sway: Include wallpaper

users/simon/modules/sway.nix

@@ -3,7 +3,33 @@ let
   common = import ./common.nix;
   solarized = common.colorschemes.solarized;
 
-  wallpaper = "${config.xdg.configHome}/sway/wallpaper"; # Symlink to the current wallpaper
+  wallpaper = pkgs.stdenv.mkDerivation {
+    name = "wallpaper";
+
+    src = pkgs.fetchurl {
+      url = "https://i.pximg.net/img-original/img/2013/10/22/04/25/37/39266182_p0.jpg";
+      sha256 = "053gc9jd4cbkkwgcirrhpzbn933dfh83l30p1sz55m5d8zx1lk65";
+      curlOpts = "--referer https://pixiv.net";
+    };
+
+    nativeBuildInputs = [
+      pkgs.unstable.waifu2x-converter-cpp
+    ];
+
+    # -o $out does not work (why?)
+    buildPhase = ''
+      waifu2x-converter-cpp -i $src -o wallpaper.png
+    '';
+
+    installPhase = ''
+      cp wallpaper.png $out
+    '';
+
+    dontUnpack = true;
+    dontConfigure = true;
+    dontFixup = true;
+  };
+
   cfg = config.wayland.windowManager.sway.config;
   thinsp = " ";
 in