Expo.java

package it.sephiroth.android.library.easing;

public class Expo implements Easing {

    @Override
    public double easeOut(double time, double start, double end, double duration) {
        return (time == duration) ? start + end : end * (-Math.pow(2.0, -10.0 * time / duration) + 1) + start;
    }

    @Override
    public double easeIn(double time, double start, double end, double duration) {
        return (time == 0) ? start : end * Math.pow(2.0, 10.0 * (time / duration - 1.0)) + start;
    }

    @Override
    public double easeInOut(double time, double start, double end, double duration) {
        if (time == 0) return start;
        if (time == duration) return start + end;
        if ((time /= duration / 2.0) < 1.0)
            return end / 2.0 * Math.pow(2.0, 10.0 * (time - 1.0)) + start;
        return end / 2.0 * (-Math.pow(2.0, -10.0 * --time) + 2.0) + start;
    }

}