finalise wallpaper

util/wallpaper.nix

@@ -0,0 +1,20 @@
+{pkgs}: {
+  palette,
+  wallpaper,
+}: let
+  str_pal = with pkgs.lib; concatStringsSep " " (builtins.foldl' (acc: el: acc ++ (attrValues el)) [] [palette.normal palette.bright palette.util]);
+in
+  pkgs.stdenv.mkDerivation rec {
+    name = "generated-wallpaper.png";
+    src = wallpaper;
+    buildInputs = [
+      pkgs.lutgen
+    ];
+
+    phases = ["installPhase"];
+
+    installPhase = ''
+      echo -e "Generating wallpaper from ${wallpaper} using palette:\n${str_pal}.."
+      ${pkgs.lib.getExe pkgs.lutgen} apply --lum 0.8 -l 10 -s 128 -n 8 -o $out ${wallpaper} -- ${str_pal}
+    '';
+  }