Mercurial > repos > rliterman > csp2

comparison CSP2/CSP2_env/env-d9b9114564458d9d-741b3de822f2aaca6c6caa4325c4afce/share/gtk-doc/html/cairo/cairo-cairo-matrix-t.html @ 68:5028fdace37b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
planemo upload commit 2e9511a184a1ca667c7be0c6321a36dc4e3d116d
author jpayne
date Tue, 18 Mar 2025 16:23:26 -0400
parents
children
comparison
equal deleted inserted replaced
67:0e9998148a16 68:5028fdace37b
1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2 <html>
3 <head>
4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
5 <title>cairo_matrix_t: Cairo: A Vector Graphics Library</title>
6 <meta name="generator" content="DocBook XSL Stylesheets V1.79.1">
7 <link rel="home" href="index.html" title="Cairo: A Vector Graphics Library">
8 <link rel="up" href="cairo-support.html" title="Utilities">
9 <link rel="prev" href="cairo-support.html" title="Utilities">
10 <link rel="next" href="cairo-Error-handling.html" title="Error handling">
11 <meta name="generator" content="GTK-Doc V1.27 (XML mode)">
12 <link rel="stylesheet" href="style.css" type="text/css">
13 </head>
14 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
15 <table class="navigation" id="top" width="100%" summary="Navigation header" cellpadding="2" cellspacing="5"><tr valign="middle">
16 <td width="100%" align="left" class="shortcuts">
17 <a href="#" class="shortcut">Top</a><span id="nav_description">  <span class="dim">|</span> 
18 <a href="#cairo-cairo-matrix-t.description" class="shortcut">Description</a></span>
19 </td>
20 <td><a accesskey="h" href="index.html"><img src="home.png" width="16" height="16" border="0" alt="Home"></a></td>
21 <td><a accesskey="u" href="cairo-support.html"><img src="up.png" width="16" height="16" border="0" alt="Up"></a></td>
22 <td><a accesskey="p" href="cairo-support.html"><img src="left.png" width="16" height="16" border="0" alt="Prev"></a></td>
23 <td><a accesskey="n" href="cairo-Error-handling.html"><img src="right.png" width="16" height="16" border="0" alt="Next"></a></td>
24 </tr></table>
25 <div class="refentry">
26 <a name="cairo-cairo-matrix-t"></a><div class="titlepage"></div>
27 <div class="refnamediv"><table width="100%"><tr>
28 <td valign="top">
29 <h2><span class="refentrytitle"><a name="cairo-cairo-matrix-t.top_of_page"></a>cairo_matrix_t</span></h2>
30 <p>cairo_matrix_t — Generic matrix operations</p>
31 </td>
32 <td class="gallery_image" valign="top" align="right"></td>
33 </tr></table></div>
34 <div class="refsect1">
35 <a name="cairo-cairo-matrix-t.functions"></a><h2>Functions</h2>
36 <div class="informaltable"><table class="informaltable" width="100%" border="0">
37 <colgroup>
38 <col width="150px" class="functions_return">
39 <col class="functions_name">
40 </colgroup>
41 <tbody>
42 <tr>
43 <td class="function_type">
44 <span class="returnvalue">void</span>
45 </td>
46 <td class="function_name">
47 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-init" title="cairo_matrix_init ()">cairo_matrix_init</a> <span class="c_punctuation">()</span>
48 </td>
49 </tr>
50 <tr>
51 <td class="function_type">
52 <span class="returnvalue">void</span>
53 </td>
54 <td class="function_name">
55 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-init-identity" title="cairo_matrix_init_identity ()">cairo_matrix_init_identity</a> <span class="c_punctuation">()</span>
56 </td>
57 </tr>
58 <tr>
59 <td class="function_type">
60 <span class="returnvalue">void</span>
61 </td>
62 <td class="function_name">
63 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-init-translate" title="cairo_matrix_init_translate ()">cairo_matrix_init_translate</a> <span class="c_punctuation">()</span>
64 </td>
65 </tr>
66 <tr>
67 <td class="function_type">
68 <span class="returnvalue">void</span>
69 </td>
70 <td class="function_name">
71 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-init-scale" title="cairo_matrix_init_scale ()">cairo_matrix_init_scale</a> <span class="c_punctuation">()</span>
72 </td>
73 </tr>
74 <tr>
75 <td class="function_type">
76 <span class="returnvalue">void</span>
77 </td>
78 <td class="function_name">
79 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-init-rotate" title="cairo_matrix_init_rotate ()">cairo_matrix_init_rotate</a> <span class="c_punctuation">()</span>
80 </td>
81 </tr>
82 <tr>
83 <td class="function_type">
84 <span class="returnvalue">void</span>
85 </td>
86 <td class="function_name">
