Kindly request your attention for a really annoying visual Java bug on Linux Mint

[Aleksei Ivanov]

Dear Stefan,

Thank you for reporting the bug.

You could have submitted the bug via https://bugreport.java.com/bugreport/


Anyway, I reproduced the issue and now I've submitted the bug for you:
https://bugs.openjdk.java.net/browse/JDK-8280482
"Window transparency bug on Linux Mint"

I attached a modified version of your testcase which creates all the 
windows on the EDT.


Even though I see the problem, there could be something wrong with the 
test, or possibly window placement. If I add a delay after a window is 
created, I can see that all the screen is getting covered gradually with 
windows and all the windows have the same level of translucency. When 
the bottom of the screen is reached, the new windows get moved above so 
that the newly created window does not cover the taskbar. This creates a 
darker rectangle seen along the bottom of the screen on the main monitor.

In my environment, the dark square area that you have on your screenshot 
is not as large, it covers only the part of the screen on the main 
monitor. At the same time, this area appears only when all the windows 
are created. Again, it could be that some of the windows of the grid get 
misplaced for whatever reason. Perhaps, the calculation of the grid has 
an error or something like that.

Eventually, it may be a bug not in Java but in the sample app. I'll play 
around with it over the weekend if I have time.

On 21/01/2022 20:10, Stefan Reich wrote:
> Dear Sirs or Madams,
>
> I make a visual recognition tool <https://gaz.ai> in Java that would
> tremendously benefit from the ability to show translucent windows. Indeed,
> Java has such an ability but it is broken on my Linux Mint 19 ThinkPad for
> unknown reasons (screenshot <https://botcompany.de/images/1103064>).
>
> All the details are here:
>
> https://github.com/adoptium/adoptium-support/issues/430
>
> I'd love to see this fixed. Not sure how reproducible it is or if there is
> anything screwed in my Linux Mint installation. Seems to run fine otherwise
> though.
>
> Many greetings,
> Stefan Reich
-- 
Regards,
Alexey