Ugly font rendering on scaled wayland display

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1

Hi,

I’ve just upgraded from Fedora-39 (KDE 5.x + Xorg) to Fedora-41 (KDE 6.2 + Wayland) and alomst everything seems to work fine so far - way better than my previous attempts to switch to wayland.

However, one thing I noticed is that text looks really ugly in KDE applications.
I am running a 4k display with 150% fractional scaling - and while firefox renders text fine and old gtk apps seem to be somehow scaled, KDE applications looks like:

grafik

Any idea what is going on here?
Subpixel antialiasing is disabled (no idea why the l in “wayland” has a blue seam anyway) and hinting is set to “light”.

Thanks & best regards, Clemens

2

Hi! It sounds a bit like this bug - 479891 – Some text glyphs in QML software are vertically mis-aligned or squished when using a fractional scale factor - except the issue here for you looks like horizontal, rather than vertical, glitches.

Still, it might be worth trying to see if it’s a different way of the same bug impacting - does the appearance of those characters get better if, as folks found in that bug report, you set the environment variable QT_SCALE_FACTOR_ROUNDING_POLICY=RoundPreferFloor for your session?