[cairo] pixman "Simplify clipping rule" problems

[Soeren Sandmann]

Siarhei Siamashka <siarhei.siamashka at gmail.com> writes:

> The one thing that worries me a bit is that apparently (almost) nobody else is
> using 'scaling-test' program. As limited as it is, it could have prevented a
> handful of broken commits already. And you can't rely on me monitoring this
> mailing list forever, effectively working as a trained monkey who just runs
> the test program occasionally and complains when something gets obviously
> broken. Seriously, should we add some 'make test' target with an easily
> interpretable result and ask commiters to reject any patches which make it
> fail unless this failure is investigated and properly explained?

Yes, such a target would be very useful, and I would certainly make
sure it passed before making releases. Some of the other test programs
could be run as well - generally the one that don't use GTK+. They
generally use assert() to check that things look right.

> I did some experiments (without setting source clipping) and it really seems
> like only change 2 is visible in these tests, I did not find any other
> differences when compared to old pixman versions. Looks like it is time to
> update 'scaling-test' program with a new reference crc32 value. Patch is
> attached.

I have updated the crc value. In the meantime I fixed some bugs in the
region code that changed the output. In particular, scaling-test ends
up clipping to empty rectangles, which confused the region code.



Soren