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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="id-1.6.3.4"></a>Changes that need to be done at the time of the switch</h2></div></div></div>
<p>
This section outlines porting tasks that you need to tackle when
you get to the point that you actually build your application against
GTK+ 3. Making it possible to prepare for these in GTK+ 2.24 would
have been either impossible or impractical.
</p>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.3"></a>Replace size_request by get_preferred_width/height</h3></div></div></div>
<p>
The request-phase of the traditional GTK+ geometry management
has been replaced by a more flexible height-for-width system,
which is described in detail in the API documentation
(see <a class="xref" href="GtkWidget.html#geometry-management" title="Height-for-width Geometry Management">the section called “Height-for-width Geometry Management”</a>). As a consequence,
the ::size-request signal and vfunc has been removed from
<a class="link" href="GtkWidget.html#GtkWidgetClass" title="struct GtkWidgetClass"><span class="type">GtkWidgetClass</span></a>. The replacement for <code class="function">size_request()</code> can
take several levels of sophistication:
</p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
<p>
As a minimal replacement to keep current functionality,
you can simply implement the <a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-width"><code class="function">GtkWidgetClass.get_preferred_width()</code></a> and
<a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-height"><code class="function">GtkWidgetClass.get_preferred_height()</code></a> vfuncs by calling your existing
<code class="function">size_request()</code> function. So you go from
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
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<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_class_init</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">MyWidgetClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">class</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkWidgetClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget_class </span><span class="symbol">=</span><span class="normal"> </span><span class="function">GTK_WIDGET_CLASS</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">class</span><span class="symbol">);</span>
<span class="normal"> </span><span class="comment">/* ... */</span>
<span class="normal"> widget_class</span><span class="symbol">-></span><span class="normal">size_request </span><span class="symbol">=</span><span class="normal"> my_widget_size_request</span><span class="symbol">;</span>
<span class="normal"> </span><span class="comment">/* ... */</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
<p>
to something that looks more like this:
</p>
<p>
</p>
<div class="informalexample">
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<tbody>
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<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_get_preferred_width</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_width</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_width</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkRequisition</span><span class="normal"> requisition</span><span class="symbol">;</span>
<span class="normal"> </span><span class="function">my_widget_size_request</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">requisition</span><span class="symbol">);</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_width </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_width </span><span class="symbol">=</span><span class="normal"> requisition</span><span class="symbol">.</span><span class="normal">width</span><span class="symbol">;</span>
<span class="cbracket">}</span>
<span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_get_preferred_height</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_height</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_height</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkRequisition</span><span class="normal"> requisition</span><span class="symbol">;</span>
<span class="normal"> </span><span class="function">my_widget_size_request</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">requisition</span><span class="symbol">);</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_height </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_height </span><span class="symbol">=</span><span class="normal"> requisition</span><span class="symbol">.</span><span class="normal">height</span><span class="symbol">;</span>
<span class="cbracket">}</span>
<span class="normal"> </span><span class="comment">/* ... */</span>
<span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_class_init</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">MyWidgetClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">class</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkWidgetClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget_class </span><span class="symbol">=</span><span class="normal"> </span><span class="function">GTK_WIDGET_CLASS</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">class</span><span class="symbol">);</span>
<span class="normal"> </span><span class="comment">/* ... */</span>
<span class="normal"> widget_class</span><span class="symbol">-></span><span class="normal">get_preferred_width </span><span class="symbol">=</span><span class="normal"> my_widget_get_preferred_width</span><span class="symbol">;</span>
<span class="normal"> widget_class</span><span class="symbol">-></span><span class="normal">get_preferred_height </span><span class="symbol">=</span><span class="normal"> my_widget_get_preferred_height</span><span class="symbol">;</span>
<span class="normal"> </span><span class="comment">/* ... */</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
<p>
Sometimes you can make things a little more streamlined
by replacing your existing <code class="function">size_request()</code> implementation by
one that takes an orientation parameter:
</p>
<p>
</p>
<div class="informalexample">
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<tbody>
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<td class="listing_lines" align="right"><pre>1
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<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_get_preferred_size</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">GtkOrientation</span><span class="normal"> orientation</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_size</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_size</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* do things that are common for both orientations ... */</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">orientation </span><span class="symbol">==</span><span class="normal"> <a href="gtk3-Standard-Enumerations.html#GTK-ORIENTATION-HORIZONTAL:CAPS">GTK_ORIENTATION_HORIZONTAL</a></span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* do stuff that only applies to width... */</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_size </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_size </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">...</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="normal"> </span><span class="keyword">else</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* do stuff that only applies to height... */</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_size </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_size </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">...</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="cbracket">}</span>
<span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_get_preferred_width</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_width</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_width</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="function">my_widget_get_preferred_size</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> <a href="gtk3-Standard-Enumerations.html#GTK-ORIENTATION-HORIZONTAL:CAPS">GTK_ORIENTATION_HORIZONTAL</a></span><span class="symbol">,</span>
<span class="normal"> minimal_width</span><span class="symbol">,</span>
<span class="normal"> natural_width</span><span class="symbol">);</span>
<span class="cbracket">}</span>
<span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">my_widget_get_preferred_height</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimal_height</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural_height</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="function">my_widget_get_preferred_size</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> <a href="gtk3-Standard-Enumerations.html#GTK-ORIENTATION-VERTICAL:CAPS">GTK_ORIENTATION_VERTICAL</a></span><span class="symbol">,</span>
<span class="normal"> minimal_height</span><span class="symbol">,</span>
<span class="normal"> natural_height</span><span class="symbol">);</span>
<span class="cbracket">}</span>
<span class="normal"> </span><span class="comment">/* ... */</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
</li>
<li class="listitem">
<p>If your widget can cope with a small size,
but would appreciate getting some more space (a common
example would be that it contains ellipsizable labels),
you can do that by making your <a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-width"><code class="function">GtkWidgetClass.get_preferred_width()</code></a> /
<a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-height"><code class="function">GtkWidgetClass.get_preferred_height()</code></a>
functions return a smaller value for <em class="parameter"><code>minimal</code></em> than for <em class="parameter"><code>natural</code></em>.
