The image surface code doesn't reliably work on images larger than
32767 in width or height. This patch makes the image surface
constructors fail by returning a surface in the CAIRO_STATUS_INVALID_SIZE
state when given negative or too large dimensions so that client code
gets a prompt and correct error rather than flaky rendering on large
images.
Instead of tagging the sources, which is insensitive to changes, track the
known failure modes by recording the current fail as an xfail.png
reference. (We also introduce a new.png to track a fresh error, so that
they are not lost in the noise of the old XFAILs and hopefully do not
cause everyone to fret).
As we have removed the XFAIL tagging we find, surprise surprise, that some
tests are now working -- so review all the reference images (as also some
.ref.png now should be .xfail.png).
Note: I've only checked image,pdf,ps,svg. The test surfaces report some
failures that probably need to addressed in source. I've not correct the
changes for win32 and quartz. Nor fixed up the experimental backends.
This test attempts to trigger failures in those backend clone_similar
methods that have size restrictions on the resulting image. It also
triggers errors in scaling down large image surfaces as the image
backend also fails this test.
