diff --git a/api/current.txt b/api/current.txt
index d7fce791085f6..37954fe19a932 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -11276,6 +11276,7 @@ package android.graphics {
     method public static int blue(int);
     method public static void colorToHSV(int, float[]);
     method public static int green(int);
+    method public static float luminance(int);
     method public static int parseColor(java.lang.String);
     method public static int red(int);
     method public static int rgb(int, int, int);
diff --git a/api/system-current.txt b/api/system-current.txt
index ece53276167eb..d19175993d148 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -11613,6 +11613,7 @@ package android.graphics {
     method public static int blue(int);
     method public static void colorToHSV(int, float[]);
     method public static int green(int);
+    method public static float luminance(int);
     method public static int parseColor(java.lang.String);
     method public static int red(int);
     method public static int rgb(int, int, int);
diff --git a/core/java/com/android/internal/policy/PhoneWindow.java b/core/java/com/android/internal/policy/PhoneWindow.java
index 1068b512307dd..cae84732d31f0 100644
--- a/core/java/com/android/internal/policy/PhoneWindow.java
+++ b/core/java/com/android/internal/policy/PhoneWindow.java
@@ -4021,7 +4021,7 @@ public class PhoneWindow extends Window implements MenuBuilder.Callback {
             // dark or the light button frame.
             TypedValue value = new TypedValue();
             getContext().getTheme().resolveAttribute(R.attr.colorPrimary, value, true);
-            if (Color.brightness(value.data) < 0.5) {
+            if (Color.luminance(value.data) < 0.5) {
                 nonClientDecorView = (NonClientDecorView) mLayoutInflater.inflate(
                         R.layout.non_client_decor_dark, null);
             } else {
diff --git a/graphics/java/android/graphics/Color.java b/graphics/java/android/graphics/Color.java
index 23d26eb88108c..80e79f61d236c 100644
--- a/graphics/java/android/graphics/Color.java
+++ b/graphics/java/android/graphics/Color.java
@@ -117,89 +117,21 @@ public class Color {
     }
 
     /**
-     * Returns the hue component of a color int.
-     * 
-     * @return A value between 0.0f and 1.0f
-     * 
-     * @hide Pending API council
-     */
-    public static float hue(@ColorInt int color) {
-        int r = (color >> 16) & 0xFF;
-        int g = (color >> 8) & 0xFF;
-        int b = color & 0xFF;
-
-        int V = Math.max(b, Math.max(r, g));
-        int temp = Math.min(b, Math.min(r, g));
-
-        float H;
-
-        if (V == temp) {
-            H = 0;
-        } else {
-            final float vtemp = (float) (V - temp);
-            final float cr = (V - r) / vtemp;
-            final float cg = (V - g) / vtemp;
-            final float cb = (V - b) / vtemp;
-
-            if (r == V) {
-                H = cb - cg;
-            } else if (g == V) {
-                H = 2 + cr - cb;
-            } else {
-                H = 4 + cg - cr;
-            }
-
-            H /= 6.f;
-            if (H < 0) {
-                H++;
-            }
-        }
-
-        return H;
-    }
-
-    /**
-     * Returns the saturation component of a color int.
-     * 
-     * @return A value between 0.0f and 1.0f
-     * 
-     * @hide Pending API council
-     */
-    public static float saturation(@ColorInt int color) {
-        int r = (color >> 16) & 0xFF;
-        int g = (color >> 8) & 0xFF;
-        int b = color & 0xFF;
-
-
-        int V = Math.max(b, Math.max(r, g));
-        int temp = Math.min(b, Math.min(r, g));
-
-        float S;
-
-        if (V == temp) {
-            S = 0;
-        } else {
-            S = (V - temp) / (float) V;
-        }
-
-        return S;
-    }
-
-    /**
-     * Returns the brightness component of a color int.
+     * Returns the relative luminance of a color.
+     * <p>
+     * Assumes sRGB encoding. Based on the formula for relative luminance
+     * defined in WCAG 2.0, W3C Recommendation 11 December 2008.
      *
-     * @return A value between 0.0f and 1.0f
-     *
-     * @hide Pending API council
+     * @return a value between 0 (darkest black) and 1 (lightest white)
      */
-    public static float brightness(@ColorInt int color) {
-        int r = (color >> 16) & 0xFF;
-        int g = (color >> 8) & 0xFF;
-        int b = color & 0xFF;
-
-        int V = Math.max(b, Math.max(r, g));
-
-        return (V / 255.f);
+    public static float luminance(@ColorInt int color) {
+        double red = Color.red(color) / 255.0;
+        red = red < 0.03928 ? red / 12.92 : Math.pow((red + 0.055) / 1.055, 2.4);
+        double green = Color.green(color) / 255.0;
+        green = green < 0.03928 ? green / 12.92 : Math.pow((green + 0.055) / 1.055, 2.4);
+        double blue = Color.blue(color) / 255.0;
+        blue = blue < 0.03928 ? blue / 12.92 : Math.pow((blue + 0.055) / 1.055, 2.4);
+        return (float) ((0.2126 * red) + (0.7152 * green) + (0.0722 * blue));
     }
 
     /**