For <em class="parameter"><code>minimal</code></em>, you probably want to return the same value
that your <code class="function">size_request()</code> function returned before (since
<code class="function">size_request()</code> was defined as returning the minimal size
a widget can work with). A simple way to obtain good
values for <em class="parameter"><code>natural</code></em>, in the case of containers, is to use
<a class="link" href="GtkWidget.html#gtk-widget-get-preferred-width" title="gtk_widget_get_preferred_width ()"><code class="function">gtk_widget_get_preferred_width()</code></a> and
<a class="link" href="GtkWidget.html#gtk-widget-get-preferred-height" title="gtk_widget_get_preferred_height ()"><code class="function">gtk_widget_get_preferred_height()</code></a> on the children of the
container, as in the following example:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
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<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">gtk_fixed_get_preferred_height</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">minimum</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">natural</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkFixed</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">fixed </span><span class="symbol">=</span><span class="normal"> </span><span class="function">GTK_FIXED</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">);</span>
<span class="normal"> </span><span class="usertype">GtkFixedPrivate</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">priv </span><span class="symbol">=</span><span class="normal"> fixed</span><span class="symbol">-></span><span class="normal">priv</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">GtkFixedChild</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">child</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">GList</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">children</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> child_min</span><span class="symbol">,</span><span class="normal"> child_nat</span><span class="symbol">;</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimum </span><span class="symbol">=</span><span class="normal"> </span><span class="number">0</span><span class="symbol">;</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">natural </span><span class="symbol">=</span><span class="normal"> </span><span class="number">0</span><span class="symbol">;</span>
<span class="normal"> </span><span class="keyword">for</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">children </span><span class="symbol">=</span><span class="normal"> priv</span><span class="symbol">-></span><span class="normal">children</span><span class="symbol">;</span><span class="normal"> children</span><span class="symbol">;</span><span class="normal"> children </span><span class="symbol">=</span><span class="normal"> children</span><span class="symbol">-></span><span class="normal">next</span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> child </span><span class="symbol">=</span><span class="normal"> children</span><span class="symbol">-></span><span class="normal">data</span><span class="symbol">;</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(!</span><span class="function"><a href="GtkWidget.html#gtk-widget-get-visible">gtk_widget_get_visible</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">child</span><span class="symbol">-></span><span class="normal">widget</span><span class="symbol">))</span>
<span class="normal"> </span><span class="keyword">continue</span><span class="symbol">;</span>
<span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-preferred-height">gtk_widget_get_preferred_height</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">child</span><span class="symbol">-></span><span class="normal">widget</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">child_min</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">child_nat</span><span class="symbol">);</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">minimum </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#MAX:CAPS">MAX</a></span><span class="normal"> </span><span class="symbol">(*</span><span class="normal">minimum</span><span class="symbol">,</span><span class="normal"> child</span><span class="symbol">-></span><span class="normal">y </span><span class="symbol">+</span><span class="normal"> child_min</span><span class="symbol">);</span>
<span class="normal"> </span><span class="symbol">*</span><span class="normal">natural </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#MAX:CAPS">MAX</a></span><span class="normal"> </span><span class="symbol">(*</span><span class="normal">natural</span><span class="symbol">,</span><span class="normal"> child</span><span class="symbol">-></span><span class="normal">y </span><span class="symbol">+</span><span class="normal"> child_nat</span><span class="symbol">);</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
</li>
<li class="listitem"><p>
Note that the <a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-width"><code class="function">GtkWidgetClass.get_preferred_width()</code></a> /
<a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-height"><code class="function">GtkWidgetClass.get_preferred_height()</code></a> functions
only allow you to deal with one dimension at a time. If your
<code class="function">size_request()</code> handler is doing things that involve both
width and height at the same time (e.g. limiting the aspect
ratio), you will have to implement
<a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-height-for-width"><code class="function">GtkWidgetClass.get_preferred_height_for_width()</code></a>
and <a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-width-for-height"><code class="function">GtkWidgetClass.get_preferred_width_for_height()</code></a>.
</p></li>
<li class="listitem"><p>
To make full use of the new capabilities of the
height-for-width geometry management, you need to additionally
implement the <a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-height-for-width"><code class="function">GtkWidgetClass.get_preferred_height_for_width()</code></a> and
<a class="link" href="GtkWidget.html#GtkWidgetClass.get-preferred-width-for-height"><code class="function">GtkWidgetClass.get_preferred_width_for_height()</code></a>. For details on
these functions, see <a class="xref" href="GtkWidget.html#geometry-management" title="Height-for-width Geometry Management">the section called “Height-for-width Geometry Management”</a>.
</p></li>
</ul></div>
<p>
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.4"></a>Replace GdkRegion by cairo_region_t</h3></div></div></div>
<p>
Starting with version 1.10, cairo provides a region API that is
equivalent to the GDK region API (which was itself copied from
the X server). Therefore, the region API has been removed in GTK+ 3.
</p>
<p>
Porting your application to the cairo region API should be a straight
find-and-replace task. Please refer to the following table:
</p>
<div class="table">
<a name="id-1.6.3.4.4.3.1"></a><p class="title"><b>Table 1. </b></p>
<div class="table-contents"><table border="1">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>GDK</th>
<th>cairo</th>
</tr></thead>
<tbody>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#GdkRegion"><span class="type">GdkRegion</span></a></td>
<td><span class="type">cairo_region_t</span></td>
</tr>
<tr>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Points-Rectangles-and-Regions.html#GdkRectangle"><span class="type">GdkRectangle</span></a></td>
<td><span class="type">cairo_rectangle_int_t</span></td>
</tr>
<tr>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Points-Rectangles-and-Regions.html#gdk-rectangle-intersect"><code class="function">gdk_rectangle_intersect()</code></a></td>
<td>this function is still there</td>
</tr>
<tr>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Points-Rectangles-and-Regions.html#gdk-rectangle-union"><code class="function">gdk_rectangle_union()</code></a></td>
<td>this function is still there</td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-new"><code class="function">gdk_region_new()</code></a></td>
<td><code class="function">cairo_region_create()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-copy"><code class="function">gdk_region_copy()</code></a></td>
<td><code class="function">cairo_region_copy()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-destroy"><code class="function">gdk_region_destroy()</code></a></td>
<td><code class="function">cairo_region_destroy()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-rectangle"><code class="function">gdk_region_rectangle()</code></a></td>
<td><code class="function">cairo_region_create_rectangle()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-get-clipbox"><code class="function">gdk_region_get_clipbox()</code></a></td>
<td><code class="function">cairo_region_get_extents()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-get-rectangles"><code class="function">gdk_region_get_rectangles()</code></a></td>
<td>
<code class="function">cairo_region_num_rectangles()</code> and
<code class="function">cairo_region_get_rectangle()</code>
</td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-empty"><code class="function">gdk_region_empty()</code></a></td>
<td><code class="function">cairo_region_is_empty()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-equal"><code class="function">gdk_region_equal()</code></a></td>
<td><code class="function">cairo_region_equal()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-point-in"><code class="function">gdk_region_point_in()</code></a></td>
<td><code class="function">cairo_region_contains_point()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-rect-in"><code class="function">gdk_region_rect_in()</code></a></td>
<td><code class="function">cairo_region_contains_rectangle()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-offset"><code class="function">gdk_region_offset()</code></a></td>
<td><code class="function">cairo_region_translate()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-union-with-rect"><code class="function">gdk_region_union_with_rect()</code></a></td>
<td><code class="function">cairo_region_union_rectangle()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-intersect"><code class="function">gdk_region_intersect()</code></a></td>
<td><code class="function">cairo_region_intersect()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-union"><code class="function">gdk_region_union()</code></a></td>
<td><code class="function">cairo_region_union()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-subtract"><code class="function">gdk_region_subtract()</code></a></td>
<td><code class="function">cairo_region_subtract()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-xor"><code class="function">gdk_region_xor()</code></a></td>
<td><code class="function">cairo_region_xor()</code></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-shrink"><code class="function">gdk_region_shrink()</code></a></td>
<td>no replacement</td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Points-Rectangles-and-Regions.html#gdk-region-polygon"><code class="function">gdk_region_polygon()</code></a></td>
<td>no replacement, use cairo paths instead</td>
</tr>
</tbody>
</table></div>
</div>
<p><br class="table-break">
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.5"></a>Replace GdkPixmap by cairo surfaces</h3></div></div></div>
<p>
The <a href="http://library.gnome.org/devel/gdk3/gdk2-Bitmaps-and-Pixmaps.html#GdkPixmap"><span class="type">GdkPixmap</span></a> object and related functions have been removed.
