From 4e94d2d0b4acbf30d780aae6d0d46b4923853f2c Mon Sep 17 00:00:00 2001
From: James O'Leary <jamesoleary@google.com>
Date: Wed, 28 Apr 2021 15:44:14 -0400
Subject: [PATCH] Connect ColorStateList to CAM

ColorStateList recently added an attribute, lStar, that means the
color should have its perceptual luminance adjusted.

The color appearance model library transforms the given color to one
with the desired luminance.

Test: added new test to ColorStateListTest, ran atest locally,
tests passed. (no link, atest/my build is broken, can't upload results)
Bug: 186640057
Change-Id: I5252b7c03d76ec1f0a7ca97cd671e8ea63d4b88b
---
 .../android/content/res/ColorStateList.java   |  6 +++---
 .../coretests/res/color/color_with_lstar.xml  | 20 +++++++++++++++++++
 core/tests/coretests/res/values/colors.xml    |  1 +
 .../android/graphics/ColorStateListTest.java  |  6 ++++++
 4 files changed, 30 insertions(+), 3 deletions(-)
 create mode 100644 core/tests/coretests/res/color/color_with_lstar.xml

diff --git a/core/java/android/content/res/ColorStateList.java b/core/java/android/content/res/ColorStateList.java
index 45b956bd7c5d4..5b727cc47d47e 100644
--- a/core/java/android/content/res/ColorStateList.java
+++ b/core/java/android/content/res/ColorStateList.java
@@ -35,6 +35,7 @@ import android.util.Xml;
 
 import com.android.internal.R;
 import com.android.internal.graphics.ColorUtils;
+import com.android.internal.graphics.cam.Cam;
 import com.android.internal.util.ArrayUtils;
 import com.android.internal.util.GrowingArrayUtils;
 
@@ -555,9 +556,8 @@ public class ColorStateList extends ComplexColor implements Parcelable {
         final int alpha = MathUtils.constrain((int) (baseAlpha * alphaMod + 0.5f), 0, 255);
 
         if (validLStar) {
-            final double[] labColor = new double[3];
-            ColorUtils.colorToLAB(baseColor, labColor);
-            baseColor = ColorUtils.LABToColor(lStar, labColor[1], labColor[2]);
+            final Cam baseCam = ColorUtils.colorToCAM(baseColor);
+            baseColor = ColorUtils.CAMToColor(baseCam.getHue(), baseCam.getChroma(), lStar);
         }
 
         return (baseColor & 0xFFFFFF) | (alpha << 24);
diff --git a/core/tests/coretests/res/color/color_with_lstar.xml b/core/tests/coretests/res/color/color_with_lstar.xml
new file mode 100644
index 0000000000000..dcc3d6db1b0a5
--- /dev/null
+++ b/core/tests/coretests/res/color/color_with_lstar.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright (C) 2021 The Android Open Source Project
+  ~
+  ~ Licensed under the Apache License, Version 2.0 (the "License");
+  ~ you may not use this file except in compliance with the License.
+  ~ You may obtain a copy of the License at
+  ~
+  ~      http://www.apache.org/licenses/LICENSE-2.0
+  ~
+  ~ Unless required by applicable law or agreed to in writing, software
+  ~ distributed under the License is distributed on an "AS IS" BASIS,
+  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  ~ See the License for the specific language governing permissions and
+  ~ limitations under the License.
+  -->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:color="#ff0000" android:lStar="50" />
+</selector>
diff --git a/core/tests/coretests/res/values/colors.xml b/core/tests/coretests/res/values/colors.xml
index f01af8421515a..029aa0dd8eb68 100644
--- a/core/tests/coretests/res/values/colors.xml
+++ b/core/tests/coretests/res/values/colors.xml
@@ -25,5 +25,6 @@
     <drawable name="yellow">#ffffff00</drawable>
     <color name="testcolor1">#ff00ff00</color>
     <color name="testcolor2">#ffff0000</color>
+    <color name="testcolor3">#fff00000</color>
     <color name="failColor">#ff0000ff</color>
 </resources>
diff --git a/core/tests/coretests/src/android/graphics/ColorStateListTest.java b/core/tests/coretests/src/android/graphics/ColorStateListTest.java
index 1d34f93838181..a3d52eab16828 100644
--- a/core/tests/coretests/src/android/graphics/ColorStateListTest.java
+++ b/core/tests/coretests/src/android/graphics/ColorStateListTest.java
@@ -67,4 +67,10 @@ public class ColorStateListTest extends AndroidTestCase {
         int defaultColor = mResources.getColor(R.color.color_no_default);
         assertEquals(mResources.getColor(R.color.testcolor1), defaultColor);
     }
+
+    @SmallTest
+    public void testLstar() throws Exception {
+        int defaultColor = mResources.getColor(R.color.color_with_lstar);
+        assertEquals(mResources.getColor(R.color.testcolor3), defaultColor);
+    }
 }