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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="gtk-migrating-GtkStyleContext-checklist"></a>A checklist for widgets</h2></div></div></div>

 When porting your widgets to use <a class="link" href="GtkStyleContext.html" title="GtkStyleContext">GtkStyleContext</a>, this checklist
 might be useful.
 
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
 Replace <a class="link" href="GtkWidget.html#GtkWidget-style-set" title="The “style-set” signal">“style-set”</a> handlers with
 <a class="link" href="GtkWidget.html#GtkWidget-style-updated" title="The “style-updated” signal">“style-updated”</a> handlers.
 </li>
<li class="listitem">

 Try to identify the role of what you're rendering with any number
 of classes. This will replace the detail string. There is a predefined
 set of CSS classes which you can reuse where appropriate. Doing so
 will give you theming 'for free', whereas custom classes will require
 extra work in the theme. Note that complex widgets are likely to
 need different styles when rendering different parts, and style
 classes are one way to achieve this. This could result in code like
 the following (simplified) examples:
 
<div class="example">
<a name="id-1.6.4.7.3.2.2"></a>Example 46. Setting a permanent CSS class
<div class="example-contents">
 <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">static void
gtk_button_init (GtkButton *button)
{
 GtkStyleContext *context;

...

context = gtk_widget_get_style_context (GTK_WIDGET (button));

/* Set the "button" class */
 gtk_style_context_add_class (context, GTK_STYLE_CLASS_BUTTON);
}</pre></td>
 </tr>
 </tbody>
 </table>
</div>

</div>
 
 Or
 
<div class="example">
<a name="id-1.6.4.7.3.2.4"></a>Example 47. Using dynamic CSS classes for different elements
<div class="example-contents">
 <table class="listing_frame" border="0" cellpadding="0" cellspacing="0">
 <tbody>
 <tr>
 <td class="listing_lines" align="right"><pre>1
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28</pre></td>
 <td class="listing_code"><pre class="programlisting">static gboolean
gtk_spin_button_draw (GtkSpinButton *spin,
 cairo_t *cr)
{
 GtkStyleContext *context;

...

gtk_style_context_save (context);
 gtk_style_context_add_class (context, GTK_STYLE_CLASS_ENTRY);

/* Call to entry draw impl with "entry" class */
 parent_class->draw (spin, cr);

gtk_style_context_restore (context);
 gtk_style_context_save (context);

/* Render up/down buttons with the "button" class */
 gtk_style_context_add_class (context, GTK_STYLE_CLASS_BUTTON);
 draw_up_button (spin, cr);
 draw_down_button (spin, cr);

gtk_style_context_restore (context);

...
}</pre></td>
 </tr>
 </tbody>
 </table>
</div>

</div>
 
 Note that <a class="link" href="GtkStyleContext.html" title="GtkStyleContext">GtkStyleContext</a> only provides fg/bg colors, so text/base
 is done through distinctive theming of the different classes. For
 example, an entry would usually be black on white while a button
 would usually be black on light grey.
 
</li>
<li class="listitem">

 Replace all <code class="literal">gtk_paint_*()</code> calls with corresponding
 <code class="literal">gtk_render_*()</code> calls.
 

 The most distinctive changes are the use of <a class="link" href="gtk3-Standard-Enumerations.html#GtkStateFlags" title="enum GtkStateFlags">GtkStateFlags</a> to
 represent the widget state and the lack of <a class="link" href="gtk3-Standard-Enumerations.html#GtkShadowType" title="enum GtkShadowType">GtkShadowType</a>. Note
 that widget state is now passed implicitly via the context, so
 to render in a certain state, you have to temporarily set the
 state on the context, as in the following example:
 
<div class="example">
<a name="id-1.6.4.7.3.3.3"></a>Example 48. Rendering with a specific state
<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</pre></td>
 <td class="listing_code"><pre class="programlisting">gtk_style_context_save (context);
gtk_style_context_set_state (context, GTK_STATE_FLAG_ACTIVE);
gtk_render_check (context, cr, x, y, width, height);
gtk_style_context_restore (context);</pre></td>
 </tr>
 </tbody>
 </table>
</div>

</div>
 
 For <a class="link" href="GtkStyleContext.html#gtk-render-check" title="gtk_render_check ()"><code class="function">gtk_render_check()</code></a> and <a class="link" href="GtkStyleContext.html#gtk-render-option" title="gtk_render_option ()"><code class="function">gtk_render_option()</code></a>, the <code>shadow_type</code>
 parameter is replaced by the <a class="link" href="gtk3-Standard-Enumerations.html#GTK-STATE-FLAG-ACTIVE:CAPS">GTK_STATE_FLAG_ACTIVE</a> and
 <a class="link" href="gtk3-Standard-Enumerations.html#GTK-STATE-FLAG-INCONSISTENT:CAPS">GTK_STATE_FLAG_INCONSISTENT</a> state flags. For things such as
 pressed/unpressed button states, <a class="link" href="gtk3-Standard-Enumerations.html#GTK-STATE-FLAG-ACTIVE:CAPS">GTK_STATE_FLAG_ACTIVE</a> is used,
 and the CSS may style normal/active states differently to render
 outset/inset borders, respectively.
 
</li>
<li class="listitem">
 The various <code class="literal">gtk_widget_modify_*()</code> functions to
 override colors or fonts for individual widgets have been replaced
 by similar <code class="literal">gtk_widget_override_*()</code> functions.
 </li>
<li class="listitem">
 It is no longer necessary to call <a class="link" href="GtkWidget.html#gtk-widget-style-attach" title="gtk_widget_style_attach ()"><code class="function">gtk_widget_style_attach()</code></a>,
 <a class="link" href="GtkStyle.html#gtk-style-attach" title="gtk_style_attach ()"><code class="function">gtk_style_attach()</code></a>, <a class="link" href="GtkStyle.html#gtk-style-detach" title="gtk_style_detach ()"><code class="function">gtk_style_detach()</code></a> or <a class="link" href="GtkWidget.html#gtk-widget-ensure-style" title="gtk_widget_ensure_style ()"><code class="function">gtk_widget_ensure_style()</code></a>.
 </li>
<li class="listitem">
 Replace all uses of xthickness/ythickness. <a class="link" href="GtkStyleContext.html" title="GtkStyleContext">GtkStyleContext</a> uses the
 CSS box model, and there are border-width/padding/margin properties to
 replace the different applications of X and Y thickness. Note that all
 of this is merely a guideline. Widgets may choose to follow it or not.
 </li>
</ol></div>
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