Add gtk_window_set_visual() and a "visual" property. This allows
changing the window visual to the rgba one and other awesome things
(like implementing the trayicon spec).
We now return the visual of the topmost widget in widget's stack that
has a window. If no such widget exists, but a GtkWindow is a parent, we
return its visual (note: GtkWindow Will gain support for setting visuals
soon). If a window doesn't exist, we return the system visual of the
default screen.
This change has multiple reasons:
- Colormaps are gone
Now visuals are the most important resource for creating GDK windows.
- Allow widgets to change visuals for themselves and their children
By walking the hierarchy, we ensure that child windows have the same
visual as their parents by default. But widgets can still select a
different visual in their realize handler when creating the GDK
window.
- Have a replacement for gtk_widget_set_colormap()
That function is going to die with colormaps, so a replacement was
needed. That replacement is going to be gdk_window_set_visual().
- Make a future transition to no-window GTK easy
Should we ever attempt a change to make all GTK widgets no-window, a
gtk_widget_set_visual() would be silly, as only widgets with windows
can have their own visuals. So only toplevels will gain the ability to
change it.
Now that we don't create pixmaps anymore, this function is not needed
anymore. The indirection it did previously is now basically moved to
gdk_window_create_similar_surface()
The 3 functions in question were:
- gdk_pixbuf_render_threshold_alpha()
- gdk_pixbuf_render_pixmap_and_mask()
- gdk_pixbuf_render_pixmap_and_mask_for_colormap()
All of them can be replaced using Cairo if they have to. The
functionality is only needed to talk to old X interfaces and normal apps
do fine without them.
No more GdkPixmap to store the icon and its mask, but instead use cairo
surfaces. Also render the icon into the surfaces using Cairo instead of
gdk_pixbuf_render_threshold_alpha().
With Cairo 1.10 now having cairo_surface_create_for_rectangle(), we can
use them. No need to create multiple native surfaces for the same X
window (ugh) anymore.
The notion of a source drawable does not make a lot of sense for windows
that are not backed by a drawable, such as GdkOffscreenWindow after
converting it to cairo_surface_t.
gtk_widget_get_snapshot is on its way out.
The test can be added back once we have gtk_widget_draw(), but until
then, there's no way to take snapshots.
