sizeWithFont轉boundingRectWithSize

CGFloat width1=[(NSString *)ob1 sizeWithFont:[UIFont systemFontOfSize:16] constrainedToSize:CGSizeMake(1000, FONTHEIGHT)].width;
轉
CGFloat width1=[(NSString *)ob1 boundingRectWithSize:CGSizeMake(1000, FONTHEIGHT) options:

NSStringDrawingUsesLineFragmentOrigin |NSStringDrawingUsesFontLeading

attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:16]} context:nil].size.width;

boundingRectWithSize: CGSize 對應 constrainedToSize: CGSize
attributes:@{NSFontAttributeName: [ UIFont ] } 對應 sizeWithFont[ UIFont ]
options: NSStringDrawingUsesLineFragmentOrigin 默認照填
context: nil 默認照填