convertPoint:fromView:
把一个点从一个坐标系转换到接收者的坐标系 
- (CGPoint)convertPoint:(CGPoint)point fromView:(UIView *)view 

 

UIViewController生命周期

https://www.jianshu.com/p/d60b388b19f5

C API 内存分布, C++与objective-c

http://awhisper.github.io/2016/05/01/%E6%B7%B7%E7%BC%96ObjectiveC/

归档

https://www.jianshu.com/p/9c9cd8e70de4

@private @public

http://blog.csdn.net/baidu_31683691/article/details/52766228

CALayer (resentationLayer(以下简称P)和modelLayer(以下简称M)。presentationLayer负责走路(绘制内容),而modelLayer负责看路(如何绘制))

http://blog.csdn.net/u013282174/article/details/50388546