Bug 432130

Created attachment 135190 [details]
slow scrolling causes artifacts

SUMMARY
My high resolution touchpad seems to scroll in steps that are not multiple of 1px which butchers text rendering AND icons (get blurred), see attached video
This happens in every system tray view that has enough content to scroll (as far as I could test)

STEPS TO REPRODUCE
1. Have a high-res scrolling device
2. scroll slowly in any scrollable systray window

OBSERVED RESULT
Text get's butcheres/has missing pixels and lines. I guess it tries to scroll less then full pixels which behaves badly in combination with font hinting. Icons get a bit blurred on the y-axis.
You really have to look at the attachments.
By hovering over the text (highlighting it) it automatically scrolls to the next full pixel fixing the whole view. (see 'can look fine.apng')

EXPECTED RESULT
Text should always look about the same, no matter how I scroll.

SOFTWARE/OS VERSIONS
Operating System: Arch Linux
KDE Plasma Version: 5.20.5 on x11
KDE Frameworks Version: 5.78.0
Qt Version: 5.15.2
Kernel Version: 5.10.10-arch1-1
OS Type: 64-bit
Processors: 8 × AMD Ryzen 7 4700U with Radeon Graphics
Memory: 15.1 GiB of RAM
Graphics Processor: AMD RENOIR

ADDITIONAL INFORMATION
I have noticed that icons and text DO NOT scroll at the same time. Over the course of apperently two scroll events it looks like first only the text scrolls, and on the second one only icons scroll.

xinput reports my touchpad to be 'SYNA32A1:00 06CB:CE17 Touchpad'
more details if useful: https://paste.ubuntu.com/p/YR7XNhmRTq/

I am using a 1080p screen.