Bug 483112

Summary: Pixelated font with fractional scaling
Product: [Plasma] kwin Reporter: Simon <simon.adrian>
Component: wayland-genericAssignee: KWin default assignee <kwin-bugs-null>
Status: RESOLVED DUPLICATE    
Severity: normal CC: kde
Priority: NOR    
Version: 6.0.1   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: KCM using wp-fractional-scale
KCM using QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor
Zoom of letter 'e' using wp-fractional-scale
Zoom of letter 'g' using wp-fractional-scale
Zoom of letter 'e' using QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor
Zoom of letter 'g' using QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor

Description Simon 2024-03-10 13:53:06 UTC
Created attachment 166870 [details]
KCM using wp-fractional-scale

SUMMARY
***
NOTE: If you are reporting a crash, please try to attach a backtrace with debug symbols.
See https://community.kde.org/Guidelines_and_HOWTOs/Debugging/How_to_create_useful_crash_reports
***
I just upgraded from Plasma 5.27 to Plasma 6.0.1 on ArchLinux. I am on Wayland (also on 5.27) and using fractional scaling (150%). On Plasma 6.0.1, the fonts look weird (using Noto Sans at 10 pt): attachment wp-fractional-scale-v1.png is a screenshot of kcm, which shows, for example, that the horizontal line of the letter 'e' (see the search field of kcm) is roughly twice as large as the top or bottom of the letter 'e', which looks weird to me. Or consider the letter 'g' in the word 'Hintergrunddienst' (below 'Sitzung' in the tree menu), where the bottom part of 'g' is too thin.

In trying to understand, what my be the cause of my problem, I came across

https://bugreports.qt.io/browse/QTBUG-113574

Since I do have the problem with the WebEngine too, I set the environment variable

QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor

Now not only the WebEngine problem is solved, but also kcm looks like before again. From this, I conclude that before upgrading, the wp-fractional-scale-v1-extension was not used.

I am wondering if this is a won't fix. If so, I am a  bit underwhelmed with the performance of 'wp-fractional-scale-v1'. Or is there another option that I need to set?
Comment 1 Simon 2024-03-10 13:53:39 UTC
Created attachment 166871 [details]
KCM using   QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor
Comment 2 Simon 2024-03-10 13:54:15 UTC
Created attachment 166872 [details]
Zoom of letter 'e' using wp-fractional-scale
Comment 3 Simon 2024-03-10 13:54:31 UTC
Created attachment 166873 [details]
Zoom of letter 'g' using wp-fractional-scale
Comment 4 Simon 2024-03-10 13:55:02 UTC
Created attachment 166874 [details]
Zoom of letter 'e' using  QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor
Comment 5 Simon 2024-03-10 13:55:26 UTC
Created attachment 166875 [details]
Zoom of letter 'g' using  QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor
Comment 6 Simon 2024-03-11 15:40:29 UTC
Potentially a duplication of https://bugs.kde.org/show_bug.cgi?id=481233
Comment 7 David Edmundson 2024-03-14 14:11:38 UTC
Moving there, it's not an issue in kwin itself

*** This bug has been marked as a duplicate of bug 479891 ***