title: Scroll view panning prevents pinch gesture?
body: <p>I'm creating an image tiling library for use in a game project, to fit into our existing framework. I'm currently using a UIScrollView (with an empty view) to allow me to hijack the nice physics for panning around with bounce, but I had to implement my own zoom using the pinch gesture recogniser (for reasons I won't get into).</p>
  
  <p>Here's the thing, though - when I'm panning with one finger, adding a second touch and trying to zoom does nothing. I need to be absolutely still before it will allow me to zoom. When the user is panning around the image, my pinch gesture recogniser never fires unless the pan has totally finished.</p>
  
  <p>Does anyone know a way around this, that doesn't involve scrapping the UIScrollView and implementing my own pan as well?</p>
  
  <p>Here's my scrollViewDidScroll function:</p>
  
  <pre><code>- (void)scrollViewDidScroll:(UIScrollView *)scrollView
  {
      viewingBounds.origin.x = scrollView.contentOffset.x;
      // Transform the y from UIKit coordinates into OpenGL coordinates
      viewingBounds.origin.y = world.height - viewingBounds.size.height - scrollView.contentOffset.y;
      [parentScene update]; // Render the image
  }
  </code></pre>
  
  <p>My gesture recogniser is added directly to the scroll view in init:</p>
  
  <pre><code>[scrollView addGestureRecognizer:[[[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(didReceivePinch:)] autorelease]];
  </code></pre>