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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<a href="#gdk-Cairo-Interaction.description" class="shortcut">Description</a>
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<div class="refentry" title="Cairo Interaction">
<a name="gdk-Cairo-Interaction"></a><div class="titlepage"></div>
<div class="refnamediv"><table width="100%"><tr>
<td valign="top">
<h2><span class="refentrytitle"><a name="gdk-Cairo-Interaction.top_of_page"></a>Cairo Interaction</span></h2>
<p>Cairo Interaction — Functions to support using Cairo</p>
</td>
<td valign="top" align="right"></td>
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<div class="refsynopsisdiv" title="Synopsis">
<a name="gdk-Cairo-Interaction.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis">
#include <gdk/gdk.h>
<a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="returnvalue">cairo_t</span></a> * <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-create" title="gdk_cairo_create ()">gdk_cairo_create</a> (<em class="parameter"><code><a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a> *drawable</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-set-source-color" title="gdk_cairo_set_source_color ()">gdk_cairo_set_source_color</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Colormaps-and-Colors.html#GdkColor" title="GdkColor"><span class="type">GdkColor</span></a> *color</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-set-source-pixbuf" title="gdk_cairo_set_source_pixbuf ()">gdk_cairo_set_source_pixbuf</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a href="http://library.gnome.org/devel/gdk-pixbuf/unstable/gdk-pixbuf-gdk-pixbuf.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>,
<em class="parameter"><code><span class="type">double</span> pixbuf_x</code></em>,
<em class="parameter"><code><span class="type">double</span> pixbuf_y</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-set-source-pixmap" title="gdk_cairo_set_source_pixmap ()">gdk_cairo_set_source_pixmap</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code><a class="link" href="gdk-Bitmaps-and-Pixmaps.html#GdkPixmap"><span class="type">GdkPixmap</span></a> *pixmap</code></em>,
<em class="parameter"><code><span class="type">double</span> pixmap_x</code></em>,
<em class="parameter"><code><span class="type">double</span> pixmap_y</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-rectangle" title="gdk_cairo_rectangle ()">gdk_cairo_rectangle</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRectangle" title="GdkRectangle"><span class="type">GdkRectangle</span></a> *rectangle</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-region" title="gdk_cairo_region ()">gdk_cairo_region</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRegion" title="GdkRegion"><span class="type">GdkRegion</span></a> *region</code></em>);
<span class="returnvalue">void</span> <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-reset-clip" title="gdk_cairo_reset_clip ()">gdk_cairo_reset_clip</a> (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code><a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a> *drawable</code></em>);
</pre>
</div>
<div class="refsect1" title="Description">
<a name="gdk-Cairo-Interaction.description"></a><h2>Description</h2>
<p>
Cairo is a graphics
library that supports vector graphics and image compositing that
can be used with GDK. Since 2.8, GTK+ does most of its drawing
using Cairo.
</p>
<p>
GDK does not wrap the Cairo API, instead it allows to create Cairo
contexts which can be used to draw on GDK drawables. Additional
functions allow to convert GDK's rectangles and regions into
Cairo paths and to use pixbufs as sources for drawing operations.
</p>
</div>
<div class="refsect1" title="Details">
<a name="gdk-Cairo-Interaction.details"></a><h2>Details</h2>
<div class="refsect2" title="gdk_cairo_create ()">
<a name="gdk-cairo-create"></a><h3>gdk_cairo_create ()</h3>
<pre class="programlisting"><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="returnvalue">cairo_t</span></a> * gdk_cairo_create (<em class="parameter"><code><a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a> *drawable</code></em>);</pre>
<p>
Creates a Cairo context for drawing to <em class="parameter"><code>drawable</code></em>.
</p>
<p>
</p>
<div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
Note that due to double-buffering, Cairo contexts created
in a GTK+ expose event handler cannot be cached and reused
between different expose events.
</p>
</div>
<p>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>drawable</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td> A newly created Cairo context. Free with
<a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-destroy"><code class="function">cairo_destroy()</code></a> when you are done drawing.
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.8</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_set_source_color ()">
<a name="gdk-cairo-set-source-color"></a><h3>gdk_cairo_set_source_color ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_set_source_color (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Colormaps-and-Colors.html#GdkColor" title="GdkColor"><span class="type">GdkColor</span></a> *color</code></em>);</pre>
<p>
Sets the specified <a class="link" href="gdk-Colormaps-and-Colors.html#GdkColor" title="GdkColor"><span class="type">GdkColor</span></a> as the source color of <em class="parameter"><code>cr</code></em>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>color</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Colormaps-and-Colors.html#GdkColor" title="GdkColor"><span class="type">GdkColor</span></a>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.8</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_set_source_pixbuf ()">
<a name="gdk-cairo-set-source-pixbuf"></a><h3>gdk_cairo_set_source_pixbuf ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_set_source_pixbuf (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a href="http://library.gnome.org/devel/gdk-pixbuf/unstable/gdk-pixbuf-gdk-pixbuf.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a> *pixbuf</code></em>,
<em class="parameter"><code><span class="type">double</span> pixbuf_x</code></em>,
<em class="parameter"><code><span class="type">double</span> pixbuf_y</code></em>);</pre>
<p>
Sets the given pixbuf as the source pattern for the Cairo context.