In the cairo-centric world of GTK+ 3, cairo surfaces take over
the role of pixmaps.
</p>
<div class="example">
<a name="id-1.6.3.4.5.3"></a><p class="title"><b>Example 117. Creating custom cursors</b></p>
<div class="example-contents">
<p>
One place where pixmaps were commonly used is to create custom
cursors:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="usertype">GdkCursor</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cursor</span><span class="symbol">;</span>
<span class="usertype">GdkPixmap</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">pixmap</span><span class="symbol">;</span>
<span class="usertype">cairo_t</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cr</span><span class="symbol">;</span>
<span class="usertype">GdkColor</span><span class="normal"> fg </span><span class="symbol">=</span><span class="normal"> </span><span class="cbracket">{</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="normal"> </span><span class="cbracket">}</span><span class="symbol">;</span>
<span class="normal">pixmap </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://library.gnome.org/devel/gdk3/gdk2-Bitmaps-and-Pixmaps.html#gdk-pixmap-new">gdk_pixmap_new</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> </span><span class="number">1</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1</span><span class="symbol">);</span>
<span class="normal">cr </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-Cairo-Interaction.html#gdk-cairo-create">gdk_cairo_create</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">pixmap</span><span class="symbol">);</span>
<span class="function">cairo_rectangle</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1</span><span class="symbol">);</span>
<span class="function">cairo_fill</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">);</span>
<span class="function">cairo_destroy</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">);</span>
<span class="normal">cursor </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://library.gnome.org/devel/gdk3/gdk2-Cursors.html#gdk-cursor-new-from-pixmap">gdk_cursor_new_from_pixmap</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">pixmap</span><span class="symbol">,</span><span class="normal"> pixmap</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">fg</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">&</span><span class="normal">fg</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">);</span>
<span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-unref">g_object_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">pixmap</span><span class="symbol">);</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
The same can be achieved without pixmaps, by drawing onto
an image surface:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="usertype">GdkCursor</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cursor</span><span class="symbol">;</span>
<span class="usertype">cairo_surface_t</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">s</span><span class="symbol">;</span>
<span class="usertype">cairo_t</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cr</span><span class="symbol">;</span>
<span class="usertype">GdkPixbuf</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">pixbuf</span><span class="symbol">;</span>
<span class="normal">s </span><span class="symbol">=</span><span class="normal"> </span><span class="function">cairo_image_surface_create</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">CAIRO_FORMAT_A1</span><span class="symbol">,</span><span class="normal"> </span><span class="number">3</span><span class="symbol">,</span><span class="normal"> </span><span class="number">3</span><span class="symbol">);</span>
<span class="normal">cr </span><span class="symbol">=</span><span class="normal"> </span><span class="function">cairo_create</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">s</span><span class="symbol">);</span>
<span class="function">cairo_arc</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1.5</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1.5</span><span class="symbol">,</span><span class="normal"> </span><span class="number">1.5</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">2</span><span class="normal"> </span><span class="symbol">*</span><span class="normal"> M_PI</span><span class="symbol">);</span>
<span class="function">cairo_fill</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">);</span>
<span class="function">cairo_destroy</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">);</span>
<span class="normal">pixbuf </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-Pixbufs.html#gdk-pixbuf-get-from-surface">gdk_pixbuf_get_from_surface</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">s</span><span class="symbol">,</span>
<span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span>
<span class="normal"> </span><span class="number">3</span><span class="symbol">,</span><span class="normal"> </span><span class="number">3</span><span class="symbol">);</span>
<span class="function">cairo_surface_destroy</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">s</span><span class="symbol">);</span>
<span class="normal">cursor </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-Cursors.html#gdk-cursor-new-from-pixbuf">gdk_cursor_new_from_pixbuf</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">display</span><span class="symbol">,</span><span class="normal"> pixbuf</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">,</span><span class="normal"> </span><span class="number">0</span><span class="symbol">);</span>
<span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#g-object-unref">g_object_unref</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">pixbuf</span><span class="symbol">);</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
</div>
</div>
<br class="example-break">
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.6"></a>Replace GdkColormap by GdkVisual</h3></div></div></div>
<p>
For drawing with cairo, it is not necessary to allocate colors, and
a <a href="http://developer.gnome.org/gdk2/gdk3-Visuals.html#GdkVisual"><span class="type">GdkVisual</span></a> provides enough information for cairo to handle colors
in 'native' surfaces. Therefore, <a href="http://library.gnome.org/devel/gdk3/gdk2-Colormaps-and-Colors.html#GdkColormap"><span class="type">GdkColormap</span></a> and related functions
have been removed in GTK+ 3, and visuals are used instead. The
colormap-handling functions of <a class="link" href="GtkWidget.html" title="GtkWidget"><span class="type">GtkWidget</span></a> (<a href="http://library.gnome.org/devel/gtk3/GtkWidget.html#gtk-widget-set-colormap"><code class="function">gtk_widget_set_colormap()</code></a>,
etc) have been removed and <a class="link" href="GtkWidget.html#gtk-widget-set-visual" title="gtk_widget_set_visual ()"><code class="function">gtk_widget_set_visual()</code></a> has been added.
