modules/home/stylix/default.nix

@@ -17,6 +17,7 @@ let
     "moonfly"
     "nord"
     "oxocarbon"
+    "generate-from-image"
   ];
   # schemes names in `pkgs.base16-schemes` that need a suffix
   needsSuffix = [
@@ -30,11 +31,6 @@ let
   ];
   schemeName =
     if builtins.elem cfg.scheme needsSuffix then "${cfg.scheme}-${cfg.polarity}" else cfg.scheme;
-  scheme =
-    if builtins.elem cfg.scheme customSchemes then
-      ./schemes/${schemeName}.yaml
-    else
-      "${pkgs.base16-schemes}/share/themes/${schemeName}.yaml";
 
   inherit (lib)
     mkDefault
@@ -51,13 +47,13 @@ in
 
   options.stylix = {
     scheme = lib.mkOption {
-      type = types.nullOr types.str;
+      type = types.str;
       default = "dracula";
       description = ''
         Base16 color scheme name. Available options are:
         ${toString validSchemes}
 
-        Set to `null` to generate a color scheme from `stylix.image`
+        "generate-from-image" generates a color scheme from `stylix.image`
       '';
     };
   };
@@ -68,15 +64,16 @@ in
         assertion = builtins.elem cfg.scheme validSchemes;
         message = "Stylix: Invalid colorscheme '${cfg.scheme}'. Available options: ${toString validSchemes}";
       }
-      {
-        assertion = (cfg.scheme != null) || (cfg.image != null);
-        message = "Stylix: You need to set stylix.image if stylix.scheme is `null`";
-      }
     ];
 
     stylix = {
       autoEnable = mkDefault true;
-      base16Scheme = mkIf (cfg.scheme != null) scheme;
+      base16Scheme = mkIf (cfg.scheme != "generate-from-image") (
+        if builtins.elem cfg.scheme customSchemes then
+          ./schemes/${schemeName}.yaml
+        else
+          "${pkgs.base16-schemes}/share/themes/${schemeName}.yaml"
+      );
       fonts = {
         monospace = mkDefault {
           package = pkgs.hack-font;

modules/home/stylix/targets/nixvim.nix

@@ -4,11 +4,13 @@ let
   cfg = config.stylix;
   target = cfg.targets.nixvim;
 
-  inherit (lib) mkIf;
+  inherit (lib) mkIf optionalAttrs;
 in
 {
   config = mkIf cfg.enable {
     stylix.targets.nixvim.enable = false;
-    programs.nixvim.colorschemes."${cfg.scheme}".enable = !target.enable;
+    programs.nixvim.colorschemes = optionalAttrs (cfg.scheme != "generate-from-image") {
+      "${cfg.scheme}".enable = !target.enable;
+    };
   };
 }

tests/build/hm-hyprland/default.nix

@@ -23,6 +23,8 @@
   };
 
   stylix.enable = true;
+  stylix.scheme = "generate-from-image";
+  stylix.image = ./wallpaper.png;
 
   home.stateVersion = "25.11";
 }