The pattern has an extend mode of <code class="literal">CAIRO_EXTEND_NONE</code> and is aligned
so that the origin of <em class="parameter"><code>pixbuf</code></em> is <em class="parameter"><code>pixbuf_x</code></em>, <em class="parameter"><code>pixbuf_y</code></em>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <span class="type">Cairo</span> context
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixbuf</code></em> :</span></p></td>
<td>a <a href="http://library.gnome.org/devel/gdk-pixbuf/unstable/gdk-pixbuf-gdk-pixbuf.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixbuf_x</code></em> :</span></p></td>
<td>X coordinate of location to place upper left corner of <em class="parameter"><code>pixbuf</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixbuf_y</code></em> :</span></p></td>
<td>Y coordinate of location to place upper left corner of <em class="parameter"><code>pixbuf</code></em>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.8</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_set_source_pixmap ()">
<a name="gdk-cairo-set-source-pixmap"></a><h3>gdk_cairo_set_source_pixmap ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_set_source_pixmap (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code><a class="link" href="gdk-Bitmaps-and-Pixmaps.html#GdkPixmap"><span class="type">GdkPixmap</span></a> *pixmap</code></em>,
<em class="parameter"><code><span class="type">double</span> pixmap_x</code></em>,
<em class="parameter"><code><span class="type">double</span> pixmap_y</code></em>);</pre>
<p>
Sets the given pixmap as the source pattern for the Cairo context.
The pattern has an extend mode of <code class="literal">CAIRO_EXTEND_NONE</code> and is aligned
so that the origin of <em class="parameter"><code>pixmap</code></em> is <em class="parameter"><code>pixmap_x</code></em>, <em class="parameter"><code>pixmap_y</code></em>
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <span class="type">Cairo</span> context
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixmap</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Bitmaps-and-Pixmaps.html#GdkPixmap"><span class="type">GdkPixmap</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixmap_x</code></em> :</span></p></td>
<td>X coordinate of location to place upper left corner of <em class="parameter"><code>pixmap</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>pixmap_y</code></em> :</span></p></td>
<td>Y coordinate of location to place upper left corner of <em class="parameter"><code>pixmap</code></em>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.10</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_rectangle ()">
<a name="gdk-cairo-rectangle"></a><h3>gdk_cairo_rectangle ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_rectangle (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRectangle" title="GdkRectangle"><span class="type">GdkRectangle</span></a> *rectangle</code></em>);</pre>
<p>
Adds the given rectangle to the current path of <em class="parameter"><code>cr</code></em>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>rectangle</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRectangle" title="GdkRectangle"><span class="type">GdkRectangle</span></a>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.8</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_region ()">
<a name="gdk-cairo-region"></a><h3>gdk_cairo_region ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_region (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code>const <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRegion" title="GdkRegion"><span class="type">GdkRegion</span></a> *region</code></em>);</pre>
<p>
Adds the given region to the current path of <em class="parameter"><code>cr</code></em>.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>region</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Points-Rectangles-and-Regions.html#GdkRegion" title="GdkRegion"><span class="type">GdkRegion</span></a>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.8</p>
</div>
<hr>
<div class="refsect2" title="gdk_cairo_reset_clip ()">
<a name="gdk-cairo-reset-clip"></a><h3>gdk_cairo_reset_clip ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> gdk_cairo_reset_clip (<em class="parameter"><code><a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a> *cr</code></em>,
<em class="parameter"><code><a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a> *drawable</code></em>);</pre>
<p>
Resets the clip region for a Cairo context created by <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-create" title="gdk_cairo_create ()"><code class="function">gdk_cairo_create()</code></a>.
</p>
<p>
This resets the clip region to the "empty" state for the given drawable.
This is required for non-native windows since a direct call to
<a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-reset-clip"><code class="function">cairo_reset_clip()</code></a> would unset the clip region inherited from the
drawable (i.e. the window clip region), and thus let you e.g.
draw outside your window.
</p>
<p>
This is rarely needed though, since most code just create a new cairo_t
using <a class="link" href="gdk-Cairo-Interaction.html#gdk-cairo-create" title="gdk_cairo_create ()"><code class="function">gdk_cairo_create()</code></a> each time they want to draw something.
</p>
<div class="variablelist"><table border="0">
<col align="left" valign="top">
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>cr</code></em> :</span></p></td>
<td>a <a href="/usr/share/gtk-doc/html/cairo/cairo-context.html#cairo-t"><span class="type">cairo_t</span></a>
</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>drawable</code></em> :</span></p></td>
<td>a <a class="link" href="gdk-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a>
</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.18</p>
</div>
</div>
</div>
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