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<div class="chapter">
<div class="titlepage"><div>
<div><h2 class="title">
<a name="migrating-ClutterPath"></a>Migrating to ClutterPath</h2></div>
<div><div class="author">
<h3 class="author">
<span class="firstname">Emmanuele</span> <span class="surname">Bassi</span>
</h3>
<div class="affiliation"><div class="address"><p><br>
<code class="email"><<a class="email" href="mailto:ebassilinux.intel.com">ebassi<em class="parameter"><code>linux.intel.com</code></em></a>></code><br>
</p></div></div>
</div></div>
</div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="migrating-ClutterPath.html#creating-paths">Creating a <span class="type">ClutterPath</span></a></span></dt>
<dt><span class="section"><a href="iterating-paths.html">Iterating over a <span class="type">ClutterPath</span></a></span></dt>
<dt><span class="section"><a href="using-cairo.html">Integration with Cairo</a></span></dt>
</dl></div>
<p>Between Clutter 0.8 and Clutter 1.0 the <a class="link" href="ClutterBehaviourPath.html" title="ClutterBehaviourPath"><span class="type">ClutterBehaviourPath</span></a>
behaviour lost all the path manipulation functions and the
<span class="structname">ClutterBehaviourBspline</span> class was entirely
deprecated.</p>
<p>The class that replaced the path description and manipulation
functionality is called <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a>. A <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> allows
describing a path using a sequence of <a class="link" href="ClutterPath.html#ClutterPathNode"><span class="type">ClutterPathNode</span></a>s or
using a subset of the SVG path description syntax. A Path instance
also allows describing complex paths, with linear and Bezier segments
and with gaps.</p>
<p>Finally, <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> also provides integration with Cairo,
by being able to add paths described by the Cairo
<span class="structname">cairo_path_t</span> data structure and being able
to "replay" a <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> onto a <span class="structname">cairo_t</span>
Cairo context.</p>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="creating-paths"></a>Creating a <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a>
</h2></div></div></div>
<p>Before Clutter 1.0, all the path-related functions inside
<a class="link" href="ClutterBehaviourPath.html" title="ClutterBehaviourPath"><span class="type">ClutterBehaviourPath</span></a> and <span class="structname">ClutterBehaviourBspline</span>
were replicated, but were also subtly different given the different nature
of the types of path handled by the two <a class="link" href="ClutterBehaviour.html" title="ClutterBehaviour"><span class="type">ClutterBehaviour</span></a>s.</p>
<div class="example">
<a name="example-clutter-behaviour-path"></a><p class="title"><b>Example 5. ClutterBehaviourPath example</b></p>
<div class="example-contents">
<p>The following code shows how a <a class="link" href="ClutterBehaviourPath.html" title="ClutterBehaviourPath"><span class="type">ClutterBehaviourPath</span></a> was
created prior to the introduction of <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a>. The path described
is a square box between 100, 100 and 200, 200.</p>
<pre class="programlisting">
ClutterBehaviour *behaviour;
ClutterKnot knots[] = {
{ 100, 100 },
{ 200, 100 },
{ 200, 200 },
{ 100, 200 },
{ 100, 100 }
};
behaviour = clutter_behaviour_path_new (alpha, knots, G_N_ELEMENTS (knots));
</pre>
</div>
</div>
<br class="example-break"><p>The construction for a B-Spline path behaviour was similar, though
the <a class="link" href="clutter-Base-geometric-types.html#ClutterKnot"><span class="type">ClutterKnot</span></a>s could only describe a curvilinear path.</p>
<div class="example">
<a name="example-construct-clutter-path"></a><p class="title"><b>Example 6. Constructing ClutterPath</b></p>
<div class="example-contents">
<p>The following code shows how to construct a <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> and
assign it to a <a class="link" href="ClutterBehaviourPath.html" title="ClutterBehaviourPath"><span class="type">ClutterBehaviourPath</span></a>. The created path is the same as
the example above.</p>
<pre class="programlisting">
ClutterBehaviour *behaviour;
ClutterPath *path;
path = clutter_path_new ();
clutter_path_add_move_to (path, 100, 100);
clutter_path_add_line_to (path, 200, 100);
clutter_path_add_line_to (path, 200, 200);
clutter_path_add_line_to (path, 100, 200);
clutter_path_add_close (path);
behaviour = clutter_behaviour_path_new (alpha, path);
</pre>
</div>
</div>
<br class="example-break"><div class="note">A <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> object can be shared across behaviours, just
like the <a class="link" href="ClutterAlpha.html" title="ClutterAlpha"><span class="type">ClutterAlpha</span></a> objects can.</div>
<p>Path can be described by using a subset of the SVG notation for
paths as well as using <a class="link" href="ClutterPath.html#ClutterPathNode"><span class="type">ClutterPathNode</span></a> structures.</p>
<div class="example">
<a name="example-describe-clutter-path"></a><p class="title"><b>Example 7. Describing ClutterPath</b></p>
<div class="example-contents">
<p>The SVG path notation subset used by <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> is in
string format and can be both set as the whole path description
using <a class="link" href="ClutterPath.html#clutter-path-set-description" title="clutter_path_set_description ()"><code class="function">clutter_path_set_description()</code></a> or can be added to an
existing <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> using <a class="link" href="ClutterPath.html#clutter-path-add-string" title="clutter_path_add_string ()"><code class="function">clutter_path_add_string()</code></a>. The following
example shows the same path as the two examples above.</p>
<pre class="programlisting">
ClutterPath *path = clutter_path_new ();
clutter_path_set_description (path,
"M 100,100 " /* move to */
"L 200,100 " /* line to */
"L 200,200 "
"L 100,200 "
"z" /* close */);
</pre>
</div>
</div>
<br class="example-break"><p>A <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a> can describe not only linear, closed paths; it
can also describe paths with Beziér curvers and can add gaps.</p>
<div class="example">
<a name="example-describe-mixed-clutter-path"></a><p class="title"><b>Example 8. Describing a mixed ClutterPath</b></p>
<div class="example-contents">
<p>A mixed <a class="link" href="ClutterPath.html" title="ClutterPath"><span class="type">ClutterPath</span></a>, with a Beziér curve between the point
at 200, 200 and 100, 100 and both control points in 100, 200.</p>
<pre class="programlisting">
ClutterPath *path = clutter_path_new ();
clutter_path_set_description (path,
"M 100,100 "
"L 200,100 "
"L 200,200 "
"C 100,200 100,200 100,100");
</pre>
</div>
</div>
<br class="example-break">
</div>
</div>
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