Recipe 1-3 builds on the ideas presented in Recipe 1-2, but with several differences. First, it introduces multiple recognizers that work in parallel. To achieve this, the code uses three separate recognizers—rotation, pinch, and pan—and adds them all to the
gestureRecognizers property. It assigns the
DragView as the delegate for each recognizer. This allows the
DragView to implement the
gestureRecognizer:shouldRecognize-SimultaneouslyWithGestureRecognizer: delegate method, enabling these recognizers to work simultaneously. Until this method is added to return
YES as its value, only one recognizer will take charge at a time. Using parallel recognizers allows you to, for example, ...