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 | 
<a href="#id2607775" class="shortcut">Description</a></nobr></td></tr>
</table>
<div class="refentry" lang="en">
<a name="cairo-cairo-matrix-t"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2>
<a name="id2525423"></a><span class="refentrytitle">cairo_matrix_t</span>
</h2>
<p>cairo_matrix_t — Generic matrix operations</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsynopsisdiv">
<h2>Synopsis</h2>
<pre class="synopsis">
<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a>;
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-init">cairo_matrix_init</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double xx,
double yx,
double xy,
double yy,
double x0,
double y0);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-init-identity">cairo_matrix_init_identity</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-init-translate">cairo_matrix_init_translate</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double tx,
double ty);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-init-scale">cairo_matrix_init_scale</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double sx,
double sy);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-init-rotate">cairo_matrix_init_rotate</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double radians);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-translate">cairo_matrix_translate</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double tx,
double ty);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-scale">cairo_matrix_scale</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double sx,
double sy);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-rotate">cairo_matrix_rotate</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double radians);
<a href="cairo-Error-handling.html#cairo-status-t">cairo_status_t</a> <a href="cairo-cairo-matrix-t.html#cairo-matrix-invert">cairo_matrix_invert</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-multiply">cairo_matrix_multiply</a> (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *result,
const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *a,
const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *b);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-transform-distance">cairo_matrix_transform_distance</a> (const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double *dx,
double *dy);
void <a href="cairo-cairo-matrix-t.html#cairo-matrix-transform-point">cairo_matrix_transform_point</a> (const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double *x,
double *y);
</pre>
</div>
<div class="refsect1" lang="en">
<a name="id2607775"></a><h2>Description</h2>
<p><a class="indexterm" name="id2607787"></a><a class="indexterm" name="id2607795"></a>
<a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a> is used throughout cairo to convert between different
coordinate spaces. A <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a> holds an affine transformation,
such as a scale, rotation, shear, or a combination of these.
The transformation of a point (<code class="literal">x</code>,<code class="literal">y</code>)
is given by:
</p>
<pre class="programlisting">
x_new = xx * x + xy * y + x0;
y_new = yx * x + yy * y + y0;
</pre>
<p>
The current transformation matrix of a <a href="cairo-cairo-t.html#cairo-t"><span class="type">cairo_t</span></a>, represented as a
<a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>, defines the transformation from user-space
coordinates to device-space coordinates. See <a href="cairo-Transformations.html#cairo-get-matrix"><code class="function">cairo_get_matrix()</code></a> and
<a href="cairo-Transformations.html#cairo-set-matrix"><code class="function">cairo_set_matrix()</code></a>.
</p>
</div>
<div class="refsect1" lang="en">
<a name="id2607880"></a><h2>Details</h2>
<div class="refsect2" lang="en">
<a name="id2607891"></a><h3>
<a name="cairo-matrix-t"></a>cairo_matrix_t</h3>
<a class="indexterm" name="id2607903"></a><pre class="programlisting">typedef struct {
double xx; double yx;
double xy; double yy;
double x0; double y0;
} cairo_matrix_t;
</pre>
<p>
A <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a> holds an affine transformation, such as a scale,
rotation, shear, or a combination of those. The transformation of
a point (x, y) is given by:
</p>
<pre class="programlisting">
x_new = xx * x + xy * y + x0;
y_new = yx * x + yy * y + y0;
</pre>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term">double <em class="structfield"><code>xx</code></em>;</span></td>
<td> xx component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term">double <em class="structfield"><code>yx</code></em>;</span></td>
<td> yx component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term">double <em class="structfield"><code>xy</code></em>;</span></td>
<td> xy component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term">double <em class="structfield"><code>yy</code></em>;</span></td>
<td> yy component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term">double <em class="structfield"><code>x0</code></em>;</span></td>
<td> X translation component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term">double <em class="structfield"><code>y0</code></em>;</span></td>
<td> Y translation component of the affine transformation
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2604518"></a><h3>
<a name="cairo-matrix-init"></a>cairo_matrix_init ()</h3>
<a class="indexterm" name="id2604531"></a><pre class="programlisting">void cairo_matrix_init (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double xx,
double yx,
double xy,
double yy,
double x0,
double y0);</pre>
<p>
Sets <em class="parameter"><code>matrix</code></em> to be the affine transformation given by
<em class="parameter"><code>xx</code></em>, <em class="parameter"><code>yx</code></em>, <em class="parameter"><code>xy</code></em>, <em class="parameter"><code>yy</code></em>, <em class="parameter"><code>x0</code></em>, <em class="parameter"><code>y0</code></em>. The transformation is given
by:
</p>
<pre class="programlisting">
x_new = xx * x + xy * y + x0;
y_new = yx * x + yy * y + y0;
</pre>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a cairo_matrix_t
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>xx</code></em> :</span></td>
<td> xx component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>yx</code></em> :</span></td>
<td> yx component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>xy</code></em> :</span></td>
