Scaling issues with Qt Apps on Gnome

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Normally the qt configuration GUI isn’t included in the gnome editions, so to fix the HiDPI, there are other envs you can also try:

Qt 5

Since Qt 5.6, Qt 5 applications can be instructed to honor screen DPI by setting the QT_AUTO_SCREEN_SCALE_FACTOR environment variable:

export QT_AUTO_SCREEN_SCALE_FACTOR=1

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 ).

Note:

  • If you manually set the screen factor, it is important to set QT_AUTO_SCREEN_SCALE_FACTOR=0 otherwise some applications which explicitly force high DPI enabling get scaled twice.
  • QT_SCALE_FACTOR scales fonts, but QT_SCREEN_SCALE_FACTORS does not scale fonts.
  • If you also set the font DPI manually in xrdb to support other toolkits, QT_SCALE_FACTORS will give you huge fonts.
  • If you have multiple screens of differing DPI ie: Side display you may need to do QT_SCREEN_SCALE_FACTORS="2;2"

An alternative is e.g.:

QT_FONT_DPI=96 vym

This link aggregates all the configuration for most graphical interfaces and is where the info above comes from:

Qt 5 - HiDPI - ArchWiki

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