href="#SkMatrix_postRotate_py">py</a>), multiplied by <a href="#Matrix">Matrix</a>. 2712 This can be thought of as rotating about a pivot point after applying <a href="#Matrix">Matrix</a>. 2713 2714 Positive <a href="#SkMatrix_postRotate_degrees">degrees</a> rotates clockwise. 2715 2716 Given: 2717 2718 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2719 | J K L | | c -s dx | 2720 Matrix = | M N O |, R(degrees, px, py) = | s c dy | 2721 | P Q R | | 0 0 1 |</pre> 2722 2723 where 2724 2725 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2726 c = cos(degrees) 2727 s = sin(degrees) 2728 dx = s * py + (1 - c) * px 2729 dy = -s * px + (1 - c) * py</pre> 2730 2731 sets <a href="#Matrix">Matrix</a> to: 2732 2733 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2734 |c -s dx| |J K L| |cJ-sM+dx*P cK-sN+dx*Q cL-sO+dx+R| 2735 R(degrees, px, py) * Matrix = |s c dy| |M N O| = |sJ+cM+dy*P sK+cN+dy*Q sL+cO+dy*R| 2736 |0 0 1| |P Q R| | P Q R|</pre> 2737 2738 ### Parameters 2739 2740 <table> <tr> <td><a name="SkMatrix_postRotate_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 2741 angle of axes relative to upright axes</td> 2742 </tr> <tr> <td><a name="SkMatrix_postRotate_px"> <code><strong>px </strong></code> </a></td> <td> 2743 pivot x</td> 2744 </tr> <tr> <td><a name="SkMatrix_postRotate_py"> <code><strong>py </strong></code> </a></td> <td> 2745 pivot y</td> 2746 </tr> 2747 </table> 2748 2749 ### Example 2750 2751 <div><fiddle-embed name="e09194ee48a81e7b375ade473d340f0d"></fiddle-embed></div> 2752 2753 ### See Also 2754 2755 <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> 2756 2757 --- 2758 2759 <a name="SkMatrix_postRotate_2"></a> 2760 2761 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2762 void postRotate(SkScalar degrees) 2763 </pre> 2764 2765 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 2766 (0, 0), multiplied by <a href="#Matrix">Matrix</a>. 2767 This can be thought of as rotating about the origin after applying <a href="#Matrix">Matrix</a>. 2768 2769 Positive <a href="#SkMatrix_postRotate_2_degrees">degrees</a> rotates clockwise. 2770 2771 Given: 2772 2773 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2774 | J K L | | c -s 0 | 2775 Matrix = | M N O |, R(degrees, px, py) = | s c 0 | 2776 | P Q R | | 0 0 1 |</pre> 2777 2778 where 2779 2780 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2781 c = cos(degrees) 2782 s = sin(degrees)</pre> 2783 2784 sets <a href="#Matrix">Matrix</a> to: 2785 2786 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2787 | c -s dx | | J K L | | cJ-sM cK-sN cL-sO | 2788 R(degrees, px, py) * Matrix = | s c dy | | M N O | = | sJ+cM sK+cN sL+cO | 2789 | 0 0 1 | | P Q R | | P Q R |</pre> 2790 2791 ### Parameters 2792 2793 <table> <tr> <td><a name="SkMatrix_postRotate_2_degrees"> <code><strong>degrees </strong></code> </a></td> <td> 2794 angle of axes relative to upright axes</td> 2795 </tr> 2796 </table> 2797 2798 ### Example 2799 2800 <div><fiddle-embed name="52e4c53e26971af5576b30de60fa70c2"></fiddle-embed></div> 2801 2802 ### See Also 2803 2804 <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> 2805 2806 --- 2807 2808 <a name="SkMatrix_postSkew"></a> 2809 ## postSkew 2810 2811 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2812 void postSkew(SkScalar kx, SkScalar ky, SkScalar px, SkScalar py) 2813 </pre> 2814 2815 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 2816 (<a href="#SkMatrix_postSkew_px">px</a>, <a href="#SkMatrix_postSkew_py">py</a>), multiplied by <a href="#Matrix">Matrix</a>. 2817 This can be thought of as skewing about a pivot point after applying <a href="#Matrix">Matrix</a>. 2818 2819 Given: 2820 2821 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2822 | J K L | | 1 kx dx | 2823 Matrix = | M N O |, K(kx, ky, px, py) = | ky 1 dy | 2824 | P Q R | | 0 0 1 |</pre> 2825 2826 where 2827 2828 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2829 dx = -kx * py 2830 dy = -ky * px</pre> 2831 2832 sets <a href="#Matrix">Matrix</a> to: 2833 2834 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2835 | 1 kx dx| |J K L| |J+kx*M+dx*P K+kx*N+dx*Q L+kx*O+dx+R| 2836 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| 2837 | 0 0 1| |P Q R| | P Q R|</pre> 2838 2839 ### Parameters 2840 2841 <table> <tr> <td><a name="SkMatrix_postSkew_kx"> <code><strong>kx </strong></code> </a></td> <td> 2842 horizontal skew factor</td> 2843 </tr> <tr> <td><a name="SkMatrix_postSkew_ky"> <code><strong>ky </strong></code> </a></td> <td> 2844 vertical skew factor</td> 2845 </tr> <tr> <td><a name="SkMatrix_postSkew_px"> <code><strong>px </strong></code> </a></td> <td> 2846 pivot x</td> 2847 </tr> <tr> <td><a name="SkMatrix_postSkew_py"> <code><strong>py </strong></code> </a></td> <td> 2848 pivot y</td> 2849 </tr> 2850 </table> 2851 2852 ### Example 2853 2854 <div><fiddle-embed name="8c34ae3a2b7e2742bb969819737365ec"></fiddle-embed></div> 2855 2856 ### See Also 2857 2858 <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> 2859 2860 --- 2861 2862 <a name="SkMatrix_postSkew_2"></a> 2863 2864 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2865 void postSkew(SkScalar kx, SkScalar ky) 2866 </pre> 2867 2868 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 2869 (0, 0), multiplied by <a href="#Matrix">Matrix</a>. 2870 This can be thought of as skewing about the origin after applying <a href="#Matrix">Matrix</a>. 2871 2872 Given: 2873 2874 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2875 | J K L | | 1 kx 0 | 2876 Matrix = | M N O |, K(kx, ky) = | ky 1 0 | 2877 | P Q R | | 0 0 1 |</pre> 2878 2879 sets <a href="#Matrix">Matrix</a> to: 2880 2881 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2882 | 1 kx 0 | | J K L | | J+kx*M K+kx*N L+kx*O | 2883 K(kx, ky) * Matrix = | ky 1 0 | | M N O | = | ky*J+M ky*K+N ky*L+O | 2884 | 0 0 1 | | P Q R | | P Q R |</pre> 2885 2886 ### Parameters 2887 2888 <table> <tr> <td><a name="SkMatrix_postSkew_2_kx"> <code><strong>kx </strong></code> </a></td> <td> 2889 horizontal skew factor</td> 2890 </tr> <tr> <td><a name="SkMatrix_postSkew_2_ky"> <code><strong>ky </strong></code> </a></td> <td> 2891 vertical skew factor</td> 2892 </tr> 2893 </table> 2894 2895 ### Example 2896 2897 <div><fiddle-embed name="3aa2603225dff72ac53dd359f897f494"></fiddle-embed></div> 2898 2899 ### See Also 2900 2901 <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> 2902 2903 --- 2904 2905 <a name="SkMatrix_postConcat"></a> 2906 ## postConcat 2907 2908 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2909 void postConcat(const SkMatrix& other) 2910 </pre> 2911 2912 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>. 2913 This can be thought of mapping by <a href="#SkMatrix_postConcat_other">other</a> after applying <a href="#Matrix">Matrix</a>. 2914 2915 Given: 2916 2917 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2918 | J K L | | A B C | 2919 Matrix = | M N O |, other = | D E F | 2920 | P Q R | | G H I |</pre> 2921 2922 sets <a href="#Matrix">Matrix</a> to: 2923 2924 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2925 | A B C | | J K L | | AJ+BM+CP AK+BN+CQ AL+BO+CR | 2926 other * Matrix = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR | 2927 | G H I | | P Q R | | GJ+HM+IP GK+HN+IQ GL+HO+IR |</pre> 2928 2929 ### Parameters 2930 2931 <table> <tr> <td><a name="SkMatrix_postConcat_other"> <code><strong>other </strong></code> </a></td> <td> 2932 <a href="#Matrix">Matrix</a> on left side of multiply expression</td> 2933 </tr> 2934 </table> 2935 2936 ### Example 2937 2938 <div><fiddle-embed name="0a4214289249c77f48d59227c4ac4d9e"></fiddle-embed></div> 2939 2940 ### See Also 2941 2942 <a href="#SkMatrix_preConcat">preConcat</a> <a href="#SkMatrix_setConcat">setConcat</a> <a href="#SkMatrix_Concat">Concat</a> 2943 2944 --- 2945 2946 ## <a name="SkMatrix_ScaleToFit"></a> Enum SkMatrix::ScaleToFit 2947 2948 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 2949 enum <a href="#SkMatrix_ScaleToFit">ScaleToFit</a> { 2950 <a href="#SkMatrix_kFill_ScaleToFit">kFill ScaleToFit</a>, 2951 <a href="#SkMatrix_kStart_ScaleToFit">kStart ScaleToFit</a>, 2952 <a href="#SkMatrix_kCenter_ScaleToFit">kCenter ScaleToFit</a>, 2953 <a href="#SkMatrix_kEnd_ScaleToFit">kEnd ScaleToFit</a>, 2954 };</pre> 2955 2956 <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. 