[OpenJDK 2D-Dev] RFR: 8204391: Colors with alpha are painted incorrectly on Linux

[Prasanta Sadhukhan]

Fix looks good to me.

A nit in the test

61 SwingUtilities.invokeAndWait(() -> createAndShowGUI());
Since awt Frame is being created and not JFrame, there is no need of 
using EDT.

Regards
Prasanta
On 7/27/2018 1:12 AM, Phil Race wrote:
> Bug: https://bugs.openjdk.java.net/browse/JDK-8204931
> Webrev: http://cr.openjdk.java.net/~prr/8204931/
>
> There is a long evaluation in the bug report, so what I write here is 
> just a summary.
>
> This is a regression introduced by 
> https://bugs.openjdk.java.net/browse/JDK-8176795
> and specific to the Xrender pipeline
>
> The bug is that when using colors with alpha, the alpha is being 
> ignored and the colour
> copied rather than blended, since we no longer pass the 
> "pre-multiplied" flag as false.
>
> The fix is to pre-multiply the colour when storing as a pixel even for 
> an opaque xrender surface.
>
> With this fix automated jtreg tests, and tck tests pass, as well as 
> the manual TCK test that was failing.
>
> Additionally the supplied regression test passes on all platforms.
>
> -phil
>
>
>