[cairo] cairo-1.13 finally opens

[Bryce W. Harrington]

On Thu, Sep 05, 2013 at 06:42:38PM +0000, Henry (Yu) Song - SISA wrote:
> Hi, Bryce
> 
> Good points on your comments.  It is short on test cases on shadow and
> blur.  If you can help on that would be great.

I've started putting together a test case, basically a simplified
version of your example code:

  https://github.com/bryceharrington/cairogles/commits/filters-wip-test
  (This is still WIP code, not ready for merging.)

Here's a preview of the test output as it is so far:

  http://www.bryceharrington.org/files/blur-test/

I'm using the image.argb32 output as the reference, since it looks
pretty sharp and clean.  I'm not sure why the gl output is pixelated;
perhaps I need to include more of the setup code from the example or
something.

Feedback would be welcomed.  In particular, I'm looking for advice on
how to tweak things so more of the tests pass.  I'd also like to gather
ideas on further settings / shapes / algorithms / etc. to write tests
for.

Bryce