2957 <a href="#SkMatrix_ScaleToFit">ScaleToFit</a> may allow <a href="#Matrix">Matrix</a> to have unequal horizontal and vertical scaling, 2958 or may restrict <a href="#Matrix">Matrix</a> to square scaling. If restricted, <a href="#SkMatrix_ScaleToFit">ScaleToFit</a> specifies 2959 how <a href="#Matrix">Matrix</a> maps to the side or center of the destination <a href="SkRect_Reference#Rect">Rect</a>. 2960 2961 ### Constants 2962 2963 <table> 2964 <tr> 2965 <td><a name="SkMatrix_kFill_ScaleToFit"> <code><strong>SkMatrix::kFill_ScaleToFit </strong></code> </a></td><td>0</td><td>Computes <a href="#Matrix">Matrix</a> that scales in x and y independently, so that source <a href="SkRect_Reference#Rect">Rect</a> is 2966 mapped to completely fill destination <a href="SkRect_Reference#Rect">Rect</a>. The aspect ratio of source <a href="SkRect_Reference#Rect">Rect</a> 2967 may change.</td> 2968 </tr> 2969 <tr> 2970 <td><a name="SkMatrix_kStart_ScaleToFit"> <code><strong>SkMatrix::kStart_ScaleToFit </strong></code> </a></td><td>1</td><td>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> 2971 width or height to destination <a href="SkRect_Reference#Rect">Rect</a>. Aligns mapping to left and top edges 2972 of destination <a href="SkRect_Reference#Rect">Rect</a>.</td> 2973 </tr> 2974 <tr> 2975 <td><a name="SkMatrix_kCenter_ScaleToFit"> <code><strong>SkMatrix::kCenter_ScaleToFit </strong></code> </a></td><td>2</td><td>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> 2976 width or height to destination <a href="SkRect_Reference#Rect">Rect</a>. Aligns mapping to center of destination 2977 <a href="SkRect_Reference#Rect">Rect</a>.</td> 2978 </tr> 2979 <tr> 2980 <td><a name="SkMatrix_kEnd_ScaleToFit"> <code><strong>SkMatrix::kEnd_ScaleToFit </strong></code> </a></td><td>3</td><td>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> 2981 width or height to destination <a href="SkRect_Reference#Rect">Rect</a>. Aligns mapping to right and bottom 2982 edges of destination <a href="SkRect_Reference#Rect">Rect</a>.</td> 2983 </tr> 2984 </table> 2985 2986 ### Example 2987 2988 <div><fiddle-embed name="17c3070b31b700ea8f52e48af9a66b6e"></fiddle-embed></div> 2989 2990 ### See Also 2991 2992 <a href="#SkMatrix_setRectToRect">setRectToRect</a> <a href="#SkMatrix_MakeRectToRect">MakeRectToRect</a> <a href="#SkMatrix_setPolyToPoly">setPolyToPoly</a> 2993 2994 2995 2996 <a name="SkMatrix_setRectToRect"></a> 2997 ## setRectToRect 2998 2999 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3000 bool setRectToRect(const SkRect& src, const SkRect& dst, ScaleToFit stf) 3001 </pre> 3002 3003 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 3004 mapping completely fills <a href="#SkMatrix_setRectToRect_dst">dst</a> or preserves the aspect ratio, and how to align 3005 <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. 3006 Returns true if <a href="#SkMatrix_setRectToRect_dst">dst</a> is empty, and sets <a href="#Matrix">Matrix</a> to: 3007 3008 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3009 | 0 0 0 | 3010 | 0 0 0 | 3011 | 0 0 1 |</pre> 3012 3013 ### Parameters 3014 3015 <table> <tr> <td><a name="SkMatrix_setRectToRect_src"> <code><strong>src </strong></code> </a></td> <td> 3016 <a href="SkRect_Reference#Rect">Rect</a> to map from</td> 3017 </tr> <tr> <td><a name="SkMatrix_setRectToRect_dst"> <code><strong>dst </strong></code> </a></td> <td> 3018 <a href="SkRect_Reference#Rect">Rect</a> to map to</td> 3019 </tr> <tr> <td><a name="SkMatrix_setRectToRect_stf"> <code><strong>stf </strong></code> </a></td> <td> 3020 one of: <a href="#SkMatrix_kFill_ScaleToFit">kFill ScaleToFit</a>, <a href="#SkMatrix_kStart_ScaleToFit">kStart ScaleToFit</a>, 3021 <a href="#SkMatrix_kCenter_ScaleToFit">kCenter ScaleToFit</a>, <a href="#SkMatrix_kEnd_ScaleToFit">kEnd ScaleToFit</a></td> 3022 </tr> 3023 </table> 3024 3025 ### Return Value 3026 3027 true if <a href="#Matrix">Matrix</a> can represent <a href="SkRect_Reference#Rect">Rect</a> mapping 3028 3029 ### Example 3030 3031 <div><fiddle-embed name="69cdea599dcaaec35efcb24403f4287b"> 3032 3033 #### Example Output 3034 3035 ~~~~ 3036 src: 0, 0, 0, 0 dst: 0, 0, 0, 0 success: false 3037 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 3038 src: 0, 0, 0, 0 dst: 5, 6, 8, 9 success: false 3039 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 3040 src: 1, 2, 3, 4 dst: 0, 0, 0, 0 success: true 3041 [ 0.0000 0.0000 0.0000][ 0.0000 0.0000 0.0000][ 0.0000 0.0000 1.0000] 3042 src: 1, 2, 3, 4 dst: 5, 6, 8, 9 success: true 3043 [ 1.5000 0.0000 3.5000][ 0.0000 1.5000 3.0000][ 0.0000 0.0000 1.0000] 3044 ~~~~ 3045 3046 </fiddle-embed></div> 3047 3048 ### See Also 3049 3050 <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> 3051 3052 --- 3053 3054 <a name="SkMatrix_MakeRectToRect"></a> 3055 ## MakeRectToRect 3056 3057 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3058 static SkMatrix MakeRectToRect(const SkRect& src, const SkRect& dst, ScaleToFit stf) 3059 </pre> 3060 3061 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 3062 whether mapping completely fills <a href="#SkMatrix_MakeRectToRect_dst">dst</a> or preserves the aspect ratio, and how to 3063 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 3064 empty, returns <a href="#Matrix">Matrix</a> set to: 3065 3066 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3067 | 0 0 0 | 3068 | 0 0 0 | 3069 | 0 0 1 |</pre> 3070 3071 ### Parameters 3072 3073 <table> <tr> <td><a name="SkMatrix_MakeRectToRect_src"> <code><strong>src </strong></code> </a></td> <td> 3074 <a href="SkRect_Reference#Rect">Rect</a> to map from</td> 3075 </tr> <tr> <td><a name="SkMatrix_MakeRectToRect_dst"> <code><strong>dst </strong></code> </a></td> <td> 3076 <a href="SkRect_Reference#Rect">Rect</a> to map to</td> 3077 </tr> <tr> <td><a name="SkMatrix_MakeRectToRect_stf"> <code><strong>stf </strong></code> </a></td> <td> 3078 one of: <a href="#SkMatrix_kFill_ScaleToFit">kFill ScaleToFit</a>, <a href="#SkMatrix_kStart_ScaleToFit">kStart ScaleToFit</a>, 3079 <a href="#SkMatrix_kCenter_ScaleToFit">kCenter ScaleToFit</a>, <a href="#SkMatrix_kEnd_ScaleToFit">kEnd ScaleToFit</a></td> 3080 </tr> 3081 </table> 3082 3083 ### Return Value 3084 3085 <a href="#Matrix">Matrix</a> mapping <a href="#SkMatrix_MakeRectToRect_src">src</a> to <a href="#SkMatrix_MakeRectToRect_dst">dst</a> 3086 3087 ### Example 3088 3089 <div><fiddle-embed name="a1d6a6721b39350f81021f71a1b93208"> 3090 3091 #### Example Output 3092 3093 ~~~~ 3094 src: 0, 0, 0, 0 dst: 0, 0, 0, 0 3095 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 3096 src: 0, 0, 0, 0 dst: 5, 6, 8, 9 3097 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 3098 src: 1, 2, 3, 4 dst: 0, 0, 0, 0 3099 [ 0.0000 0.0000 0.0000][ 0.0000 0.0000 0.0000][ 0.0000 0.0000 1.0000] 3100 src: 1, 2, 3, 4 dst: 5, 6, 8, 9 3101 [ 1.5000 0.0000 3.5000][ 0.0000 1.5000 3.0000][ 0.0000 0.0000 1.0000] 3102 ~~~~ 3103 3104 </fiddle-embed></div> 3105 3106 ### See Also 3107 3108 <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> 3109 3110 --- 3111 3112 <a name="SkMatrix_setPolyToPoly"></a> 3113 ## setPolyToPoly 3114 3115 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3116 bool setPolyToPoly(const SkPoint src[], const SkPoint dst[], int count) 3117 </pre> 3118 3119 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. 3120 3121 If <a href="#SkMatrix_setPolyToPoly_count">count</a> is zero, sets <a href="#Matrix">Matrix</a> to identity and returns true. 3122 If <a href="#SkMatrix_setPolyToPoly_count">count</a> is one, sets <a href="#Matrix">Matrix</a> to translate and returns true. 3123 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 3124 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 3125 perspective. 3126 3127 ### Parameters 3128 3129 <table> <tr> <td><a name="SkMatrix_setPolyToPoly_src"> <code><strong>src </strong></code> </a></td> <td> 3130 <a href="SkPoint_Reference#Point">Points</a> to map from</td> 3131 </tr> <tr> <td><a name="SkMatrix_setPolyToPoly_dst"> <code><strong>dst </strong></code> </a></td> <td> 3132 <a href="SkPoint_Reference#Point">Points</a> to map to</td> 3133 </tr> <tr> <td><a name="SkMatrix_setPolyToPoly_count"> <code><strong>count </strong></code> </a></td> <td> 3134 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> 3135 </tr> 3136 </table> 3137 3138 ### Return Value 3139 3140 true if <a href="#Matrix">Matrix</a> was constructed successfully 3141 3142 ### Example 3143 3144 <div><fiddle-embed name="c851d1313e8909aaea4f0591699fdb7b"></fiddle-embed></div> 3145 3146 ### See Also 3147 3148 <a href="#SkMatrix_setRectToRect">setRectToRect</a> <a href="#SkMatrix_MakeRectToRect">MakeRectToRect</a> 3149 3150 --- 3151 3152 <a name="SkMatrix_invert"></a> 3153 ## invert 3154 3155 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3156 bool SK_WARN_UNUSED_RESULT invert(SkMatrix* inverse) const 3157 </pre> 3158 3159 Sets <a href="#SkMatrix_invert_inverse">inverse</a> to reciprocal matrix, returning true if <a href="#Matrix">Matrix</a> can be inverted. 