On Wed, 9 Apr 2025 14:42:05 GMT, Maxim Kartashev <mkartas...@openjdk.org> wrote:

> The pixels that cairo produces for GTK LaF to draw on a Swing component have 
> their alpha components pre-multiplied as per [the 
> documentation](https://www.cairographics.org/manual/cairo-Image-Surfaces.html?spm=a2ty_o01.29997173.0.0.540ac921z2EebT#cairo-format-t):
>> Pre-multiplied alpha is used. (That is, 50% transparent red is 0x80800000, 
>> not 0x80ff0000.)
> 
> The BufferedImage created from those pixels, however, has its constructor's 
> argument for `isRasterPremultiplied` set to `false` in 
> `GTKEngine.finishPainting()`. This commit corrects that.
> 
> In addition, since at least some "native" graphics color models also use 
> pre-multiplied alpha (ex.: `GLXGraphicsConfig.getColorModel()`), 
> `COLOR_MODELS` were modified to take advantage of that and avoid unnecessary 
> re-calculations of image's pixels.

This pull request has now been integrated.

Changeset: a4e9da37
Author:    Maxim Kartashev <mkartas...@openjdk.org>
Committer: Alexey Ushakov <a...@openjdk.org>
URL:       
https://git.openjdk.org/jdk/commit/a4e9da3747fe0a3c27e414787eaa97f80b24f5de
Stats:     22 lines in 1 file changed: 12 ins; 7 del; 3 mod

8354191: GTK LaF should use pre-multiplied alpha same as cairo

Reviewed-by: avu, prr

-------------

PR: https://git.openjdk.org/jdk/pull/24551

Reply via email to