RE: draw signals

["Dugas, Alan" <alan dugas analog com>]

Hmm... it looks like I may have to switch from a gtkplotcanvas to a
gtkdrawingarea.  The reason is that the gtkplotcanvas has a "draw" and an
"expose_event" handler, which is why I was trying to filter out the "draw"
signal.  Since both "draw" and "expose_event" are emitted when my pixmaps are
uncovered a redraw is being forced.  I can address this problem in a
gtkdrawingarea by simply not creating a "draw" callback as you had suggested.
I'll give that a try, thanks again for your input Mark and Carlos!



				-- Stupid Genius

> ----------
> From: 	Carlos Pereira[SMTP:carlos@pehoe.civil.ist.utl.pt]
> Sent: 	Friday, December 22, 2000 1:47 PM
> To: 	gtk-app-devel-list@gnome.org
> Subject: 	Re: draw signals
> 
> >why have a handler redraw the pixmap if nothing has changed 
> >and a simple screen update will do?
> 
> In your "expose_event" callback you have full control
> over everything. You can copy a pixmap to the drawing area
> or redraw it first, if you think that is necessary. That's
> your choice!
> 
> you can have something as this, in the "expose_event" call back:
> 
> if (some_condition) pixmap = redraw_pixmap;
> else pixmap = get_old_pixmap;
> 
> copy_pixmap_to_drawing_area (pixmap);
> 
> If some_condition is too difficult to be handled 
> automatically (and often is), then just forget 
> and redraw always.
> 
> Carlos
> 
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