3160 Geometrically, if <a href="#Matrix">Matrix</a> maps from source to destination, <a href="#SkMatrix_invert_inverse">inverse</a> <a href="#Matrix">Matrix</a> 3161 maps from destination to source. If <a href="#Matrix">Matrix</a> can not be inverted, <a href="#SkMatrix_invert_inverse">inverse</a> is 3162 unchanged. 3163 3164 ### Parameters 3165 3166 <table> <tr> <td><a name="SkMatrix_invert_inverse"> <code><strong>inverse </strong></code> </a></td> <td> 3167 storage for inverted <a href="#Matrix">Matrix</a>; may be nullptr</td> 3168 </tr> 3169 </table> 3170 3171 ### Return Value 3172 3173 true if <a href="#Matrix">Matrix</a> can be inverted 3174 3175 ### Example 3176 3177 <div><fiddle-embed name="10a10c5bf2ac7ec88e84204441fc83b6"></fiddle-embed></div> 3178 3179 ### See Also 3180 3181 <a href="#SkMatrix_Concat">Concat</a> 3182 3183 --- 3184 3185 <a name="SkMatrix_SetAffineIdentity"></a> 3186 ## SetAffineIdentity 3187 3188 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3189 static void SetAffineIdentity(SkScalar affine[6]) 3190 </pre> 3191 3192 Fills <a href="#SkMatrix_SetAffineIdentity_affine">affine</a> with identity values in column major order. 3193 Sets <a href="#SkMatrix_SetAffineIdentity_affine">affine</a> to: 3194 3195 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3196 | 1 0 0 | 3197 | 0 1 0 |</pre> 3198 3199 Affine 3x2 matrices in column major order are used by OpenGL and XPS. 3200 3201 ### Parameters 3202 3203 <table> <tr> <td><a name="SkMatrix_SetAffineIdentity_affine"> <code><strong>affine </strong></code> </a></td> <td> 3204 storage for 3x2 <a href="#SkMatrix_SetAffineIdentity_affine">affine</a> matrix</td> 3205 </tr> 3206 </table> 3207 3208 ### Example 3209 3210 <div><fiddle-embed name="e10adbd0bcc940c5d4d872db0e78e892"> 3211 3212 #### Example Output 3213 3214 ~~~~ 3215 ScaleX: 1 SkewY: 0 SkewX: 0 ScaleY: 1 TransX: 0 TransY: 0 3216 ~~~~ 3217 3218 </fiddle-embed></div> 3219 3220 ### See Also 3221 3222 <a href="#SkMatrix_setAffine">setAffine</a> <a href="#SkMatrix_asAffine">asAffine</a> 3223 3224 --- 3225 3226 <a name="SkMatrix_asAffine"></a> 3227 ## asAffine 3228 3229 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3230 bool SK_WARN_UNUSED_RESULT asAffine(SkScalar affine[6]) const 3231 </pre> 3232 3233 Fills <a href="#SkMatrix_asAffine_affine">affine</a> in column major order. Sets <a href="#SkMatrix_asAffine_affine">affine</a> to: 3234 3235 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3236 | scale-x skew-x translate-x | 3237 | skew-y scale-y translate-y |</pre> 3238 3239 If <a href="#Matrix">Matrix</a> contains perspective, returns false and leaves <a href="#SkMatrix_asAffine_affine">affine</a> unchanged. 3240 3241 ### Parameters 3242 3243 <table> <tr> <td><a name="SkMatrix_asAffine_affine"> <code><strong>affine </strong></code> </a></td> <td> 3244 storage for 3x2 <a href="#SkMatrix_asAffine_affine">affine</a> matrix; may be nullptr</td> 3245 </tr> 3246 </table> 3247 3248 ### Return Value 3249 3250 true if <a href="#Matrix">Matrix</a> does not contain perspective 3251 3252 ### Example 3253 3254 <div><fiddle-embed name="752e4a48ed1dae05765a2499c390f277"> 3255 3256 #### Example Output 3257 3258 ~~~~ 3259 ScaleX: 2 SkewY: 5 SkewX: 3 ScaleY: 6 TransX: 4 TransY: 7 3260 ~~~~ 3261 3262 </fiddle-embed></div> 3263 3264 ### See Also 3265 3266 <a href="#SkMatrix_setAffine">setAffine</a> <a href="#SkMatrix_SetAffineIdentity">SetAffineIdentity</a> 3267 3268 --- 3269 3270 <a name="SkMatrix_setAffine"></a> 3271 ## setAffine 3272 3273 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3274 void setAffine(const SkScalar affine[6]) 3275 </pre> 3276 3277 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>, 3278 column, then row, as: 3279 3280 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3281 | scale-x skew-x translate-x | 3282 | skew-y scale-y translate-y |</pre> 3283 3284 <a href="#Matrix">Matrix</a> is set, row, then column, to: 3285 3286 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3287 | scale-x skew-x translate-x | 3288 | skew-y scale-y translate-y | 3289 | 0 0 1 |</pre> 3290 3291 ### Parameters 3292 3293 <table> <tr> <td><a name="SkMatrix_setAffine_affine"> <code><strong>affine </strong></code> </a></td> <td> 3294 3x2 <a href="#SkMatrix_setAffine_affine">affine</a> matrix</td> 3295 </tr> 3296 </table> 3297 3298 ### Example 3299 3300 <div><fiddle-embed name="403370bd53526f59020a7141955d70b0"> 3301 3302 #### Example Output 3303 3304 ~~~~ 3305 ScaleX: 2 SkewY: 5 SkewX: 3 ScaleY: 6 TransX: 4 TransY: 7 3306 [ 2.0000 3.0000 4.0000][ 5.0000 6.0000 7.0000][ 0.0000 0.0000 1.0000] 3307 ~~~~ 3308 3309 </fiddle-embed></div> 3310 3311 ### See Also 3312 3313 <a href="#SkMatrix_asAffine">asAffine</a> <a href="#SkMatrix_SetAffineIdentity">SetAffineIdentity</a> 3314 3315 --- 3316 3317 ## <a name="Transform"></a> Transform 3318 3319 | name | description | 3320 | --- | --- | 3321 | <a href="#SkMatrix_mapHomogeneousPoints">mapHomogeneousPoints</a> | maps <a href="undocumented#Point3">Point3</a> array | 3322 | <a href="#SkMatrix_mapPoints">mapPoints</a> | maps <a href="SkPoint_Reference#Point">Point</a> array | 3323 | | <a href="#SkMatrix_mapPoints">mapPoints(SkPoint dst[], const SkPoint src[], int count)</a> const | 3324 | | <a href="#SkMatrix_mapPoints_2">mapPoints(SkPoint pts[], int count)</a> const | 3325 | <a href="#SkMatrix_mapRadius">mapRadius</a> | returns mean radius of mapped <a href="undocumented#Circle">Circle</a> | 3326 | <a href="#SkMatrix_mapRect">mapRect</a> | returns bounds of mapped <a href="SkRect_Reference#Rect">Rect</a> | 3327 | | <a href="#SkMatrix_mapRect">mapRect(SkRect* dst, const SkRect& src)</a> const | 3328 | | <a href="#SkMatrix_mapRect_2">mapRect(SkRect* rect)</a> const | 3329 | <a href="#SkMatrix_mapRectScaleTranslate">mapRectScaleTranslate</a> | returns bounds of mapped <a href="SkRect_Reference#Rect">Rect</a> | 3330 | <a href="#SkMatrix_mapRectToQuad">mapRectToQuad</a> | maps <a href="SkRect_Reference#Rect">Rect</a> to <a href="SkPoint_Reference#Point">Point</a> array | 3331 | <a href="#SkMatrix_mapVector">mapVector</a> | maps <a href="SkPoint_Reference#Vector">Vector</a> | 3332 | | <a href="#SkMatrix_mapVector">mapVector(SkScalar dx, SkScalar dy, SkVector* result)</a> const | 3333 | | <a href="#SkMatrix_mapVector_2">mapVector(SkScalar dx, SkScalar dy)</a> const | 3334 | <a href="#SkMatrix_mapVectors">mapVectors</a> | maps <a href="SkPoint_Reference#Vector">Vector</a> array | 3335 | | <a href="#SkMatrix_mapVectors">mapVectors(SkVector dst[], const SkVector src[], int count)</a> const | 3336 | | <a href="#SkMatrix_mapVectors_2">mapVectors(SkVector vecs[], int count)</a> const | 3337 | <a href="#SkMatrix_mapXY">mapXY</a> | maps <a href="SkPoint_Reference#Point">Point</a> | 3338 | | <a href="#SkMatrix_mapXY">mapXY(SkScalar x, SkScalar y, SkPoint* result)</a> const | 3339 | | <a href="#SkMatrix_mapXY_2">mapXY(SkScalar x, SkScalar y)</a> const | 3340 3341 <a name="SkMatrix_mapPoints"></a> 3342 ## mapPoints 3343 3344 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3345 void mapPoints(SkPoint dst[], const SkPoint src[], int count) const 3346 </pre> 3347 3348 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 3349 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: 3350 3351 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3352 | A B C | | x | 3353 Matrix = | D E F |, pt = | y | 3354 | G H I | | 1 |</pre> 3355 3356 where 3357 3358 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3359 for (i = 0; i < count; ++i) { 3360 x = src[i].fX 3361 y = src[i].fY 3362 }</pre> 3363 3364 each <a href="#SkMatrix_mapPoints_dst">dst</a> <a href="SkPoint_Reference#Point">Point</a> is computed as: 3365 3366 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3367 |A B C| |x| Ax+By+C Dx+Ey+F 3368 Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , ------- 3369 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3370 3371 <a href="#SkMatrix_mapPoints_src">src</a> and <a href="#SkMatrix_mapPoints_dst">dst</a> may point to the same storage. 