stylix: add config.lib.stylix.{mkHexColor,mkOpacityHexColor} functions

Co-authored-by: NAHO <90870942+trueNAHO@users.noreply.github.com>

doc/src/modules.md

@@ -182,6 +182,15 @@ individually.
 Also note that reading generated files with `builtins.readFile` can be very slow
 and should be avoided.
 
+
+### Hexadecimal colors
+
+- config.lib.stylix.mkHexColor`: Converts a hex `color` (e.g., `RRGGBB` or
+  `#RRGGBB`) to `0xRRGGBB`.
+
+- `config.lib.stylix.mkOpacityHexColor`: Converts a hex `color` and `opacity`
+  (0–1) to `0xRRGGBBAA`.
+
 ## How to apply other things
 
 For everything else, like fonts and wallpapers, you can just take option values

stylix/colors.nix

@@ -0,0 +1,16 @@
+{ lib, ... }:
+{
+  config.lib.stylix = {
+    mkHexColor = color: "0x${lib.removePrefix "#" color}";
+
+    mkOpacityHexColor =
+      let
+        opacityHex =
+          percentage:
+          lib.throwIfNot (percentage >= 0 && percentage <= 1)
+            "value must be between 0 and 1 (inclusive): ${toString percentage}"
+            (lib.toHexString (builtins.floor (percentage * 255 + 0.5)));
+      in
+      color: opacity: "0x${opacityHex opacity}${lib.removePrefix "#" color}";
+  };
+}

stylix/darwin/default.nix

@@ -9,6 +9,7 @@ in
 {
   imports = [
     ./palette.nix
+    ../colors.nix
     ../fonts.nix
     ../home-manager-integration.nix
     ../opacity.nix

stylix/droid/default.nix

@@ -6,6 +6,7 @@ in
   imports = [
     ./fonts.nix
     ./palette.nix
+    ../colors.nix
     ../fonts.nix
     ../home-manager-integration.nix
     ../opacity.nix

stylix/hm/default.nix

@@ -11,6 +11,7 @@ in
     ./cursor.nix
     ./icons.nix
     ./palette.nix
+    ../colors.nix
     ../cursor.nix
     ../fonts.nix
     ../icons.nix

stylix/nixos/default.nix

@@ -10,6 +10,7 @@ in
   imports = [
     ./cursor.nix
     ./palette.nix
+    ../colors.nix
     ../cursor.nix
     ../fonts.nix
     ../home-manager-integration.nix