Multi-touch

智能与灵活与工作量>_<
http://www.oschina.net/question/213217_45564
处理复杂的多点触摸序列:
http://www.apple.com.cn/developer/iphone/library/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/EventHandling/EventHandling.html#//apple_ref/doc/uid/TP40007072-CH9-SW16

scroll view :
http://stackoverflow.com/questions/3648967/how-to-recognize-swipe-gesture-in-uiscrollview
http://www.cnblogs.com/kimimaro/archive/2012/03/20/2407670.html
两点间距离＝。＝
http://forums.macrumors.com/archive/index.php/t-508042.html


//    UIEvent :
//    - (NSSet *)allTouches;
//    - (NSSet *)touchesForWindow:(UIWindow *)window;
//    - (NSSet *)touchesForView:(UIView *)view;
//    - (NSSet *)touchesForGestureRecognizer:(UIGestureRecognizer *)gestureMulti-touch

//    NSSet *allTouches = [event allTouches];
//    NSLog(@"有几个点触摸  %d", [allTouches count]);

//    UITouch *touch = [touches anyObject];
//    NSLog(@"同一点累计单击次数  %d", [touch tapCount]);