3372 3373 ### Parameters 3374 3375 <table> <tr> <td><a name="SkMatrix_mapPoints_dst"> <code><strong>dst </strong></code> </a></td> <td> 3376 storage for mapped <a href="SkPoint_Reference#Point">Points</a></td> 3377 </tr> <tr> <td><a name="SkMatrix_mapPoints_src"> <code><strong>src </strong></code> </a></td> <td> 3378 <a href="SkPoint_Reference#Point">Points</a> to transform</td> 3379 </tr> <tr> <td><a name="SkMatrix_mapPoints_count"> <code><strong>count </strong></code> </a></td> <td> 3380 number of <a href="SkPoint_Reference#Point">Points</a> to transform</td> 3381 </tr> 3382 </table> 3383 3384 ### Example 3385 3386 <div><fiddle-embed name="f99dcb00296d0c56b6c0e178e94b3534"></fiddle-embed></div> 3387 3388 ### See Also 3389 3390 <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> 3391 3392 --- 3393 3394 <a name="SkMatrix_mapPoints_2"></a> 3395 3396 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3397 void mapPoints(SkPoint pts[], int count) const 3398 </pre> 3399 3400 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 3401 each <a href="SkPoint_Reference#Point">Point</a> by <a href="#Matrix">Matrix</a>. Given: 3402 3403 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3404 | A B C | | x | 3405 Matrix = | D E F |, pt = | y | 3406 | G H I | | 1 |</pre> 3407 3408 where 3409 3410 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3411 for (i = 0; i < count; ++i) { 3412 x = pts[i].fX 3413 y = pts[i].fY 3414 }</pre> 3415 3416 each resulting <a href="#SkMatrix_mapPoints_2_pts">pts</a> <a href="SkPoint_Reference#Point">Point</a> is computed as: 3417 3418 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3419 |A B C| |x| Ax+By+C Dx+Ey+F 3420 Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , ------- 3421 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3422 3423 ### Parameters 3424 3425 <table> <tr> <td><a name="SkMatrix_mapPoints_2_pts"> <code><strong>pts </strong></code> </a></td> <td> 3426 storage for mapped <a href="SkPoint_Reference#Point">Points</a></td> 3427 </tr> <tr> <td><a name="SkMatrix_mapPoints_2_count"> <code><strong>count </strong></code> </a></td> <td> 3428 number of <a href="SkPoint_Reference#Point">Points</a> to transform</td> 3429 </tr> 3430 </table> 3431 3432 ### Example 3433 3434 <div><fiddle-embed name="428ca171ae3bd0d3f992458ac598b97b"></fiddle-embed></div> 3435 3436 ### See Also 3437 3438 <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> 3439 3440 --- 3441 3442 <a name="SkMatrix_mapHomogeneousPoints"></a> 3443 ## mapHomogeneousPoints 3444 3445 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3446 void mapHomogeneousPoints(SkPoint3 dst[], const SkPoint3 src[], int count) const 3447 </pre> 3448 3449 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 3450 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: 3451 3452 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3453 | A B C | | x | 3454 Matrix = | D E F |, src = | y | 3455 | G H I | | z |</pre> 3456 3457 each resulting <a href="#SkMatrix_mapHomogeneousPoints_dst">dst</a> <a href="SkPoint_Reference#Point">Point</a> is computed as: 3458 3459 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3460 |A B C| |x| 3461 Matrix * src = |D E F| |y| = |Ax+By+Cz Dx+Ey+Fz Gx+Hy+Iz| 3462 |G H I| |z|</pre> 3463 3464 ### Parameters 3465 3466 <table> <tr> <td><a name="SkMatrix_mapHomogeneousPoints_dst"> <code><strong>dst </strong></code> </a></td> <td> 3467 storage for mapped <a href="undocumented#Point3">Point3</a> array</td> 3468 </tr> <tr> <td><a name="SkMatrix_mapHomogeneousPoints_src"> <code><strong>src </strong></code> </a></td> <td> 3469 <a href="undocumented#Point3">Point3</a> array to transform</td> 3470 </tr> <tr> <td><a name="SkMatrix_mapHomogeneousPoints_count"> <code><strong>count </strong></code> </a></td> <td> 3471 items in <a href="undocumented#Point3">Point3</a> array to transform</td> 3472 </tr> 3473 </table> 3474 3475 ### Example 3476 3477 <div><fiddle-embed name="d56f93e4bc763c7ba4914321ed07a8b5"></fiddle-embed></div> 3478 3479 ### See Also 3480 3481 <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> 3482 3483 --- 3484 3485 <a name="SkMatrix_mapXY"></a> 3486 ## mapXY 3487 3488 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3489 void mapXY(SkScalar x, SkScalar y, SkPoint* result) const 3490 </pre> 3491 3492 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: 3493 3494 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3495 | A B C | | x | 3496 Matrix = | D E F |, pt = | y | 3497 | G H I | | 1 |</pre> 3498 3499 <a href="#SkMatrix_mapXY_result">result</a> is computed as: 3500 3501 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3502 |A B C| |x| Ax+By+C Dx+Ey+F 3503 Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , ------- 3504 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3505 3506 ### Parameters 3507 3508 <table> <tr> <td><a name="SkMatrix_mapXY_x"> <code><strong>x </strong></code> </a></td> <td> 3509 <a href="#SkMatrix_mapXY_x">x</a>-coordinate of <a href="SkPoint_Reference#Point">Point</a> to map</td> 3510 </tr> <tr> <td><a name="SkMatrix_mapXY_y"> <code><strong>y </strong></code> </a></td> <td> 3511 <a href="#SkMatrix_mapXY_y">y</a>-coordinate of <a href="SkPoint_Reference#Point">Point</a> to map</td> 3512 </tr> <tr> <td><a name="SkMatrix_mapXY_result"> <code><strong>result </strong></code> </a></td> <td> 3513 storage for mapped <a href="SkPoint_Reference#Point">Point</a></td> 3514 </tr> 3515 </table> 3516 3517 ### Example 3518 3519 <div><fiddle-embed name="9e50185d502dc6903783679a84106089"></fiddle-embed></div> 3520 3521 ### See Also 3522 3523 <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> 3524 3525 --- 3526 3527 <a name="SkMatrix_mapXY_2"></a> 3528 3529 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3530 SkPoint mapXY(SkScalar x, SkScalar y) const 3531 </pre> 3532 3533 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: 3534 3535 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3536 | A B C | | x | 3537 Matrix = | D E F |, pt = | y | 3538 | G H I | | 1 |</pre> 3539 3540 result is computed as: 3541 3542 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3543 |A B C| |x| Ax+By+C Dx+Ey+F 3544 Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , ------- 3545 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3546 3547 ### Parameters 3548 3549 <table> <tr> <td><a name="SkMatrix_mapXY_2_x"> <code><strong>x </strong></code> </a></td> <td> 3550 <a href="#SkMatrix_mapXY_2_x">x</a>-coordinate of <a href="SkPoint_Reference#Point">Point</a> to map</td> 3551 </tr> <tr> <td><a name="SkMatrix_mapXY_2_y"> <code><strong>y </strong></code> </a></td> <td> 3552 <a href="#SkMatrix_mapXY_2_y">y</a>-coordinate of <a href="SkPoint_Reference#Point">Point</a> to map</td> 3553 </tr> 3554 </table> 3555 3556 ### Return Value 3557 3558 mapped <a href="SkPoint_Reference#Point">Point</a> 3559 3560 ### Example 3561 3562 <div><fiddle-embed name="b1ead09c67a177ab8eace12b061610a7"></fiddle-embed></div> 3563 3564 ### See Also 3565 3566 <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> 3567 3568 --- 3569 3570 <a name="SkMatrix_mapVectors"></a> 3571 ## mapVectors 3572 3573 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3574 void mapVectors(SkVector dst[], const SkVector src[], int count) const 3575 </pre> 3576 3577 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 3578 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 3579 <a href="#Matrix">Matrix</a> translation as zero. Given: 3580 3581 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3582 | A B 0 | | x | 3583 Matrix = | D E 0 |, src = | y | 3584 | G H I | | 1 |</pre> 3585 3586 where 3587 3588 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3589 for (i = 0; i < count; ++i) { 3590 x = src[i].fX 3591 y = src[i].fY 3592 }</pre> 3593 3594 each <a href="#SkMatrix_mapVectors_dst">dst</a> <a href="SkPoint_Reference#Vector">Vector</a> is computed as: 3595 3596 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3597 |A B 0| |x| Ax+By Dx+Ey 3598 Matrix * src = |D E 0| |y| = |Ax+By Dx+Ey Gx+Hy+I| = ------- , ------- 3599 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3600 3601 <a href="#SkMatrix_mapVectors_src">src</a> and <a href="#SkMatrix_mapVectors_dst">dst</a> may point to the same storage. 