Android animation interpolator: bounceInterpolator

Android animation interpolator: bounceInterpolator

Bounce Interpolator
8 * (1.1226t)^2               for t<0.31489
8 * (1.1226t–0.54719)^2 + 0.7 for 0.31489≤t<0.65990
8 * (1.1226t–0.8526)^2 + 0.9  for 0.65990≤t<0.85908
8 * (1.1226t–1.0435)^2 + 0.95  for 0.85908≤t

bunce

 

Demo:

 

 

Source:


@HasNativeInterpolator
public class BounceInterpolator extends BaseInterpolator implements NativeInterpolatorFactory {
    public BounceInterpolator() {
    }

    @SuppressWarnings({"UnusedDeclaration"})
    public BounceInterpolator(Context context, AttributeSet attrs) {
    }

    private static float bounce(float t) {
        return t * t * 8.0f;
    }

    public float getInterpolation(float t) {
        // _b(t) = t * t * 8
        // bs(t) = _b(t) for t < 0.3535
        // bs(t) = _b(t - 0.54719) + 0.7 for t < 0.7408
        // bs(t) = _b(t - 0.8526) + 0.9 for t < 0.9644
        // bs(t) = _b(t - 1.0435) + 0.95 for t <= 1.0
        // b(t) = bs(t * 1.1226)
        t *= 1.1226f;
        if (t < 0.3535f) return bounce(t);
        else if (t < 0.7408f) return bounce(t - 0.54719f) + 0.7f;
        else if (t < 0.9644f) return bounce(t - 0.8526f) + 0.9f;
        else return bounce(t - 1.0435f) + 0.95f;
    }

    /** @hide */
    @Override
    public long createNativeInterpolator() {
        return NativeInterpolatorFactoryHelper.createBounceInterpolator();
    }
}