{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} ''; }