How To Enable HiDPI Fractional Scaling For Wayland Or X11 On Ubuntu 19.04 Disco Dingo

As many of you already know, GNOME 3.32 includes experimental HiDPI fractional scaling for Wayland, but what you might now be aware of is that thanks to Marco Trevisan, it's also possible to use fractional scaling with the X11 session on Ubuntu 19.04 Disco Dingo. This article explains how to enable fractional scaling on Ubuntu 19.04 with GNOME 3.32 using both Wayland and X11 (default) sessions.

So what's this factional scaling? The default GNOME scaling only allows scaling the user interface in whole numbers (e.g. 100%, 200%), and this doesn't work well with every HiDPI monitor; this is where fractional scaling comes in, which allows scaling using fractions, so users can set scaling percentages like 125% or 150%.

To enable experimental fractional scaling on Wayland (requires GNOME 3.32+), use this:

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

To enable experimental fractional scaling on X11 (requires Ubuntu 19.04 Disco Dingo), the default Ubuntu session, use:

gsettings set org.gnome.mutter experimental-features "['x11-randr-fractional-scaling']"

In both Wayland and X11 cases, to use fractional scaling open Settings, go to Devices -> Displays and you'll be able to set a fractional scale (like 125% or 150%) there:

Fractional scaling Ubuntu 19.04 Disco Dingo

It's worth noting that using fractional scaling on X11 has effects like increased CPU and GPU usage. This only solution for this right now is to use a Wayland session instead.

Want to reset this and disable fractional scaling? In both Wayland and X11 cases, reset it using:

gsettings reset org.gnome.mutter experimental-features

Sources: Treviño's Blog and discourse.ubuntu.com