结构体与字符串之间的转换

UIKIT_EXTERN NSString *NSStringFromCGPoint(CGPoint point);
UIKIT_EXTERN NSString *NSStringFromCGSize(CGSize size);
UIKIT_EXTERN NSString *NSStringFromCGRect(CGRect rect);
UIKIT_EXTERN NSString *NSStringFromCGAffineTransform(CGAffineTransform transform);
UIKIT_EXTERN NSString *NSStringFromUIEdgeInsets(UIEdgeInsets insets);
 
UIKIT_EXTERN CGPoint CGPointFromString(NSString *string);
UIKIT_EXTERN CGSize CGSizeFromString(NSString *string);
UIKIT_EXTERN CGRect CGRectFromString(NSString *string);
UIKIT_EXTERN CGAffineTransform CGAffineTransformFromString(NSString *string);
UIKIT_EXTERN UIEdgeInsets UIEdgeInsetsFromString(NSString *string);