Bug 477900

Summary: In various apps on Wayland, window resizing causes various visual elements to tremble.
Product: [Plasma] kwin Reporter: funkybomber
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED UPSTREAM    
Severity: normal CC: aleixpol, nate
Priority: NOR Keywords: qt6, wayland
Version: master   
Target Milestone: ---   
Platform: Neon   
OS: Linux   
URL: https://bugreports.qt.io/browse/QTBUG-116982
Latest Commit: Version Fixed In:
Attachments: Trembling visual elements on resize

Description funkybomber 2023-12-02 09:38:49 UTC
Created attachment 163750 [details]
Trembling visual elements on resize

SUMMARY
***
On window resize (Dolphin) the menu items and other visual elements are trembly. Please review the attached .webm video file to get a better understanding of the issue.
On window resize (Discover) various visual elements are also trembly. I could not capture that bug with Spectacle in Discover as the bug would NOT manifest itself while Spectacle was recording!

This error does not happen under X11
***


STEPS TO REPRODUCE
1. Install KDE Neon Unstable in QEMU
2. Open a window of either Dolphin or Discover
3. Resize the window using the mouse cursor

OBSERVED RESULT
Various visual elements are trembly.

EXPECTED RESULT
No visual elements are trembly.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE Neon Unstable edition
(available in About System)
KDE Plasma Version: 5.90.0
KDE Frameworks Version: 5.246.0
Qt Version: 6.6.0
Kernel version: 6.2.0-37-generic (64-bit)
Graphics Platform: Wayland

Tested in a Virtual Machine (in QEMU v4.0.0) with the following specs:
Processor: 2 × Intel® Core™ i3-4150 CPU @ 3.50GHz
Memory: 3.8 GiB of RAM
Graphics Processor: llvmpipe
Manufacturer: QEMU
Product name: Standard PC (Q35 + ICH9, 2009)
System version: pc-q35-6.2
Comment 1 Nate Graham 2023-12-05 21:18:11 UTC
Probably quite relevant:
> Graphics Processor: llvmpipe

Are there any windows that are *not* affected?
Comment 2 funkybomber 2023-12-06 02:12:41 UTC
(In reply to Nate Graham from comment #1)
> Probably quite relevant:
> > Graphics Processor: llvmpipe
> 
> Are there any windows that are *not* affected?

Interestingly yes!

Programs tested that are not NOT affected:
Kate
Okular
Ark
Gwenview
Info Center
Synaptic
VLC


Other programs which are affected:
Konsole
System Monitor


This list is not exhaustive. Please advise if you would like me to test more programs.
Comment 3 Nate Graham 2023-12-07 18:46:39 UTC
I can't see any pattern there. :/
Comment 4 Vlad Zahorodnii 2023-12-14 12:40:09 UTC
In order to fix bouncy-ness in apps that use qtwidgets, like dolphin, you need at least qt 6.6.1 containing https://invent.kde.org/qt/qt/qtwayland/-/commit/55f30d3b93c78f732ad0c720bf59d5707009f41d

For apps that use qtquick, like discover or system settings, you need https://codereview.qt-project.org/c/qt/qtwayland/+/503676 however. It's still work in progress. In either casei, it's an upstream issue.