Created attachment 169107 [details] 2x Zoomed comparison between 100% and 150% scaling SUMMARY The wallpaper looks slightly blurry when using fractional scaling, even when it has the same resolution as the screen. This might be because the image is scaled up with the system scale only to be resized again to fit the screen. STEPS TO REPRODUCE 1. Use a wallpaper with clear lines/edges 2. Set the system scale to a non-integer value OBSERVED RESULT The wallpaper looks blurry because it is unnecessarily resized EXPECTED RESULT The wallpaper is displayed as-is, unaffected by the system scale SOFTWARE/OS VERSIONS Linux: Fedora Kinoite 40.20240429.0 KDE Plasma Version: 6.0.4 KDE Frameworks Version: 6.1.0 Qt Version: 6.7.0 ADDITIONAL INFORMATION That the wallpaper is scaled with the system scale becomes especially obvious when using the "centered" positioning mode for the wallpaper. Even though the image should fit the screen perfectly, it is sized up according to the system scale factor.
Is this on wayland or x11 or both?
It happens the same way on both wayland and x11.
Yup, I'm afraid this is expected due to the way fractional scaling works on Qt: we can't fractionally scale some things but not others, unfortunately. Well, I mean technically we could, but since the scaling is per-process, it would require splitting up plasmashell into multiple processes which is considered infeasible for the time being.