Changing the font antialiasing settings in Plasma breaks the rendering in GTK programs. For example setting RGB subpixel rendering with slight hinting gives a fine (much better than default) result in Qt programs (including Plasma) but looks terrible in everything using GTK (Firefox...). I tried the same settings on other Linux systems and some managed it properly (Solus, Kubuntu, OpenMandriva...) while others brought me the same problem (Fedora, Void).
Thank you for pointing this out; and the comparisons. Assigning to tmb for 'gtk+3.0', CC'ing Olav as its recent committer, Thierry for GTK4.0, in the hope that someone will be able to throw light on this. Please re-assign as you see fit.
Assignee: bugsquad => tmbCC: (none) => olav, thierry.vignaudSummary: GTK programs ignore Plasma font antialiasing settings => GTK programs ignore Qt font antialiasing settings
Isn't that a Plasma bug instead?
CC: (none) => mageia
It might also be a problem within xsettings-kde. This syncs the KDE settings with xsettings. Under X11 GTK should follow these settings. I think Mageia installs this by default. I requested commit rights ages ago. Seems last commit was in 2016. Though if I check the Fedora package, they mention it's old and replaced by kde-gtk-config. More investigation needed. ;)
I just tried the Xfce live ISO and to my surprise I got the same problem with it: enabling RGB subpixel rendering gave me a poor rendering across the whole desktop. This means that the problem has nothing to do with Plasma but is related to subpixel rendering in GTK.
Summary: GTK programs ignore Qt font antialiasing settings => subpixel rendering is broken in GTK programs
CC: (none) => fri
Still a major annoyance in Mageia 8.
Version: 7 => 8Severity: normal => major
Where are the settings for this found?
In the fonts settings. For example in Xfce settings panel -> Appearance -> Fonts -> Rendering. Plasma has a similar option in its settings panel, as probably most desktop environments do.