<td> xy component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>yy</code></em> :</span></td>
<td> yy component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>x0</code></em> :</span></td>
<td> X translation component of the affine transformation
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>y0</code></em> :</span></td>
<td> Y translation component of the affine transformation
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611143"></a><h3>
<a name="cairo-matrix-init-identity"></a>cairo_matrix_init_identity ()</h3>
<a class="indexterm" name="id2611154"></a><pre class="programlisting">void cairo_matrix_init_identity (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix);</pre>
<p>
Modifies <em class="parameter"><code>matrix</code></em> to be an identity transformation.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody><tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr></tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611209"></a><h3>
<a name="cairo-matrix-init-translate"></a>cairo_matrix_init_translate ()</h3>
<a class="indexterm" name="id2611219"></a><pre class="programlisting">void cairo_matrix_init_translate (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double tx,
double ty);</pre>
<p>
Initializes <em class="parameter"><code>matrix</code></em> to a transformation that translates by <em class="parameter"><code>tx</code></em> and
<em class="parameter"><code>ty</code></em> in the X and Y dimensions, respectively.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a cairo_matrix_t
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>tx</code></em> :</span></td>
<td> amount to translate in the X direction
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>ty</code></em> :</span></td>
<td> amount to translate in the Y direction
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611327"></a><h3>
<a name="cairo-matrix-init-scale"></a>cairo_matrix_init_scale ()</h3>
<a class="indexterm" name="id2611338"></a><pre class="programlisting">void cairo_matrix_init_scale (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double sx,
double sy);</pre>
<p>
Initializes <em class="parameter"><code>matrix</code></em> to a transformation that scales by <em class="parameter"><code>sx</code></em> and <em class="parameter"><code>sy</code></em>
in the X and Y dimensions, respectively.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a cairo_matrix_t
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>sx</code></em> :</span></td>
<td> scale factor in the X direction
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>sy</code></em> :</span></td>
<td> scale factor in the Y direction
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611448"></a><h3>
<a name="cairo-matrix-init-rotate"></a>cairo_matrix_init_rotate ()</h3>
<a class="indexterm" name="id2611460"></a><pre class="programlisting">void cairo_matrix_init_rotate (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double radians);</pre>
<p>
Initialized <em class="parameter"><code>matrix</code></em> to a transformation that rotates by <em class="parameter"><code>radians</code></em>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a cairo_matrix_t
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>radians</code></em> :</span></td>
<td> angle of rotation, in radians. The direction of rotation
is defined such that positive angles rotate in the direction from
the positive X axis toward the positive Y axis. With the default
axis orientation of cairo, positive angles rotate in a clockwise
direction.
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611547"></a><h3>
<a name="cairo-matrix-translate"></a>cairo_matrix_translate ()</h3>
<a class="indexterm" name="id2611558"></a><pre class="programlisting">void cairo_matrix_translate (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double tx,
double ty);</pre>
<p>
Applies a translation by <em class="parameter"><code>tx</code></em>, <em class="parameter"><code>ty</code></em> to the transformation in
<em class="parameter"><code>matrix</code></em>. The effect of the new transformation is to first translate
the coordinates by <em class="parameter"><code>tx</code></em> and <em class="parameter"><code>ty</code></em>, then apply the original transformation
to the coordinates.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a cairo_matrix_t
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>tx</code></em> :</span></td>
<td> amount to translate in the X direction
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>ty</code></em> :</span></td>
<td> amount to translate in the Y direction
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611683"></a><h3>
<a name="cairo-matrix-scale"></a>cairo_matrix_scale ()</h3>
<a class="indexterm" name="id2611695"></a><pre class="programlisting">void cairo_matrix_scale (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double sx,
double sy);</pre>
<p>
Applies scaling by <em class="parameter"><code>tx</code></em>, <em class="parameter"><code>ty</code></em> to the transformation in <em class="parameter"><code>matrix</code></em>. The
effect of the new transformation is to first scale the coordinates
by <em class="parameter"><code>sx</code></em> and <em class="parameter"><code>sy</code></em>, then apply the original transformation to the coordinates.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>sx</code></em> :</span></td>
<td> scale factor in the X direction
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>sy</code></em> :</span></td>
<td> scale factor in the Y direction
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611825"></a><h3>
<a name="cairo-matrix-rotate"></a>cairo_matrix_rotate ()</h3>
<a class="indexterm" name="id2611837"></a><pre class="programlisting">void cairo_matrix_rotate (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double radians);</pre>
<p>
Applies rotation by <em class="parameter"><code>radians</code></em> to the transformation in
<em class="parameter"><code>matrix</code></em>. The effect of the new transformation is to first rotate the
coordinates by <em class="parameter"><code>radians</code></em>, then apply the original transformation
to the coordinates.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>radians</code></em> :</span></td>
<td> angle of rotation, in radians. The direction of rotation
is defined such that positive angles rotate in the direction from
the positive X axis toward the positive Y axis. With the default
axis orientation of cairo, positive angles rotate in a clockwise
direction.
