SMScrollView

SMScrollView is a subclass of UIScrollView with the following additions:

• It maintains the position of the view returned by its delegate's viewForZoomingInScrollView: in the center of its own boundaries.
• It has a double-tap gesture to zoom in and out the view returned by its delegate's viewForZoomingInScrollView:. Specifically, when its zoomScale == minimumZoomScale, it zooms-in the view to the tapped point and to the scale defined by by the maximumZoomScale. Otherwise, when zoomScale > minimumZoomScale, it zooms-out to a scale defined by the minimumZoomScale. The double-tap gesture is available through the doubleTapGestureRecognizer property to disable or adjust the gesture behavior.
• When its size is changed, for example due to a change in an interface orientation, then:
  1. If its fitOnSizeChange == YES, then its content is rescaled to fit its new size, up to the scale of 1.0, such that the content is never stretched.
  2. If fitOnSizeChange == NO, then it maintains zoomed view's center point in center after the size is changed. However, if stickToBounds property was set to YES and the scroll-view was scrolled to one of its boundaries before the size change, then it is kept at these boundaries instead of keeping the center point in center.