Bug 418982 - Bad font rendering on title bars.
Summary: Bad font rendering on title bars.
Status: RESOLVED UPSTREAM
Alias: None
Product: kwin
Classification: Plasma
Component: aurorae (show other bugs)
Version: 5.18.3
Platform: Arch Linux Linux
: NOR normal
Target Milestone: ---
Assignee: KWin default assignee
URL: https://bugreports.qt.io/browse/QTBUG...
Keywords:
Depends on:
Blocks:
 
Reported: 2020-03-18 10:05 UTC by David Rubio
Modified: 2020-03-19 07:56 UTC (History)
1 user (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Letters individually moving when resizing the title, instead of moving the whole string smoothly. (445.14 KB, video/x-matroska)
2020-03-18 10:05 UTC, David Rubio
Details
Closer look. Look at the letter "o" in home (23.50 KB, video/x-matroska)
2020-03-18 10:31 UTC, David Rubio
Details

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Description David Rubio 2020-03-18 10:05:40 UTC
Created attachment 126866 [details]
Letters individually moving when resizing the title, instead of moving the whole string smoothly.

SUMMARY
When resizing an aurorae window, the letters of the title change position, sometimes making the font kerning extremely bad. Video showing an example is attached. 

STEPS TO REPRODUCE
1. Choose an aurorae theme (Qogir-dark-circle, in this case)
2. Resize the window horizontally
3. Look closely at the window title

OBSERVED RESULT
Letters of the title move around, making font kerning appear extremely bad.

EXPECTED RESULT
Letters stay still, title moves smoothly with the window (Breeze does it properly, for example)

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Linux 5.5.8-21-tkg-MuQSS
KDE Plasma Version: 5.18.3
KDE Frameworks Version: 5.68.0
Qt Version: 5.14.1

ADDITIONAL INFORMATION
Comment 1 David Rubio 2020-03-18 10:31:59 UTC
Created attachment 126867 [details]
Closer look. Look at the letter "o" in home
Comment 2 David Rubio 2020-03-18 14:22:52 UTC
Sorry. Didn't see the bug upstream. I have a question though, why is Breeze not affected by this issue? Is it not possible to mitigate it using the examples on the Kerning.qml file on the bug upstream? 

It's really a quite annoying bug and it makes Aurorae basically unusable for a lot of people.
Comment 3 Christoph Feck 2020-03-18 17:18:58 UTC
Breeze doesn't use QtQuick, but only QPainter.
Comment 4 David Rubio 2020-03-18 18:46:02 UTC
(In reply to Christoph Feck from comment #3)
> Breeze doesn't use QtQuick, but only QPainter.

Makes sense, thanks!
Comment 5 Vlad Zahorodnii 2020-03-19 07:56:58 UTC
Yes, Breeze uses QPainter. I've been told that QtQuick does some shady stuff in shaders to align text to the pixel grid. Maybe that has something to do with why kerning is off.