iOS 计算文字宽高

//计算文字宽高
- (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font maxSize:(CGSize)maxSize {
    NSDictionary *attrs = @{NSFontAttributeName : font};
    return [text boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;
}