[cairo] Clip region problems
otaylor at redhat.com
Wed May 18 12:49:40 PDT 2005
On Wed, 2005-05-18 at 11:54 -0700, Keith Packard wrote:
> > * Using a surface as a source for drawing to itself is going to be a
> > problem, but it's already a problem, so that's nothing new.
> Yes, clipping in this environment is ill-defined. X actually defines
> the clip in this case only for output; input is not affected by
I think this is clearly the semantic we want. The problem is that
libpixman and RENDER don't work that way.
For A => B we temporarily clear the clip on A when using it as a source.
But for A => A we need to "fork" the input surface when operating from a
surface to itself with a clip. (Create another Picture really.)
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