</p>
<div class="example">
<a name="id-1.6.3.4.6.3"></a><p class="title"><b>Example 118. Setting up a translucent window</b></p>
<div class="example-contents">
<p>You might have a screen-changed handler like the following
to set up a translucent window with an alpha-channel:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">on_alpha_screen_changed</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">GdkScreen</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">old_screen</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">label</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GdkScreen</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">screen </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-screen">gtk_widget_get_screen</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">);</span>
<span class="normal"> </span><span class="usertype">GdkColormap</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">colormap </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://library.gnome.org/devel/gdk3/GdkScreen.html#gdk-screen-get-rgba-colormap">gdk_screen_get_rgba_colormap</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">screen</span><span class="symbol">);</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">colormap </span><span class="symbol">==</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">)</span>
<span class="normal"> colormap </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://library.gnome.org/devel/gdk3/GdkScreen.html#gdk-screen-get-default-colormap">gdk_screen_get_default_colormap</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">screen</span><span class="symbol">);</span>
<span class="normal"> </span><span class="function"><a href="http://library.gnome.org/devel/gtk3/GtkWidget.html#gtk-widget-set-colormap">gtk_widget_set_colormap</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">,</span><span class="normal"> colormap</span><span class="symbol">);</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
With visuals instead of colormaps, this will look as follows:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> </span><span class="type">void</span>
<span class="function">on_alpha_screen_changed</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWindow</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">window</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">GdkScreen</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">old_screen</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">label</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GdkScreen</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">screen </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-screen">gtk_widget_get_screen</a></span><span class="normal"> </span><span class="symbol">(</span><span class="function">GTK_WIDGET</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">window</span><span class="symbol">));</span>
<span class="normal"> </span><span class="usertype">GdkVisual</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">visual </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/GdkScreen.html#gdk-screen-get-rgba-visual">gdk_screen_get_rgba_visual</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">screen</span><span class="symbol">);</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">visual </span><span class="symbol">==</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">)</span>
<span class="normal"> visual </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/GdkScreen.html#gdk-screen-get-system-visual">gdk_screen_get_system_visual</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">screen</span><span class="symbol">);</span>
<span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-set-visual">gtk_widget_set_visual</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">window</span><span class="symbol">,</span><span class="normal"> visual</span><span class="symbol">);</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<br class="example-break">
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.7"></a>GdkDrawable is gone</h3></div></div></div>
<p>
<a href="http://library.gnome.org/devel/gdk3/gdk2-Drawing-Primitives.html#GdkDrawable"><span class="type">GdkDrawable</span></a> has been removed in GTK+ 3, together with <a href="http://library.gnome.org/devel/gdk3/gdk2-Bitmaps-and-Pixmaps.html#GdkPixmap"><span class="type">GdkPixmap</span></a>
and <a href="http://library.gnome.org/devel/gdk3/gdk2-Images.html#GdkImage"><span class="type">GdkImage</span></a>. The only remaining drawable class is <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GdkWindow"><span class="type">GdkWindow</span></a>.
For dealing with image data, you should use a <span class="type">cairo_surface_t</span> or
a <a href="http://library.gnome.org/devel/gdk-pixbuf/unstable/gdk-pixbuf-The-GdkPixbuf-Structure.html#GdkPixbuf"><span class="type">GdkPixbuf</span></a>.
</p>
<p>
GdkDrawable functions that are useful with windows have been replaced
by corresponding GdkWindow functions:
</p>
<div class="table">
<a name="id-1.6.3.4.7.3.1"></a><p class="title"><b>Table 2. GdkDrawable to GdkWindow</b></p>
<div class="table-contents"><table summary="GdkDrawable to GdkWindow" border="1">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>GDK 2.x</th>
<th>GDK 3</th>
</tr></thead>
<tbody>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Drawing-Primitives.html#gdk-drawable-get-visual"><code class="function">gdk_drawable_get_visual()</code></a></td>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-get-visual"><code class="function">gdk_window_get_visual()</code></a></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Drawing-Primitives.html#gdk-drawable-get-size"><code class="function">gdk_drawable_get_size()</code></a></td>
<td>
<a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-get-width"><code class="function">gdk_window_get_width()</code></a>
<a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-get-height"><code class="function">gdk_window_get_height()</code></a>
</td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Pixbufs.html#gdk-pixbuf-get-from-drawable"><code class="function">gdk_pixbuf_get_from_drawable()</code></a></td>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Pixbufs.html#gdk-pixbuf-get-from-window"><code class="function">gdk_pixbuf_get_from_window()</code></a></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Drawing-Primitives.html#gdk-drawable-get-clip-region"><code class="function">gdk_drawable_get_clip_region()</code></a></td>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-get-clip-region"><code class="function">gdk_window_get_clip_region()</code></a></td>
</tr>
<tr>
<td><a href="http://library.gnome.org/devel/gdk3/gdk2-Drawing-Primitives.html#gdk-drawable-get-visible-region"><code class="function">gdk_drawable_get_visible_region()</code></a></td>
<td><a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-get-visible-region"><code class="function">gdk_window_get_visible_region()</code></a></td>
</tr>
</tbody>
</table></div>
</div>
<p><br class="table-break">
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.8"></a>Event filtering</h3></div></div></div>
<p>
If your application uses the low-level event filtering facilities in GDK,
there are some changes you need to be aware of.
