CGSize textBlockMinSize = {TEXTLABEL_MAX_WIDTH, CGFLOAT_MAX};
CGSize retSize;
NSAttributedString *attributedString = _textLabel.attributedText;
CGRect boundingRect = [attributedString boundingRectWithSize:textBlockMinSize options:NSStringDrawingUsesLineFragmentOrigin context:nil];
retSize = boundingRect.size;
我用这个办法计算出来的size不准，应该怎么计算带有自定义表情的attributedString的size？不是emoji
表情格式是[中文]