81 lines
3.0 KiB
Java
81 lines
3.0 KiB
Java
/*
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* Copyright (C) 2014 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package android.graphics.animation;
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import android.animation.TimeInterpolator;
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import android.util.TimeUtils;
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import android.view.Choreographer;
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/**
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* Interpolator that builds a lookup table to use. This is a fallback for
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* building a native interpolator from a TimeInterpolator that is not marked
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* with {@link HasNativeInterpolator}
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*
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* This implements TimeInterpolator to allow for easier interop with Animators
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* @hide
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*/
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@HasNativeInterpolator
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public class FallbackLUTInterpolator implements NativeInterpolator, TimeInterpolator {
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// If the duration of an animation is more than 300 frames, we cap the sample size to 300.
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private static final int MAX_SAMPLE_POINTS = 300;
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private TimeInterpolator mSourceInterpolator;
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private final float[] mLut;
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/**
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* Used to cache the float[] LUT for use across multiple native
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* interpolator creation
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*/
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public FallbackLUTInterpolator(TimeInterpolator interpolator, long duration) {
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mSourceInterpolator = interpolator;
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mLut = createLUT(interpolator, duration);
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}
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private static float[] createLUT(TimeInterpolator interpolator, long duration) {
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long frameIntervalNanos = Choreographer.getInstance().getFrameIntervalNanos();
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int animIntervalMs = (int) (frameIntervalNanos / TimeUtils.NANOS_PER_MS);
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// We need 2 frame values as the minimal.
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int numAnimFrames = Math.max(2, (int) Math.ceil(((double) duration) / animIntervalMs));
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numAnimFrames = Math.min(numAnimFrames, MAX_SAMPLE_POINTS);
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float[] values = new float[numAnimFrames];
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float lastFrame = numAnimFrames - 1;
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for (int i = 0; i < numAnimFrames; i++) {
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float inValue = i / lastFrame;
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values[i] = interpolator.getInterpolation(inValue);
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}
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return values;
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}
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@Override
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public long createNativeInterpolator() {
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return NativeInterpolatorFactory.createLutInterpolator(mLut);
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}
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/**
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* Used to create a one-shot float[] LUT & native interpolator
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*/
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public static long createNativeInterpolator(TimeInterpolator interpolator, long duration) {
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float[] lut = createLUT(interpolator, duration);
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return NativeInterpolatorFactory.createLutInterpolator(lut);
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}
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@Override
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public float getInterpolation(float input) {
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return mSourceInterpolator.getInterpolation(input);
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}
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}
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