Re: Some questions on double buffering and expose in gtk2.

[Havoc Pennington <hp redhat com>]

Martin Sevior <msevior mccubbin ph unimelb edu au> writes: 
> After drawing to a gtk-drawable, expose events are generated when part of
> the drawable is unobscured. What should I do with these? For gtk 1.2 I
> connected an expose event handler to a void callback and
> just redrew the exposed rectangle. This doesn't seem to work consistently
> in gtk2. I get regions of blank areas in drawables.
> 
> I guess it's because of the double buffering in gtk2.

Doubtful. Connecting to expose_event is still the right thing.

Maybe the "void callback" is the problem? I think expose_event
callbacks are supposed to have a return value.

If you were doing manual backing store with a pixmap, just blow all
that code away to simplify things, it's no longer required.

There's a --gtk-debug=updates if you build your own GTK that may help.

> So what is the right way to handle expose events for gtk2? Is this
> documented somewhere? Where?

GtkDrawingArea overview section in the ref docs may discuss this some,
I don't remember.

Havoc