I'm using Openbox on X11.

For some reason, font hinting in Qt6 applications appears to be forcefully disabled. I'm using qt6ct to set the font to the default sans-serif font (in my case, Noto Sans), size 9. Exactly the same as my GTK settings.
As the screenshot below shows, the word "Edit" in Prism Launcher (a Qt6 application) looks very different from the same word in GIMP.

The font looks this way in every other Qt6 application I've tested. Manually disabling font hinting via fontconfig produced the same results in GTK applications.

Even weirder, Qt5 applications seem to display the font just fine; below is a screenshot from qt5ct.

I suspect this might be a regression in Qt. I did a full system upgrade last night, which updated Qt6-related packages from 6.10.2 to 6.11.0.

Things I've tried so far:

• Playing with the value of the QT_QPA_PLATFORMTHEME environment variable (tried qt5ct, qt6ct, gtk3, removing altogether)

• Changing different fontconfig settings (LCD filter, hinting styles)

• Manually changing various font flags in qt6ct.conf

• Restarting X11 (many times)

Last edited by 7xnl (2026-06-01 05:07:34)