RFR: 8357390 : java/awt/Toolkit/ScreenInsetsTest/ScreenInsetsTest.java Test failing on Ubuntu 24.04 SBR Hosts

[Harshitha Onkar]

On Thu, 29 May 2025 14:53:51 GMT, Anass Baya <abaya at openjdk.org> wrote:

> **Issue:**
> The bottom inset is different from the expected value by 2 pixels.
> 
> **Analysis:**
> In [JDK-8349351](https://bugs.openjdk.org/browse/JDK-8349351), we agreed that a small difference between the expected and actual inset values could happen due to scaling. So, we accepted a small margin of error. Harshita suggested allowing a margin of 2 or 3 pixels. However, we decided to accept only a 1-pixel margin since it was enough for scaling loss and the test was passing consistently on CI. 
> 
> But here we have a different origin of the error. On our OCI Ubuntu 24.04 hosts with X11, the _NET_WORKAREA most of the time returns a value that is 2px greater than the actual working area. We have verified that the source of the issue is not from our code. It seems to be related to the window manager.
> 
> When the issue occurs, running xprop -root | grep _NET_WORKAREA returns a value that is 2px larger than expected. In a system with a bottom inset of 30px, a top inset of 32px, and a screen resolution of 1920x1080, when the issue occurs, the _NET_WORKAREA value is as follows:
> 
>> _NET_WORKAREA(CARDINAL) = 0, 32, 1920, 1020, 0, 32, 1920, 10**20** 
> 
> However, it should be:
>  
>> _NET_WORKAREA(CARDINAL) = 0, 32, 1920, 1020, 0, 32, 1920, 10**18** 
> 
> Wich is the output of the command when the issue doest not occur.
> 
> after discution with @aivanov-jdk a 2 pixels margin error is acceptibe 
> 
> **Proposed Fix:**
> Increase the allowed margin to 2 pixels.

@anass-baya Couple of things regarding this PR:

- There is a title mismatch please remove the prefix "Draft:" so that jcheck passes and rfr label is added to PR.

- I wasn't able to get it to fail on Ubuntu 24.04, is fractional scaling setting enabled on SBR nodes ? Although even with fractional scale enabled I wasn't able to replicate the issue with different uiScales (1, 1.25, 1.5, 2)

- Can you please add test logs from the node it is failing on?

- Headsup: RDP1 for jdk25 is on 5th June, 2025. In case you are planning to add this fix to 25 then it requires to be approved and integrated before the fork.

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PR Review: https://git.openjdk.org/jdk/pull/25521#pullrequestreview-2893594494