C# PrintDocument 80 热敏打印机 , 顶部空间如何缩小

Question

C# PrintDocument 80 热敏打印机 , 顶部空间如何缩小

  private void btnPrint_Click(object sender, EventArgs e)
  {
      if (selectedCustomers == null)
      {
          this.ShowErrorTip("请选择打印的客户!");
          return;
      }
      string documentName = selectedCustomers.Name;
      string printName = IniSettings.GetPrint();
      if (printName == null || string.IsNullOrEmpty(printName))
      {
          this.ShowErrorTip("请先在设置中，配置打印机！");
          return;
      }
      var flag = PosPrint(printName, documentName);
      if (flag)
      {
          printDataList.ForEach(n =>
          {
              PrintReadControlsRemove(n.ContentId.ToString());
              PrintReadControlsRemove(n.CategoryId.ToString());
          });
          printDataList.Clear();
          Task.Factory.StartNew(() => ActionQueryStorysByCategoryId(selectedCustomers.Id, selectedCategoryId));
          this.ShowSuccessTip("打印成功");
      }
      else
      {
          this.ShowErrorTip("打印失败,请重试");
      }
  }

  public bool PosPrint(string PrintName = "", string documentName = "", int num = 1)
  {
      using (PrintDocument printDocument = new PrintDocument())
      {
          try
          {
              printDocument.DocumentName = documentName;
              printDocument.PrintController = new StandardPrintController();
              printDocument.DefaultPageSettings.Margins = new Margins(0, 0, 0, 0);
              if (!string.IsNullOrEmpty(PrintName))
              {
                  printDocument.PrinterSettings.PrinterName = PrintName;
              }
              //Copies属性不生效 改用for循环执行print打印多份
              //if (num > 1 && num < 32768)//超过一份才赋值，否则不是赋值，就算不赋也是默认1份，不这样判断时常会报SIZE错误
              //printDocument.PrinterSettings.Copies = Convert.ToInt16(num);
              printDocument.PrintPage += new PrintPageEventHandler(this.PosPrintPage);
              if (printDocument.PrinterSettings.IsValid)
              {
                  printDocument.Print();
                  return true;
              }
              return false;
          }
          catch (Exception e)
          {
              this.ShowErrorTip(e.Message);
              return false;
          }
      }
  }


  private void PosPrintPage(object sender, PrintPageEventArgs e)
  {
      if (selectedCustomers == null)
      {
          this.ShowErrorTip("请选择打印的客户!");
          return;
      }
      string documentName = selectedCustomers.Name; 
      int Ltop = 0;
      float width = e.PageSettings.PaperSize.Width - e.PageSettings.Margins.Left - e.PageSettings.Margins.Right;//计算出有效打印区域的宽度    
      int TitleHeight = 0;
      Graphics graphics = CreateGraphics();

      string FontFamily = "微软雅黑";
      // 需求 字体大小
      float PrtFont = 10;
      // 类型 字题大小
      float TitlePrtFont = 12;
      // 字体间距
      int spacing = 6;
      // 左边间距
      int leftSpacing = 0;
      // 右边间距
      int rightSpacing = 0;

      Font _font = new Font(FontFamily, PrtFont);
      SolidBrush solidBrush = new SolidBrush(System.Drawing.Color.Black);

      // 客户
      string Title = documentName;
      _font = new Font(FontFamily, TitlePrtFont, FontStyle.Bold);
      SizeF sizeF = graphics.MeasureString(Title, _font);
      TitleHeight = Convert.ToInt32(sizeF.Height) - 25;
      e.Graphics.DrawString(Title, _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串    


      // 日期
      DateTime now = DateTime.Now;
      string dateFormat = now.ToString("yyyy/MM/dd");
      _font = new Font(FontFamily, TitlePrtFont, FontStyle.Bold);
      sizeF = graphics.MeasureString(dateFormat, _font);
      TitleHeight = Convert.ToInt32(sizeF.Height) - 25;
      float DateTitleWidth = e.PageSettings.PaperSize.Width - e.PageSettings.Margins.Left - e.PageSettings.Margins.Right - sizeF.Width;
      e.Graphics.DrawString(dateFormat, _font, solidBrush, DateTitleWidth, Ltop + TitleHeight); //绘制字符串    

      string LogoPath = Application.StartupPath + "Resources\\split.png";
      System.IO.FileStream fs = null;
      fs = new System.IO.FileStream(LogoPath, System.IO.FileMode.Open, System.IO.FileAccess.Read);
      Image Logo = System.Drawing.Image.FromStream(fs);
      fs.Close();
      float LogoTitleWidth = e.PageSettings.PaperSize.Width - e.PageSettings.Margins.Left - e.PageSettings.Margins.Right;
      Logo = resizeImage(Logo, new Size((int)LogoTitleWidth, 20)); //调整img大小
      TitleHeight = TitleHeight + 35;
      e.Graphics.DrawImage(Logo, 0, TitleHeight);