87 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-translate" title="cairo_matrix_translate ()">cairo_matrix_translate</a> <span class="c_punctuation">()</span>
88 </td>
89 </tr>
90 <tr>
91 <td class="function_type">
92 <span class="returnvalue">void</span>
93 </td>
94 <td class="function_name">
95 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-scale" title="cairo_matrix_scale ()">cairo_matrix_scale</a> <span class="c_punctuation">()</span>
96 </td>
97 </tr>
98 <tr>
99 <td class="function_type">
100 <span class="returnvalue">void</span>
101 </td>
102 <td class="function_name">
103 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-rotate" title="cairo_matrix_rotate ()">cairo_matrix_rotate</a> <span class="c_punctuation">()</span>
104 </td>
105 </tr>
106 <tr>
107 <td class="function_type">
108 <a class="link" href="cairo-Error-handling.html#cairo-status-t" title="enum cairo_status_t"><span class="returnvalue">cairo_status_t</span></a>
109 </td>
110 <td class="function_name">
111 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-invert" title="cairo_matrix_invert ()">cairo_matrix_invert</a> <span class="c_punctuation">()</span>
112 </td>
113 </tr>
114 <tr>
115 <td class="function_type">
116 <span class="returnvalue">void</span>
117 </td>
118 <td class="function_name">
119 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-multiply" title="cairo_matrix_multiply ()">cairo_matrix_multiply</a> <span class="c_punctuation">()</span>
120 </td>
121 </tr>
122 <tr>
123 <td class="function_type">
124 <span class="returnvalue">void</span>
125 </td>
126 <td class="function_name">
127 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-transform-distance" title="cairo_matrix_transform_distance ()">cairo_matrix_transform_distance</a> <span class="c_punctuation">()</span>
128 </td>
129 </tr>
130 <tr>
131 <td class="function_type">
132 <span class="returnvalue">void</span>
133 </td>
134 <td class="function_name">
135 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-transform-point" title="cairo_matrix_transform_point ()">cairo_matrix_transform_point</a> <span class="c_punctuation">()</span>
136 </td>
137 </tr>
138 </tbody>
139 </table></div>
140 </div>
141 <div class="refsect1">
142 <a name="cairo-cairo-matrix-t.other"></a><h2>Types and Values</h2>
143 <div class="informaltable"><table class="informaltable" width="100%" border="0">
144 <colgroup>
145 <col width="150px" class="name">
146 <col class="description">
147 </colgroup>
148 <tbody><tr>
149 <td class="datatype_keyword"> </td>
150 <td class="function_name"><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t">cairo_matrix_t</a></td>
151 </tr></tbody>
152 </table></div>
153 </div>
154 <div class="refsect1">
155 <a name="cairo-cairo-matrix-t.description"></a><h2>Description</h2>
156 <p><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> is used throughout cairo to convert between different
157 coordinate spaces. A <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> holds an affine transformation,
158 such as a scale, rotation, shear, or a combination of these.
159 The transformation of a point (<code class="literal">x</code>,<code class="literal">y</code>)
160 is given by:</p>
161 <pre class="programlisting">
162 x_new = xx * x + xy * y + x0;
163 y_new = yx * x + yy * y + y0;
164 </pre>
165 <p>The current transformation matrix of a <a class="link" href="cairo-cairo-t.html#cairo-t" title="cairo_t"><span class="type">cairo_t</span></a>, represented as a
166 <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a>, defines the transformation from user-space
167 coordinates to device-space coordinates. See <a class="link" href="cairo-Transformations.html#cairo-get-matrix" title="cairo_get_matrix ()"><code class="function">cairo_get_matrix()</code></a> and
168 <a class="link" href="cairo-Transformations.html#cairo-set-matrix" title="cairo_set_matrix ()"><code class="function">cairo_set_matrix()</code></a>.</p>
169 </div>
170 <div class="refsect1">
171 <a name="cairo-cairo-matrix-t.functions_details"></a><h2>Functions</h2>
172 <div class="refsect2">
173 <a name="cairo-matrix-init"></a><h3>cairo_matrix_init ()</h3>
174 <pre class="programlisting"><span class="returnvalue">void</span>
175 cairo_matrix_init (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
176 <em class="parameter"><code><span class="type">double</span> xx</code></em>,
