0 Replies Latest reply on Sep 28, 2018 3:17 AM by bhargav venkatesh

    Converting an image from png to grf(hex) using javascript

    bhargav venkatesh

      Hi,

      I need to print an image using javascript and serverside used is PHP. When I clicked the image it stores in the database in the png format and I  want to print that image through the zebra gc420t using javascript

      Do I need to convert the image to grf(hex)

      If yes how can I convert to grf using javascript

      I am using this code

       

      //this the code of Devdemo.js

      var available_printers = null;

      var selected_category = null;

      var default_printer = null;

      var selected_printer = null;

      var format_start = "^XA^LL200^FO80,50^A0N36,36^FD";

      var format_end = "^FS^XZ";

      var default_mode = true;

       

       

      function setup_web_print()

      {

      $('#printer_select').on('change', onPrinterSelected);

      showLoading("Loading Printer Information...");

      default_mode = true;

      selected_printer = null;

      available_printers = null;

      selected_category = null;

      default_printer = null;

       

      BrowserPrint.getDefaultDevice('printer', function(printer)

      {

      default_printer = printer

      if((printer != null) && (printer.connection != undefined))

      {

      selected_printer = printer;

      var printer_details = $('#printer_details');

      var selected_printer_div = $('#selected_printer');

       

      selected_printer_div.text("Using Default Printer: " + printer.name);

      hideLoading();

      printer_details.show();

      $('#print_form').show();

       

       

      }

      BrowserPrint.getLocalDevices(function(printers)

      {

      available_printers = printers;

      var sel = document.getElementById("printers");

      var printers_available = false;

      sel.innerHTML = "";

      if (printers != undefined)

      {

      for(var i = 0; i < printers.length; i++)

      {

      if (printers[i].connection == 'usb')

      {

      var opt = document.createElement("option");

      opt.innerHTML = printers[i].connection + ": " + printers[i].uid;

      opt.value = printers[i].uid;

      sel.appendChild(opt);

      printers_available = true;

      }

      }

      }

       

      if(!printers_available)

      {

      showErrorMessage("No Zebra Printers could be found!");

      hideLoading();

      $('#print_form').hide();

      return;

      }

      else if(selected_printer == null)

      {

      default_mode = false;

      changePrinter();

      $('#print_form').show();

      hideLoading();

      }

      }, undefined, 'printer');

      },

      function(error_response)

      {

      showBrowserPrintNotFound();

      });

      };

       

      function showBrowserPrintNotFound()

      {

      showErrorMessage("An error occurred while attempting to connect to your Zebra Printer. You may not have Zebra Browser Print installed, or it may not be running. Install Zebra Browser Print, or start the Zebra Browser Print Service, and try again.");

      };

       

      function sendData(photoURL)

      {

       

      var test;

      $.ajax({

                  url: 'db/zpl.php?photo='+photoURL,

                  cache: false,

                  contentType: false,

                  processData: false,

                  type: 'GET',

                  success: function(data) {

                  test=data;

                  console.log("From ZPL:"+data);

                  }

              });

       

      var mob="",lap="",other="";

      if($("#emobile").val()==="on"){

      mob="Mobile";

      }

       

      if($("#elaptop").val()==="on"){

      lap="Laptop";

      }

          if($("#eother").val()==="on"){

      other="Other";

      }

      showLoading("Printing...");

      checkPrinterStatus( function (text){

      if (text == "Ready to Print")

      {

       

      selected_printer.send("^XA N ^XZ");

      // selected_printer.send("^XA~DGE:ZLOGO.GRF,2580,030,"+test+"^XZ");

       

      selected_printer.send("~DYE:SAMPLE,A,GRF,5000,030"+test+",A");

       

       

      //selected_printer.send("^XA^BY2^FO165,13^BCN,49,N,N,N^SN00095C00001,1,Y^FS^A0N,28,28^FO490,47^FD17/10/2017^FS^A0N,26,24^FO157,162^FDCOLGATE GYE^FS^A0N,26,24^FO499,13^FDFEC.EMIS^FS^A0N,66,60^FO157,90^SN00099C00001,1,Y^FS^FO150,180^XGE:SAMPLE.GRF,1,1^FS^PQ1,1,1,y^FS^XZ");

       

      // selected_printer.send("^XA^FO100,100^IMR:SAMPLE.GRF^FS^FO100,200^IMR:SAMPLE.GRF^FS^FO100,300^IMR:SAMPLE.GRF^FS^FO100,400^IMR:SAMPLE.GRF^FS^FO100,500^IMR:SAMPLE.GRF^FS^XZ");

      //this is the function where i am passing to the printer

      selected_printer.send("^XA^FX Second section with recipient address and permit information. ^CFA,30 ^FO50,50^FDVisitor Name:"+$("#user").val()+"^FS ^FO50,80^FDCompany:"+$("#compName").val()+"^FS  ^FO50,110^FDTo Meet:"+$("#toMeet").val()+"^FS ^FO50,150^FDPurpose:"+$("#reason").val()+"^FS ^FO50,190^FDAuthorise^FS ^FO50,220^FDto Carry:"+mob+" "+lap+"^FS ^FO500,50^XGR:SAMPLE.GRF,1,1^FS^XZ");

       

       

      //selected_printer.send("^XA ^FX Second section with recipient address and permit information. ^CFA,30 ^FO50,30^FDJohn Doe^FS ^FO50,70^FD100 Main Street^FS ^FO50,110^FDSpringfield TN 39021^FS ^FO50,150^FDUnited States (USA)^FS ^XZ");

