At the moment one can setup the scale for display in sets of 0.1 see Display Configuration -> scale display. However the /usr/bin/startkde +153 and /usr/bin/startplasmacompositor +104 both set QT_DEVICE_PIXEL_RATIO only for integers. both lines shall be changed to if test "$kdeglobals_kscreen_scalefactor" != "1" ; then also scale display may offer "safe" values for scalling (steps of 0.25) Alin Reproducible: Always
Only integers work for that variable. which is why we only set them to integers. You can try and argue the case with Qt, but a lot of drawing code does go weird with non integer stuff.
I have no idea what artefacts do you see... I used 1.5 on my computer with no issues. the same on my phone I used qt5 with non integer pixel ratios without issues. anyhow changing the start script to allow non-integers does not change with anything the behaviour right now. The users who want to be "safe" can still use integers... the rest can use non-integers. Alin
I don't see any artefacts because as I said, it doesn't work with non integers From Qt5.5 qxcbscreen.cpp: static bool dpr_scaling_enabled = (qgetenv("QT_DEVICE_PIXEL_RATIO").toInt() > 1 Your phone is maybe wayland?
Did some research, QT_SCALE_FACTOR (the Qt 5.6 one which is renamed) is float based. I'll make sure to keep that when I do the port.
FYI, on 5.6 now this will work.