Add theme configuration (gtk,qt,cursor)

home/themes/cursor.nix

@@ -0,0 +1,16 @@
+{
+  osConfig,
+  ...
+}: let
+  cfg = osConfig.myOptions.home-manager.theme.cursor;
+in {
+  home = {
+    pointerCursor = {
+      package = cfg.package;
+      name = cfg.name;
+      size = cfg.size;
+      gtk.enable = true;
+      x11.enable = true;
+    };
+  };
+}

home/themes/default.nix

@@ -0,0 +1,7 @@
+{
+  imports = [
+    ./gtk.nix
+    ./qt.nix
+    ./cursor.nix
+  ];
+}

home/themes/gtk.nix

@@ -0,0 +1,80 @@
+{
+  osConfig,
+  config,
+  pkgs,
+  lib,
+  ...
+}: let
+  cfg = osConfig.myOptions.home-manager.theme.gtk;
+in {
+  home = {
+    packages = with pkgs; [
+      glib # gsettings
+      cfg.theme.package
+      cfg.iconTheme.package
+    ];
+
+    sessionVariables = {
+      # set GTK theme to the name specified by the gtk theme package
+      GTK_THEME = "${cfg.theme.name}";
+
+      # gtk applications should use filepickers specified by xdg
+      GTK_USE_PORTAL = "${toString (if cfg.usePortal then 1 else 0)}";
+    };
+  };
+
+  gtk = {
+    enable = true;
+
+    theme = {
+      name = cfg.theme.name;
+      package = cfg.theme.package;
+    };
+
+    iconTheme = {
+      name = cfg.iconTheme.name;
+      package = cfg.iconTheme.package;
+    };
+
+    font = {
+      name = cfg.font.name;
+      size = cfg.font.size;
+    };
+
+    gtk2 = {
+      configLocation = "${config.xdg.configHome}/gtk-2.0/gtkrc";
+      extraConfig = ''
+        gtk-xft-antialias=1
+        gtk-xft-hinting=1
+        gtk-xft-hintstyle="hintslight"
+        gtk-xft-rgba="rgb"
+      '';
+    };
+
+    gtk3.extraConfig = {
+      gtk-toolbar-style = "GTK_TOOLBAR_BOTH";
+      gtk-toolbar-icon-size = "GTK_ICON_SIZE_LARGE_TOOLBAR";
+      gtk-decoration-layout = "appmenu:none";
+      gtk-button-images = 1;
+      gtk-menu-images = 1;
+      gtk-enable-event-sounds = 0;
+      gtk-enable-input-feedback-sounds = 0;
+      gtk-xft-antialias = 1;
+      gtk-xft-hinting = 1;
+      gtk-xft-hintstyle = "hintslight";
+      gtk-error-bell = 0;
+      gtk-application-prefer-dark-theme = true;
+    };
+
+    gtk4.extraConfig = {
+      gtk-decoration-layout = "appmenu:none";
+      gtk-enable-event-sounds = 0;
+      gtk-enable-input-feedback-sounds = 0;
+      gtk-xft-antialias = 1;
+      gtk-xft-hinting = 1;
+      gtk-xft-hintstyle = "hintslight";
+      gtk-error-bell = 0;
+      gtk-application-prefer-dark-theme = true;
+    };
+  };
+}

home/themes/qt.nix

@@ -0,0 +1,57 @@
+{
+  pkgs,
+  lib,
+  osConfig,
+  ...
+}: let
+  inherit (lib) mkIf mkMerge;
+
+  cfg = osConfig.myOptions.home-manager.theme.qt;
+in {
+  qt = {
+    enable = true;
+    platformTheme.name = mkIf cfg.forceGtk "gtk";  # just an override for QT_QPA_PLATFORMTHEME, takes "gtk", "gnome", "qtct" or "kde"
+    style = mkIf (!cfg.forceGtk) {
+      name = cfg.theme.name;
+      package = cfg.theme.package;
+    };
+  };
+
+  home = {
+    packages = with pkgs;
+      mkMerge [
+        [
+          # libraries and programs to ensure that qt applications load without issue
+          # breeze-icons is added as a fallback
+          libsForQt5.qt5ct
+          kdePackages.qt6ct
+          breeze-icons
+        ]
+
+        (mkIf cfg.forceGtk [
+          # libraries to ensure that "gtk" platform theme works
+          # as intended after the following PR:
+          # <https://github.com/nix-community/home-manager/pull/5156>
+          libsForQt5.qtstyleplugins
+          qt6Packages.qt6gtk2
+        ])
+      ];
+
+    sessionVariables = {
+      # scaling - 1 means no scaling
+      QT_AUTO_SCREEN_SCALE_FACTOR = "1";
+
+      # use wayland as the default backend, fallback to xcb if wayland is not available
+      QT_QPA_PLATFORM = "wayland;xcb";
+
+      # disable window decorations everywhere
+      QT_WAYLAND_DISABLE_WINDOWDECORATION = "1";
+
+      # remain backwards compatible with qt5
+      DISABLE_QT5_COMPAT = "0";
+
+      # tell calibre to use the dark theme, because the light one hurts my eyes
+      CALIBRE_USE_DARK_PALETTE = "1";
+    };
+  };
+}