I run Gnome, which has pretty good support for my HiDPI screen. However, when I run QT apps I can't seem to find a way to scale the fonts. Is there a way to do this without installing a full version of KDE?
Since Qt 5.6, Qt 5 applications can be instructed to honor screen DPI by setting the
QT_AUTO_SCREEN_SCALE_FACTOR environment variable. If automatic detection of DPI does not produce the desired effect, scaling can be set manually per-screen (
QT_SCREEN_SCALE_FACTORS) or globally (
QT_SCALE_FACTOR). You can also use
QT_FONT_DPI to adjust scaling of text.
You can try this recipe from the archwiki
Qt5 applications can often be run at higher dpi by setting the QT_DEVICE_PIXEL_RATIO environment variable. Note that the variable has to be set to a whole integer, so setting it to 1.5 will not work.
This can for instance be enabled by creating a file
And set the executable bit on it.
QT automatically scales the font based on the screen's DPI:
The traditional approach to supporting high DPI has been one where Qt scaled fonts automatically [...]
I had the problem that my screen has 166 dpi, but the font sizes chosen by Qt were much too large. Luckily, there is a way to tell Qt to assume a smaller value by setting
QT_FONT_DPI. For me, 128 is nice.
(I'm using cinnamon as desktop environment, and it pushes the configured font sizes for Gtk 1:1 to Qt, which is what brings this issue)
I had the problem, that apps like KeepassXC and VLC have tiny, unreadable fonts now in Linux Mint 20 Ulyana (Cinnamon Edition).
To make my QT-Apps look normal, I needed both solutions mentioned here and put following lines into
# For the graphical elements export QT_SCALE_FACTOR=1.5 # To make the fonts readable export QT_FONT_DPI=96
Although I read, that QT scales automatically, scaling only the fonts lead to strange look with unexpected line breaks.