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Migration guide: Add an example for colormap -> visual

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This commit is contained in:
Matthias Clasen
2010-09-24 20:02:01 -04:00
committed by Benjamin Otte
parent d3a90eae72
commit b522a1b367
1 changed files with 66 additions and 8 deletions
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74
docs/reference/gtk/migrating-2to3.xml
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@ -396,9 +396,6 @@ cairo_destroy (cr);
In the cairo-centric world of GTK+ 3, cairo surfaces
take over the role of pixmaps.
</para>
<para>
FIXME: example
</para>
</section>
<section>
@ -411,9 +408,44 @@ cairo_destroy (cr);
colormap-handling functions of #GtkWidget (gtk_widget_set_colormap(),
etc) have been removed and gtk_window_set_visual() has been added.
</para>
<para>
FIXME: example
<example><title>Setting up a translucent window</title>
<para>You might have a screen-changed handler like the following
to set up a translucent window with an alpha-channel:
</para>
<programlisting>
static void
on_alpha_screen_changed (GtkWidget *widget,
GdkScreen *old_screen,
GtkWidget *label)
{
GdkScreen *screen = gtk_widget_get_screen (widget);
GdkColormap *colormap = gdk_screen_get_rgba_colormap (screen);
if (colormap == NULL)
colormap = gdk_screen_get_default_colormap (screen);
gtk_widget_set_colormap (widget, colormap);
}
</programlisting>
<para>
With visuals instead of colormaps, this will look as follows:
</para>
<programlisting>
static void
on_alpha_screen_changed (GtkWindow *window,
GdkScreen *old_screen,
GtkWidget *label)
{
GdkScreen *screen = gtk_widget_get_screen (GTK_WIDGET (window));
GdkVisual *visual = gdk_screen_get_rgba_visual (screen);
if (visual == NULL)
visual = gdk_screen_get_system_visual (screen);
gtk_window_set_visual (window, visual);
}
</programlisting>
</example>
</section>
<section>
@ -480,9 +512,35 @@ cairo_destroy (cr);
implementations will usually just use the cairo context that has been
passed in for this.
</para>
<para>
FIXME: example
</para>
<example><title>A simple ::draw function</title>
<programlisting>
gboolean
gtk_arrow_draw (GtkWidget *widget,
cairo_t *cr)
{
gint x, y;
gint width, height;
gint extent;
width = gtk_widget_get_allocated_width (widget);
height = gtk_widget_get_allocated_height (widget);
extent = MIN (width - 2 * PAD, height - 2 * PAD);
x = PAD;
y = PAD;
gtk_paint_arrow (gtk_widget_get_style (widget),
cr,
gtk_widget_get_state (widget),
GTK_SHADOW_OUT,
widget,
"arrow",
widget->priv->arrow_type,
TRUE,
x, y, extent, extent);
}
</programlisting>
</example>
</section>
<section>