[cairo] Call to cairo_paint triggers an assertion

[M Joonas Pihlaja]

Hi Tim,

I ran your program on my 64 bit Debian Linux Etch machine using 
gtk+-2.0 version 2.12.12, whatever aged X.org server comes with Debian 
stable, and various combinations of cairo 1.6.4, 1.8.x, and the 
current cairo master, but couldn't trigger the assertion you saw.  It 
even ran cleanly under valgrind.  Provided the GTK part of the code is 
okay, and it looks fine to me (but then I know very little about GTK), 
I don't see why it should crash for you.  If updating to cairo 1.8.6 
doesn't help you, then perhaps you could give some more information 
about your platform and versions of things.  That might help someone 
with your platform to track down the bug.

Cheers,

Joonas