3602 3603 ### Parameters 3604 3605 <table> <tr> <td><a name="SkMatrix_mapVectors_dst"> <code><strong>dst </strong></code> </a></td> <td> 3606 storage for mapped <a href="SkPoint_Reference#Vector">Vectors</a></td> 3607 </tr> <tr> <td><a name="SkMatrix_mapVectors_src"> <code><strong>src </strong></code> </a></td> <td> 3608 <a href="SkPoint_Reference#Vector">Vectors</a> to transform</td> 3609 </tr> <tr> <td><a name="SkMatrix_mapVectors_count"> <code><strong>count </strong></code> </a></td> <td> 3610 number of <a href="SkPoint_Reference#Vector">Vectors</a> to transform</td> 3611 </tr> 3612 </table> 3613 3614 ### Example 3615 3616 <div><fiddle-embed name="918a9778c3d7d5cb306692784399f6dc"></fiddle-embed></div> 3617 3618 ### See Also 3619 3620 <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> 3621 3622 --- 3623 3624 <a name="SkMatrix_mapVectors_2"></a> 3625 3626 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3627 void mapVectors(SkVector vecs[], int count) const 3628 </pre> 3629 3630 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 3631 <a href="#Matrix">Matrix</a>, treating <a href="#Matrix">Matrix</a> translation as zero. Given: 3632 3633 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3634 | A B 0 | | x | 3635 Matrix = | D E 0 |, vec = | y | 3636 | G H I | | 1 |</pre> 3637 3638 where 3639 3640 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3641 for (i = 0; i < count; ++i) { 3642 x = vecs[i].fX 3643 y = vecs[i].fY 3644 }</pre> 3645 3646 each result <a href="SkPoint_Reference#Vector">Vector</a> is computed as: 3647 3648 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3649 |A B 0| |x| Ax+By Dx+Ey 3650 Matrix * vec = |D E 0| |y| = |Ax+By Dx+Ey Gx+Hy+I| = ------- , ------- 3651 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3652 3653 ### Parameters 3654 3655 <table> <tr> <td><a name="SkMatrix_mapVectors_2_vecs"> <code><strong>vecs </strong></code> </a></td> <td> 3656 <a href="SkPoint_Reference#Vector">Vectors</a> to transform, and storage for mapped <a href="SkPoint_Reference#Vector">Vectors</a></td> 3657 </tr> <tr> <td><a name="SkMatrix_mapVectors_2_count"> <code><strong>count </strong></code> </a></td> <td> 3658 number of <a href="SkPoint_Reference#Vector">Vectors</a> to transform</td> 3659 </tr> 3660 </table> 3661 3662 ### Example 3663 3664 <div><fiddle-embed name="5754501a00a1323e76353fb53153e939"></fiddle-embed></div> 3665 3666 ### See Also 3667 3668 <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> 3669 3670 --- 3671 3672 <a name="SkMatrix_mapVector"></a> 3673 ## mapVector 3674 3675 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3676 void mapVector(SkScalar dx, SkScalar dy, SkVector* result) const 3677 </pre> 3678 3679 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>, 3680 treating <a href="#Matrix">Matrix</a> translation as zero. Given: 3681 3682 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3683 | A B 0 | | dx | 3684 Matrix = | D E 0 |, vec = | dy | 3685 | G H I | | 1 |</pre> 3686 3687 each <a href="#SkMatrix_mapVector_result">result</a> <a href="SkPoint_Reference#Vector">Vector</a> is computed as: 3688 3689 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3690 |A B 0| |dx| A*dx+B*dy D*dx+E*dy 3691 Matrix * vec = |D E 0| |dy| = |A*dx+B*dy D*dx+E*dy G*dx+H*dy+I| = ----------- , ----------- 3692 |G H I| | 1| G*dx+H*dy+I G*dx+*dHy+I</pre> 3693 3694 ### Parameters 3695 3696 <table> <tr> <td><a name="SkMatrix_mapVector_dx"> <code><strong>dx </strong></code> </a></td> <td> 3697 x-coordinate of <a href="SkPoint_Reference#Vector">Vector</a> to map</td> 3698 </tr> <tr> <td><a name="SkMatrix_mapVector_dy"> <code><strong>dy </strong></code> </a></td> <td> 3699 y-coordinate of <a href="SkPoint_Reference#Vector">Vector</a> to map</td> 3700 </tr> <tr> <td><a name="SkMatrix_mapVector_result"> <code><strong>result </strong></code> </a></td> <td> 3701 storage for mapped <a href="SkPoint_Reference#Vector">Vector</a></td> 3702 </tr> 3703 </table> 3704 3705 ### Example 3706 3707 <div><fiddle-embed name="aed143fc6cd0bce4ed029b98d1e61f2d"></fiddle-embed></div> 3708 3709 ### See Also 3710 3711 <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> 3712 3713 --- 3714 3715 <a name="SkMatrix_mapVector_2"></a> 3716 3717 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3718 SkVector mapVector(SkScalar dx, SkScalar dy) const 3719 </pre> 3720 3721 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. 3722 Given: 3723 3724 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3725 | A B 0 | | dx | 3726 Matrix = | D E 0 |, vec = | dy | 3727 | G H I | | 1 |</pre> 3728 3729 each result <a href="SkPoint_Reference#Vector">Vector</a> is computed as: 3730 3731 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3732 |A B 0| |dx| A*dx+B*dy D*dx+E*dy 3733 Matrix * vec = |D E 0| |dy| = |A*dx+B*dy D*dx+E*dy G*dx+H*dy+I| = ----------- , ----------- 3734 |G H I| | 1| G*dx+H*dy+I G*dx+*dHy+I</pre> 3735 3736 ### Parameters 3737 3738 <table> <tr> <td><a name="SkMatrix_mapVector_2_dx"> <code><strong>dx </strong></code> </a></td> <td> 3739 x-coordinate of <a href="SkPoint_Reference#Vector">Vector</a> to map</td> 3740 </tr> <tr> <td><a name="SkMatrix_mapVector_2_dy"> <code><strong>dy </strong></code> </a></td> <td> 3741 y-coordinate of <a href="SkPoint_Reference#Vector">Vector</a> to map</td> 3742 </tr> 3743 </table> 3744 3745 ### Return Value 3746 3747 mapped <a href="SkPoint_Reference#Vector">Vector</a> 3748 3749 ### Example 3750 3751 <div><fiddle-embed name="8bf1518db3f369696cd3065b541a8bd7"></fiddle-embed></div> 3752 3753 ### See Also 3754 3755 <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> 3756 3757 --- 3758 3759 <a name="SkMatrix_mapRect"></a> 3760 ## mapRect 3761 3762 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3763 bool mapRect(SkRect* dst, const SkRect& src) const 3764 </pre> 3765 3766 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>. 3767 Returns true if mapped corners are <a href="#SkMatrix_mapRect_dst">dst</a> corners. 3768 3769 Returned value is the same as calling <a href="#SkMatrix_rectStaysRect">rectStaysRect</a>. 3770 3771 ### Parameters 3772 3773 <table> <tr> <td><a name="SkMatrix_mapRect_dst"> <code><strong>dst </strong></code> </a></td> <td> 3774 storage for bounds of mapped <a href="SkPoint_Reference#Point">Points</a></td> 3775 </tr> <tr> <td><a name="SkMatrix_mapRect_src"> <code><strong>src </strong></code> </a></td> <td> 3776 <a href="SkRect_Reference#Rect">Rect</a> to map</td> 3777 </tr> 3778 </table> 3779 3780 ### Return Value 3781 3782 true if <a href="#SkMatrix_mapRect_dst">dst</a> is equivalent to mapped <a href="#SkMatrix_mapRect_src">src</a> 3783 3784 ### Example 3785 3786 <div><fiddle-embed name="dbcf928b035a31ca69c99392e2e2cca9"></fiddle-embed></div> 3787 3788 ### See Also 3789 3790 <a href="#SkMatrix_mapPoints">mapPoints</a><sup><a href="#SkMatrix_mapPoints_2">[2]</a></sup> <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> 3791 3792 --- 3793 3794 <a name="SkMatrix_mapRect_2"></a> 3795 3796 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3797 bool mapRect(SkRect* rect) const 3798 </pre> 3799 3800 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>. 3801 Returns true if mapped corners are computed <a href="#SkMatrix_mapRect_2_rect">rect</a> corners. 3802 3803 Returned value is the same as calling <a href="#SkMatrix_rectStaysRect">rectStaysRect</a>. 3804 3805 ### Parameters 3806 3807 <table> <tr> <td><a name="SkMatrix_mapRect_2_rect"> <code><strong>rect </strong></code> </a></td> <td> 3808 rectangle to map, and storage for bounds of mapped corners</td> 3809 </tr> 3810 </table> 3811 3812 ### Return Value 3813 3814 true if result is equivalent to mapped src 3815 3816 ### Example 3817 3818 <div><fiddle-embed name="5fafd0bd23d1ed37425b970b4a3c6cc9"></fiddle-embed></div> 3819 3820 ### See Also 3821 3822 <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> 3823 3824 --- 3825 3826 <a name="SkMatrix_mapRectToQuad"></a> 3827 ## mapRectToQuad 3828 3829 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3830 void mapRectToQuad(SkPoint dst[4], const SkRect& rect) const 3831 </pre> 3832 3833 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 3834 <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: 3835 (<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), 3836 (<a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fLeft, <a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fBottom). 