</p>
<p>
The special-purpose GdkEventClient events and the <a href="http://library.gnome.org/devel/gdk3/gdk2-Events.html#gdk-add-client-message-filter"><code class="function">gdk_add_client_message_filter()</code></a> and <a href="http://library.gnome.org/devel/gdk3/GdkDisplay.html#gdk-display-add-client-message-filter"><code class="function">gdk_display_add_client_message_filter()</code></a> functions have been
removed. Receiving X11 ClientMessage events is still possible, using
the general <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-add-filter"><code class="function">gdk_window_add_filter()</code></a> API. A client message filter like
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GdkFilterReturn">GdkFilterReturn</a></span>
<span class="function">message_filter</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GdkXEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">xevent</span><span class="symbol">,</span><span class="normal"> </span><span class="usertype">GdkEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">event</span><span class="symbol">,</span><span class="normal"> </span><span class="usertype">gpointer</span><span class="normal"> data</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">XClientMessageEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">evt </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">XClientMessageEvent </span><span class="symbol">*)</span><span class="normal">xevent</span><span class="symbol">;</span>
<span class="normal"> </span><span class="comment">/* do something with evt ... */</span>
<span class="cbracket">}</span>
<span class="normal"> </span><span class="symbol">...</span>
<span class="normal">message_type </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-Properties-and-Atoms.html#gdk-atom-intern">gdk_atom_intern</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"MANAGER"</span><span class="symbol">,</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS">FALSE</a></span><span class="symbol">);</span>
<span class="function"><a href="http://library.gnome.org/devel/gdk3/GdkDisplay.html#gdk-display-add-client-message-filter">gdk_display_add_client_message_filter</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">display</span><span class="symbol">,</span><span class="normal"> message_type</span><span class="symbol">,</span><span class="normal"> message_filter</span><span class="symbol">,</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
then looks like this:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">static</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GdkFilterReturn">GdkFilterReturn</a></span>
<span class="function">event_filter</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GdkXEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">xevent</span><span class="symbol">,</span><span class="normal"> </span><span class="usertype">GdkEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">event</span><span class="symbol">,</span><span class="normal"> </span><span class="usertype">gpointer</span><span class="normal"> data</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">XClientMessageEvent</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">evt</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">GdkAtom</span><span class="normal"> message_type</span><span class="symbol">;</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(((</span><span class="normal">XEvent </span><span class="symbol">*)</span><span class="normal">xevent</span><span class="symbol">)-></span><span class="normal">type </span><span class="symbol">!=</span><span class="normal"> ClientMessage</span><span class="symbol">)</span>
<span class="normal"> </span><span class="keyword">return</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GDK-FILTER-CONTINUE:CAPS">GDK_FILTER_CONTINUE</a></span><span class="symbol">;</span>
<span class="normal"> evt </span><span class="symbol">=</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">XClientMessageEvent </span><span class="symbol">*)</span><span class="normal">xevent</span><span class="symbol">;</span>
<span class="normal"> message_type </span><span class="symbol">=</span><span class="normal"> </span><span class="function">XInternAtom</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">evt</span><span class="symbol">-></span><span class="normal">display</span><span class="symbol">,</span><span class="normal"> </span><span class="string">"MANAGER"</span><span class="symbol">,</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#FALSE:CAPS">FALSE</a></span><span class="symbol">);</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">evt</span><span class="symbol">-></span><span class="normal">message_type </span><span class="symbol">!=</span><span class="normal"> message_type</span><span class="symbol">)</span>
<span class="normal"> </span><span class="keyword">return</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GDK-FILTER-CONTINUE:CAPS">GDK_FILTER_CONTINUE</a></span><span class="symbol">;</span>
<span class="normal"> </span><span class="comment">/* do something with evt ... */</span>
<span class="cbracket">}</span>
<span class="normal"> </span><span class="symbol">...</span>
<span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-add-filter">gdk_window_add_filter</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">,</span><span class="normal"> message_filter</span><span class="symbol">,</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#NULL:CAPS">NULL</a></span><span class="symbol">);</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
One advantage of using an event filter is that you can actually
remove the filter when you don't need it anymore, using
<a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#gdk-window-remove-filter"><code class="function">gdk_window_remove_filter()</code></a>.
</p>
<p>
The other difference to be aware of when working with event filters
in GTK+ 3 is that GDK now uses XI2 by default when available. That
means that your application does not receive core X11 key or button
events. Instead, all input events are delivered as XIDeviceEvents.
As a short-term workaround for this, you can force your application
to not use XI2, with <a href="http://developer.gnome.org/gdk2/GdkDeviceManager.html#gdk-disable-multidevice"><code class="function">gdk_disable_multidevice()</code></a>. In the long term,
you probably want to rewrite your event filter to deal with
XIDeviceEvents.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.9"></a>Backend-specific code</h3></div></div></div>
<p>
In GTK+ 2.x, GDK could only be compiled for one backend at a time,
and the <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-X11:CAPS"><code class="literal">GDK_WINDOWING_X11</code></a> or <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-WIN32:CAPS"><code class="literal">GDK_WINDOWING_WIN32</code></a> macros could
be used to find out which one you are dealing with:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="preproc">#ifdef</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-X11:CAPS">GDK_WINDOWING_X11</a></span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">timestamp </span><span class="symbol">!=</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Events.html#GDK-CURRENT-TIME:CAPS">GDK_CURRENT_TIME</a></span><span class="symbol">)</span>
<span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-X-Window-System-Interaction.html#gdk-x11-window-set-user-time">gdk_x11_window_set_user_time</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">gdk_window</span><span class="symbol">,</span><span class="normal"> timestamp</span><span class="symbol">);</span>
<span class="preproc">#endif</span>
<span class="preproc">#ifdef</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-WIN32:CAPS">GDK_WINDOWING_WIN32</a></span>
<span class="normal"> </span><span class="comment">/* ... win32 specific code ... */</span>
<span class="preproc">#endif</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
In GTK+ 3, GDK can be built with multiple backends, and currently
used backend has to be determined at runtime, typically using
type-check macros on a <a href="http://developer.gnome.org/gdk2/GdkDisplay.html"><span class="type">GdkDisplay</span></a> or <a href="http://developer.gnome.org/gdk2/gdk3-Windows.html#GdkWindow"><span class="type">GdkWindow</span></a>. You still need
to use the <span class="type">GDK_WINDOWING</span> macros to only compile code referring
to supported backends:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="preproc">#ifdef</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-X11:CAPS">GDK_WINDOWING_X11</a></span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="function">GDK_IS_X11_DISPLAY</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">display</span><span class="symbol">))</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">timestamp </span><span class="symbol">!=</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-Events.html#GDK-CURRENT-TIME:CAPS">GDK_CURRENT_TIME</a></span><span class="symbol">)</span>
<span class="normal"> </span><span class="function"><a href="http://developer.gnome.org/gdk2/gdk3-X-Window-System-Interaction.html#gdk-x11-window-set-user-time">gdk_x11_window_set_user_time</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">gdk_window</span><span class="symbol">,</span><span class="normal"> timestamp</span><span class="symbol">);</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="normal"> </span><span class="keyword">else</span>
<span class="preproc">#endif</span>
<span class="preproc">#ifdef</span><span class="normal"> <a href="http://developer.gnome.org/gdk2/gdk3-General.html#GDK-WINDOWING-WIN32:CAPS">GDK_WINDOWING_WIN32</a></span>
<span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="function">GDK_IS_WIN32_DISPLAY</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">display</span><span class="symbol">))</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* ... win32 specific code ... */</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="normal"> </span><span class="keyword">else</span>
<span class="preproc">#endif</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Message-Logging.html#g-warning">g_warning</a></span><span class="normal"> </span><span class="symbol">(</span><span class="string">"Unsupported GDK backend"</span><span class="symbol">);</span>
<span class="normal"> </span><span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
<p>
If you used the pkg-config variable <code class="varname">target</code> to
conditionally build part of your project depending on the GDK backend,
for instance like this:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="function">AM_CONDITIONAL</span><span class="symbol">(</span><span class="normal">BUILD_X11</span><span class="symbol">,</span><span class="normal"> test `$PKG_CONFIG </span><span class="symbol">--</span><span class="normal">variable</span><span class="symbol">=</span><span class="usertype">target</span><span class="normal"> gtk</span><span class="symbol">+-</span><span class="number">2.0</span><span class="normal">` </span><span class="symbol">=</span><span class="normal"> </span><span class="string">"x11"</span><span class="symbol">)</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
then you should now use the M4 macro provided by GTK+ itself:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="function">GTK_CHECK_BACKEND</span><span class="symbol">([</span><span class="normal">x11</span><span class="symbol">],</span><span class="normal"> </span><span class="symbol">[</span><span class="number">3.0</span><span class="symbol">.</span><span class="number">2</span><span class="symbol">],</span><span class="normal"> </span><span class="symbol">[</span><span class="normal">have_x11</span><span class="symbol">=</span><span class="normal">yes</span><span class="symbol">],</span><span class="normal"> </span><span class="symbol">[</span><span class="normal">have_x11</span><span class="symbol">=</span><span class="normal">no</span><span class="symbol">])</span>
<span class="function">AM_CONDITIONAL</span><span class="symbol">(</span><span class="normal">BUILD_x11</span><span class="symbol">,</span><span class="normal"> </span><span class="symbol">[</span><span class="normal">test </span><span class="string">"x$have_x11"</span><span class="normal"> </span><span class="symbol">=</span><span class="normal"> </span><span class="string">"xyes"</span><span class="symbol">])</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.10"></a>GtkPlug and GtkSocket</h3></div></div></div>
<p>
The <a class="link" href="GtkPlug.html" title="GtkPlug"><span class="type">GtkPlug</span></a> and <a class="link" href="GtkSocket.html" title="GtkSocket"><span class="type">GtkSocket</span></a> widgets are now X11-specific, and you
have to include the <code class="filename"><gtk/gtkx.h></code> header
to use them. The previous section about proper handling of
backend-specific code applies, if you care about other backends.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.11"></a>The GtkWidget::draw signal</h3></div></div></div>
<p>
The GtkWidget <a href="http://library.gnome.org/devel/gtk3/GtkWidget.html#GtkWidget-expose-event"><span class="type">"expose-event"</span></a> signal has been replaced by
a new <a class="link" href="GtkWidget.html#GtkWidget-draw" title='The "draw" signal'><span class="type">"draw"</span></a> signal, which takes a <span class="type">cairo_t</span> instead of
an expose event. The cairo context is being set up so that the origin
at (0, 0) coincides with the upper left corner of the widget, and
is properly clipped.
