Backport Interpolator in PhoneCommon to enable some animation on Kitkat

am: 216bca2e12

* commit '216bca2e12c63b7146d0a8a400658955c1303aa4':
  Backport Interpolator in PhoneCommon to enable some animation on Kitkat

2 files changed, 131 insertions, 4 deletions

diff --git a/src/com/android/phone/common/animation/AnimUtils.java b/src/com/android/phone/common/animation/AnimUtils.java
index 85c5a59..8124b7b 100644
--- a/src/com/android/phone/common/animation/AnimUtils.java
+++ b/src/com/android/phone/common/animation/AnimUtils.java
@@ -22,7 +22,8 @@ import android.animation.ValueAnimator;
 import android.view.View;
 import android.view.ViewPropertyAnimator;
 import android.view.animation.Interpolator;
-import android.view.animation.PathInterpolator;
+
+import com.android.phone.common.compat.PathInterpolatorCompat;
 
 import java.lang.Float;
 
@@ -30,9 +31,12 @@ public class AnimUtils {
     public static final int DEFAULT_DURATION = -1;
     public static final int NO_DELAY = 0;
 
-    public static final Interpolator EASE_IN = new PathInterpolator(0.0f, 0.0f, 0.2f, 1.0f);
-    public static final Interpolator EASE_OUT = new PathInterpolator(0.4f, 0.0f, 1.0f, 1.0f);
-    public static final Interpolator EASE_OUT_EASE_IN = new PathInterpolator(0.4f, 0, 0.2f, 1);
+    public static final Interpolator EASE_IN = PathInterpolatorCompat.create(
+            0.0f, 0.0f, 0.2f, 1.0f);
+    public static final Interpolator EASE_OUT = PathInterpolatorCompat.create(
+            0.4f, 0.0f, 1.0f, 1.0f);
+    public static final Interpolator EASE_OUT_EASE_IN = PathInterpolatorCompat.create(
+            0.4f, 0, 0.2f, 1);
 
     public static class AnimationCallback {
         public void onAnimationEnd() {}
diff --git a/src/com/android/phone/common/compat/PathInterpolatorCompat.java b/src/com/android/phone/common/compat/PathInterpolatorCompat.java
new file mode 100644
index 0000000..7697bf3
--- /dev/null
+++ b/src/com/android/phone/common/compat/PathInterpolatorCompat.java
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2015 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
+ */
+
+package com.android.phone.common.compat;
+
+import android.graphics.Path;
+import android.graphics.PathMeasure;
+import android.view.animation.Interpolator;
+import android.view.animation.PathInterpolator;
+
+import com.android.contacts.common.compat.CompatUtils;
+
+public class PathInterpolatorCompat {
+    public static Interpolator create(float controlX1, float controlY1,
+            float controlX2, float controlY2) {
+        if (CompatUtils.isLollipopCompatible()) {
+            return new PathInterpolator(controlX1, controlY1, controlX2, controlY2);
+        }
+        return new PathInterpolatorBase(controlX1, controlY1, controlX2, controlY2);
+    }
+
+    private static class PathInterpolatorBase implements Interpolator {
+        /**
+         * Governs the accuracy of the approximation of the {@link Path}.
+         */
+        private static final float PRECISION = 0.002f;
+
+        private final float[] mX;
+        private final float[] mY;
+
+        public PathInterpolatorBase(Path path) {
+            final PathMeasure pathMeasure = new PathMeasure(path, false /* forceClosed */);
+
+            final float pathLength = pathMeasure.getLength();
+            final int numPoints = (int) (pathLength / PRECISION) + 1;
+
+            mX = new float[numPoints];
+            mY = new float[numPoints];
+
+            final float[] position = new float[2];
+            for (int i = 0; i < numPoints; ++i) {
+                final float distance = (i * pathLength) / (numPoints - 1);
+                pathMeasure.getPosTan(distance, position, null /* tangent */);
+
+                mX[i] = position[0];
+                mY[i] = position[1];
+            }
+        }
+
+        public PathInterpolatorBase(float controlX, float controlY) {
+            this(createQuad(controlX, controlY));
+        }
+
+        public PathInterpolatorBase(float controlX1, float controlY1,
+                                    float controlX2, float controlY2) {
+            this(createCubic(controlX1, controlY1, controlX2, controlY2));
+        }
+
+        @Override
+        public float getInterpolation(float t) {
+            if (t <= 0.0f) {
+                return 0.0f;
+            } else if (t >= 1.0f) {
+                return 1.0f;
+            }
+
+            // Do a binary search for the correct x to interpolate between.
+            int startIndex = 0;
+            int endIndex = mX.length - 1;
+            while (endIndex - startIndex > 1) {
+                int midIndex = (startIndex + endIndex) / 2;
+                if (t < mX[midIndex]) {
+                    endIndex = midIndex;
+                } else {
+                    startIndex = midIndex;
+                }
+            }
+
+            final float xRange = mX[endIndex] - mX[startIndex];
+            if (xRange == 0) {
+                return mY[startIndex];
+            }
+
+            final float tInRange = t - mX[startIndex];
+            final float fraction = tInRange / xRange;
+
+            final float startY = mY[startIndex];
+            final float endY = mY[endIndex];
+
+            return startY + (fraction * (endY - startY));
+        }
+
+        private static Path createQuad(float controlX, float controlY) {
+            final Path path = new Path();
+            path.moveTo(0.0f, 0.0f);
+            path.quadTo(controlX, controlY, 1.0f, 1.0f);
+            return path;
+        }
+
+        private static Path createCubic(float controlX1, float controlY1,
+                                        float controlX2, float controlY2) {
+            final Path path = new Path();
+            path.moveTo(0.0f, 0.0f);
+            path.cubicTo(controlX1, controlY1, controlX2, controlY2, 1.0f, 1.0f);
+            return path;
+        }
+    }
+
+}
+