_adapter _buttonHandled _gestureRecognized _ignorePt _lastPt _magnifierView _points _recognizers _startPt _tapCount _tapPoint _touchCount acquireFrontDoc activeView activiteView addContextAction:block: addDelegate: clearCachedData contextActionEnabled coreView createGraphView::: createMagnifierView:refView:parentView: delayTap delegates dispatchTapPending dynamicShapeView: exportPNG: flags gestureEnabled hideContextActions imageCache initWithFrame:flags: locker mainView moveHandler: onContextAction: panHandler: panRecognizer pinchRecognizer pressHandler: pressRecognizer releaseDoc: removeDelegate: rotationRecognizer setupGestureRecognizers snapshot stopRecord: tapHandler: tapRecognizer tearDown twoTapsHandler: twoTapsRecognizer viewAdapter viewAdapter2 viewToMagnify

snapshot() - (UIImage *) snapshot 得到静态图形的快照，自动释放 函数调用图: 这是这个函数的调用关系图: