通过CGMutablePathRef动画在drawRect中绘制的框

my aim is to drow an empty rounded box, that should appear as a hole, onto my UIView to show what's under. I made this by overriding drawRect method as shown below. This gives me the ability to create a rounded rect of the size of my holeRect property (which is a CGRect), drop an inner shadow into it and place it on my view, clearing (using my aim is to drow an empty rounded box, that sh