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>In other words, the cairo context of the draw signal is set
up in 'widget coordinates', which is different from traditional expose
event handlers, which always assume 'window coordinates'.
</p>
</div>
<p>
The widget is expected to draw itself with its allocated size, which
is available via the new <a class="link" href="GtkWidget.html#gtk-widget-get-allocated-width" title="gtk_widget_get_allocated_width ()"><code class="function">gtk_widget_get_allocated_width()</code></a> and
<a class="link" href="GtkWidget.html#gtk-widget-get-allocated-height" title="gtk_widget_get_allocated_height ()"><code class="function">gtk_widget_get_allocated_height()</code></a> functions. It is not necessary to
check for <code class="function">GTK_WIDGET_IS_DRAWABLE()</code>, since GTK+ already does this check
before emitting the <a class="link" href="GtkWidget.html#GtkWidget-draw" title='The "draw" signal'><span class="type">"draw"</span></a> signal.
</p>
<p>
There are some special considerations for widgets with multiple windows.
Expose events are window-specific, and widgets with multiple windows
could expect to get an expose event for each window that needs to be
redrawn. Therefore, multi-window expose event handlers typically look
like this:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">event</span><span class="symbol">-></span><span class="normal">window </span><span class="symbol">==</span><span class="normal"> widget</span><span class="symbol">-></span><span class="normal">window1</span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* ... draw window1 ... */</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="keyword">else</span><span class="normal"> </span><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">event</span><span class="symbol">-></span><span class="normal">window </span><span class="symbol">==</span><span class="normal"> widget</span><span class="symbol">-></span><span class="normal">window2</span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* ... draw window2 ... */</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="symbol">...</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
In contrast, the <a class="link" href="GtkWidget.html#GtkWidget-draw" title='The "draw" signal'><span class="type">"draw"</span></a> signal handler may have to draw multiple
windows in one call. GTK+ has a convenience function
<a class="link" href="GtkWidget.html#gtk-cairo-should-draw-window" title="gtk_cairo_should_draw_window ()"><code class="function">gtk_cairo_should_draw_window()</code></a> that can be used to find out if
a window needs to be drawn. With that, the example above would look
like this (note that the 'else' is gone):
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="function"><a href="GtkWidget.html#gtk-cairo-should-draw-window">gtk_cairo_should_draw_window</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">,</span><span class="normal"> widget</span><span class="symbol">-></span><span class="normal">window1</span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* ... draw window1 ... */</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="keyword">if</span><span class="normal"> </span><span class="symbol">(</span><span class="function"><a href="GtkWidget.html#gtk-cairo-should-draw-window">gtk_cairo_should_draw_window</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">cr</span><span class="symbol">,</span><span class="normal"> widget</span><span class="symbol">-></span><span class="normal">window2</span><span class="symbol">)</span>
<span class="normal"> </span><span class="cbracket">{</span>
<span class="normal"> </span><span class="comment">/* ... draw window2 ... */</span>
<span class="normal"> </span><span class="cbracket">}</span>
<span class="symbol">...</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
Another convenience function that can help when implementing
::draw for multi-window widgets is <a class="link" href="GtkWidget.html#gtk-cairo-transform-to-window" title="gtk_cairo_transform_to_window ()"><code class="function">gtk_cairo_transform_to_window()</code></a>,
which transforms a cairo context from widget-relative coordinates
to window-relative coordinates. You may want to use <code class="function">cairo_save()</code> and
<code class="function">cairo_restore()</code> when modifying the cairo context in your draw function.
</p>
<p>
All GtkStyle drawing functions (<a class="link" href="GtkStyle.html#gtk-paint-box" title="gtk_paint_box ()"><code class="function">gtk_paint_box()</code></a>, etc) have been changed
to take a <span class="type">cairo_t</span> instead of a window and a clip area. ::draw
implementations will usually just use the cairo context that has been
passed in for this.