177 <em class="parameter"><code><span class="type">double</span> yx</code></em>,
178 <em class="parameter"><code><span class="type">double</span> xy</code></em>,
179 <em class="parameter"><code><span class="type">double</span> yy</code></em>,
180 <em class="parameter"><code><span class="type">double</span> x0</code></em>,
181 <em class="parameter"><code><span class="type">double</span> y0</code></em>);</pre>
182 <p>Sets <em class="parameter"><code>matrix</code></em>
183 to be the affine transformation given by
184 <em class="parameter"><code>xx</code></em>
185 , <em class="parameter"><code>yx</code></em>
186 , <em class="parameter"><code>xy</code></em>
187 , <em class="parameter"><code>yy</code></em>
188 , <em class="parameter"><code>x0</code></em>
189 , <em class="parameter"><code>y0</code></em>
190 . The transformation is given
191 by:</p>
192 <pre class="programlisting">
193 x_new = xx * x + xy * y + x0;
194 y_new = yx * x + yy * y + y0;
195 </pre>
196 <div class="refsect3">
197 <a name="cairo-matrix-init.parameters"></a><h4>Parameters</h4>
198 <div class="informaltable"><table class="informaltable" width="100%" border="0">
199 <colgroup>
200 <col width="150px" class="parameters_name">
201 <col class="parameters_description">
202 <col width="200px" class="parameters_annotations">
203 </colgroup>
204 <tbody>
205 <tr>
206 <td class="parameter_name"><p>matrix</p></td>
207 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
208 <td class="parameter_annotations"> </td>
209 </tr>
210 <tr>
211 <td class="parameter_name"><p>xx</p></td>
212 <td class="parameter_description"><p>xx component of the affine transformation</p></td>
213 <td class="parameter_annotations"> </td>
214 </tr>
215 <tr>
216 <td class="parameter_name"><p>yx</p></td>
217 <td class="parameter_description"><p>yx component of the affine transformation</p></td>
218 <td class="parameter_annotations"> </td>
219 </tr>
220 <tr>
221 <td class="parameter_name"><p>xy</p></td>
222 <td class="parameter_description"><p>xy component of the affine transformation</p></td>
223 <td class="parameter_annotations"> </td>
224 </tr>
225 <tr>
226 <td class="parameter_name"><p>yy</p></td>
227 <td class="parameter_description"><p>yy component of the affine transformation</p></td>
228 <td class="parameter_annotations"> </td>
229 </tr>
230 <tr>
231 <td class="parameter_name"><p>x0</p></td>
232 <td class="parameter_description"><p>X translation component of the affine transformation</p></td>
233 <td class="parameter_annotations"> </td>
234 </tr>
235 <tr>
236 <td class="parameter_name"><p>y0</p></td>
237 <td class="parameter_description"><p>Y translation component of the affine transformation</p></td>
238 <td class="parameter_annotations"> </td>
239 </tr>
240 </tbody>
241 </table></div>
242 </div>
243 <p class="since">Since: 1.0</p>
244 </div>
245 <hr>
246 <div class="refsect2">
247 <a name="cairo-matrix-init-identity"></a><h3>cairo_matrix_init_identity ()</h3>
248 <pre class="programlisting"><span class="returnvalue">void</span>
249 cairo_matrix_init_identity (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>);</pre>
250 <p>Modifies <em class="parameter"><code>matrix</code></em>
251 to be an identity transformation.</p>
252 <div class="refsect3">
253 <a name="cairo-matrix-init-identity.parameters"></a><h4>Parameters</h4>
254 <div class="informaltable"><table class="informaltable" width="100%" border="0">
255 <colgroup>
256 <col width="150px" class="parameters_name">
257 <col class="parameters_description">
258 <col width="200px" class="parameters_annotations">
259 </colgroup>
260 <tbody><tr>
261 <td class="parameter_name"><p>matrix</p></td>
262 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
263 <td class="parameter_annotations"> </td>
264 </tr></tbody>
265 </table></div>
266 </div>
267 <p class="since">Since: 1.0</p>
268 </div>
269 <hr>
270 <div class="refsect2">
271 <a name="cairo-matrix-init-translate"></a><h3>cairo_matrix_init_translate ()</h3>
272 <pre class="programlisting"><span class="returnvalue">void</span>
273 cairo_matrix_init_translate (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
274 <em class="parameter"><code><span class="type">double</span> tx</code></em>,
275 <em class="parameter"><code><span class="type">double</span> ty</code></em>);</pre>
276 <p>Initializes <em class="parameter"><code>matrix</code></em>
277 to a transformation that translates by <em class="parameter"><code>tx</code></em>
278 and
