C# comport 打印图像

  public string GetLogo()
    {
        string logo = "";
        if (!File.Exists(@"C:\bitmap.bmp"))
            return null;
         BitmapData data = GetBitmapData(@"C:\bitmap.bmp");
         BitArray dots = data.Dots;
         byte[] width = BitConverter.GetBytes(data.Width);

         int offset = 0;
         MemoryStream stream = new MemoryStream();
         BinaryWriter bw = new BinaryWriter(stream);

         bw.Write((char)0x1B);
         bw.Write('@');

         bw.Write((char)0x1B);
         bw.Write('3');
         bw.Write((byte)24);

         while (offset < data.Height)
         {
             bw.Write((char)0x1B);
             bw.Write('*');         // bit-image mode
             bw.Write((byte)33);    // 24-dot double-density
             bw.Write(width[0]);  // width low byte
             bw.Write(width[1]);  // width high byte

             for (int x = 0; x < data.Width; ++x)
             {
                 for (int k = 0; k < 3; ++k)
                 {
                     byte slice = 0;
                     for (int b = 0; b < 8; ++b)
                     {
                         int y = (((offset / 8) + k) * 8) + b;
                         // Calculate the location of the pixel we want in the bit array.
                         // It'll be at (y * width) + x.
                         int i = (y * data.Width) + x;

                         // If the image is shorter than 24 dots, pad with zero.
                         bool v = false;
                         if (i < dots.Length)
                         {
                             v = dots[i];
                         }
                         slice |= (byte)((v ? 1 : 0) << (7 - b));
                     }

                     bw.Write(slice);
                 }
             }
             offset += 24;
             bw.Write((char)0x0A);
         }
         // Restore the line spacing to the default of 30 dots.
         bw.Write((char)0x1B);
         bw.Write('3');
         bw.Write((byte)30);

         bw.Flush();
         byte[] bytes = stream.ToArray();
         return logo + Encoding.Default.GetString(bytes);
    }

    public BitmapData GetBitmapData(string bmpFileName)
    {
        using (var bitmap = (Bitmap)Bitmap.FromFile(bmpFileName))
        {
            var threshold = 127;
            var index = 0;
            double multiplier = 570; // this depends on your printer model. for Beiyang you should use 1000
            double scale = (double)(multiplier/(double)bitmap.Width);
            int xheight = (int)(bitmap.Height * scale);int xwidth =(int)(bitmap.Width* scale);var dimensions = xwidth * xheight;var dots =newBitArray(dimensions);for(var y =0; y < xheight; y++){for(var x =0; x < xwidth; x++){var _x =(int)(x / scale);var _y =(int)(y / scale);var color = bitmap.GetPixel(_x, _y);var luminance =(int)(color.R *0.3+ color.G *0.59+ color.B *0.11);
                    dots[index]=(luminance < threshold);
                    index++;}}returnnewBitmapData(){Dots= dots,Height=(int)(bitmap.Height*scale),Width=(int)(bitmap.Width*scale)};}}publicclassBitmapData{publicBitArrayDots{
            get;set;}publicintHeight{
            get;set;}publicintWidth{
            get;set;}}