RFR: 8373946: Synth ProgressBarUI implementation confuses background painting with border painting [v2]

[Prasanta Sadhukhan]

On Thu, 18 Dec 2025 19:19:17 GMT, Phil Race <prr at openjdk.org> wrote:

>> Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Test rename fix
>
> test/jdk/javax/swing/plaf/synth/TestSynthProgressBarBorder.java line 45:
> 
>> 43: import javax.swing.UIManager;
>> 44: 
>> 45: public class TestSynthProgressBarBorder {
> 
> I would rename this to be specifically about Nimbus.
> GTK L&F is a synth L&F and its rendering is controlled by how GTK renders, so it may display a background the same as the parent container.

ok updated..

> test/jdk/javax/swing/plaf/synth/TestSynthProgressBarBorder.java line 54:
> 
>> 52:         Please check if 50% progress is rendered in the progress bar
>> 53:         and rest 50% is rendered as blank bar
>> 54:         with Nimbus default background color.
> 
> Hmm.
> First I think Nimbus uses gradients, not solid colors.
> 2nd you are basically asking the tester to verify something they don't know. I read this and wonder "what is that default background, how do I know if it is right" ? 
> Since the bug *specific to Nimbus* is that YOU know Nimbus paints a visually distinctive background is just to ask the tester to verify that.
> 
> Although I believe this could actually be automated. You just need to verify that if you set the value to 0, then it passes if any pixel in the progress bar is different than the pixels of the parent container - which you can make a solid color I think.

There are basically 2 checks that we are doing. One is at 50% time to check if no background is done and another at 0%..
It could be automated but since we need to push it soon I made it manual.

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PR Review Comment: https://git.openjdk.org/jdk/pull/28885#discussion_r2633246052
PR Review Comment: https://git.openjdk.org/jdk/pull/28885#discussion_r2633250902