279 <em class="parameter"><code>ty</code></em>
280 in the X and Y dimensions, respectively.</p>
281 <div class="refsect3">
282 <a name="cairo-matrix-init-translate.parameters"></a><h4>Parameters</h4>
283 <div class="informaltable"><table class="informaltable" width="100%" border="0">
284 <colgroup>
285 <col width="150px" class="parameters_name">
286 <col class="parameters_description">
287 <col width="200px" class="parameters_annotations">
288 </colgroup>
289 <tbody>
290 <tr>
291 <td class="parameter_name"><p>matrix</p></td>
292 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
293 <td class="parameter_annotations"> </td>
294 </tr>
295 <tr>
296 <td class="parameter_name"><p>tx</p></td>
297 <td class="parameter_description"><p>amount to translate in the X direction</p></td>
298 <td class="parameter_annotations"> </td>
299 </tr>
300 <tr>
301 <td class="parameter_name"><p>ty</p></td>
302 <td class="parameter_description"><p>amount to translate in the Y direction</p></td>
303 <td class="parameter_annotations"> </td>
304 </tr>
305 </tbody>
306 </table></div>
307 </div>
308 <p class="since">Since: 1.0</p>
309 </div>
310 <hr>
311 <div class="refsect2">
312 <a name="cairo-matrix-init-scale"></a><h3>cairo_matrix_init_scale ()</h3>
313 <pre class="programlisting"><span class="returnvalue">void</span>
314 cairo_matrix_init_scale (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
315 <em class="parameter"><code><span class="type">double</span> sx</code></em>,
316 <em class="parameter"><code><span class="type">double</span> sy</code></em>);</pre>
317 <p>Initializes <em class="parameter"><code>matrix</code></em>
318 to a transformation that scales by <em class="parameter"><code>sx</code></em>
319 and <em class="parameter"><code>sy</code></em>
320
321 in the X and Y dimensions, respectively.</p>
322 <div class="refsect3">
323 <a name="cairo-matrix-init-scale.parameters"></a><h4>Parameters</h4>
324 <div class="informaltable"><table class="informaltable" width="100%" border="0">
325 <colgroup>
326 <col width="150px" class="parameters_name">
327 <col class="parameters_description">
328 <col width="200px" class="parameters_annotations">
329 </colgroup>
330 <tbody>
331 <tr>
332 <td class="parameter_name"><p>matrix</p></td>
333 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
334 <td class="parameter_annotations"> </td>
335 </tr>
336 <tr>
337 <td class="parameter_name"><p>sx</p></td>
338 <td class="parameter_description"><p>scale factor in the X direction</p></td>
339 <td class="parameter_annotations"> </td>
340 </tr>
341 <tr>
342 <td class="parameter_name"><p>sy</p></td>
343 <td class="parameter_description"><p>scale factor in the Y direction</p></td>
344 <td class="parameter_annotations"> </td>
345 </tr>
346 </tbody>
347 </table></div>
348 </div>
349 <p class="since">Since: 1.0</p>
350 </div>
351 <hr>
352 <div class="refsect2">
353 <a name="cairo-matrix-init-rotate"></a><h3>cairo_matrix_init_rotate ()</h3>
354 <pre class="programlisting"><span class="returnvalue">void</span>
355 cairo_matrix_init_rotate (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
356 <em class="parameter"><code><span class="type">double</span> radians</code></em>);</pre>
357 <p>Initialized <em class="parameter"><code>matrix</code></em>
358 to a transformation that rotates by <em class="parameter"><code>radians</code></em>
359 .</p>
360 <div class="refsect3">
361 <a name="cairo-matrix-init-rotate.parameters"></a><h4>Parameters</h4>
362 <div class="informaltable"><table class="informaltable" width="100%" border="0">
363 <colgroup>
364 <col width="150px" class="parameters_name">
365 <col class="parameters_description">
366 <col width="200px" class="parameters_annotations">
367 </colgroup>
368 <tbody>
369 <tr>
370 <td class="parameter_name"><p>matrix</p></td>
371 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
372 <td class="parameter_annotations"> </td>
373 </tr>
374 <tr>
375 <td class="parameter_name"><p>radians</p></td>
376 <td class="parameter_description"><p>angle of rotation, in radians. The direction of rotation
377 is defined such that positive angles rotate in the direction from
378 the positive X axis toward the positive Y axis. With the default
379 axis orientation of cairo, positive angles rotate in a clockwise
380 direction.</p></td>
381 <td class="parameter_annotations"> </td>
382 </tr>
383 </tbody>
384 </table></div>
385 </div>
386 <p class="since">Since: 1.0</p>
387 </div>
