I am looking for an equivalent of the following gnome setup, in KDE:
Under gnome+X11, I can get instant scaling of gnome apps, KDE apps and chrome/chromium (>v49) when plugging my high-dpi monitor (27" 4K) by running:
gsettings set org.gnome.desktop.interface text-scaling-factor 1.4
Note that (in a neophyte's words) this is not doing framebuffer-level scaling (that would be gnome's scaling-factor), it' only telling the toolkits to use bigger fonts (images are not affected).
This gets picked-up instantly by gnome, qt, chrome. Other aps, like Intellij IDEs or Firefox need a restart (for Firefox I could script in a change of layout.css.devPixelsPerPx
).
On the other hand, in KDE, both Plasma "Displays - Scale Display" and "Fonts - Force fonts DPI" settings require a restart of all apps including the same KDE apps which autodetected the gnome scaling change!!
This may be due to the KDE-GTK theme picking up the gnome setting, but still, it means Qt can redraw the interface in response to the change.
Am I overlooking something? Can I modify the same low-level setting underlying the gnome one, from KDE? Is there something that can be improved in KDE code to improve the situation?