Geek Igor

Zoom and Kubuntu 18.04

Fix annoying issues with Zoom and HiDPI on Kubuntu 18.04.

I’ve got a new laptop for my work for Elastic recently. This time I’ve opted for a Thinkpad and not for a MacBook. I’ve installed Kubuntu 18.04. Linux on desktop or laptop gives you a lot of opportunities to blog about something you’ve fixed. Here comes a first one.

How to make zoom — the conferencing software — play nicely with kubntu?

What’s the issues?

Super small fonts with Zoom and HiDPI display

Linux and HiDPI still have some way to go. In this case, the issue is that with my KDE configuration (scaling = 2.0), zoom is so small, that it is unreadable.

The solution is simple (huge thanks to my colleagues from our internal #linux room :)). Just use experiment with the QT_SCALE_FACTOR env variable before starting zoom.

To make it convenient in ubuntu, I’ve added it to the zoom launcher:

$ sudo $EDITOR /usr/share/applications/Zoom.desktop
# Change `Exec` to something like
# Exec=/usr/bin/env QT_SCALE_FACTOR=2 /usr/bin/zoom %U

Before: Before - zoom is small

After: After - zoom is OK

Zoom uses its own url scheme, e.g. open zoommtg:// to join a meeting. Usually, even on linux, it is recognized correctly “out of the box” (after the installation that is). In case of kubuntu, I’ve needed to use a trick from the indispensable arch linux wiki:

Tip: Although deprecated, several applications still read/write to ~/.local/share/applications/mimeapps.list. To simplify maintenance, simply symlink it.

$ ln -s ~/.config/mimeapps.list ~/.local/share/applications/mimeapps.list

Note that the symlink must be in this direction because xdg-utils deletes and recreates ~/.config/mimeapps.list when it writes to it, which will break any symbolic/hard links.

I’ve also issued this command first, but I think it is issued by the package installer as well, so it wasn’t needed.

$ xdg-mime default Zoom.desktop x-scheme-handler/zoommtg

With these two “fixes” in place, the machine is ready for the video conferencing.