388 <hr>
389 <div class="refsect2">
390 <a name="cairo-matrix-translate"></a><h3>cairo_matrix_translate ()</h3>
391 <pre class="programlisting"><span class="returnvalue">void</span>
392 cairo_matrix_translate (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
393 <em class="parameter"><code><span class="type">double</span> tx</code></em>,
394 <em class="parameter"><code><span class="type">double</span> ty</code></em>);</pre>
395 <p>Applies a translation by <em class="parameter"><code>tx</code></em>
396 , <em class="parameter"><code>ty</code></em>
397 to the transformation in
398 <em class="parameter"><code>matrix</code></em>
399 . The effect of the new transformation is to first translate
400 the coordinates by <em class="parameter"><code>tx</code></em>
401 and <em class="parameter"><code>ty</code></em>
402 , then apply the original transformation
403 to the coordinates.</p>
404 <div class="refsect3">
405 <a name="cairo-matrix-translate.parameters"></a><h4>Parameters</h4>
406 <div class="informaltable"><table class="informaltable" width="100%" border="0">
407 <colgroup>
408 <col width="150px" class="parameters_name">
409 <col class="parameters_description">
410 <col width="200px" class="parameters_annotations">
411 </colgroup>
412 <tbody>
413 <tr>
414 <td class="parameter_name"><p>matrix</p></td>
415 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
416 <td class="parameter_annotations"> </td>
417 </tr>
418 <tr>
419 <td class="parameter_name"><p>tx</p></td>
420 <td class="parameter_description"><p>amount to translate in the X direction</p></td>
421 <td class="parameter_annotations"> </td>
422 </tr>
423 <tr>
424 <td class="parameter_name"><p>ty</p></td>
425 <td class="parameter_description"><p>amount to translate in the Y direction</p></td>
426 <td class="parameter_annotations"> </td>
427 </tr>
428 </tbody>
429 </table></div>
430 </div>
431 <p class="since">Since: 1.0</p>
432 </div>
433 <hr>
434 <div class="refsect2">
435 <a name="cairo-matrix-scale"></a><h3>cairo_matrix_scale ()</h3>
436 <pre class="programlisting"><span class="returnvalue">void</span>
437 cairo_matrix_scale (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
438 <em class="parameter"><code><span class="type">double</span> sx</code></em>,
439 <em class="parameter"><code><span class="type">double</span> sy</code></em>);</pre>
440 <p>Applies scaling by <em class="parameter"><code>sx</code></em>
441 , <em class="parameter"><code>sy</code></em>
442 to the transformation in <em class="parameter"><code>matrix</code></em>
443 . The
444 effect of the new transformation is to first scale the coordinates
445 by <em class="parameter"><code>sx</code></em>
446 and <em class="parameter"><code>sy</code></em>
447 , then apply the original transformation to the coordinates.</p>
448 <div class="refsect3">
449 <a name="cairo-matrix-scale.parameters"></a><h4>Parameters</h4>
450 <div class="informaltable"><table class="informaltable" width="100%" border="0">
451 <colgroup>
452 <col width="150px" class="parameters_name">
453 <col class="parameters_description">
454 <col width="200px" class="parameters_annotations">
455 </colgroup>
456 <tbody>
457 <tr>
458 <td class="parameter_name"><p>matrix</p></td>
459 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
460 <td class="parameter_annotations"> </td>
461 </tr>
462 <tr>
463 <td class="parameter_name"><p>sx</p></td>
464 <td class="parameter_description"><p>scale factor in the X direction</p></td>
465 <td class="parameter_annotations"> </td>
466 </tr>
467 <tr>
468 <td class="parameter_name"><p>sy</p></td>
469 <td class="parameter_description"><p>scale factor in the Y direction</p></td>
470 <td class="parameter_annotations"> </td>
471 </tr>
472 </tbody>
473 </table></div>
474 </div>
475 <p class="since">Since: 1.0</p>
476 </div>
477 <hr>
478 <div class="refsect2">
479 <a name="cairo-matrix-rotate"></a><h3>cairo_matrix_rotate ()</h3>
480 <pre class="programlisting"><span class="returnvalue">void</span>
481 cairo_matrix_rotate (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
482 <em class="parameter"><code><span class="type">double</span> radians</code></em>);</pre>
483 <p>Applies rotation by <em class="parameter"><code>radians</code></em>
484 to the transformation in
485 <em class="parameter"><code>matrix</code></em>
486 . The effect of the new transformation is to first rotate the
487 coordinates by <em class="parameter"><code>radians</code></em>
