Add theming support

hosts/configuration.nix

@@ -38,6 +38,11 @@
   #   xkbVariant = "";
   # };
 
+  environment.defaultCursor = {
+    enable = true;
+    theme = "breeze_cursors";
+  };
+
   time.timeZone = "Europe/Berlin";
   i18n = {
     defaultLocale = "en_US.UTF-8";

modules/theming/cursor.nix

@@ -0,0 +1,44 @@
+# Module to set a default cursor theme
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+with lib; let
+  cfg = config.environment.defaultCursor;
+
+  indexThemeText = theme: generators.toINI {} {"icon theme" = {Inherits = "${theme}";};};
+
+  mkDefaultCursorFile = theme:
+    pkgs.writeTextDir
+    "share/icons/default/index.theme"
+    "${indexThemeText theme}";
+
+  defaultCursorPkg = mkDefaultCursorFile cfg.theme;
+in {
+  options = {
+    environment.defaultCursor = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Whether to set a default cursor theme for graphical environments.
+        '';
+      };
+
+      theme = mkOption {
+        type = types.str;
+        default = "";
+        example = "Adwaita";
+        description = "The name of the defualt cursor theme.";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    environment.systemPackages = [
+      defaultCursorPkg
+    ];
+  };
+}

modules/theming/default.nix

@@ -0,0 +1,5 @@
+[
+  # ./gtk.nix
+  # ./qt.nix
+  ./cursor.nix
+]

modules/theming/gtk.nix

@@ -0,0 +1,20 @@
+{
+  config,
+  lib,
+  pkgs,
+  vars,
+  ...
+}: {
+  home-manager.users.${vars.user} = {
+    gtk.enable = true;
+
+    # gtk.cursorTheme.package = pkgs.bibata-cursors;
+    # gtk.cursorTheme.name = "Bibata-Modern-Ice";
+
+    gtk.theme.package = pkgs.adw-gtk3;
+    gtk.theme.name = "adw-gtk3";
+
+    # gtk.iconTheme.package = gruvboxPlus;
+    # gtk.iconTheme.name = "GruvboxPlus";
+  };
+}

modules/theming/qt.nix

@@ -0,0 +1,31 @@
+{
+  config,
+  lib,
+  pkgs,
+  vars,
+  ...
+}: {
+  environment.systemPackages = with pkgs; [
+    libsForQt5.qtstyleplugins
+    libsForQt5.qtstyleplugin-kvantum
+    #other stuff
+  ];
+  home-manager.users.${vars.user} = {
+    qt.enable = true;
+
+    # platform theme "gtk" or "gnome"
+    qt.platformTheme = "gtk";
+
+    # name of the qt theme
+    qt.style.name = "adwaita";
+
+    # detected automatically:
+    # adwaita, adwaita-dark, adwaita-highcontrast,
+    # adwaita-highcontrastinverse, breeze,
+    # bb10bright, bb10dark, cde, cleanlooks,
+    # gtk2, motif, plastique
+
+    # package to use
+    qt.style.package = pkgs.adwaita-qt;
+  };
+}