RE: draw signals

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

I see...  but if all that has happened is that a pixmap became exposed, why
have a handler redraw the pixmap if nothing has changed and a simple screen
update will do?  It seems somewhat inefficient to do so, especially if
multiple pixmaps are involved.  If I can find a way to only update the
screen with an existing pixmap then I can save time and memory :-)  I guess
that's the problem I'm trying to solve: how do I prevent a pixmap from being
redrawn when a simple screen update will do?  Is it possible to do this
when, say, a window/widget gets uncovered?  The "draw" signal seems to only
complicate things during an "expose_event".  Any help with this would be
greatly appreciated.



				-- Stupid Genius

> ----------
> From: 	Mark Leisher[SMTP:mleisher@crl.nmsu.edu]
> Sent: 	Friday, December 22, 2000 11:52 AM
> To: 	gtk-app-devel-list@gnome.org
> Subject: 	RE: draw signals
> 
> 
>     Alan> Carlos, Thanks for your response.  I would love to forget about
>     Alan> "draw" :-) However, I don't see how I can.  Everytime I uncover
> a
>     Alan> portion of a window with a pixmap in it, I get an "expose_event"
>     Alan> (which I use to refresh the screen) and a "draw" signal which
>     Alan> repaints my pixmap and then refreshes the screen a second time.
> The
>     Alan> repainting of my pixmap seems unnecessary IMHO and is forcing me
> to
>     Alan> allocate memory and attach data to every pixmap I use.  I would
> like
>     Alan> to eliminate this redundancy so that I don't need to use up the
>     Alan> extra memory and waste time doing the same thing twice.  Any
> ideas
>     Alan> on how to solve this problem would be greatly appreciated!
> 
> I think Carlos was saying that your expose event handler should draw the
> pixmap and then update the screen from the pixmap.  Then you can ignore
> the
> draw events.
> 
> Or does your code need to have these separate for some reason?
> --------------------------------------------------------------------------
> ---
> Mark Leisher
> Computing Research Lab            Cinema, radio, television, magazines are
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