Bug 510029

Summary: Display scaling causes visual artifacts for Desktop Effects (Mouse Tracker)
Product: [Plasma] kwin Reporter: Frederik Siefert <frederik.e.siefert>
Component: effects-variousAssignee: KWin default assignee <kwin-bugs-null>
Status: CONFIRMED ---    
Severity: minor CC: akselmo, nate
Priority: NOR    
Version First Reported In: 6.4.5   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: Track Mouse Effect Artefacts.

Description Frederik Siefert 2025-09-28 16:09:10 UTC
Created attachment 185343 [details]
Track Mouse Effect Artefacts.

SUMMARY
Using a high resolution display with a display scale higher than 100% (tested with 75, 125, 150, 200%)  introduces noticeable jitters for the Mouse Tracker Desktop Effect.

STEPS TO REPRODUCE
1. Set Display Scaling to a value other than 100%
2. Enable the Track Mouse Desktop Effect.
3. Show Track Mouse effect.

OBSERVED RESULT
The rings for the effect will stutter, lag, jump around, and partially disappear.

EXPECTED RESULT
Expected the ring animation to be fluid regardless of Display Scaling.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux 
KDE Plasma Version: 6.4.5
KDE Frameworks Version: 6.18.0
Qt Version: 6.9.2
Kernel Version: 6.16.8-arch3-1 (64-bit)
Graphics Platform: Wayland
Comment 1 Akseli Lahtinen 2025-09-29 08:58:31 UTC
Can confirm with 125%.

Operating System: Fedora Linux 42
KDE Plasma Version: 6.5.80
KDE Frameworks Version: 6.19.0
Qt Version: 6.9.2
Kernel Version: 6.16.8-200.fc42.x86_64 (64-bit)
Graphics Platform: Wayland
Processors: 12 × AMD Ryzen 5 3600 6-Core Processor
Memory: 16 GiB of RAM (15.5 GiB usable)
Graphics Processor: AMD Radeon RX 6600