Re: disabling auto background clear

[John Cupitt <john cupitt ng-london org uk>]

Havoc Pennington wrote:
> 
> John Cupitt <john cupitt ng-london org uk> writes:
> > I looked at gdk, and I think gdk_window_set_background() does
> > XSetWindowBackground( color->pixel ), so I'm not sure this will work :-(
> >
> > You can give NULL to gdk_window_set_back_pixmap(), but that doesn't seem
> > to help me either.
> 
> It looks like set_back_pixmap(window, NULL) should work. Doesn't it
> work for you?
> 
> Havoc

Ooops, yes it does, I was setting the wrong window :-( Thanks very much
for checking.

Anyway, it works now. I found three techniques ... subclass
drawing_area, implement widget->realize(), and either:

- gdk_window_set_back_pixmap( widget->window, NULL, FALSE );

- gdk_window_set_static_gravities( widget->window, TRUE );

  (I think this only works if the server correctly implements
  the gravity tricks used for guffaw scrolling)

- include <gdk/gdkx.h>, and call XChangeWindowAttributes() to turn
  on NorthWest bit_gravity

  (I think this works everywhere, but obviously makes it rather 
  X-specific)

John