From 7ba5128423b1437ac0aa59a3a443cd8960b524da Mon Sep 17 00:00:00 2001
From: Natalie Weizenbaum <nweiz@google.com>
Date: Wed, 14 Oct 2020 16:15:46 -0700
Subject: [PATCH] Add color.whiteness() and color.blackness() functions (#1110)

See sass/sass#2834
See #1089
---
 CHANGELOG.md                 | 11 +++++++++++
 lib/src/functions/color.dart | 12 ++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b5162f63..3fcaa0cd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 ## 1.28.0
 
+* Add a [`color.hwb()`] function to `sass:color` that can express colors in [HWB] format.
+
+[`color.hwb()`]: https://sass-lang.com/documentation/modules/color#hwb
+[HWB]: https://en.wikipedia.org/wiki/HWB_color_model
+
+* Add [`color.whiteness()`] and [`color.blackness()`] functions to `sass:color`
+  to get a color's [HWB] whiteness and blackness components.
+
+[`color.whiteness()`]: https://sass-lang.com/documentation/modules/color#whiteness
+[`color.blackness()`]: https://sass-lang.com/documentation/modules/color#blackness
+
 ### Dart API
 
 * Add [HWB] support to the `SassColor` class, including a `SassColor.hwb()`
diff --git a/lib/src/functions/color.dart b/lib/src/functions/color.dart
index faa8ba53..99153fa7 100644
--- a/lib/src/functions/color.dart
+++ b/lib/src/functions/color.dart
@@ -281,6 +281,18 @@ final module = BuiltInModule("color", functions: [
     }
   }),
 
+  _function(
+    "whiteness",
+    r"$color",
+    (arguments) =>
+        SassNumber(arguments.first.assertColor("color").whiteness, "%")),
+
+  _function(
+    "blackness",
+    r"$color",
+    (arguments) =>
+        SassNumber(arguments.first.assertColor("color").blackness, "%")),
+
   // ### Opacity
   _removedColorFunction("opacify", "alpha"),
   _removedColorFunction("fade-in", "alpha"),