</p>
<div class="example">
<a name="id-1.6.3.4.11.7"></a><p class="title"><b>Example 119. A simple ::draw function</b></p>
<div class="example-contents">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="normal"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Basic-Types.html#gboolean">gboolean</a></span>
<span class="function">gtk_arrow_draw</span><span class="normal"> </span><span class="symbol">(</span><span class="usertype">GtkWidget</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget</span><span class="symbol">,</span>
<span class="normal"> </span><span class="usertype">cairo_t</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">cr</span><span class="symbol">)</span>
<span class="cbracket">{</span>
<span class="normal"> </span><span class="usertype">GtkStyleContext</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">context</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> width</span><span class="symbol">,</span><span class="normal"> height</span><span class="symbol">;</span>
<span class="normal"> </span><span class="usertype">gint</span><span class="normal"> extent</span><span class="symbol">;</span>
<span class="normal"> context </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-style-context">gtk_widget_get_style_context</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">);</span>
<span class="normal"> width </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-allocated-width">gtk_widget_get_allocated_width</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">);</span>
<span class="normal"> height </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="GtkWidget.html#gtk-widget-get-allocated-height">gtk_widget_get_allocated_height</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">widget</span><span class="symbol">);</span>
<span class="normal"> extent </span><span class="symbol">=</span><span class="normal"> </span><span class="function"><a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Standard-Macros.html#MIN:CAPS">MIN</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">width </span><span class="symbol">-</span><span class="normal"> </span><span class="number">2</span><span class="normal"> </span><span class="symbol">*</span><span class="normal"> PAD</span><span class="symbol">,</span><span class="normal"> height </span><span class="symbol">-</span><span class="normal"> </span><span class="number">2</span><span class="normal"> </span><span class="symbol">*</span><span class="normal"> PAD</span><span class="symbol">);</span>
<span class="normal"> x </span><span class="symbol">=</span><span class="normal"> PAD</span><span class="symbol">;</span>
<span class="normal"> y </span><span class="symbol">=</span><span class="normal"> PAD</span><span class="symbol">;</span>
<span class="normal"> </span><span class="function"><a href="GtkStyleContext.html#gtk-render-arrow">gtk_render_arrow</a></span><span class="normal"> </span><span class="symbol">(</span><span class="normal">context</span><span class="symbol">,</span><span class="normal"> rc</span><span class="symbol">,</span><span class="normal"> <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/glib/glib-Numerical-Definitions.html#G-PI:CAPS">G_PI</a> </span><span class="symbol">/</span><span class="normal"> </span><span class="number">2</span><span class="symbol">,</span><span class="normal"> x</span><span class="symbol">,</span><span class="normal"> y</span><span class="symbol">,</span><span class="normal"> extent</span><span class="symbol">);</span>
<span class="cbracket">}</span></pre></td>
</tr>
</tbody>
</table>
</div>
</div>
<br class="example-break">
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.12"></a>GtkProgressBar orientation</h3></div></div></div>
<p>
In GTK+ 2.x, <a class="link" href="GtkProgressBar.html" title="GtkProgressBar"><span class="type">GtkProgressBar</span></a> and <a class="link" href="GtkCellRendererProgress.html" title="GtkCellRendererProgress"><span class="type">GtkCellRendererProgress</span></a> were using the
GtkProgressBarOrientation enumeration to specify their orientation and
direction. In GTK+ 3, both the widget and the cell renderer implement
<a class="link" href="gtk3-Orientable.html#GtkOrientable"><span class="type">GtkOrientable</span></a>, and have an additional 'inverted' property to determine
their direction. Therefore, a call to <a href="http://library.gnome.org/devel/gtk3/GtkProgressBar.html#gtk-progress-bar-set-orientation"><code class="function">gtk_progress_bar_set_orientation()</code></a>
needs to be replaced by a pair of calls to
<a class="link" href="gtk3-Orientable.html#gtk-orientable-set-orientation" title="gtk_orientable_set_orientation ()"><code class="function">gtk_orientable_set_orientation()</code></a> and <a class="link" href="GtkProgressBar.html#gtk-progress-bar-set-inverted" title="gtk_progress_bar_set_inverted ()"><code class="function">gtk_progress_bar_set_inverted()</code></a>.
The following values correspond:
</p>
<div class="table">
<a name="id-1.6.3.4.12.2.7"></a><p class="title"><b>Table 3. </b></p>
<div class="table-contents"><table border="1">
<colgroup>
<col class="1">
<col class="2">
<col class="3">
</colgroup>
<thead>
<tr>
<th>GTK+ 2.x</th>
<th colspan="2">GTK+ 3</th>
</tr>
<tr>
<th>GtkProgressBarOrientation</th>
<th>GtkOrientation</th>
<th>inverted</th>
</tr>
</thead>
<tbody>
<tr>
<td>GTK_PROGRESS_LEFT_TO_RIGHT</td>
<td>GTK_ORIENTATION_HORIZONTAL</td>
<td>FALSE</td>
</tr>
<tr>
<td>GTK_PROGRESS_RIGHT_TO_LEFT</td>
<td>GTK_ORIENTATION_HORIZONTAL</td>
<td>TRUE</td>
</tr>
<tr>
<td>GTK_PROGRESS_TOP_TO_BOTTOM</td>
<td>GTK_ORIENTATION_VERTICAL</td>
<td>FALSE</td>
</tr>
<tr>
<td>GTK_PROGRESS_BOTTOM_TO_TOP</td>
<td>GTK_ORIENTATION_VERTICAL</td>
<td>TRUE</td>
</tr>
</tbody>
</table></div>
</div>
<p><br class="table-break">
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.13"></a>Check your expand and fill flags</h3></div></div></div>
<p>
The behaviour of expanding widgets has changed slightly in GTK+ 3,
compared to GTK+ 2.x. It is now 'inherited', i.e. a container that
has an expanding child is considered expanding itself. This is often
the desired behaviour. In places where you don't want this to happen,
setting the container explicity as not expanding will stop the
expand flag of the child from being inherited. See
<a class="link" href="GtkWidget.html#gtk-widget-set-hexpand" title="gtk_widget_set_hexpand ()"><code class="function">gtk_widget_set_hexpand()</code></a> and <a class="link" href="GtkWidget.html#gtk-widget-set-vexpand" title="gtk_widget_set_vexpand ()"><code class="function">gtk_widget_set_vexpand()</code></a>.
</p>
<p>
If you experience sizing problems with widgets in ported code,
carefully check the <span class="type">"expand"</span> and <span class="type">"fill"</span> flags of your
boxes.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.14"></a>Scrolling changes</h3></div></div></div>
<p>
The default values for the <a class="link" href="GtkScrolledWindow.html#GtkScrolledWindow--hscrollbar-policy" title='The "hscrollbar-policy" property'><span class="type">"hscrollbar-policy"</span></a> and
<a class="link" href="GtkScrolledWindow.html#GtkScrolledWindow--vscrollbar-policy" title='The "vscrollbar-policy" property'><span class="type">"vscrollbar-policy"</span></a> properties have been changed from
'never' to 'automatic'. If your application was relying on the default
value, you will have explicitly set it explicitly.
