title: How to cancel a sequence of UITouch events?
body: <p>I have a <code>UIImage</code> view that responds to touch events. I want to cancel the touch sequence, i.e., further calls to <code>touchesMoved:</code>, if the touch goes outside of certain bounds. How can I do that?</p>
  
  <p>I know that in <code>touchesMoved:</code> I can inspect the coordinates of the touch object and ignore it, but what I don't know is how to cancel the sequence altogether. I don't see any method documented in the <a href="http://developer.apple.com/library/ios/#documentation/uikit/reference/UIResponder_Class/Reference/Reference.html" rel="noreferrer">Apple Developer <code>UIResponder</code> Reference</a> that I can call to cancel a touch sequence.</p>