NSRange (范围);(location,位置 length,长度;
NSPoint /CGpoint(点);
NSSize /CGSize(大小)
CGPoint p1 = CGPointZero == CGPointMake(0, 0)代表原点
CGSizeZero == CGSizeMake(0, 0);代表大小为0
CGRect rec = CGRectMake(0, 0, 10, 10);
CGRect re = CGRectMake(CGPointMake(<#CGFloat x#>, <#CGFloat y#>), CGSizeMake(<#CGFloat width#>, <#CGFloat height#>))
//判断两个坐标是否相等
BOOL b = CGPointEqualToPoint(CGPointMake(10, 10), CGPointMake(10, 10));