2 * Copyright (C) 2014 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 package com.android.internal.view.animation;
19 import android.animation.TimeInterpolator;
20 import android.util.TimeUtils;
21 import android.view.Choreographer;
24 * Interpolator that builds a lookup table to use. This is a fallback for
25 * building a native interpolator from a TimeInterpolator that is not marked
26 * with {@link HasNativeInterpolator}
28 * This implements TimeInterpolator to allow for easier interop with Animators
30 @HasNativeInterpolator
31 public class FallbackLUTInterpolator implements NativeInterpolatorFactory, TimeInterpolator {
33 private TimeInterpolator mSourceInterpolator;
34 private final float mLut[];
37 * Used to cache the float[] LUT for use across multiple native
38 * interpolator creation
40 public FallbackLUTInterpolator(TimeInterpolator interpolator, long duration) {
41 mSourceInterpolator = interpolator;
42 mLut = createLUT(interpolator, duration);
45 private static float[] createLUT(TimeInterpolator interpolator, long duration) {
46 long frameIntervalNanos = Choreographer.getInstance().getFrameIntervalNanos();
47 int animIntervalMs = (int) (frameIntervalNanos / TimeUtils.NANOS_PER_MS);
48 // We need 2 frame values as the minimal.
49 int numAnimFrames = Math.max(2, (int) Math.ceil(((double) duration) / animIntervalMs));
50 float values[] = new float[numAnimFrames];
51 float lastFrame = numAnimFrames - 1;
52 for (int i = 0; i < numAnimFrames; i++) {
53 float inValue = i / lastFrame;
54 values[i] = interpolator.getInterpolation(inValue);
60 public long createNativeInterpolator() {
61 return NativeInterpolatorFactoryHelper.createLutInterpolator(mLut);
65 * Used to create a one-shot float[] LUT & native interpolator
67 public static long createNativeInterpolator(TimeInterpolator interpolator, long duration) {
68 float[] lut = createLUT(interpolator, duration);
69 return NativeInterpolatorFactoryHelper.createLutInterpolator(lut);
73 public float getInterpolation(float input) {
74 return mSourceInterpolator.getInterpolation(input);