title: iOS rotate view around an anchor point and follow touch
body: <p>I need to create a circular rating meter in iOS, it's like a UISlider only curved 3/4 around a circle. I need to rotate a UIImageView (which is the rating needle) around an anchor point, by dragging an invisible touchable handle area the will follow the tip of the needle. The angle of the needle will determine a value. </p>
  
  <p>I am struggling to find an elegant solution. Any thoughts?</p>