[cairo] clipping bug

[Radek Doulík]

On Wed, 2005-08-24 at 02:45 -0700, Carl Worth wrote:
> On Tue, 23 Aug 2005 21:13:41 +0200, Radek Doulík wrote:
> > I am attaching patch for cairo/test directory with clip-all test which
> > demonstrates that problem. Note that it enables X synchronization in
> > cairo-test.c.
> 
> Thanks for the test case. That really makes bug reports much more
> useful. To include this in cairo/test, could you send it again with
> Copyright and licensing information?

Okie, I am attaching new patch.

> > Perhaps someone who knows the clipping code can cook a quick fix.
> 
> When the size of the clip is zero, by definition no drawing operation
> can have any effect. So it should be easy to bail out quite early in
> this case.
> 
> Here's a patch that does make the test stop crashing, but I'm quite
> sure this patch is not correct since it will probably break all
> unbounded operators. (And even if the patch were correct, it's likely
> only addressing one of a family of bugs).

I prepared a fix which stops compositing even earlier. That way it will
not hide other bugs, where compositing with zero width or height. It is
included in the new patch.

Cheers
Radek

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