private int getFlipDuration(int deltaFlipDistance) {
        float distance = Math.abs(deltaFlipDistance);
        return (int) (MAX_SINGLE_PAGE_FLIP_ANIM_DURATION * Math.sqrt(distance
                / FLIP_DISTANCE_PER_PAGE));
    }
@param deltaFlipDistance The distance to flip.
@return The duration for a flip, bigger deltaFlipDistance = longer
duration. The increase if duration gets smaller for bigger values
of deltaFlipDistance.
app/src/main/java/home/smart/fly/animations/customview/flipview/FlipView.java