nix-git/modules/gnome-fractional-scaling.nix

{ config, pkgs, lib, ... }:
{
  # https://wiki.archlinux.org/title/HiDPI#Wayland
  # Results in blurry font in non-Wayland applications :/

  # https://wiki.archlinux.org/title/HiDPI#Xorg

  # https://devicetests.com/set-different-scaling-multi-monitors-gnome
  #   "scale-monitor-framebuffer": This allows GNOME to scale each monitor’s framebuffer independently, which is necessary for per-monitor scaling.
  #   "x11-randr-fractional-scaling": This allows fractional scaling, which gives you finer control over the scaling factor.

  # TODO: Open issue. Fractional scaling can't be enabled with multiple monitors.
  # TODO: X11 or Wayland or both?
  #   https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/2076
  #   https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/2365
  #   -> https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/2008355

  assertions = [{
    assertion = config.services.xserver.displayManager.gdm.wayland;
    message = "Fractional scaling is only supported for Wayland. There is a patch for X11, but we no longer apply it in an overlay. See e.g. https://aur.archlinux.org/packages/mutter-x11-scaling";
  }];

  programs.dconf.enable = true;

  home-manager.users.yoda = { osConfig, config, pkgs, ... }: {
    dconf.settings = {
      "org/gnome/mutter" = {
        experimental-features = ["scale-monitor-framebuffer" "xwayland-native-scaling"];
      };
    };
  };
}