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From: asente@adobe.com (Paul Asente)
Newsgroups: comp.windows.x
Subject: Re: fast, flicker-free animation, how?
Message-ID: <7898@adobe.UUCP>
Date: 1 Nov 90 23:31:48 GMT
References: <16223@hydra.gatech.EDU>
Sender: news@adobe.COM
Organization: Adobe Systems Inc.
Lines: 24

In article <16223@hydra.gatech.EDU> robert@shangri-la.gatech.edu (Robert Viduya) writes:
>I'm working on a program that animates some simple geometric entities and
>displays them in a window...
>Drawing the entities doesn't take any significant
>time but getting X to display them quickly seems to be a big stumbling block.
>I've tried three different methods:
>
>	Draw into an offscreen pixmap and then use XCopyArea to put it
>	into the window.  This is the slowest and I get about 4 frames
>	per second.  It does, however, produce no annoying flicker.

How big is your image?  Unless your X implementation is extremely bad, you
should be able to do much better than 4 frames per second this way for
"moderate" sized windows (say, 400x400).

I have an application that essentially bounces around a 100x100 object within
a 400x400 window, and I get about 72 frames per second on a DECstation
5000, using Display PostScript to do the imaging into the pixmap.  You have to 
be a little bit clever and set the clipping region not to update parts of the
window you're not changing.  I can update an animation where the entire 400x400
window is changing at about 36 frames per second.

	-paul asente
		asente@adobe.com	...decwrl!adobe!asente