3837 3838 <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; 3839 <a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fTop may be greater than or equal to <a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fBottom. 3840 3841 Given: 3842 3843 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3844 | A B C | | x | 3845 Matrix = | D E F |, pt = | y | 3846 | G H I | | 1 |</pre> 3847 3848 where pt is initialized from each of (<a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fLeft, <a href="#SkMatrix_mapRectToQuad_rect">rect</a>.fTop), 3849 (<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), 3850 each <a href="#SkMatrix_mapRectToQuad_dst">dst</a> <a href="SkPoint_Reference#Point">Point</a> is computed as: 3851 3852 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3853 |A B C| |x| Ax+By+C Dx+Ey+F 3854 Matrix * pt = |D E F| |y| = |Ax+By+C Dx+Ey+F Gx+Hy+I| = ------- , ------- 3855 |G H I| |1| Gx+Hy+I Gx+Hy+I</pre> 3856 3857 ### Parameters 3858 3859 <table> <tr> <td><a name="SkMatrix_mapRectToQuad_dst"> <code><strong>dst </strong></code> </a></td> <td> 3860 storage for mapped corner <a href="SkPoint_Reference#Point">Points</a></td> 3861 </tr> <tr> <td><a name="SkMatrix_mapRectToQuad_rect"> <code><strong>rect </strong></code> </a></td> <td> 3862 <a href="SkRect_Reference#Rect">Rect</a> to map</td> 3863 </tr> 3864 </table> 3865 3866 ### Example 3867 3868 <div><fiddle-embed name="c69cd2a590b5733c3cbc92cb9ceed3f5"></fiddle-embed></div> 3869 3870 ### See Also 3871 3872 <a href="#SkMatrix_mapRect">mapRect</a><sup><a href="#SkMatrix_mapRect_2">[2]</a></sup> <a href="#SkMatrix_mapRectScaleTranslate">mapRectScaleTranslate</a> 3873 3874 --- 3875 3876 <a name="SkMatrix_mapRectScaleTranslate"></a> 3877 ## mapRectScaleTranslate 3878 3879 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3880 void mapRectScaleTranslate(SkRect* dst, const SkRect& src) const 3881 </pre> 3882 3883 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 3884 elements other than scale or translate: asserts if SK_DEBUG is defined; 3885 otherwise, results are undefined. 3886 3887 ### Parameters 3888 3889 <table> <tr> <td><a name="SkMatrix_mapRectScaleTranslate_dst"> <code><strong>dst </strong></code> </a></td> <td> 3890 storage for bounds of mapped <a href="SkPoint_Reference#Point">Points</a></td> 3891 </tr> <tr> <td><a name="SkMatrix_mapRectScaleTranslate_src"> <code><strong>src </strong></code> </a></td> <td> 3892 <a href="SkRect_Reference#Rect">Rect</a> to map</td> 3893 </tr> 3894 </table> 3895 3896 ### Example 3897 3898 <div><fiddle-embed name="62bc26989c2b4c2a54d516596a71dd97"></fiddle-embed></div> 3899 3900 ### See Also 3901 3902 <a href="#SkMatrix_mapRect">mapRect</a><sup><a href="#SkMatrix_mapRect_2">[2]</a></sup> <a href="#SkMatrix_mapRectToQuad">mapRectToQuad</a> <a href="#SkMatrix_isScaleTranslate">isScaleTranslate</a> <a href="#SkMatrix_rectStaysRect">rectStaysRect</a> 3903 3904 --- 3905 3906 <a name="SkMatrix_mapRadius"></a> 3907 ## mapRadius 3908 3909 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3910 SkScalar mapRadius(SkScalar radius) const 3911 </pre> 3912 3913 Returns geometric mean <a href="#SkMatrix_mapRadius_radius">radius</a> of ellipse formed by constructing <a href="undocumented#Circle">Circle</a> of 3914 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 3915 equal to the major axis length times the minor axis length. 3916 Result is not meaningful if <a href="#Matrix">Matrix</a> contains perspective elements. 3917 3918 ### Parameters 3919 3920 <table> <tr> <td><a name="SkMatrix_mapRadius_radius"> <code><strong>radius </strong></code> </a></td> <td> 3921 <a href="undocumented#Circle">Circle</a> size to map</td> 3922 </tr> 3923 </table> 3924 3925 ### Return Value 3926 3927 average mapped <a href="#SkMatrix_mapRadius_radius">radius</a> 3928 3929 ### Example 3930 3931 <div><fiddle-embed name="6d6f2082fcf59d9f02bfb1758b87db69"><div>The area enclosed by a square with sides equal to mappedRadius is the same as 3932 the area enclosed by the ellipse major and minor axes.</div></fiddle-embed></div> 3933 3934 ### See Also 3935 3936 <a href="#SkMatrix_mapVector">mapVector</a><sup><a href="#SkMatrix_mapVector_2">[2]</a></sup> 3937 3938 --- 3939 3940 <a name="SkMatrix_isFixedStepInX"></a> 3941 ## isFixedStepInX 3942 3943 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3944 bool isFixedStepInX() const 3945 </pre> 3946 3947 Returns true if a unit step in x at some y mapped through <a href="#Matrix">Matrix</a> can be 3948 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>, 3949 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>. 3950 3951 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> 3952 does not include rotation or skewing along the y-axis. 3953 3954 ### Return Value 3955 3956 true if <a href="#Matrix">Matrix</a> does not have complex perspective 3957 3958 ### Example 3959 3960 <div><fiddle-embed name="ab57b232acef69f26de9cb23d23c8a1a"> 3961 3962 #### Example Output 3963 3964 ~~~~ 3965 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 3966 isFixedStepInX: true 3967 [ 1.0000 0.0000 0.0000][ 0.0000 2.0000 0.0000][ 0.0000 0.0000 1.0000] 3968 isFixedStepInX: true 3969 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.0000 0.1000 1.0000] 3970 isFixedStepInX: true 3971 [ 1.0000 0.0000 0.0000][ 0.0000 2.0000 0.0000][ 0.0000 0.1000 1.0000] 3972 isFixedStepInX: true 3973 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.1000 0.0000 1.0000] 3974 isFixedStepInX: false 3975 [ 1.0000 0.0000 0.0000][ 0.0000 2.0000 0.0000][ 0.1000 0.0000 1.0000] 3976 isFixedStepInX: false 3977 [ 1.0000 0.0000 0.0000][ 0.0000 1.0000 0.0000][ 0.1000 0.1000 1.0000] 3978 isFixedStepInX: false 3979 [ 1.0000 0.0000 0.0000][ 0.0000 2.0000 0.0000][ 0.1000 0.1000 1.0000] 3980 isFixedStepInX: false 3981 ~~~~ 3982 3983 </fiddle-embed></div> 3984 3985 ### See Also 3986 3987 <a href="#SkMatrix_fixedStepInX">fixedStepInX</a> <a href="#SkMatrix_getType">getType</a> 3988 3989 --- 3990 3991 <a name="SkMatrix_fixedStepInX"></a> 3992 ## fixedStepInX 3993 3994 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 3995 SkVector fixedStepInX(SkScalar y) const 3996 </pre> 3997 3998 Returns <a href="SkPoint_Reference#Vector">Vector</a> representing a unit step in x at <a href="#SkMatrix_fixedStepInX_y">y</a> mapped through <a href="#Matrix">Matrix</a>. 3999 If <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> is false, returned value is undefined. 4000 4001 ### Parameters 4002 4003 <table> <tr> <td><a name="SkMatrix_fixedStepInX_y"> <code><strong>y </strong></code> </a></td> <td> 4004 position of line parallel to x-axis</td> 4005 </tr> 4006 </table> 4007 4008 ### Return Value 4009 4010 <a href="SkPoint_Reference#Vector">Vector</a> advance of mapped unit step in x 4011 4012 ### Example 4013 4014 <div><fiddle-embed name="fad6b92b21b1e1deeae61978cec2d232"></fiddle-embed></div> 4015 4016 ### See Also 4017 4018 <a href="#SkMatrix_isFixedStepInX">isFixedStepInX</a> <a href="#SkMatrix_getType">getType</a> 4019 4020 --- 4021 4022 <a name="SkMatrix_cheapEqualTo"></a> 4023 ## cheapEqualTo 4024 4025 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4026 bool cheapEqualTo(const SkMatrix& m) const 4027 </pre> 4028 4029 Returns true if <a href="#Matrix">Matrix</a> equals <a href="#SkMatrix_cheapEqualTo_m">m</a>, using an efficient comparison. 4030 4031 Returns false when the sign of zero values is the different; when one 4032 matrix has positive zero value and the other has negative zero value. 4033 4034 Returns true even when both <a href="#Matrix">Matrices</a> contain NaN. 4035 4036 NaN never equals any value, including itself. To improve performance, NaN values 4037 are treated as bit patterns that are equal if their bit patterns are equal. 