[OpenJDK 2D-Dev] request for review: JDK-7082809 : xrender artifacts caused by different interpretation of SRC operator

[Clemens Eisserer]

Please review my fix for bug "JDK-7082809 : xrender artifacts caused
by different interpretation of SRC operator" located at:
http://cr.openjdk.java.net/~ceisserer/7082809/webrev.05/
A manual test-case is available at:
http://cr.openjdk.java.net/~ceisserer/7082809/CompositeTest.java

Problem description:
There are a few differences between the composition operators of
Java2D and xrender.
One difference is e.g. that for SRC the destination is never read
inside the composition rectangle, which affects MaskFills and text
rendering (where the glyph geometry is stored inside small
mask-images).
The xrender pipeline ignored most of those differences for now and
focussed on correctness and performance with SRC_OVER.
Beside 7082809, this patch also fixes the "TranTest2" and
"AlphaCompositeTest" JCK tests as well as a issue with older versions
of IntelliJ.

Fix description:
This patch tries to correct this sloppiness by either falling back to
software-loops for uncommon operations which haven't been implemented
in a correct way, or to implement work-arrounds for common-cases which
do not map 1:1 to xrender.

Thanks, Clemens