treewide: make stylix.image optional

.github/workflows/check.yml

@@ -77,7 +77,12 @@ jobs:
       - uses: DeterminateSystems/nix-installer-action@v16
         with:
           extra-conf: |-
-            allow-import-from-derivation = false
+            allow-import-from-derivation = ${{
+              startsWith(matrix.check.key, 'testbed:') &&
+              contains(matrix.check.key, ':schemeless') &&
+              'true' ||
+              'false'
+            }}
 
       - run: |
           nix build --no-update-lock-file --print-build-logs \

docs/src/configuration.md

@@ -16,53 +16,12 @@ To enable the Stylix module, declare:
 > examples which don't include it. No other settings will take effect unless
 > `stylix.enable` is set to `true`.
 
-## Wallpaper
-
-To start theming, you need to set a wallpaper image.
-
-```nix
-{
-  stylix.image = ./wallpaper.png;
-}
-```
-
-The option accepts derivations as well as paths, so you can fetch an image
-directly from the internet:
-
-```nix
-{
-  stylix.image = pkgs.fetchurl {
-    url = "https://www.pixelstalk.net/wp-content/uploads/2016/05/Epic-Anime-Awesome-Wallpapers.jpg";
-    sha256 = "enQo3wqhgf0FEPHj2coOCvo7DuZv+x5rL/WIo4qPI50=";
-  };
-}
-```
-
 ## Color scheme
 
-### Generated schemes
-
-If you only set a wallpaper, Stylix will use a
-[genetic algorithm](https://en.wikipedia.org/wiki/Genetic_algorithm)
-to create a color scheme. The quality of these schemes can vary, but more
-colorful images tend to have better results.
-
-You can force a light or dark scheme using the polarity option:
-
-```nix
-{
-  stylix.polarity = "dark";
-}
-```
-
-The current scheme can be previewed in a web browser at either
-[`/etc/stylix/palette.html`](file:///etc/stylix/palette.html) for NixOS, or
-`~/.config/stylix/palette.html` for Home Manager.
-
 ### Handmade schemes
 
-If you prefer a handmade color scheme, you can choose anything from
-[the Tinted Theming repository](https://github.com/tinted-theming/schemes):
+To set a [Tinted Theming](https://github.com/tinted-theming/schemes) color
+scheme, declare:
 
 ```nix
 {
@@ -116,6 +75,46 @@ For more complex configurations you may find it simpler to use
 See [base16.nix](https://github.com/SenchoPens/base16.nix) documentation for
 usage examples.
 
+## Wallpaper
+
+To set a wallpaper, provide a path or an arbitrary derivation:
+
+- ```nix
+  {
+    stylix.image = ./wallpaper.png;
+  }
+  ```
+
+- ```nix
+  {
+    stylix.image = pkgs.fetchurl {
+      url = "https://www.pixelstalk.net/wp-content/uploads/2016/05/Epic-Anime-Awesome-Wallpapers.jpg";
+      sha256 = "enQo3wqhgf0FEPHj2coOCvo7DuZv+x5rL/WIo4qPI50=";
+    };
+  }
+  ```
+
+If `stylix.base16Scheme` is undeclared, Stylix generates a color scheme based on
+the wallpaper using a [genetic
+algorithm](https://en.wikipedia.org/wiki/Genetic_algorithm). Note that more
+colorful images tend to yield better results. The algorithm's polarity can be
+schewed towards a dark or light theme with:
+
+- ```nix
+  {
+    stylix.polarity = "dark";
+  }
+  ```
+
+- ```nix
+  {
+    stylix.polarity = "light";
+  }
+  ```
+
+The generated color scheme can be viewed at `/etc/stylix/palette.html` on NixOS,
+or at `~/.config/stylix/palette.html` on Home Manager.
+
 ## Fonts
 
 The default combination of fonts is:

modules/feh/hm.nix

@@ -4,16 +4,21 @@
   lib,
   ...
 }:
-
+let
+  cfg = config.stylix.targets.feh;
+in
 {
-  options.stylix.targets.feh.enable =
-    config.lib.stylix.mkEnableTarget "the desktop background using Feh" true;
+  options.stylix.targets.feh = {
+    enable = config.lib.stylix.mkEnableTarget "the desktop background using Feh" (
+      config.stylix.image != null
+    );
+  };
 
   config.xsession.initExtra =
     lib.mkIf
       (
         config.stylix.enable
-        && config.stylix.targets.feh.enable
+        && cfg.enable
         && (
           with config.xsession.windowManager;
           bspwm.enable

modules/feh/nixos.nix

@@ -4,16 +4,21 @@
   lib,
   ...
 }:
-
+let
+  cfg = config.stylix.targets.feh;
+in
 {
-  options.stylix.targets.feh.enable =
-    config.lib.stylix.mkEnableTarget "the desktop background using Feh" true;
+  options.stylix.targets.feh = {
+    enable = config.lib.stylix.mkEnableTarget "the desktop background using Feh" (
+      config.stylix.image != null
+    );
+  };
 
   config.services.xserver.displayManager.sessionCommands =
     lib.mkIf
       (
         config.stylix.enable
-        && config.stylix.targets.feh.enable
+        && cfg.enable
         && (with config.services.xserver.windowManager; xmonad.enable || i3.enable)
       )
       (

modules/gnome/hm.nix

@@ -9,6 +9,7 @@ let
   inherit (config.stylix.fonts) sansSerif serif monospace;
   fontSize = toString config.stylix.fonts.sizes.applications;
   documentFontSize = toString (config.stylix.fonts.sizes.applications - 1);
+  cfg = config.stylix.targets.gnome;
 
   activator = pkgs.writeShellApplication {
     name = "stylix-activate-gnome";
@@ -42,10 +43,12 @@ let
 
 in
 {
-  options.stylix.targets.gnome.enable =
-    config.lib.stylix.mkEnableTarget "GNOME" true;
+  options.stylix.targets.gnome = {
+    enable = config.lib.stylix.mkEnableTarget "GNOME" true;
+    useWallpaper = config.lib.stylix.mkEnableWallpaper "GNOME" true;
+  };
 
-  config = lib.mkIf (config.stylix.enable && config.stylix.targets.gnome.enable) {
+  config = lib.mkIf (config.stylix.enable && cfg.enable) {
     dconf.settings = {
       "org/gnome/desktop/background" = {
         color-shading-type = "solid";
@@ -64,8 +67,8 @@ in
           # Seemingly no tile support... :(
           else
             "zoom";
-        picture-uri = "file://${config.stylix.image}";
-        picture-uri-dark = "file://${config.stylix.image}";
+        picture-uri = lib.mkIf cfg.useWallpaper "file://${config.stylix.image}";
+        picture-uri-dark = lib.mkIf cfg.useWallpaper "file://${config.stylix.image}";
       };
 
       "org/gnome/desktop/interface" = {