From a8123630390621e0868f6238d8e83dca94318b37 Mon Sep 17 00:00:00 2001
From: Daniel Langbein <daniel@systemli.org>
Date: Mon, 18 Sep 2023 21:49:26 +0200
Subject: [PATCH] fractional scaling in X11/Wayland

---
 modules/gnome-fractional-scaling.nix | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/modules/gnome-fractional-scaling.nix b/modules/gnome-fractional-scaling.nix
index d6c1cc8..ce4f8ff 100644
--- a/modules/gnome-fractional-scaling.nix
+++ b/modules/gnome-fractional-scaling.nix
@@ -1,4 +1,4 @@
-{ config, pkgs, ... }:
+{ config, pkgs, lib, ... }:
 
 {
   # https://wiki.archlinux.org/title/HiDPI#Wayland
@@ -11,7 +11,9 @@
   # Overlays.
   # https://nixos.wiki/wiki/Overlays#In_NixOS
   # https://discourse.nixos.org/t/use-specific-pkg-version-in-overlay/32741/3
-  nixpkgs.overlays = [
+
+  # If on X11, then use patched version of mutter.
+  nixpkgs.overlays = lib.mkIf (! config.services.xserver.displayManager.gdm.wayland) [
     (
       # Patched version of mutter 44.2.
       # Outdated example: https://nixos.wiki/wiki/Overlays#Overriding_a_package_inside_a_scope
@@ -55,10 +57,13 @@
     dconf.settings = {
       "org/gnome/mutter" = {
         experimental-features = [
-          # Wayland fractional scaling
-          "scale-monitor-framebuffer"
-          # X11 fractional scaling
-          "x11-randr-fractional-scaling"
+          (
+            if (osConfig.services.xserver.displayManager.gdm.wayland)
+            # Wayland fractional scaling
+            then "scale-monitor-framebuffer"
+            # X11 fractional scaling
+            else "x11-randr-fractional-scaling"
+          )
         ];
       };
     };