Does composition render double-buffering useless?

Carlos Eduardo Rodrigues Diógenes cerdiogenes at
Thu Jul 6 05:52:36 PDT 2006

On Thu, 2006-07-06 at 12:15 +0200, Clemens Eisserer wrote:
> Thanks a lot for answering!
> > displayed on screen.  Most compositing managers listen for damage
> > events on the off-screen pixmaps and recomposite immediately when
> > damage occurs.
> But don't they use some heuristics to optimize the composition step?
> I imagine that composition after every simple damage (line, small
> rect, ...) would damage performance quite a lot.
> I'll do some tests, maybe this could be made optional ... if the users
> wants this, he/she gets it ;)
> However I guess this could lower performance ... since more damage
> situations eventuelly have to be handled. Nothing is as easy as it
> seems ;)

When you are reading from the Xlib event stack you could know if the
Damage event that you receive is the last one, if not, you could read
the next and union the regions that was damaged. Only after you read all
the damage events you update the screen.

> lg Clemens
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Carlos Eduardo Rodrigues Diógenes
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