动态计算文本高度的时候需要注意什么？

原文：iOS面试题大全

    + (CGSize)contentSizeForContent:(NSString *)content withFixedWidth:(CGFloat)width {
        CGSize maxSize = CGSizeMake(width, MAXFLOAT);
        UIFont *font = [UIFont systemFontOfSize:14.0];
        NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
        paragraphStyle.alignment = NSTextAlignmentLeft;
        CGRect suggestRect = [content boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName: font, NSParagraphStyleAttributeName: paragraphStyle} context:nil];
        
        CGSize resultSize = CGSizeMake(width, ceil(suggestRect.size.height));
        
        return resultSize;
    }

    + (CGSize)conten