How to do 4k on Linux in 22

High resolution displays are great. Not just to count pixels but because you get real good font rendering and graphics without aliasing. Sadly it’s still something requires a bit of tinkering.

Scaling is great

If you want 4k you may want scaling. Ultimately what sold me is fonts. Pixelated approximation aka anti-aliasing is straining for human eyes¹ and CJK scripts are hard to read at lower resolutions. Most icons and avatars look blurry if you’re using a web browser or a chat app. I even use 125% on a 1080p screen because it improves the rendering and still results in a comfortable user experience.

Ramp up the scaling factor in GNOME

The good news is that this is finally a setting for every monitor if you’re using more than one. For a 3840x2160 screen for example you may want 200%. Simple. Done.

Wait a minute, what about other resolutions like 2560x1440? Or that 1920x1080 screen that I mentioned before? Let this be the first of many experimental options you’ll be learning about here:

gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"

After this is set you need to restart. After that more scaling options will appear in the monitor settings!

Firefox and Thunderbird look ugly

In particular the Wayland support for Mozilla apps is still experimental and hence not enabled out of the box. As a result you get scaled up fonts and icons. To use it you need an environment variable that you could simply add to your ~/.bashrc or whatever shell init file:

export MOZ_ENABLE_WAYLAND=1

Don’t forget this will only apply in a freshly logged in shell.

Proper scaling in Chrome and Chromium

Both of the browsers will seem to work but you still get upscaled fonts and graphics. That’s because the support is considered experimental (deja-vu, eh?).

There’s a file called $XDG_CONFIG_HOME/chrome-flags.conf or chromium-flags.conf respectively. If you’re installing everything from flatpaks like me this probably translates to something like ~/.var/app/com.google.Chrome/config/chrome-flags.conf. Otherwise you’ll find the equivalent files in ~/.config or wherever your configuration places these files.

You can also add these flags directly on the command-line, or to a .desktop file in ~/.local/share/applications. Personally I prefer config files which I can sync without overriding more than necessary.

--enable-features=UseOzonePlatform
--ozone-platform=wayland

Bonus: Dark mode

Something that also isn’t well-documented is dark mode on Chrom{e,ium} for Linux. This really has little to do with high resolutions but it is strongly related to the comfort of my eyes so I decided to include it here. You can add it the same way as the other options:

--enable-features=WebUIDarkMode
--force-dark-mode