Some time ago I got a laptop with a 4k display. I am not using that one with
external monitors, but I still may be able to help a bit. With earlier versions
of Plasma, scaling was pretty much not working. I was looking at tiny text all
the time.This changed at some point - I think when Plasma 5.6 rolled around, but not
exactly sure. Anyway, what I did was switching my scaling (System Settings >
Display and Monitor > Display Configuration > Scale Display) back to 1, so not
scaling up. On the other hand I set my font DPI (System Settings > Font > Fonts
> Force fonts DPI) to 96 (after ticking the box of course). Since that version
of Plasma, all interfaces appear to scale nicely in response to this. Firefox
and Chrome apparently respect that setting too (although I may have played
around a bit with settings there, cannot remember).Hopefully, the fonts DPI works across displays, given that Plasma knows the DPI
of the monitor...?Thom2016-09-21 1:42 GMT+02:00 Rubin Abdi <rubin@starset.net>:I recently switched to an X1 Carbon 4th gen with the nicer HIDPI display. Sadly the rest of the desktop displays I plug into are still the old density. I noticed recently in 5.7.4 that most Qt based applications will do some notion of font DPI re-rendering when a window moves from one display to another, which is a step in the right direction though I wish there were some more exposed settings to specify which scaling factors for each monitor independently.Konsole has sadly stopped displaying the bitmap font Terminus properly on the HIDPI display (the letters look squished and the kerning is horrible), however when it pops onto my desktop display it looks fine. Using any other normal truetype or openfont causes 1px wide horizontal and vertical lines to get cut through the window displaying whatever is under it whenever there's a bunch of text that scrolls by or if I highlight text.Chrome (Chromium) thankfully respects my KDE global scale factor of 1.5, however it absolutely doesn't care about this new behavior of rescaling when the window moves between one display to another. It's been driving me mad to the point where I'm now saving up for a new 4k monitor just so I don't have to deal with this issue anymore.Anyone have some good tricks dealing with these issues?