Re: Background pixmap

[Owen Taylor <otaylor redhat com>]

Dennis Bj|rklund <dennisb@cs.chalmers.se> writes:

> Hi!
> 
> I'm trying to reduce the flicker that comes when you opaque resize a
> windows. One thing that reduces the flicker is if you can stop the
> widgets from clearing the background first. If you later on is going to
> paint the entire widget, then it doesn't help to clear the background
> anyway.
> 
> It works for most widgets but I can't get it to work for the toplevel
> windows. I do it by setting the pixmap (all five of them) of the widget
> to GDK_PARENT_RELATIVE which I guess sets the background pixmap to
> None with X is supposed to interpret as don't paint background??
> 
> I read the gtk-source to find out what GDK_PARENT_RELATIVE do. The
> biggest problem with GTK is still that there is no documentation. 
> 
> I guess that I have missunderstod something since I cant get it to
> work.
> 
> I would be very happy if someone could show me some code that opens a
> toplevel windows where there is NO painting going on at all. So that
> when you open it you see a window-frame (from the WM) and in the
> interior you see whatever was there before.

To set the background of a GdkWindow to None, do:

 gdk_window_set_back_pixmap (window, NULL, FALSE);

You can't do this from a RC file, because it isn't a difference
in appearance.

However, to do this for a GtkWindow and have it stick, you have
to tell GTK+ not to touch the background. You can do this
using:

void	   gtk_widget_set_app_paintable	  (GtkWidget	       *widget,
					   gboolean		app_paintable);

Look at the last few months of the gtk-devel-list archives
if you want more information on the subject of opaque resizing,
etc.

Regards,
                                        Owen