another 16bpp crasher
RHEL QE found a crasher with the fix from !710 (merged) . It looks like I was a little too hopeful at things being able to cope with 16bpp. cairo ended up stuffing a 16bpp GC from the operation into a cache to reuse later, assuming (from the picture format) that it was 32bpp.
This changeset reverts the commit and changes the code to stop using XRender picture formats as a middleman for figuring out the visual.
Edited by Ray Strode