1 /* 2 * Copyright (C) 2014 The Android Open Source Project 3 * 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 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 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. 15 */ 16 17 package com.android.internal.view.animation; 18 19 import android.animation.TimeInterpolator; 20 import android.util.TimeUtils; 21 import android.view.Choreographer; 22 23 /** 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} 27 * 28 * This implements TimeInterpolator to allow for easier interop with Animators 29 */ 30 @HasNativeInterpolator 31 public class FallbackLUTInterpolator implements NativeInterpolatorFactory, TimeInterpolator { 32 33 private TimeInterpolator mSourceInterpolator; 34 private final float mLut[]; 35 36 /** 37 * Used to cache the float[] LUT for use across multiple native 38 * interpolator creation 39 */ 40 public FallbackLUTInterpolator(TimeInterpolator interpolator, long duration) { 41 mSourceInterpolator = interpolator; 42 mLut = createLUT(interpolator, duration); 43 } 44 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 int numAnimFrames = (int) Math.ceil(duration / animIntervalMs); 49 float values[] = new float[numAnimFrames]; 50 float lastFrame = numAnimFrames - 1; 51 for (int i = 0; i < numAnimFrames; i++) { 52 float inValue = i / lastFrame; 53 values[i] = interpolator.getInterpolation(inValue); 54 } 55 return values; 56 } 57 58 @Override 59 public long createNativeInterpolator() { 60 return NativeInterpolatorFactoryHelper.createLutInterpolator(mLut); 61 } 62 63 /** 64 * Used to create a one-shot float[] LUT & native interpolator 65 */ 66 public static long createNativeInterpolator(TimeInterpolator interpolator, long duration) { 67 float[] lut = createLUT(interpolator, duration); 68 return NativeInterpolatorFactoryHelper.createLutInterpolator(lut); 69 } 70 71 @Override 72 public float getInterpolation(float input) { 73 return mSourceInterpolator.getInterpolation(input); 74 } 75 } 76
