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From: klee@chico.pa.dec.com (Ken Lee)
Newsgroups: comp.windows.x
Subject: Re: X double buffering
Keywords: double buffering
Message-ID: <1929@bacchus.dec.com>
Date: 16 Oct 89 18:19:45 GMT
References: <170@med.Stanford.EDU> <181@wbcs.UUCP>
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Reply-To: klee@decwrl.dec.com
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Organization: DEC Western Software Laboratory
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In article <170@med.Stanford.EDU>, rick@hanauma.stanford.edu (Richard
Ottolini) writes:
> In article <181@wbcs.UUCP> doug@wbcs.UUCP (Doug Kratky) writes:
> >Could someone give me hints, code fragments, or examples
> >on "double-buffering" with X?
> 
> Draw into an offscreen pixmap, then copy it onto screen.

This isn't really "double buffering".  Double buffering avoids the copy
by writing to 2 different planes (or groups of planes) of a multi-plane
display, then fiddling with the colormap to determine which planes
show.  The advantage of this approach is that, on most systems,
changing the colormap is much faster than copying pixmaps.  As I
mentioned earlier, some of the X11R3 demo programs, such as ico,
implement double buffering.

Ken Lee
DEC Western Software Laboratory, Palo Alto, Calif.
Internet: klee@decwrl.dec.com
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