Zebra Printer - Not Printing PNG Stream *Provided my own answer*

Question

I think I'm very close to getting this to print. However it still isn't. There is no exception thrown and it does seem to be hitting the zebra printer, but nothing. Its a long shot as I think most people are in the same position I am and know little about it. Any help anyone can give no matter how small will be welcomed, I'm losing the will to live

using (var response = request.GetResponse())
            {
                using (var responseStream = response.GetResponseStream())
                {
                    using (var stream = new MemoryStream())
                    {
                        if (responseStream == null)
                        {
                            return;
                        }

                        responseStream.CopyTo(stream);
                        stream.Position = 0;

                        using (var zipout = ZipFile.Read(stream))
                        {
                            using (var ms = new MemoryStream())
                            {
                                foreach (var e in zipout.Where(e => e.FileName.Contains(".png")))
                                {
                                    e.Extract(ms);
                                }

                                if (ms.Length <= 0)
                                {
                                    return;
                                }

                                var binaryData = ms.ToArray();

                                byte[] compressedFileData;

                                //  Compress the data using the LZ77 algorithm.
                                using (var outStream = new MemoryStream())
                                {
                                    using (var compress = new DeflateStream(outStream, CompressionMode.Compress, true))
                                    {
                                        compress.Write(binaryData, 0, binaryData.Length);
                                        compress.Flush();
                                        compress.Close();
                                    }
                                    compressedFileData = outStream.ToArray();
                                }

                                //  Encode the compressed data using the MIME Base64 algorithm.
                                var base64 = Convert.ToBase64String(compressedFileData);

                                //  Calculate a CRC across the encoded data.
                                var crc = Calc(Convert.FromBase64String(base64));

                                //  Add a unique header to differentiate the new format from the existing ASCII hexadecimal encoding.
                                var finalData = string.Format(":Z64:{0}:{1}", base64, crc);

                                var zplToSend = "~DYR:LOGO,P,P," + finalData.Length + ",," + finalData;
                                const string PrintImage = "^XA^FO0,0^IMR:LOGO.PNG^FS^XZ";

                                try
                                {
                                    var client = new System.Net.Sockets.TcpClient();
                                    client.Connect(IpAddress, Port);

                                    var writer = new StreamWriter(client.GetStream(), Encoding.UTF8);
                                    writer.Write(zplToSend);
                                    writer.Flush();
                                    writer.Write(PrintImage);
                                    writer.Close();
                                    client.Close();
                                }
                                catch (Exception ex)
                                {
                                    // Catch Exception
                                }
                            }
                        }
                    }
                }
            }

    private static ushort Calc(byte[] data)
    {
        ushort wCrc = 0;

        for (var i = 0; i < data.Length; i++)
        {
            wCrc ^= (ushort)(data[i] << 8);

            for (var j = 0; j < 8; j++)
            {
                if ((wCrc & 0x8000) != 0)
                {
                    wCrc = (ushort)((wCrc << 1) ^ 0x1021);
                }
                else
                {
                    wCrc <<= 1;
                }
            }
        }

        return wCrc;
    }

Answer 1

Easy once you know how. Zebra ZPL logo example in base64

Python3

import crcmod
import base64
crc16 = crcmod.predefined.mkCrcFun('xmodem')
s = hex(crc16(ZPL_LOGO.encode()))[2:]
print (f"crc16: {s}")

Poorly documented may I say the least

Answer 2

The following code is working for me. The issue was the commands, these are very very important! Overview of the command I have used below, more can be found here

PrintImage

^XA Start Format Description The ^XA command is used at the beginning of ZPL II code. It is the opening bracket and indicates the start of a new label format. This command is substituted with a single ASCII control character STX (control-B, hexadecimal 02). Format ^XA Comments Valid ZPL II format requires that label formats should start with the ^XA command and end with the ^XZ command.

^FO Field Origin Description The ^FO command sets a field origin, relative to the label home (^LH) position. ^FO sets the upper-left corner of the field area by defining points along the x-axis and y-axis independent of the rotation. Format ^FOx,y,z

• x = x-axis location (in dots) Accepted Values: 0 to 32000 Default Value: 0
• y = y-axis location (in dots) Accepted Values: 0 to 32000 Default Value: 0
• z = justification The z parameter is only supported in firmware versions V60.14.x, V50.14.x, or later. Accepted Values: 0 = left justification 1 = right justification 2 = auto justification (script dependent) Default Value: last accepted ^FW value or ^FW default

^IM Image Move Description The ^IM command performs a direct move of an image from storage area into the bitmap. The command is identical to the ^XG command (Recall Graphic), except there are no sizing parameters. Format ^IMd:o.x

• d = location of stored object Accepted Values: R:, E:, B:, and A: Default Value: search priority
• o = object name Accepted Values: 1 to 8 alphanumeric characters Default Value: if a name is not specified, UNKNOWN is used
• x = extension Fixed Value: .GRF, .PNG

^FS Field Separator Description The ^FS command denotes the end of the field definition. Alternatively, ^FS command can also be issued as a single ASCII control code SI (Control-O, hexadecimal 0F). Format ^FS

^XZ End Format Description The ^XZ command is the ending (closing) bracket. It indicates the end of a label format. When this command is received, a label prints. This command can also be issued as a single ASCII control character ETX (Control-C, hexadecimal 03). Format ^XZ Comments Label formats must start with the ^XA command and end with the ^XZ command to be in valid ZPL II format.

zplToSend

^MN Media Tracking Description This command specifies the media type being used and the black mark offset in dots. This bulleted list shows the types of media associated with this command:

• Continuous Media – this media has no physical characteristic (such as a web, notch, perforation, black mark) to separate labels. Label length is determined by the ^LL command.
• Continuous Media, variable length – same as Continuous Media, but if portions of the printed label fall outside of the defined label length, the label size will automatically be extended to contain them. This label length extension applies only to the current label. Note that ^MNV still requires the use of the ^LL command to define the initial desired label length.
• Non-continuous Media – this media has some type of physical characteristic (such as web, notch, perforation, black mark) to separate the labels.

