How to create a dynamic GRF image for printing ZPL ZEBRA

Question

I have a problem.

I am creating a dynamic BMP image and trying to send it to a ZEBRA printer using ZPL commands. I need to convert BMP to GRF image. I think my hex code extracted using a BMP image is not correct.

The printed image is blurry and incorrect.

This is my code:

string bitmapFilePath = @oldArquivo; // file is attached to this support article byte[] bitmapFileData = System.IO.File.ReadAllBytes(bitmapFilePath); int fileSize = bitmapFileData.Length; Bitmap ImgTemp = new Bitmap(bitmapFilePath); Size ImgSize = ImgTemp.Size; ImgTemp.Dispose(); // The following is known about test.bmp. It is up to the developer // to determine this information for bitmaps besides the given test.bmp. int width = ImgSize.Width; int height = ImgSize.Height; int bitmapDataOffset = 62; // 62 = header of the image int bitmapDataLength = fileSize - 62;// 8160; double widthInBytes = Math.Ceiling(width / 8.0); // Copy over the actual bitmap data from the bitmap file. // This represents the bitmap data without the header information. byte[] bitmap = new byte[bitmapDataLength]; Buffer.BlockCopy(bitmapFileData, bitmapDataOffset, bitmap, 0, (bitmapDataLength)); // Invert bitmap colors for (int i = 0; i < bitmapDataLength; i++) { bitmap[i] ^= 0xFF; } // Create ASCII ZPL string of hexadecimal bitmap data string ZPLImageDataString = BitConverter.ToString(bitmap).Replace("-", string.Empty); string comandoCompleto = "~DG" + nomeImagem + ".GRF,0" + bitmapDataLength.ToString() + ",0" + widthInBytes.ToString() + "," + ZPLImageDataString; 

Answer 1

Try using the following code. Not tested!

 public static string CreateGRF(string filename, string imagename) { Bitmap bmp = null; BitmapData imgData = null; byte[] pixels; int x, y, width; StringBuilder sb; IntPtr ptr; try { bmp = new Bitmap(filename); imgData = bmp.LockBits(new Rectangle(0, 0, bmp.Width, bmp.Height), ImageLockMode.ReadOnly, PixelFormat.Format1bppIndexed); width = (bmp.Width + 7) / 8; pixels = new byte[width]; sb = new StringBuilder(width * bmp.Height * 2); ptr = imgData.Scan0; for (y = 0; y < bmp.Height; y++) { Marshal.Copy(ptr, pixels, 0, width); for (x = 0; x < width; x++) sb.AppendFormat("{0:X2}", (byte)~pixels[x]); ptr = (IntPtr)(ptr.ToInt64() + imgData.Stride); } } finally { if (bmp != null) { if (imgData != null) bmp.UnlockBits(imgData); bmp.Dispose(); } } return String.Format("~DG{0}.GRF,{1},{2},", imagename, width * y, width) + sb.ToString(); } 

Answer 2

It should be noted that the conversion of the bitmap should be monochrome (i.e. 1 bit per pixel). There is an example of the Zebra knowledge base that demonstrates printing a simple monochrome image in ZPL: https://km.zebra.com/kb/index?page=answeropen&type=open&searchid=1356730396931&answerid=16777216&iqaction=5&url=https%3A%2F%2Fkm.zebra .com% 2Fkb% 2Findex% 3Fpage% 3Dcontent% 26id% 3DSA304% 26actp% 3Dsearch% 26viewlocale% 3Den_US & highlightinfo = 4194550,131,153 # . If you can convert images to monochrome bitmaps, you should follow this example.

 // Given a monochrome bitmap file, one can read // information about that bitmap from the header // information in the file. This information includes // bitmap height, width, bitsPerPixel, etc. It is required // that a developer understands the basic bitmap format and // how to extract the following data in order to proceed. // A simple search online for 'bitmap format' should yield // all the needed information. Here, for our example, we simply // declare what the bitmap information is, since we are working // with a known sample file. string bitmapFilePath = @"test.bmp"; // file is attached to this support article byte[] bitmapFileData = System.IO.File.ReadAllBytes(bitmapFilePath); int fileSize = bitmapFileData.Length; // The following is known about test.bmp. It is up to the developer // to determine this information for bitmaps besides the given test.bmp. int bitmapDataOffset = 62; int width = 255; int height = 255; int bitsPerPixel = 1; // Monochrome image required! int bitmapDataLength = 8160; double widthInBytes = Math.Ceiling(width / 8.0); // Copy over the actual bitmap data from the bitmap file. // This represents the bitmap data without the header information. byte[] bitmap = new byte[bitmapDataLength]; Buffer.BlockCopy(bitmapFileData, bitmapDataOffset, bitmap, 0, bitmapDataLength); // Invert bitmap colors for (int i = 0; i < bitmapDataLength; i++) { bitmap[i] ^= 0xFF; } // Create ASCII ZPL string of hexadecimal bitmap data string ZPLImageDataString = BitConverter.ToString(bitmap); ZPLImageDataString = ZPLImageDataString.Replace("-", string.Empty); // Create ZPL command to print image string[] ZPLCommand = new string[4]; ZPLCommand[0] = "^XA"; ZPLCommand[1] = "^FO20,20"; ZPLCommand[2] = "^GFA, " + bitmapDataLength.ToString() + "," + bitmapDataLength.ToString() + "," + widthInBytes.ToString() + "," + ZPLImageDataString; ZPLCommand[3] = "^XZ"; // Connect to printer string ipAddress = "10.3.14.42"; int port = 9100; System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient(); client.Connect(ipAddress, port); System.Net.Sockets.NetworkStream stream = client.GetStream(); // Send command strings to printer foreach (string commandLine in ZPLCommand) { stream.Write(ASCIIEncoding.ASCII.GetBytes(commandLine), 0, commandLine.Length); stream.Flush(); } // Close connections stream.Close(); client.Close(); 

Answer 3

I admit that there is a problem, the application creates a file for the printer and converts the image, but only if it has a size of 255 x 255, each time causing problems. Instead, the graphic is displayed on a printout interrupted by lines. I tried the height and width with different parameters, I gave it a few 255, but that failed. Maybe someone knows how to change the algorithm? congratulated Peter

Answer 4

Add 2 to widthInBytes - it works !!!

  int bitmapDataOffset = int.Parse(bitmapFileData[10].ToString()); ; int width = 624;// int.Parse(bitmapFileData[18].ToString()); ; int height = int.Parse(bitmapFileData[22].ToString()); ; int bitsPerPixel = int.Parse(bitmapFileData[28].ToString()); // Monochrome image required! int bitmapDataLength = bitmapFileData.Length - bitmapDataOffset; double widthInBytes = Math.Ceiling(width / 8.0)+2;