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2611939"></a><h3>
<a name="cairo-matrix-invert"></a>cairo_matrix_invert ()</h3>
<a class="indexterm" name="id2611951"></a><pre class="programlisting"><a href="cairo-Error-handling.html#cairo-status-t">cairo_status_t</a> cairo_matrix_invert (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix);</pre>
<p>
Changes <em class="parameter"><code>matrix</code></em> to be the inverse of it's original value. Not
all transformation matrices have inverses; if the matrix
collapses points together (it is <em class="firstterm">degenerate</em>),
then it has no inverse and this function will fail.
</p>
<p>
Returns: If <em class="parameter"><code>matrix</code></em> has an inverse, modifies <em class="parameter"><code>matrix</code></em> to
be the inverse matrix and returns <a href="cairo-Error-handling.html#CAIRO-STATUS-SUCCESS:CAPS"><code class="literal">CAIRO_STATUS_SUCCESS</code></a>. Otherwise,</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><span class="emphasis"><em>Returns</em></span> :</span></td>
<td>
<a href="cairo-Error-handling.html#CAIRO-STATUS-INVALID-MATRIX:CAPS"><code class="literal">CAIRO_STATUS_INVALID_MATRIX</code></a>.
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2612064"></a><h3>
<a name="cairo-matrix-multiply"></a>cairo_matrix_multiply ()</h3>
<a class="indexterm" name="id2612075"></a><pre class="programlisting">void cairo_matrix_multiply (<a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *result,
const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *a,
const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *b);</pre>
<p>
Multiplies the affine transformations in <em class="parameter"><code>a</code></em> and <em class="parameter"><code>b</code></em> together
and stores the result in <em class="parameter"><code>result</code></em>. The effect of the resulting
transformation is to first apply the transformation in <em class="parameter"><code>a</code></em> to the
coordinates and then apply the transformation in <em class="parameter"><code>b</code></em> to the
coordinates.
</p>
<p>
It is allowable for <em class="parameter"><code>result</code></em> to be identical to either <em class="parameter"><code>a</code></em> or <em class="parameter"><code>b</code></em>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>result</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a> in which to store the result
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>a</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>b</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2612242"></a><h3>
<a name="cairo-matrix-transform-distance"></a>cairo_matrix_transform_distance ()</h3>
<a class="indexterm" name="id2612255"></a><pre class="programlisting">void cairo_matrix_transform_distance (const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double *dx,
double *dy);</pre>
<p>
Transforms the distance vector (<em class="parameter"><code>dx</code></em>,<em class="parameter"><code>dy</code></em>) by <em class="parameter"><code>matrix</code></em>. This is
similar to <a href="cairo-cairo-matrix-t.html#cairo-matrix-transform-point"><code class="function">cairo_matrix_transform_point()</code></a> except that the translation
components of the transformation are ignored. The calculation of
the returned vector is as follows:
</p>
<p>
</p>
<pre class="programlisting">
dx2 = dx1 * a + dy1 * c;
dy2 = dx1 * b + dy1 * d;
</pre>
<p>
</p>
<p>
Affine transformations are position invariant, so the same vector
always transforms to the same vector. If (<em class="parameter"><code>x1</code></em>,<em class="parameter"><code>y1</code></em>) transforms
to (<em class="parameter"><code>x2</code></em>,<em class="parameter"><code>y2</code></em>) then (<em class="parameter"><code>x1</code></em>+<em class="parameter"><code>dx1</code></em>,<em class="parameter"><code>y1</code></em>+<em class="parameter"><code>dy1</code></em>) will transform to
(<em class="parameter"><code>x1</code></em>+<em class="parameter"><code>dx2</code></em>,<em class="parameter"><code>y1</code></em>+<em class="parameter"><code>dy2</code></em>) for all values of <em class="parameter"><code>x1</code></em> and <em class="parameter"><code>x2</code></em>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>dx</code></em> :</span></td>
<td> X component of a distance vector. An in/out parameter
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>dy</code></em> :</span></td>
<td> Y component of a distance vector. An in/out parameter
</td>
</tr>
</tbody>
</table></div>
</div>
<hr>
<div class="refsect2" lang="en">
<a name="id2612446"></a><h3>
<a name="cairo-matrix-transform-point"></a>cairo_matrix_transform_point ()</h3>
<a class="indexterm" name="id2612458"></a><pre class="programlisting">void cairo_matrix_transform_point (const <a href="cairo-cairo-matrix-t.html#cairo-matrix-t">cairo_matrix_t</a> *matrix,
double *x,
double *y);</pre>
<p>
Transforms the point (<em class="parameter"><code>x</code></em>, <em class="parameter"><code>y</code></em>) by <em class="parameter"><code>matrix</code></em>.</p>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td>
<span class="term"><em class="parameter"><code>matrix</code></em> :</span></td>
<td> a <a href="cairo-cairo-matrix-t.html#cairo-matrix-t"><span class="type">cairo_matrix_t</span></a>
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>x</code></em> :</span></td>
<td> X position. An in/out parameter
</td>
</tr>
<tr>
<td>
<span class="term"><em class="parameter"><code>y</code></em> :</span></td>
<td> Y position. An in/out parameter
</td>
</tr>
</tbody>
</table></div>
</div>
</div>
</div>
</body>
</html>