[OpenJDK 2D-Dev] Strange text rendering with SRC + Extra Alpha

[Denis Lila]

Hello.

After noticing some weird things I made some modifications to
Clemens' test. I've attached the results and the tester.
The most interesting results are the first 18 lines in each
image, all of which are produced by rendering to INT_RBG type
buffered images. The first 6 lines have both AA_ON and subpixel aa.
Lines 7-12 have only subpixel AA, and lines 13-18 have only AA_ON.
In each group of 6, the only thing that changes is the order in
which the hints, the composite, and the colour are set.

Lines 1-6 and 13-18 don't look right on closed jdk (1.6.0_21-b06).
The only thing they have in common is that the AA hint is on.
Lines 7-12 look ok - they only have LCD AA. We can see that the order
doesn't matter.

On openJDK7 (with a build of a fresh clone of the 2d tree) lines
1-3 look like what Clemens is seeing, but the next 3 don't look bad,
even though all of the first 6 lines are supposed to be drawn with
a black colour, SRC compositing, and both AA_ON and LCD AA.
The same goes for lines 13-15. What lines 1-3 and 13-15 have in
common is that the colour is set after the composite.
Lines 7-12 still look ok, but they are a bit different from what closed
java produces, even though subpixel antialiasing is clearly used in both.

That's it for my observations.
Regards,
Denis.

----- "Clemens Eisserer" <linuxhippy at gmail.com> wrote:

> Hi again,
> 
> Attached is the sample program as well as the output I get on
> jdk7b99,
> when running the sample program attached.
> 
> - Clemens
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