Ubuntu, like other Linux distributions uses the GNOME Display Manager (GDM) as its, well, display manager, though most of us tend to think of or refer to it as the login screen.
To customise the Ubuntu login screen, such as setting a different theme or icon set, changing the login screen background image or colour, or getting night light to apply when viewing it, you can use a 3rd-party tool called GDM Settings.
The app is written in Python and uses libadwaita for its UI, so it looks great on the modern Ubuntu desktop and adapts gracefully when resizing the window or running on width-constrained displays.
GDM Settings lets you:
- Set login screen background image/colour
- Change login screen theme, icons, and cursor
- Change font, font sizes, and scaling factor
- Show battery percentage in login screen
- Customise top bar text and background colours
- Set mouse/touchpad behaviours
- Enable/disable on-screen options (e.g., user list)
- Power settings (e.g., dim screen, screen timeout)
- Enable Night Light support
Plus a fair bit more.
GDM Settings is not an official GNOME tool. Use it cautiously, at your own risk. I get the impression a few of the tweaks/options available in the app aren’t adjusting values intended to be user-configurable, i.e., they alter hardcoded settings, ad-hoc.
When looking into the app I also encountered a few reports of individuals who’d used this tool to make a seemingly safe modification, such as changing the login screen color, only to discover that GDM doesn’t load after, resulting in the frustrating “Oh no! Something has gone wrong” error screen.
Just keep that in mind.
Getting GDM Settings
GDM Settings is available in the repos of Ubuntu 23.10 (and Debian Testing), so you can install it through the new App Center (remember to filter for Debian packages) or via apt using
sudo apt install gdm-settings (thanks to the app’s dev, Mazhar H. for letting me know).
You can also install GDM Settings from Flathub but you should be aware that the sandboxed nature of Flatpak means a few features of the tool are not available or may not work.