Scale QT Apps for HiDPI
Most of Ubuntu/GNOME scale nicely with a high dpi (hidpi) display, there has been built-in support since 19.04 and now fractional scaling is just a simple toggle away in the latest 20.04.
I use a 4K external monitor so a 150% scaling works great, however, not for all apps. Zoom is the most common app that appears really small on my hidpi display.
Zoom is written using the QT toolkit, that does not inherent the scaling setting from GNOME. You can fix this by setting an environment variable prior to running Zoom.
Starting Zoom like this fixes it:
If you do not want to start Zoom from the command-line, you can edit the desktop file that launches zoom. This can be found at:
You need to edit the Exec line and add an additional
env to the start. So the final line in the desktop entry looks like:
Exec=env QT_SCALE_FACTOR=2 /usr/bin/zoom %U
With that in place, each time launching Zoom I get it scaled properly. Here's the entire desktop entry for reference:
[Desktop Entry] Name=Zoom Comment=Zoom Video Conference Exec=env QT_SCALE_FACTOR=2 /usr/bin/zoom %U Icon=Zoom.png Terminal=false Type=Application Encoding=UTF-8 Categories=Network;Application; StartupWMClass=Zoom MimeType=x-scheme-handler/zoommtg;x-scheme-handler/zoomus;x-scheme-handler/tel;x-scheme-handler/callto;x-scheme-handler/zoomphonecall;application/x-zoom X-KDE-Protocols=zoommtg;zoomus;tel;callto;zoomphonecall; Name[en_US]=Zoom
Now, who can help me with Gimp?