      }

      else

      {

      printerError(text);

      }

      });

      };

      function checkPrinterStatus(finishedFunction)

      {

      selected_printer.sendThenRead("~HQES",

      function(text){

      var that = this;

      var statuses = new Array();

      var ok = false;

      var is_error = text.charAt(70);

      var media = text.charAt(88);

      var head = text.charAt(87);

      var pause = text.charAt(84);

      // check each flag that prevents printing

      if (is_error == '0')

      {

      ok = true;

      statuses.push("Ready to Print");

      }

      if (media == '1')

      statuses.push("Paper out");

      if (media == '2')

      statuses.push("Ribbon Out");

      if (media == '4')

      statuses.push("Media Door Open");

      if (media == '8')

      statuses.push("Cutter Fault");

      if (head == '1')

      statuses.push("Printhead Overheating");

      if (head == '2')

      statuses.push("Motor Overheating");

      if (head == '4')

      statuses.push("Printhead Fault");

      if (head == '8')

      statuses.push("Incorrect Printhead");

      if (pause == '1')

      statuses.push("Printer Paused");

      if ((!ok) && (statuses.Count == 0))

      statuses.push("Error: Unknown Error");

      finishedFunction(statuses.join());

      }, printerError);

      };

      function hidePrintForm()

      {

      $('#print_form').hide();

      };

      function showPrintForm()

      {

      $('#print_form').show();

      };

      function showLoading(text)

      {

      $('#loading_message').text(text);

      $('#printer_data_loading').show();

      hidePrintForm();

      $('#printer_details').hide();

      $('#printer_select').hide();

      };

      function printComplete()

      {

      hideLoading();

      alert ("Printing complete");

      }

      function hideLoading()

      {

      $('#printer_data_loading').hide();

      if(default_mode == true)

      {

      showPrintForm();

      $('#printer_details').show();

      }

      else

      {

      $('#printer_select').show();

      showPrintForm();

      }

      };

      function changePrinter()

      {

      default_mode = false;

      selected_printer = null;

      $('#printer_details').hide();

      if(available_printers == null)

      {

      showLoading("Finding Printers...");

      $('#print_form').hide();

      setTimeout(changePrinter, 200);

      return;

      }

      $('#printer_select').show();

      onPrinterSelected();

      }

       

       

      function onPrinterSelected()

      {

      selected_printer = available_printers[$('#printers')[0].selectedIndex];

      }

       

       

      function showErrorMessage(text)

      {

      $('#main').hide();

      $('#error_div').show();

      $('#error_message').html(text);

      }

       

       

      function printerError(text)

      {

      showErrorMessage("An error occurred while printing. Please try again." + text);

      }

       

       

      function trySetupAgain()

      {

      $('#main').show();

      $('#error_div').hide();

      setup_web_print();

      //hideLoading();

      }

       

      //I am converting the image from png to grf using this code

       

       

      <?php

      /**

      * Converts a PNG image to a .GRF file for use with Zebra printers

      *

      * The input is preferably a 1-bit black/white image but RGB images

      * are accepted as well.

      *

      * This function uses PHP's GD library image functions.

      *

      * @copyright Thomas Bruederli <inbox@brotherli.ch>

      *

      * @param string $filename Path to the input file

      * @param string $targetname Name of the GRF file reference

      * @return string ZPL command for uploading the graphic image (~DG)

      */

      function image2grf($filename, $targetname = 'R:SAMPLE.GRF')

      {

        $info = getimagesize($filename);

        $im = imagecreatefrompng($filename);

        $width = $info[0]; // imagesx($im);

        $height = $info[1]; // imagesy($im);

        $depth = $info['bits'] ?: 1;

        $threshold = $depth > 1 ? 160 : 0;

        $hexString = '';

        $byteShift = 7;

        $currentByte = 0;

        // iterate over all image pixels

        for ($y = 0; $y < $height; $y++) {

          for ($x = 0; $x < $width; $x++) {

            $color = imagecolorat($im, $x, $y);

            // compute gray value from RGB color

            if ($depth > 1) {

              $value = max($color >> 16, $color >> 8 & 255, $color & 255);

            } else {

              $value = $color;

            }

            // set (inverse) bit for the current pixel

            $currentByte |= (($value > $threshold ? 0 : 1) << $byteShift);

            $byteShift--;

            // 8 pixels filled one byte => append to output as hex

            if ($byteShift < 0) {

              $hexString .= sprintf('%02X', $currentByte);

              $currentByte = 0;

              $byteShift = 7;

            }

          }

          // append last byte at end of row

          if ($byteShift < 7) {

            $hexString .= sprintf('%02X', $currentByte);

            $currentByte = 0;

            $byteShift = 7;

          }

          $hexString .= PHP_EOL;

        }

        // compose ZPL ~DG command

        $totalBytes = ceil(($width * $height) / 8);

        $bytesPerRow = ceil($width / 8);

        return sprintf('~DG%s,%05d,%03d,' . PHP_EOL, $targetname, $totalBytes, $bytesPerRow) . $hexString;

      }

      // Usage:

      print image2grf('HD.png', 'R:SAMPLE.GRF');

      // print "^XA^FO20,20^XGR:SAMPLE.GRF,1,1^FS^XZ" . PHP_EOL;

       

      Any alternative that I can print the image in png format

      please look at the code and provide the solution

      Thanks in advance...