its All about Gestures

Gestures are swipe,pan,zoom

Difference between Pan and Swipe

By definition, a swipe gesture is necessarily also a pan gesture -- both involve translational movement of touch points. The difference is in the recognizer semantics: a pan recognizer looks for the beginning of translational movement and continues to report movement in any direction over time, while a swipe recognizer makes an instantaneous decision as to whether the user's touches moved linearly in the required direction.

By default, no two recognizers will recognize the same gesture, so there's a conflict between pan and swipe. Most likely, your pan recognizer "wins" the conflict because its gesture is simpler / more general: A swipe is a pan but a pan may not be a swipe, so the pan recognizes first and excludes other recognizers.

You should be able to resolve this conflict using the delegate methodgestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:, or perhaps without delegation by making the pan recognizer depend on the swipe recognizer withrequireGestureRecognizerToFail:.

With the conflict resolved, you should be able to simulate a one-finger swipe by quickly dragging the mouse. (Though as the mouse is more precise than your finger, it's a bit more finicky than doing the real thing on a device.) Two-finger pan/swipe can be done by holding the Option & Shift keys.

Pinch and Rotate

Just like we could get the translation from the pan gesture recotnizer, we can get the scale and rotation from the UIPinchGestureRecognizer and UIRotationGestureRecognizer.

Every view has a transform that is applied to it, which you can think of as information on the rotation, scale, and translation that should be applied to the view. Apple has a lot of built in methods to make working with a transform easy such as CGAffineTransformScale (to scale a given transform) and CGAffineTransformRotate (to rotate a given transform). 

Simultaneous Gesture Recognizers

 By default, once one gesture recognizer on a view “claims” the gesture, no others can recognize a gesture from that point on.

However, you can change this by overriding a method in the UIGestureRecognizer delegate.

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer { return YES; }

This method tells the gesture recognizer whether it is OK to recognize a gesture if another (given) recognizer has already detected a gesture. The default implementation always returns NO – we switch it to always return YES here.

UIGestureRecognizer Dependencies

requireGestureRecognizerToFail is a method we can use of to negate one gesture