iOS 9 SDK Development

Pinching and Panning

How can we play with images on iOS? The whole point of a touch interface is to provide the feeling of interacting directly with our data, so we should be thinking of moving the image around with a drag, zooming in and out of it with pinch gestures, and so forth.

Let’s take a look at what gesture recognizers give us. Here’s a table summarizing the concrete subclasses of UIGestureRecognizer and the important properties and/or methods exposed by each:

Class	Important Properties and Methods
UILongPressGestureRecognizer	minimumPressDuration, allowableMovement
UIPanGestureRecognizer	translationInView:, velocityInView:
UIPinchGestureRecognizer	scale, velocity
UIRotationGestureRecognizer	rotation, velocity
UIScreenEdgePanGestureRecognizer ...