I've implemented pinch-to-zoom in a bunch of different contexts, and I agree that it's easy to do a half-assed version. AFAIK that's not what Apple patented, and you're free to implement half-assed pinch-to-zoom to your heart's content (although you may be infringing an earlier patent).
http://www.theverge.com/2012/8/30/3279628/apple-pinch-to-zoo...
I've implemented pinch-to-zoom in a bunch of different contexts, and I agree that it's easy to do a half-assed version. AFAIK that's not what Apple patented, and you're free to implement half-assed pinch-to-zoom to your heart's content (although you may be infringing an earlier patent).