From 1f513a97f7a9e4baf9805c091a592e385294b43b Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Thu, 24 Nov 2011 16:46:23 +0100
Subject: [PATCH 1/4] Add contrast function

---
 lib/less/functions.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lib/less/functions.js b/lib/less/functions.js
index 96dcc8c4c..2406eb514 100644
--- a/lib/less/functions.js
+++ b/lib/less/functions.js
@@ -124,6 +124,14 @@ tree.functions = {
     greyscale: function (color) {
         return this.desaturate(color, new(tree.Dimension)(100));
     },
+    contrast: function (color) {
+        var hsl = color.toHSL();
+        if (hsl.l > 0.5) {
+            return this.rgba(0, 0, 0, 1.0);
+        } else {
+            return this.rgba(255, 255, 255, 1.0);
+        }
+    },
     e: function (str) {
         return new(tree.Anonymous)(str instanceof tree.JavaScript ? str.evaluated : str);
     },

From 4a081ad6fb358ac17f62ebe55e85c094bda49942 Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Thu, 24 Nov 2011 23:14:15 +0100
Subject: [PATCH 2/4] Add LESS tests for contrast

---
 test/less/functions.less | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/less/functions.less b/test/less/functions.less
index 1af78bc80..d37e47537 100644
--- a/test/less/functions.less
+++ b/test/less/functions.less
@@ -17,6 +17,8 @@
   greyscale: greyscale(#203c31);
   spin-p: spin(hsl(340, 50%, 50%), 40);
   spin-n: spin(hsl(30, 50%, 50%), -40);
+  contrast-white: contrast(#fff);
+  contrast-black: contrast(#000);
   format: %("rgb(%d, %d, %d)", @r, 128, 64);
   format-string: %("hello %s", "world");
   format-multiple: %("hello %s %d", "earth", 2);

From 5f593b5857dc533985681327f96e7891b58fed3b Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Thu, 24 Nov 2011 23:16:12 +0100
Subject: [PATCH 3/4] Add CSS test results for contrast

---
 test/css/functions.css | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/test/css/functions.css b/test/css/functions.css
index f33b9869b..1024dff98 100644
--- a/test/css/functions.css
+++ b/test/css/functions.css
@@ -14,6 +14,8 @@
   greyscale: #2e2e2e;
   spin-p: #bf6a40;
   spin-n: #bf4055;
+  contrast-white: #000000;
+  contrast-black: #ffffff;
   format: "rgb(32, 128, 64)";
   format-string: "hello world";
   format-multiple: "hello earth 2";

From 32e41896a6c4a303d0608a9f87279d2e7b160559 Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Tue, 10 Jan 2012 23:49:13 +0100
Subject: [PATCH 4/4] Add optional light and dark parameters

Merged latest from upstream and updated tests too, all pass.
---
 lib/less/functions.js    | 18 +++++++++++++-----
 test/css/functions.css   |  2 ++
 test/less/functions.less |  2 ++
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/lib/less/functions.js b/lib/less/functions.js
index 83175378e..98a4517f5 100644
--- a/lib/less/functions.js
+++ b/lib/less/functions.js
@@ -124,12 +124,20 @@ tree.functions = {
     greyscale: function (color) {
         return this.desaturate(color, new(tree.Dimension)(100));
     },
-    contrast: function (color) {
+    contrast: function (color, light, dark) {
         var hsl = color.toHSL();
-        if (hsl.l > 0.5) {
-            return this.rgba(0, 0, 0, 1.0);
-        } else {
-            return this.rgba(255, 255, 255, 1.0);
+        if (arguments.length == 1) {
+            if (hsl.l > 0.5) {
+                return this.rgba(0, 0, 0, 1.0);
+            } else {
+                return this.rgba(255, 255, 255, 1.0);
+            }
+        } else if (arguments.length == 3) {
+            if (hsl.l > 0.5) {
+                return dark;
+            } else {
+                return light;
+            }
         }
     },
     e: function (str) {
diff --git a/test/css/functions.css b/test/css/functions.css
index 1a92bef63..1d3873746 100644
--- a/test/css/functions.css
+++ b/test/css/functions.css
@@ -16,6 +16,8 @@
   spin-n: #bf4055;
   contrast-white: #000000;
   contrast-black: #ffffff;
+  contrast-light: #111111;
+  contrast-dark: #eeeeee;
   format: "rgb(32, 128, 64)";
   format-string: "hello world";
   format-multiple: "hello earth 2";
diff --git a/test/less/functions.less b/test/less/functions.less
index 0ad85374c..097adcf70 100644
--- a/test/less/functions.less
+++ b/test/less/functions.less
@@ -19,6 +19,8 @@
   spin-n: spin(hsl(30, 50%, 50%), -40);
   contrast-white: contrast(#fff);
   contrast-black: contrast(#000);
+  contrast-light: contrast(#fff, #eeeeee, #111111);
+  contrast-dark: contrast(#000, #eeeeee, #111111);
   format: %("rgb(%d, %d, %d)", @r, 128, 64);
   format-string: %("hello %s", "world");
   format-multiple: %("hello %s %d", "earth", 2);