title: IKImage Gesture zoom rotate
body: <p>In my application I use IKImageview to preview a image,and by default it supports two finger gestures like moving up,down,left,right.
  Now I want to add rotate and zoom gestures to it ,does anyone has any good ideas?
  Thank you very much.</p>
  
  <p>does anyone know how to subclass IKImageview to support zoom gesture?</p>