</p>
<p>
The ::set-scroll-adjustments signal on GtkWidget has been replaced
by the <a class="link" href="GtkScrollable.html" title="GtkScrollable"><span class="type">GtkScrollable</span></a> interface which must be implemented by a widget
that wants to be placed in a <a class="link" href="GtkScrolledWindow.html" title="GtkScrolledWindow"><span class="type">GtkScrolledWindow</span></a>. Instead of emitting
::set-scroll-adjustments, the scrolled window simply sets the
<span class="type">"hadjustment"</span> and <span class="type">"vadjustment"</span> properties.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.15"></a>GtkObject is gone</h3></div></div></div>
<p>
GtkObject has been removed in GTK+ 3. Its remaining functionality,
the ::destroy signal, has been moved to GtkWidget. If you have non-widget
classes that are directly derived from GtkObject, you have to make
them derive from <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GInitiallyUnowned"><span class="type">GInitiallyUnowned</span></a> (or, if you don't need the floating
functionality, <a href="/home/kou/work/ruby/ruby-gnome2.win32/glib2/vendor/local/share/gtk-doc/html/gobject/gobject-The-Base-Object-Type.html#GObject"><span class="type">GObject</span></a>). If you have widgets that override the
destroy class handler, you have to adjust your class_init function,
since destroy is now a member of GtkWidgetClass:
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="usertype">GtkObjectClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">object_class </span><span class="symbol">=</span><span class="normal"> </span><span class="function">GTK_OBJECT_CLASS</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">class</span><span class="symbol">);</span>
<span class="normal">object_class</span><span class="symbol">-></span><span class="normal">destroy </span><span class="symbol">=</span><span class="normal"> my_destroy</span><span class="symbol">;</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
becomes
</p>
<div class="informalexample">
<table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
<tbody>
<tr>
<td class="listing_lines" align="right"><pre>1
2
3</pre></td>
<td class="listing_code"><pre class="programlisting"><span class="usertype">GtkWidgetClass</span><span class="normal"> </span><span class="symbol">*</span><span class="normal">widget_class </span><span class="symbol">=</span><span class="normal"> </span><span class="function">GTK_WIDGET_CLASS</span><span class="normal"> </span><span class="symbol">(</span><span class="normal">class</span><span class="symbol">);</span>
<span class="normal">widget_class</span><span class="symbol">-></span><span class="normal">destroy </span><span class="symbol">=</span><span class="normal"> my_destroy</span><span class="symbol">;</span></pre></td>
</tr>
</tbody>
</table>
</div>
<p>
In the unlikely case that you have a non-widget class that is derived
from GtkObject and makes use of the destroy functionality, you have
to implement ::destroy yourself.
</p>
<p>
If your program used functions like gtk_object_get or gtk_object_set,
these can be replaced directly with g_object_get or g_object_set. In
fact, most every gtk_object_* function can be replaced with the
corresponding g_object_ function, even in GTK+ 2 code. The one exception
to this rule is gtk_object_destroy, which can be replaced with
gtk_widget_destroy, again in both GTK+ 2 and GTK+ 3.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.16"></a>GtkEntryCompletion signal parameters</h3></div></div></div>
<p>
The <a class="link" href="GtkEntryCompletion.html#GtkEntryCompletion-match-selected" title='The "match-selected" signal'><span class="type">"match-selected"</span></a> and
<a class="link" href="GtkEntryCompletion.html#GtkEntryCompletion-cursor-on-match" title='The "cursor-on-match" signal'><span class="type">"cursor-on-match"</span></a> signals were erroneously
given the internal filter model instead of the users model.
This oversight has been fixed in GTK+ 3; if you have handlers
for these signals, they will likely need slight adjustments.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.17"></a>Resize grips</h3></div></div></div>
<p>
The resize grip functionality has been moved from <a class="link" href="GtkStatusbar.html" title="GtkStatusbar"><span class="type">GtkStatusbar</span></a>
to <a class="link" href="GtkWindow.html" title="GtkWindow"><span class="type">GtkWindow</span></a>. Any window can now have resize grips, regardless whether
it has a statusbar or not. The functions
<a href="http://library.gnome.org/devel/gtk3/GtkStatusbar.html#gtk-statusbar-set-has-resize-grip"><code class="function">gtk_statusbar_set_has_resize_grip()</code></a> and <a href="http://library.gnome.org/devel/gtk3/GtkStatusbar.html#gtk-statusbar-get-has-resize-grip"><code class="function">gtk_statusbar_get_has_resize_grip()</code></a>
have disappeared, and instead there are now
<a class="link" href="GtkWindow.html#gtk-window-set-has-resize-grip" title="gtk_window_set_has_resize_grip ()"><code class="function">gtk_window_set_has_resize_grip()</code></a> and <a class="link" href="GtkWindow.html#gtk-window-get-has-resize-grip" title="gtk_window_get_has_resize_grip ()"><code class="function">gtk_window_get_has_resize_grip()</code></a>.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.18"></a>Prevent mixed linkage</h3></div></div></div>
<p>
Linking against GTK+ 2.x and GTK+ 3 in the same process is problematic
and can lead to hard-to-diagnose crashes. The <a class="link" href="gtk3-General.html#gtk-init" title="gtk_init ()"><code class="function">gtk_init()</code></a> function in
both GTK+ 2.22 and in GTK+ 3 tries to detect this situation and abort
with a diagnostic message, but this check is not 100% reliable (e.g. if
the problematic linking happens only in loadable modules).
</p>
<p>
Direct linking of your application against both versions of GTK+ is
easy to avoid; the problem gets harder when your application is using
libraries that are themselves linked against some version of GTK+.
In that case, you have to verify that you are using a version of the
library that is linked against GTK+ 3.
</p>
<p>
If you are using packages provided by a distributor, it is likely that
parallel installable versions of the library exist for GTK+ 2.x and
GTK+ 3, e.g for vte, check for vte3; for webkitgtk look for webkitgtk3,
and so on.
</p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="id-1.6.3.4.19"></a>Install GTK+ modules in the right place</h3></div></div></div>
<p>
Some software packages install loadable GTK+ modules such as theme engines,
gdk-pixbuf loaders or input methods. Since GTK+ 3 is parallel-installable
with GTK+ 2.x, the two GTK+ versions have separate locations for their
loadable modules. The location for GTK+ 2.x is
<code class="filename"><em class="replaceable"><code>libdir</code></em>/gtk-2.0</code>
(and its subdirectories), for GTK+ 3 the location is
<code class="filename"><em class="replaceable"><code>libdir</code></em>/gtk-3.0</code>
(and its subdirectories).
</p>
<p>
For some kinds of modules, namely input methods and pixbuf loaders,
GTK+ keeps a cache file with extra information about the modules.
For GTK+ 2.x, these cache files are located in
<code class="filename"><em class="replaceable"><code>sysconfdir</code></em>/gtk-2.0</code>.
For GTK+ 3, they have been moved to
<code class="filename"><em class="replaceable"><code>libdir</code></em>/gtk-3.0/3.0.0/</code>.
The commands that create these cache files have been renamed with a -3
suffix to make them parallel-installable.
</p>
<p>
Note that GTK+ modules often link against libgtk, libgdk-pixbuf, etc.
If that is the case for your module, you have to be careful to link the
GTK+ 2.x version of your module against the 2.x version of the libraries,
and the GTK+ 3 version against hte 3.x versions. Loading a module linked
against libgtk 2.x into an application using GTK+ 3 will lead to
unhappiness and must be avoided.
</p>
</div>
</div>
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