      if (printDataList == null)
      {
          e.HasMorePages = false;
          return;
      }
      TitleHeight = TitleHeight - 17;
      foreach (PrintData printData in printDataList)
      {
          if (printData.DataType == 0)
          {
              string CategoryName = printData.CategoryName;
              _font = new Font(FontFamily, TitlePrtFont, FontStyle.Bold);
              SizeF size = graphics.MeasureString(CategoryName, _font);
              // 加35 黑色横线间隔
              TitleHeight = TitleHeight + Convert.ToInt32(size.Height) + spacing;
              e.Graphics.DrawString(CategoryName, _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串 
          }
          else
          {
              string ContentName = printData.sequence + "、" + printData.ContentName;
              _font = new Font(FontFamily, PrtFont, FontStyle.Regular);
              SizeF ContentName_SizeF = graphics.MeasureString(ContentName, _font);
              if (ContainsNewLine(ContentName.ToString()))
              {
                  string newContentName = ContentName.Replace("\r\n", string.Empty);
                  newContentName = ContentName.Replace("\n", string.Empty);
                  ContentName_SizeF = graphics.MeasureString(newContentName, _font);
              }

              if (ContentName_SizeF.Width > width)
              {
                  // 计算纸的有效宽度
                  int z_width = (int)width - leftSpacing - rightSpacing - 22;
                  // 新行
                  StringBuilder new_row = new StringBuilder();
                  foreach (char c in ContentName)
                  {
                      new_row.Append(c);

                      SizeF new_row_SizeF = graphics.MeasureString(new_row.ToString(), _font);
                      if ((int)Math.Ceiling((double)new_row_SizeF.Width) > z_width)
                      {
                          new_row.Append(Environment.NewLine);

                          TitleHeight = TitleHeight + Convert.ToInt32(ContentName_SizeF.Height) + spacing;
                          e.Graphics.DrawString(new_row.ToString(), _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串  
                          new_row.Clear();
                      }
                      else if (ContainsNewLine(c.ToString()))
                      {
                          TitleHeight = TitleHeight + fontHeight;
                          new_row.Clear();
                      }
                  }
                  if (new_row.Length > 0)
                  {
                      TitleHeight = TitleHeight + Convert.ToInt32(ContentName_SizeF.Height) + spacing;
                      e.Graphics.DrawString(new_row.ToString(), _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串  
                  }


                  //// "测" 一个字的宽度
                  //SizeF Test_SizeF = graphics.MeasureString("测", _font);
                  //// 每行可以放的 字数
                  //int wordQty = (int)Math.Ceiling((double)width / Test_SizeF.Width);
                  //if (width == 284)
                  //{
                  //    wordQty = 17;
                  //}
                  ////  行数
                  //int row = (int)Math.Ceiling((double)ContentName .Length / wordQty);
                  //int length = wordQty;
                  //int startIndex = 0;
                  //for (int i = 0; i < row; i++)
                  //{
                  //    startIndex = i * wordQty;
                  //    if (ContentName.Length - startIndex <= length)
                  //    {
                  //        length = ContentName.Length - startIndex;
                  //    }
                  //    string newContentName = ContentName.Substring(startIndex, length);

                  //    _font = new Font(FontFamily, PrtFont, FontStyle.Regular);
                  //    SizeF newContentName_SizeF = graphics.MeasureString(newContentName, _font);
                  //    TitleHeight = TitleHeight + Convert.ToInt32(newContentName_SizeF.Height) + spacing;
                  //    e.Graphics.DrawString(newContentName, _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串
                  //}

              }
              else
              {
                  TitleHeight = TitleHeight + Convert.ToInt32(ContentName_SizeF.Height) + spacing;
                  e.Graphics.DrawString(ContentName, _font, solidBrush, leftSpacing, Ltop + TitleHeight); //绘制字符串  
              }
          }
      }

      // 增加票尾空行，方便切纸
      //int FootEmptyLine = 3;
      //if (FootEmptyLine > 0)
      //{
      //    string EndRow = "";
      //    SizeF Test_SizeF = graphics.MeasureString("测", _font);

      //    for (int a = 0; a < FootEmptyLine; a++)
      //    {
      //        if (a == FootEmptyLine - 1)
      //            EndRow += (".   \r\n");
      //        else
      //            EndRow += ("   \r\n");
      //    }
      //    e.Graphics.DrawString(EndRow, _font, solidBrush, 0, Ltop + TitleHeight); //绘制字符串 

      //}

      e.HasMorePages = false;
  }

Answer 1

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要缩小热敏打印机的顶部空间，你可以通过调整打印设置的边距来实现。在你的代码中，你已经设置了打印文档的边距为0，但这可能并不足以完全消除顶部空间，因为热敏打印机通常有一些固有的最小边距。你可以尝试减小边距的值，看看是否可以缩小顶部空间。在你的代码中，你可以尝试将 printDocument.DefaultPageSettings.Margins 的值设置得更小一些。但是请注意，过于接近热敏打印机的物理硬件限制可能会导致打印质量下降或无法打印。

然而，基于你提供的代码，看起来你想要做的是在 PosPrintPage 方法中调整顶部空间，而不是改变整个文档的边距。你可以在绘制标题和内容之前增加或减少 Ltop 变量的值来改变顶部空间。但请注意不要设置得太低，以免内容被热敏打印机的硬件部分（如打印头）遮挡。

关于你的代码，我有一些建议来提高效率和可读性：

1. 使用字符串拼接来构建打印内容的时候可以考虑使用 StringBuilder 来提高性能。特别是当你需要多次连接字符串时。
2. 当创建字体对象时，可以考虑将字体对象创建放在循环外部以提高性能。字体对象在创建时是比较昂贵的操作，如果频繁创建会增加性能开销。
3. 考虑将常用的变量（如 solidBrush）设为类的成员变量或静态变量以提高性能。

至于具体的代码调整，你需要根据你的打印机和热敏纸的具体情况进行微调。我建议你先尝试减小边距的值，然后观察打印效果，根据实际效果进行调整。