This way, we can specify a colormap when constructing windows. And ew
must do that to avoid BadMatch from XCreateWindow when we use a
different visual.
Also add a priv pointer to GdkVisual and use it for the GdkVisualPrivate
structure. Then Make GdkVisualPrivate actually private to
gdkvisual-x11.c and make other callers use proper function calls to
access it.
Direct and TrueColor visuals don't alloc colors, so they don't need to
fiddle with colormaps. Just copy the code that computes the pixel value
from gdkcolor-x11.c and use it. For other visual types, don't set the
background color and fallback to background = None.
This removes:
gtk_widget_set_default_colormap()
gtk_widget_get_default_colormap()
gtk_widget_get_default_visual()
Colormaps are gone, and the default visual is the system visual of the
default screen.
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()
