Created attachment 120502 [details] screenshot STEPS TO REPRODUCE 1. open system settings > display and monitor > click "Scale display" button and set display scale factor to 1.2 2. relogin 3. open system settings > icons OBSERVED RESULT As we can see in the attached screenshot, preview of the icon themes is blurry EXPECTED RESULT preview of the icon themes looks crisp SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.15.90 KDE Frameworks Version: 5.58.0 Qt Version: 5.13 beta4
Can't reproduce, can you retest with new plasma and reopen if needed.
This issue persists only on X11 session. Operating System: Arch Linux KDE Plasma Version: 5.17.1 KDE Frameworks Version: 5.63.0 Qt Version: 5.13.1
Can reproduce on X11, but it's subtle. I wonder if there's anything we can really do here. Anything that's pixel-perfect at an integer scale factor is bound to be blurry when using fractional scaling.
Is it only the preview that looks blurry, or also after applying? If it is only the preview, I guess there should be something that can be done about it. Also, a bit off topic: What is the reason, why scaling leads to blurry things? I don't exactly understand that. If one scales images with image editing software, I never noticed such behavior. So I wonder whether it is just me not noticing it or whether there are better ways to do this (different algorithms maybe).
Photographs are much less sensitive to upscaling/downscaling blurriness because of the nature of what's being phorographed. By contrast, the effect is noticeable even with excellent scaling algorithms for graphics which are designed to be pixel-perfect--for example those which make heavy use of single-pixel lines. There is on algorithm I'm aware of that can make a single-pixel line that perfectly falls on physical pixels look good when scaled 1.5x, because there aren't fractional pixels. There may be fractional sub-pixels, but those cannot be used in the same way.
Alright. Just did a short testing and you are right. I guess I never used scaling in a way where it was noticeable. Testing different algorithms with GIMP, there is a noticeable difference between them. Not sure what algorithm is used by KDE to scale, though. I created some examples with comparison of different algorithms for this, since this is offtopic, maybe I can attach them to a different bug report.
Done - see https://bugs.kde.org/show_bug.cgi?id=425190
(In reply to Nate Graham from comment #3) > Can reproduce on X11, but it's subtle. I wonder if there's anything we can > really do here. Anything that's pixel-perfect at an integer scale factor is > bound to be blurry when using fractional scaling. From the experiments conducted in the bug report I linked above, it seems like not all scaled images need to look blurred. So if that should be the underlying problem, that can be improved.
Can reproduce with display scale 125%. Operating System: Arch Linux KDE Plasma Version: 5.25.90 KDE Frameworks Version: 5.98.0 Qt Version: 5.15.6 Graphics Platform: X11