28 lines
838 B
Java
28 lines
838 B
Java
package com.aoleyun.os;
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import android.animation.TimeInterpolator;
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public class LogAccelerateInterpolator implements TimeInterpolator {
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int mBase;
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int mDrift;
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final float mLogScale;
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public LogAccelerateInterpolator(int base, int drift) {
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mBase = base;
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mDrift = drift;
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mLogScale = 1f / computeLog(1, mBase, mDrift);
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}
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static float computeLog(float t, int base, int drift) {
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return (float) -Math.pow(base, -t) + 1 + (drift * t);
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}
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@Override
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public float getInterpolation(float t) {
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// Due to rounding issues, the interpolation doesn't quite reach 1 even though it should.
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// To account for this, we short-circuit to return 1 if the input is 1.
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return Float.compare(t, 1f) == 0 ? 1f : 1 - computeLog(1 - t, mBase, mDrift) * mLogScale;
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}
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}
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