How to recognise a specific gesture

Please bear with me because my query is difficult to explain.

Is it possible to recognise a specific touch action or gesture on the iPad and then raise an event when this action occurs?

Imagine the user wrote the letter 'i' on the touch screen. So that would involve first recognising that the user tapped the screen once (for the dot on the 'i') and then a second time for the rest of the letter 'i').

Do you think this is at all possible? From my beginner knowledge I believe it is possible if you store 2 different sets and then compare it roughly to some constant开发者_如何学JAVA value.

Any ideas?

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You should take a look at UIGestureRecognizer.