488 , then apply the original transformation
489 to the coordinates.</p>
490 <div class="refsect3">
491 <a name="cairo-matrix-rotate.parameters"></a><h4>Parameters</h4>
492 <div class="informaltable"><table class="informaltable" width="100%" border="0">
493 <colgroup>
494 <col width="150px" class="parameters_name">
495 <col class="parameters_description">
496 <col width="200px" class="parameters_annotations">
497 </colgroup>
498 <tbody>
499 <tr>
500 <td class="parameter_name"><p>matrix</p></td>
501 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
502 <td class="parameter_annotations"> </td>
503 </tr>
504 <tr>
505 <td class="parameter_name"><p>radians</p></td>
506 <td class="parameter_description"><p>angle of rotation, in radians. The direction of rotation
507 is defined such that positive angles rotate in the direction from
508 the positive X axis toward the positive Y axis. With the default
509 axis orientation of cairo, positive angles rotate in a clockwise
510 direction.</p></td>
511 <td class="parameter_annotations"> </td>
512 </tr>
513 </tbody>
514 </table></div>
515 </div>
516 <p class="since">Since: 1.0</p>
517 </div>
518 <hr>
519 <div class="refsect2">
520 <a name="cairo-matrix-invert"></a><h3>cairo_matrix_invert ()</h3>
521 <pre class="programlisting"><a class="link" href="cairo-Error-handling.html#cairo-status-t" title="enum cairo_status_t"><span class="returnvalue">cairo_status_t</span></a>
522 cairo_matrix_invert (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>);</pre>
523 <p>Changes <em class="parameter"><code>matrix</code></em>
524 to be the inverse of its original value. Not
525 all transformation matrices have inverses; if the matrix
526 collapses points together (it is <em class="firstterm">degenerate</em>),
527 then it has no inverse and this function will fail.</p>
528 <div class="refsect3">
529 <a name="cairo-matrix-invert.parameters"></a><h4>Parameters</h4>
530 <div class="informaltable"><table class="informaltable" width="100%" border="0">
531 <colgroup>
532 <col width="150px" class="parameters_name">
533 <col class="parameters_description">
534 <col width="200px" class="parameters_annotations">
535 </colgroup>
536 <tbody><tr>
537 <td class="parameter_name"><p>matrix</p></td>
538 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
539 <td class="parameter_annotations"> </td>
540 </tr></tbody>
541 </table></div>
542 </div>
543 <div class="refsect3">
544 <a name="cairo-matrix-invert.returns"></a><h4>Returns</h4>
545 <p> If <em class="parameter"><code>matrix</code></em>
546 has an inverse, modifies <em class="parameter"><code>matrix</code></em>
547 to
548 be the inverse matrix and returns <a class="link" href="cairo-Error-handling.html#CAIRO-STATUS-SUCCESS:CAPS"><code class="literal">CAIRO_STATUS_SUCCESS</code></a>. Otherwise,
549 returns <a class="link" href="cairo-Error-handling.html#CAIRO-STATUS-INVALID-MATRIX:CAPS"><code class="literal">CAIRO_STATUS_INVALID_MATRIX</code></a>.</p>
550 </div>
551 <p class="since">Since: 1.0</p>
552 </div>
553 <hr>
554 <div class="refsect2">
555 <a name="cairo-matrix-multiply"></a><h3>cairo_matrix_multiply ()</h3>
556 <pre class="programlisting"><span class="returnvalue">void</span>
557 cairo_matrix_multiply (<em class="parameter"><code><a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *result</code></em>,
558 <em class="parameter"><code>const <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *a</code></em>,
559 <em class="parameter"><code>const <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *b</code></em>);</pre>
560 <p>Multiplies the affine transformations in <em class="parameter"><code>a</code></em>
561 and <em class="parameter"><code>b</code></em>
562 together
563 and stores the result in <em class="parameter"><code>result</code></em>
564 . The effect of the resulting
565 transformation is to first apply the transformation in <em class="parameter"><code>a</code></em>
566 to the
567 coordinates and then apply the transformation in <em class="parameter"><code>b</code></em>
568 to the
569 coordinates.</p>
570 <p>It is allowable for <em class="parameter"><code>result</code></em>
571 to be identical to either <em class="parameter"><code>a</code></em>
572 or <em class="parameter"><code>b</code></em>
573 .</p>
574 <div class="refsect3">
575 <a name="cairo-matrix-multiply.parameters"></a><h4>Parameters</h4>
576 <div class="informaltable"><table class="informaltable" width="100%" border="0">
