{ config, lib, pkgs, ... }: with lib; let xcfg = config.services.xserver; cfg = xcfg.desktopManager; # If desktop manager `d' isn't capable of setting a background and # the xserver is enabled, the `feh' program is used as a fallback. needBGCond = d: ! (d ? bgSupport && d.bgSupport) && xcfg.enable; in { # Note: the order in which desktop manager modules are imported here # determines the default: later modules (if enabled) are preferred. # E.g., if KDE is enabled, it supersedes xterm. imports = [ ./none.nix ./xterm.nix ./xfce.nix ./kde5.nix ./lumina.nix ./lxqt.nix ./enlightenment.nix ./gnome3.nix ./kodi.nix ]; options = { services.xserver.desktopManager = { session = mkOption { internal = true; default = []; example = singleton { name = "kde"; bgSupport = true; start = "..."; }; description = '' Internal option used to add some common line to desktop manager scripts before forwarding the value to the displayManager. ''; apply = list: { list = map (d: d // { manage = "desktop"; start = d.start + optionalString (needBGCond d) '' if test -e $HOME/.background-image; then ${pkgs.feh}/bin/feh --bg-scale $HOME/.background-image fi ''; }) list; needBGPackages = [] != filter needBGCond list; }; }; default = mkOption { type = types.str; default = ""; example = "none"; description = "Default desktop manager loaded if none have been chosen."; apply = defaultDM: if defaultDM == "" && cfg.session.list != [] then (head cfg.session.list).name else if any (w: w.name == defaultDM) cfg.session.list then defaultDM else throw '' Default desktop manager (${defaultDM}) not found. Probably you want to change services.xserver.desktopManager.default = "${defaultDM}"; to one of ${concatMapStringsSep "\n " (w: "services.xserver.desktopManager.default = \"${w.name}\";") cfg.session.list} ''; }; }; }; config = { services.xserver.displayManager.session = cfg.session.list; environment.systemPackages = mkIf cfg.session.needBGPackages [ pkgs.feh ]; }; }