计算含有表情文字的NSAttributedString的size

/**
   *  返回UILabel自适应后的size
   *
   *  @param aString 字符串
   *  @param width   指定宽度
   *  @param height  指定高度
   *
   *  @return CGSize
   */
  + (CGSize)sizeLabelToFit:(NSAttributedString *)aString width:(CGFloat)width height:(CGFloat)height {
     UILabel *tempLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, 0, width, height)];
     tempLabel.attributedText = aString;
     tempLabel.numberOfLines = 0;
     [tempLabel sizeToFit];
     CGSize size = tempLabel.frame.size;
     size = CGSizeMake(CGFloat_ceil(size.width), CGFloat_ceil(size.height));
     return size;
  }