Format ^MNa,b

• a = media being used Accepted Values: N = continuous media Y = non-continuous media web sensing d, e W = non-continuous media web sensing d, e M = non-continuous media mark sensing A = auto-detects the type of media during calibration d, f V = continuous media, variable length g Default Value: a value must be entered or the command is ignored
• b = black mark offset in dots This sets the expected location of the media mark relative to the point of separation between documents. If set to 0, the media mark is expected to be found at the point of separation. (i.e., the perforation, cut point, etc.) All values are listed in dots. This parameter is ignored unless the a parameter is set to M. If this parameter is missing, the default value is used. Accepted Values: -80 to 283 for direct-thermal only printers -240 to 566 for 600 dpi printers -75 to 283 for KR403 printers -120 to 283 for all other printers Default Value: 0

~DY Download Objects Description The ~DY command downloads to the printer graphic objects or fonts in any supported format. This command can be used in place of ~DG for more saving and loading options. ~DY is the preferred command to download TrueType fonts on printers with firmware later than X.13. It is faster than ~DU. The ~DY command also supports downloading wireless certificate files. Format ~DYd:f,b,x,t,w,data

Note When using certificate files, your printer supports: - Using Privacy Enhanced Mail (PEM) formatted certificate files. - Using the client certificate and private key as two files, each downloaded separately. - Using exportable PAC files for EAP-FAST. - Zebra recommends using Linear sty

• d = file location .NRD and .PAC files reside on E: in firmware versions V60.15.x, V50.15.x, or later. Accepted Values: R:, E:, B:, and A: Default Value: R:
• f = file name Accepted Values: 1 to 8 alphanumeric characters Default Value: if a name is not specified, UNKNOWN is used
• b = format downloaded in data field .TTE and .TTF are only supported in firmware versions V60.14.x, V50.14.x, or later. Accepted Values: A = uncompressed (ZB64, ASCII) B = uncompressed (.TTE, .TTF, binary) C = AR-compressed (used only by Zebra’s BAR-ONE® v5) P = portable network graphic (.PNG) - ZB64 encoded Default Value: a value must be specified

clearDownLabel

^ID Description The ^ID command deletes objects, graphics, fonts, and stored formats from storage areas. Objects can be deleted selectively or in groups. This command can be used within a printing format to delete objects before saving new ones, or in a stand-alone format to delete objects.

The image name and extension support the use of the asterisk (*) as a wild card. This allows you to easily delete a selected groups of objects. Format ^IDd:o.x

• d = location of stored object Accepted Values: R:, E:, B:, and A: Default Value: R:
• o = object name Accepted Values: any 1 to 8 character name Default Value: if a name is not specified, UNKNOWN is used

• x = extension Accepted Values: any extension conforming to Zebra conventions Default Value: .GRF

      const string PrintImage = "^XA^FO0,0,0^IME:LOGO.PNG^FS^XZ";
      var zplImageData = string.Empty;
  
          using (var response = request.GetResponse())
          {
              using (var responseStream = response.GetResponseStream())
              {
                  using (var stream = new MemoryStream())
                  {
                      if (responseStream == null)
                      {
                          return;
                      }
  
                      responseStream.CopyTo(stream);
                      stream.Position = 0;
  
                      using (var zipout = ZipFile.Read(stream))
                      {
                          using (var ms = new MemoryStream())
                          {
                              foreach (var e in zipout.Where(e => e.FileName.Contains(".png")))
                              {
                                  e.Extract(ms);
                              }
  
                              if (ms.Length <= 0)
                              {
                                  return;
                              }
  
                              var binaryData = ms.ToArray();
  
                              foreach (var b in binaryData)
                              {
                                  var hexRep = string.Format("{0:X}", b);
                                  if (hexRep.Length == 1)
                                  {
                                      hexRep = "0" + hexRep;
                                  }
  
                                  zplImageData += hexRep;
                              }
  
                              var zplToSend = "^XA" + "^FO0,0,0" + "^MNN" + "~DYE:LOGO,P,P," + binaryData.Length + ",," + zplImageData + "^XZ";
  
                              var label = GenerateStreamFromString(zplToSend);
  
                              var client = new System.Net.Sockets.TcpClient();
                              client.Connect(IpAddress, Port);
  
                              label.CopyTo(client.GetStream());
                              label.Flush();
  
                              client.Close();
  
                              var cmd = GenerateStreamFromString(PrintImage);
  
                              var client2 = new System.Net.Sockets.TcpClient();
                              client2.Connect(IpAddress, Port);
  
                              cmd.CopyTo(client2.GetStream());
                              cmd.Flush();
  
                              client2.Close();var clearDownLabel = GenerateStreamFromString("^XA^IDR:LOGO.PNG^FS^XZ");
  
                              var client3 = new System.Net.Sockets.TcpClient();
                              client3.Connect(IpAddress, Port);
  
                              clearDownLabel.CopyTo(client3.GetStream());
                              clearDownLabel.Flush();
  
                              client3.Close();
                          }
                      }
                  }
              }
          }
      }