protected float calcDistance(MotionEvent event) {
		if(event.getPointerCount() <= 1) {
			return 0f;
		}else{
			float x = event.getX(0) - event.getX(1);
			float y = event.getY(0) - event.getY(1);
			return (float) Math.sqrt(x * x + y * y);
		}
	}
<p>en</p>
<p>jp</p>
<p>cn</p>

@author limc 
@version v1.0 2014/06/20 17:33:01
src/src/cn/limc/androidcharts/event/ZoomGestureDetector.java