4038 4039 ### Parameters 4040 4041 <table> <tr> <td><a name="SkMatrix_cheapEqualTo_m"> <code><strong>m </strong></code> </a></td> <td> 4042 <a href="#Matrix">Matrix</a> to compare</td> 4043 </tr> 4044 </table> 4045 4046 ### Return Value 4047 4048 true if <a href="#SkMatrix_cheapEqualTo_m">m</a> and <a href="#Matrix">Matrix</a> are represented by identical bit patterns 4049 4050 ### Example 4051 4052 <div><fiddle-embed name="39016b3cfc6bbabb09348a53822ce508"> 4053 4054 #### Example Output 4055 4056 ~~~~ 4057 identity: a == b a.cheapEqualTo(b): true 4058 neg zero: a == b a.cheapEqualTo(b): false 4059 one NaN: a != b a.cheapEqualTo(b): false 4060 both NaN: a != b a.cheapEqualTo(b): true 4061 ~~~~ 4062 4063 </fiddle-embed></div> 4064 4065 ### See Also 4066 4067 <a href="#SkMatrix_equal_operator">operator==(const SkMatrix& a, const SkMatrix& b)</a> 4068 4069 --- 4070 4071 <a name="SkMatrix_equal_operator"></a> 4072 ## operator== 4073 4074 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4075 bool operator==(const SkMatrix& a, const SkMatrix& b) 4076 </pre> 4077 4078 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 4079 even if sign of zero values are different. Returns false if either <a href="#Matrix">Matrix</a> 4080 contains NaN, even if the other <a href="#Matrix">Matrix</a> also contains NaN. 4081 4082 ### Parameters 4083 4084 <table> <tr> <td><a name="SkMatrix_equal_operator_a"> <code><strong>a </strong></code> </a></td> <td> 4085 <a href="#Matrix">Matrix</a> to compare</td> 4086 </tr> <tr> <td><a name="SkMatrix_equal_operator_b"> <code><strong>b </strong></code> </a></td> <td> 4087 <a href="#Matrix">Matrix</a> to compare</td> 4088 </tr> 4089 </table> 4090 4091 ### Return Value 4092 4093 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 4094 4095 ### Example 4096 4097 <div><fiddle-embed name="3902859150b0f0c4aeb1f25d00434baa"> 4098 4099 #### Example Output 4100 4101 ~~~~ 4102 identity: a == b a.cheapEqualTo(b): true 4103 ~~~~ 4104 4105 </fiddle-embed></div> 4106 4107 ### See Also 4108 4109 <a href="#SkMatrix_cheapEqualTo">cheapEqualTo</a> <a href="#SkMatrix_notequal_operator">operator!=(const SkMatrix& a, const SkMatrix& b)</a> 4110 4111 --- 4112 4113 <a name="SkMatrix_notequal_operator"></a> 4114 ## operator!= 4115 4116 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4117 bool operator!=(const SkMatrix& a, const SkMatrix& b) 4118 </pre> 4119 4120 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 4121 even if sign of zero values are different. Returns true if either <a href="#Matrix">Matrix</a> 4122 contains NaN, even if the other <a href="#Matrix">Matrix</a> also contains NaN. 4123 4124 ### Parameters 4125 4126 <table> <tr> <td><a name="SkMatrix_notequal_operator_a"> <code><strong>a </strong></code> </a></td> <td> 4127 <a href="#Matrix">Matrix</a> to compare</td> 4128 </tr> <tr> <td><a name="SkMatrix_notequal_operator_b"> <code><strong>b </strong></code> </a></td> <td> 4129 <a href="#Matrix">Matrix</a> to compare</td> 4130 </tr> 4131 </table> 4132 4133 ### Return Value 4134 4135 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 4136 4137 ### Example 4138 4139 <div><fiddle-embed name="8a8fadf5fd294daa4ee152833cc0dc0e"></fiddle-embed></div> 4140 4141 ### See Also 4142 4143 <a href="#SkMatrix_cheapEqualTo">cheapEqualTo</a> <a href="#SkMatrix_equal_operator">operator==(const SkMatrix& a, const SkMatrix& b)</a> 4144 4145 --- 4146 4147 ## <a name="Utility"></a> Utility 4148 4149 | name | description | 4150 | --- | --- | 4151 | <a href="#SkMatrix_dirtyMatrixTypeCache">dirtyMatrixTypeCache</a> | sets internal cache to unknown state | 4152 | <a href="#SkMatrix_dump">dump</a> | sends text representation using floats to standard output | 4153 | <a href="#SkMatrix_toString">toString</a> | converts <a href="#Matrix">Matrix</a> to machine readable form | 4154 4155 <a name="SkMatrix_dump"></a> 4156 ## dump 4157 4158 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4159 void dump() const 4160 </pre> 4161 4162 Writes text representation of <a href="#Matrix">Matrix</a> to standard output. Floating point values 4163 are written with limited precision; it may not be possible to reconstruct 4164 original <a href="#Matrix">Matrix</a> from output. 4165 4166 ### Example 4167 4168 <div><fiddle-embed name="8d72a4818e5a9188348f6c08ab5d8a40"> 4169 4170 #### Example Output 4171 4172 ~~~~ 4173 [ 0.7071 -0.7071 0.0000][ 0.7071 0.7071 0.0000][ 0.0000 0.0000 1.0000] 4174 [ 0.7071 -0.7071 0.0000][ 0.7071 0.7071 0.0000][ 0.0000 0.0000 1.0000] 4175 matrix != nearlyEqual 4176 ~~~~ 4177 4178 </fiddle-embed></div> 4179 4180 ### See Also 4181 4182 <a href="#SkMatrix_toString">toString</a> 4183 4184 --- 4185 4186 <a name="SkMatrix_toString"></a> 4187 ## toString 4188 4189 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4190 void toString(SkString* str) const 4191 </pre> 4192 4193 Creates string representation of <a href="#Matrix">Matrix</a>. Floating point values 4194 are written with limited precision; it may not be possible to reconstruct 4195 original <a href="#Matrix">Matrix</a> from output. 4196 4197 ### Parameters 4198 4199 <table> <tr> <td><a name="SkMatrix_toString_str"> <code><strong>str </strong></code> </a></td> <td> 4200 storage for string representation of <a href="#Matrix">Matrix</a></td> 4201 </tr> 4202 </table> 4203 4204 ### Example 4205 4206 <div><fiddle-embed name="1d86e43958e42b8eaaa9b16df1baa4c8"> 4207 4208 #### Example Output 4209 4210 ~~~~ 4211 mStr [ 0.7071 -0.7071 0.0000][ 0.7071 0.7071 0.0000][ 0.0000 0.0000 1.0000] 4212 neStr [ 0.7071 -0.7071 0.0000][ 0.7071 0.7071 0.0000][ 0.0000 0.0000 1.0000] 4213 matrix != nearlyEqual 4214 ~~~~ 4215 4216 </fiddle-embed></div> 4217 4218 ### See Also 4219 4220 <a href="#SkMatrix_dump">dump</a> 4221 4222 --- 4223 4224 <a name="SkMatrix_getMinScale"></a> 4225 ## getMinScale 4226 4227 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4228 SkScalar getMinScale() const 4229 </pre> 4230 4231 Returns the minimum scaling factor of <a href="#Matrix">Matrix</a> by decomposing the scaling and 4232 skewing elements. 4233 Returns -1 if scale factor overflows or <a href="#Matrix">Matrix</a> contains perspective. 4234 4235 ### Return Value 4236 4237 minimum scale factor 4238 4239 ### Example 4240 4241 <div><fiddle-embed name="1d6f67904c88a806c3731879e9af4ae5"> 4242 4243 #### Example Output 4244 4245 ~~~~ 4246 matrix.getMinScale() 24 4247 ~~~~ 4248 4249 </fiddle-embed></div> 4250 4251 ### See Also 4252 4253 <a href="#SkMatrix_getMaxScale">getMaxScale</a> <a href="#SkMatrix_getMinMaxScales">getMinMaxScales</a> 4254 4255 --- 4256 4257 <a name="SkMatrix_getMaxScale"></a> 4258 ## getMaxScale 4259 4260 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4261 SkScalar getMaxScale() const 4262 </pre> 4263 4264 Returns the maximum scaling factor of <a href="#Matrix">Matrix</a> by decomposing the scaling and 4265 skewing elements. 4266 Returns -1 if scale factor overflows or <a href="#Matrix">Matrix</a> contains perspective. 4267 4268 ### Return Value 4269 4270 maximum scale factor 4271 4272 ### Example 4273 4274 <div><fiddle-embed name="3fee4364929899649cf9efc37897e964"> 4275 4276 #### Example Output 4277 4278 ~~~~ 4279 matrix.getMaxScale() 42 4280 ~~~~ 4281 4282 </fiddle-embed></div> 4283 4284 ### See Also 4285 4286 <a href="#SkMatrix_getMinScale">getMinScale</a> <a href="#SkMatrix_getMinMaxScales">getMinMaxScales</a> 4287 4288 --- 4289 4290 <a name="SkMatrix_getMinMaxScales"></a> 4291 ## getMinMaxScales 4292 4293 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4294 bool SK_WARN_UNUSED_RESULT getMinMaxScales(SkScalar scaleFactors[2]) const 4295 </pre> 4296 4297 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 4298 maximum scaling factor. Scaling factors are computed by decomposing 4299 the <a href="#Matrix">Matrix</a> scaling and skewing elements. 4300 4301 Returns true if <a href="#SkMatrix_getMinMaxScales_scaleFactors">scaleFactors</a> are found; otherwise, returns false and sets 4302 <a href="#SkMatrix_getMinMaxScales_scaleFactors">scaleFactors</a> to undefined values. 4303 4304 ### Parameters 4305 4306 <table> <tr> <td><a name="SkMatrix_getMinMaxScales_scaleFactors"> <code><strong>scaleFactors </strong></code> </a></td> <td> 4307 storage for minimum and maximum scale factors</td> 4308 </tr> 4309 </table> 4310 4311 ### Return Value 4312 4313 true if scale factors were computed correctly 4314 4315 ### Example 4316 4317 <div><fiddle-embed name="cd4dc63d3e04226f0b5861ba8925e223"> 4318 4319 #### Example Output 4320 4321 ~~~~ 4322 matrix.getMinMaxScales() false 2 2 4323 ~~~~ 4324 4325 </fiddle-embed></div> 4326 4327 ### See Also 4328 4329 <a href="#SkMatrix_getMinScale">getMinScale</a> <a href="#SkMatrix_getMaxScale">getMaxScale</a> 4330 4331 --- 4332 4333 <a name="SkMatrix_decomposeScale"></a> 4334 ## decomposeScale 4335 4336 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4337 bool decomposeScale(SkSize* scale, SkMatrix* remaining = nullptr) const 4338 </pre> 4339 4340 Decomposes <a href="#Matrix">Matrix</a> into <a href="#SkMatrix_decomposeScale_scale">scale</a> components and whatever remains. Returns false if 4341 <a href="#Matrix">Matrix</a> could not be decomposed. 