577 <colgroup>
578 <col width="150px" class="parameters_name">
579 <col class="parameters_description">
580 <col width="200px" class="parameters_annotations">
581 </colgroup>
582 <tbody>
583 <tr>
584 <td class="parameter_name"><p>result</p></td>
585 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> in which to store the result</p></td>
586 <td class="parameter_annotations"> </td>
587 </tr>
588 <tr>
589 <td class="parameter_name"><p>a</p></td>
590 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
591 <td class="parameter_annotations"> </td>
592 </tr>
593 <tr>
594 <td class="parameter_name"><p>b</p></td>
595 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
596 <td class="parameter_annotations"> </td>
597 </tr>
598 </tbody>
599 </table></div>
600 </div>
601 <p class="since">Since: 1.0</p>
602 </div>
603 <hr>
604 <div class="refsect2">
605 <a name="cairo-matrix-transform-distance"></a><h3>cairo_matrix_transform_distance ()</h3>
606 <pre class="programlisting"><span class="returnvalue">void</span>
607 cairo_matrix_transform_distance (<em class="parameter"><code>const <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
608 <em class="parameter"><code><span class="type">double</span> *dx</code></em>,
609 <em class="parameter"><code><span class="type">double</span> *dy</code></em>);</pre>
610 <p>Transforms the distance vector (<em class="parameter"><code>dx</code></em>
611 ,<em class="parameter"><code>dy</code></em>
612 ) by <em class="parameter"><code>matrix</code></em>
613 . This is
614 similar to <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-transform-point" title="cairo_matrix_transform_point ()"><code class="function">cairo_matrix_transform_point()</code></a> except that the translation
615 components of the transformation are ignored. The calculation of
616 the returned vector is as follows:</p>
617 <pre class="programlisting">
618 dx2 = dx1 * a + dy1 * c;
619 dy2 = dx1 * b + dy1 * d;
620 </pre>
621 <p>Affine transformations are position invariant, so the same vector
622 always transforms to the same vector. If (<em class="parameter"><code>x1</code></em>
623 ,<em class="parameter"><code>y1</code></em>
624 ) transforms
625 to (<em class="parameter"><code>x2</code></em>
626 ,<em class="parameter"><code>y2</code></em>
627 ) then (<em class="parameter"><code>x1</code></em>
628 +<em class="parameter"><code>dx1</code></em>
629 ,<em class="parameter"><code>y1</code></em>
630 +<em class="parameter"><code>dy1</code></em>
631 ) will transform to
632 (<em class="parameter"><code>x1</code></em>
633 +<em class="parameter"><code>dx2</code></em>
634 ,<em class="parameter"><code>y1</code></em>
635 +<em class="parameter"><code>dy2</code></em>
636 ) for all values of <em class="parameter"><code>x1</code></em>
637 and <em class="parameter"><code>x2</code></em>
638 .</p>
639 <div class="refsect3">
640 <a name="cairo-matrix-transform-distance.parameters"></a><h4>Parameters</h4>
641 <div class="informaltable"><table class="informaltable" width="100%" border="0">
642 <colgroup>
643 <col width="150px" class="parameters_name">
644 <col class="parameters_description">
645 <col width="200px" class="parameters_annotations">
646 </colgroup>
647 <tbody>
648 <tr>
649 <td class="parameter_name"><p>matrix</p></td>
650 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
651 <td class="parameter_annotations"> </td>
652 </tr>
653 <tr>
654 <td class="parameter_name"><p>dx</p></td>
655 <td class="parameter_description"><p>X component of a distance vector. An in/out parameter</p></td>
656 <td class="parameter_annotations"> </td>
657 </tr>
658 <tr>
659 <td class="parameter_name"><p>dy</p></td>
660 <td class="parameter_description"><p>Y component of a distance vector. An in/out parameter</p></td>
661 <td class="parameter_annotations"> </td>
662 </tr>
663 </tbody>
664 </table></div>
665 </div>
666 <p class="since">Since: 1.0</p>
667 </div>
668 <hr>
669 <div class="refsect2">
670 <a name="cairo-matrix-transform-point"></a><h3>cairo_matrix_transform_point ()</h3>
671 <pre class="programlisting"><span class="returnvalue">void</span>
672 cairo_matrix_transform_point (<em class="parameter"><code>const <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> *matrix</code></em>,
673 <em class="parameter"><code><span class="type">double</span> *x</code></em>,
674 <em class="parameter"><code><span class="type">double</span> *y</code></em>);</pre>
