Quart.java

package it.sephiroth.android.library.easing;

public class Quart implements Easing {

    @Override
    public double easeOut(double t, double b, double c, double d) {
        return -c * ((t = t / d - 1) * t * t * t - 1) + b;
    }

    @Override
    public double easeIn(double t, double b, double c, double d) {
        return c * (t /= d) * t * t * t + b;
    }

    @Override
    public double easeInOut(double t, double b, double c, double d) {
        if ((t /= d / 2) < 1) return c / 2 * t * t * t * t + b;
        return -c / 2 * ((t -= 2) * t * t * t - 2) + b;
    }

}