4342 4343 Sets <a href="#SkMatrix_decomposeScale_scale">scale</a> to portion of <a href="#Matrix">Matrix</a> that scales in x and y. Sets <a href="#SkMatrix_decomposeScale_remaining">remaining</a> to <a href="#Matrix">Matrix</a> 4344 with x and y scaling factored out. <a href="#SkMatrix_decomposeScale_remaining">remaining</a> may be passed as nullptr 4345 to determine if <a href="#Matrix">Matrix</a> can be decomposed without computing remainder. 4346 4347 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 4348 unchanged if <a href="#Matrix">Matrix</a> contains perspective; <a href="#SkMatrix_decomposeScale_scale">scale</a> factors are not finite, or 4349 are nearly zero. 4350 4351 On success<a href="#Matrix">Matrix</a> = <a href="#SkMatrix_decomposeScale_scale">scale</a> * Remaining 4352 4353 ### Parameters 4354 4355 <table> <tr> <td><a name="SkMatrix_decomposeScale_scale"> <code><strong>scale </strong></code> </a></td> <td> 4356 x and y scaling factors; may be nullptr</td> 4357 </tr> <tr> <td><a name="SkMatrix_decomposeScale_remaining"> <code><strong>remaining </strong></code> </a></td> <td> 4358 <a href="#Matrix">Matrix</a> without scaling; may be nullptr</td> 4359 </tr> 4360 </table> 4361 4362 ### Return Value 4363 4364 true if <a href="#SkMatrix_decomposeScale_scale">scale</a> can be computed 4365 4366 ### Example 4367 4368 <div><fiddle-embed name="139b874da0a3ede1f3df88119085c0aa"> 4369 4370 #### Example Output 4371 4372 ~~~~ 4373 [ 0.0000 -0.2500 0.0000][ 0.5000 0.0000 0.0000][ 0.0000 0.0000 1.0000] 4374 success: true scale: 0.5, 0.25 4375 [ 0.0000 -0.5000 0.0000][ 2.0000 0.0000 0.0000][ 0.0000 0.0000 1.0000] 4376 [ 0.0000 -0.2500 0.0000][ 0.5000 0.0000 0.0000][ 0.0000 0.0000 1.0000] 4377 ~~~~ 4378 4379 </fiddle-embed></div> 4380 4381 ### See Also 4382 4383 <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> 4384 4385 --- 4386 4387 <a name="SkMatrix_I"></a> 4388 ## I 4389 4390 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4391 static const SkMatrix& I() 4392 </pre> 4393 4394 Returns reference to const identity <a href="#Matrix">Matrix</a>. Returned <a href="#Matrix">Matrix</a> is set to: 4395 4396 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4397 | 1 0 0 | 4398 | 0 1 0 | 4399 | 0 0 1 |</pre> 4400 4401 ### Return Value 4402 4403 const identity <a href="#Matrix">Matrix</a> 4404 4405 ### Example 4406 4407 <div><fiddle-embed name="d961d91020f19037204a8c3fd8cb1060"> 4408 4409 #### Example Output 4410 4411 ~~~~ 4412 m1 == m2 4413 m2 == m3 4414 ~~~~ 4415 4416 </fiddle-embed></div> 4417 4418 ### See Also 4419 4420 <a href="#SkMatrix_reset">reset</a> <a href="#SkMatrix_setIdentity">setIdentity</a> 4421 4422 --- 4423 4424 <a name="SkMatrix_InvalidMatrix"></a> 4425 ## InvalidMatrix 4426 4427 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4428 static const SkMatrix& InvalidMatrix() 4429 </pre> 4430 4431 Returns reference to a const <a href="#Matrix">Matrix</a> with invalid values. Returned <a href="#Matrix">Matrix</a> is set 4432 to: 4433 4434 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4435 | SK_ScalarMax SK_ScalarMax SK_ScalarMax | 4436 | SK_ScalarMax SK_ScalarMax SK_ScalarMax | 4437 | SK_ScalarMax SK_ScalarMax SK_ScalarMax |</pre> 4438 4439 ### Return Value 4440 4441 const invalid <a href="#Matrix">Matrix</a> 4442 4443 ### Example 4444 4445 <div><fiddle-embed name="af0b72360c1c7a25b4754bfa47011dd5"> 4446 4447 #### Example Output 4448 4449 ~~~~ 4450 scaleX 3.40282e+38 4451 ~~~~ 4452 4453 </fiddle-embed></div> 4454 4455 ### See Also 4456 4457 SeeAlso <a href="#SkMatrix_getType">getType</a> 4458 4459 --- 4460 4461 <a name="SkMatrix_Concat"></a> 4462 ## Concat 4463 4464 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4465 static SkMatrix Concat(const SkMatrix& a, const SkMatrix& b) 4466 </pre> 4467 4468 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>. 4469 4470 Given: 4471 4472 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4473 | A B C | | J K L | 4474 a = | D E F |, b = | M N O | 4475 | G H I | | P Q R |</pre> 4476 4477 sets <a href="#Matrix">Matrix</a> to: 4478 4479 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4480 | A B C | | J K L | | AJ+BM+CP AK+BN+CQ AL+BO+CR | 4481 a * b = | D E F | * | M N O | = | DJ+EM+FP DK+EN+FQ DL+EO+FR | 4482 | G H I | | P Q R | | GJ+HM+IP GK+HN+IQ GL+HO+IR |</pre> 4483 4484 ### Parameters 4485 4486 <table> <tr> <td><a name="SkMatrix_Concat_a"> <code><strong>a </strong></code> </a></td> <td> 4487 <a href="#Matrix">Matrix</a> on left side of multiply expression</td> 4488 </tr> <tr> <td><a name="SkMatrix_Concat_b"> <code><strong>b </strong></code> </a></td> <td> 4489 <a href="#Matrix">Matrix</a> on right side of multiply expression</td> 4490 </tr> 4491 </table> 4492 4493 ### Return Value 4494 4495 <a href="#Matrix">Matrix</a> computed from <a href="#SkMatrix_Concat_a">a</a> times <a href="#SkMatrix_Concat_b">b</a> 4496 4497 ### Example 4498 4499 <div><fiddle-embed name="6b4562c7052da94f3d5b2412dca41946"><div><a href="#SkMatrix_setPolyToPoly">setPolyToPoly</a> creates perspective matrices, one the inverse of the other. 4500 Multiplying the matrix by its inverse turns into an identity matrix.</div></fiddle-embed></div> 4501 4502 ### See Also 4503 4504 <a href="#SkMatrix_preConcat">preConcat</a> <a href="#SkMatrix_postConcat">postConcat</a> 4505 4506 --- 4507 4508 <a name="SkMatrix_dirtyMatrixTypeCache"></a> 4509 ## dirtyMatrixTypeCache 4510 4511 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4512 void dirtyMatrixTypeCache() 4513 </pre> 4514 4515 Sets internal cache to unknown state. Use to force update after repeated 4516 modifications to <a href="#Matrix">Matrix</a> element reference returned by <a href="#SkMatrix_array1_operator">operator[](int index)</a>. 4517 4518 ### Example 4519 4520 <div><fiddle-embed name="f4365ef332f51f7fd25040e0771ba9a2"> 4521 4522 #### Example Output 4523 4524 ~~~~ 4525 with identity matrix: x = 24 4526 after skew x mod: x = 24 4527 after 2nd skew x mod: x = 24 4528 after dirty cache: x = 66 4529 ~~~~ 4530 4531 </fiddle-embed></div> 4532 4533 ### See Also 4534 4535 <a href="#SkMatrix_array1_operator">operator[](int index)</a> <a href="#SkMatrix_getType">getType</a> 4536 4537 --- 4538 4539 <a name="SkMatrix_setScaleTranslate"></a> 4540 ## setScaleTranslate 4541 4542 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4543 void setScaleTranslate(SkScalar sx, SkScalar sy, SkScalar tx, SkScalar ty) 4544 </pre> 4545 4546 Initializes <a href="#Matrix">Matrix</a> with scale and translate elements. 4547 4548 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4549 | sx 0 tx | 4550 | 0 sy ty | 4551 | 0 0 1 |</pre> 4552 4553 ### Parameters 4554 4555 <table> <tr> <td><a name="SkMatrix_setScaleTranslate_sx"> <code><strong>sx </strong></code> </a></td> <td> 4556 horizontal scale factor to store</td> 4557 </tr> <tr> <td><a name="SkMatrix_setScaleTranslate_sy"> <code><strong>sy </strong></code> </a></td> <td> 4558 vertical scale factor to store</td> 4559 </tr> <tr> <td><a name="SkMatrix_setScaleTranslate_tx"> <code><strong>tx </strong></code> </a></td> <td> 4560 horizontal translation to store</td> 4561 </tr> <tr> <td><a name="SkMatrix_setScaleTranslate_ty"> <code><strong>ty </strong></code> </a></td> <td> 4562 vertical translation to store</td> 4563 </tr> 4564 </table> 4565 4566 ### Example 4567 4568 <div><fiddle-embed name="fed43797f13796529cb6731385d6f8f3"> 4569 4570 #### Example Output 4571 4572 ~~~~ 4573 [ 1.0000 0.0000 3.0000][ 0.0000 2.0000 4.0000][ 0.0000 0.0000 1.0000] 4574 ~~~~ 4575 4576 </fiddle-embed></div> 4577 4578 ### See Also 4579 4580 <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> 4581 4582 --- 4583 4584 <a name="SkMatrix_isFinite"></a> 4585 ## isFinite 4586 4587 <pre style="padding: 1em 1em 1em 1em;width: 62.5em; background-color: #f0f0f0"> 4588 bool isFinite() const 4589 </pre> 4590 4591 Returns true if all elements of the matrix are finite. Returns false if any 4592 element is infinity, or NaN. 4593 4594 ### Return Value 4595 4596 true if matrix has only finite elements 4597 4598 ### Example 4599 4600 <div><fiddle-embed name="bc6c6f6a5df770287120d87f81b922eb"> 4601 4602 #### Example Output 4603 4604 ~~~~ 4605 [ 1.0000 0.0000 nan][ 0.0000 1.0000 0.0000][ 0.0000 0.0000 1.0000] 4606 matrix is finite: false 4607 matrix != matrix 4608 ~~~~ 4609 4610 </fiddle-embed></div> 4611 4612 ### See Also 4613 4614 operator== 4615 4616 --- 4617 4618
