more rice stuff

modules/home-manager/wallpaper.nix

@@ -0,0 +1,26 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.my.wallpapers;
+  args = lib.concatStringsSep " " (lib.mapAttrsToList
+    (monitor: img: "--output ${monitor} --zoom ${lib.escapeShellArg img}") cfg);
+in
+{
+  options.my.wallpapers = lib.mkOption {
+    type = lib.types.attrsOf lib.types.path;
+    default = { };
+    description = "Wallpaper image per monitor output name.";
+  };
+
+  config = lib.mkIf (cfg != { }) {
+    home.packages = [ pkgs.xwallpaper ];
+
+    xdg.configFile."wallpaper/set.sh" = {
+      executable = true;
+      text = ''
+        #!/bin/sh
+        ${pkgs.xwallpaper}/bin/xwallpaper ${args}
+      '';
+    };
+  };
+}