https://bugs.kde.org/show_bug.cgi?id=477455
Bug ID: 477455
Summary: Software cursor repaints are glitchy with fractional
scaling sometimes
Classification: Plasma
Product: kwin
Version: 5.27.9
Platform: Other
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: wayland-generic
Assignee: kwin-bugs-n...@kde.org
Reporter: l...@asahilina.net
Target Milestone: ---
Created attachment 163421
--> https://bugs.kde.org/attachment.cgi?id=163421&action=edit
Screenshot of the issue
SUMMARY
When using fractional scaling with software cursors, sometimes cursor repaints
leave behind one-pixel-wide regions of damage.
The easiest way to reproduce this is on window decorations after killing
plasmashell, but I think this is the same bug as other glitches that happen
elsewhere (like when enabling the Blur effect and hovering over the Plasma
taskbar). I think in many cases something else triggers a full screen repaint
(or a larger repaint in general) and hides the bug.
STEPS TO REPRODUCE
1. Use software cursors (KWIN_FORCE_SW_CURSOR=1 or a platform with no HW
cursors)
2. Configure a non-integer display scale
2. killall plasmashell
3. Hover over window decorations
OBSERVED RESULT
See attached screenshot (on the System Settings decorations). I took that with
Spectacle video mode since normal screenshot mode always seemed to force a
repaint and cleared out the damage, so please ignore the lower general quality.
I think the duplicate cursor is a Spectacle thing (it's probably overlaying its
own cursor on top of the software cursor that is already part of the
framebuffer, which is probably another bug somewhere...).
EXPECTED RESULT
Correct rendering
SOFTWARE/OS VERSIONS
Operating System: Fedora Linux Asahi Remix 39
KDE Plasma Version: 5.27.9
KDE Frameworks Version: 5.111.0
Qt Version: 5.15.11
Kernel Version: 6.6.0-asahi-00861-g9b58b16aa50d (64-bit)
Graphics Platform: Wayland
Processors: 12
Memory: 54.5 GiB of RAM
Graphics Processor: Apple M2 Max
Product Name: Apple MacBook Pro (16-inch, M2 Max, 2023)
ADDITIONAL INFORMATION
--
You are receiving this mail because:
You are watching all bug changes.