675 <p>Transforms the point (<em class="parameter"><code>x</code></em>
676 , <em class="parameter"><code>y</code></em>
677 ) by <em class="parameter"><code>matrix</code></em>
678 .</p>
679 <div class="refsect3">
680 <a name="cairo-matrix-transform-point.parameters"></a><h4>Parameters</h4>
681 <div class="informaltable"><table class="informaltable" width="100%" border="0">
682 <colgroup>
683 <col width="150px" class="parameters_name">
684 <col class="parameters_description">
685 <col width="200px" class="parameters_annotations">
686 </colgroup>
687 <tbody>
688 <tr>
689 <td class="parameter_name"><p>matrix</p></td>
690 <td class="parameter_description"><p>a <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a></p></td>
691 <td class="parameter_annotations"> </td>
692 </tr>
693 <tr>
694 <td class="parameter_name"><p>x</p></td>
695 <td class="parameter_description"><p>X position. An in/out parameter</p></td>
696 <td class="parameter_annotations"> </td>
697 </tr>
698 <tr>
699 <td class="parameter_name"><p>y</p></td>
700 <td class="parameter_description"><p>Y position. An in/out parameter</p></td>
701 <td class="parameter_annotations"> </td>
702 </tr>
703 </tbody>
704 </table></div>
705 </div>
706 <p class="since">Since: 1.0</p>
707 </div>
708 </div>
709 <div class="refsect1">
710 <a name="cairo-cairo-matrix-t.other_details"></a><h2>Types and Values</h2>
711 <div class="refsect2">
712 <a name="cairo-matrix-t"></a><h3>cairo_matrix_t</h3>
713 <pre class="programlisting">typedef struct {
714 double xx; double yx;
715 double xy; double yy;
716 double x0; double y0;
717 } cairo_matrix_t;
718 </pre>
719 <p>A <a class="link" href="cairo-cairo-matrix-t.html#cairo-matrix-t" title="cairo_matrix_t"><span class="type">cairo_matrix_t</span></a> holds an affine transformation, such as a scale,
720 rotation, shear, or a combination of those. The transformation of
721 a point (x, y) is given by:</p>
722 <pre class="programlisting">
723 x_new = xx * x + xy * y + x0;
724 y_new = yx * x + yy * y + y0;
725 </pre>
726 <div class="refsect3">
727 <a name="cairo-matrix-t.members"></a><h4>Members</h4>
728 <div class="informaltable"><table class="informaltable" width="100%" border="0">
729 <colgroup>
730 <col width="300px" class="struct_members_name">
731 <col class="struct_members_description">
732 <col width="200px" class="struct_members_annotations">
733 </colgroup>
734 <tbody>
735 <tr>
736 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.xx"></a>xx</code></em>;</p></td>
737 <td class="struct_member_description"><p>xx component of the affine transformation</p></td>
738 <td class="struct_member_annotations"> </td>
739 </tr>
740 <tr>
741 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.yx"></a>yx</code></em>;</p></td>
742 <td class="struct_member_description"><p>yx component of the affine transformation</p></td>
743 <td class="struct_member_annotations"> </td>
744 </tr>
745 <tr>
746 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.xy"></a>xy</code></em>;</p></td>
747 <td class="struct_member_description"><p>xy component of the affine transformation</p></td>
748 <td class="struct_member_annotations"> </td>
749 </tr>
750 <tr>
751 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.yy"></a>yy</code></em>;</p></td>
752 <td class="struct_member_description"><p>yy component of the affine transformation</p></td>
753 <td class="struct_member_annotations"> </td>
754 </tr>
755 <tr>
756 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.x0"></a>x0</code></em>;</p></td>
757 <td class="struct_member_description"><p>X translation component of the affine transformation</p></td>
758 <td class="struct_member_annotations"> </td>
759 </tr>
760 <tr>
761 <td class="struct_member_name"><p><span class="type">double</span> <em class="structfield"><code><a name="cairo-matrix-t.y0"></a>y0</code></em>;</p></td>
762 <td class="struct_member_description"><p>Y translation component of the affine transformation</p></td>
763 <td class="struct_member_annotations"> </td>
764 </tr>
765 </tbody>
766 </table></div>
767 </div>
768 <p class="since">Since: 1.0</p>
769 </div>
770 </div>
771 <div class="refsect1">
772 <a name="cairo-cairo-matrix-t.see-also"></a><h2>See Also</h2>
773 <p><a class="link" href="cairo-cairo-t.html#cairo-t" title="cairo_t"><span class="type">cairo_t</span></a></p>
774 </div>
775 </div>
776 <div class="footer">
777 <hr>Generated by GTK-Doc V1.27</div>
778 </body>
779 </html>