使用 Zebra 打印机的 PHP 或 Javascript 将 RGB 图像转换为 Floyd-Steinberg 图像
Converting RGB image to Floyd-Steinberg image using PHP or Javascript for Zebra printers
我正在开发一个基于桌面的 PHP 应用程序，我们需要在其中捕获人物图像并使用 Zebra GC420t 打印机将其打印在标签上
预期的图像应如下图所示。
当我尝试打印时，它给出了如下图所示的输出。
我使用以下代码将 rgb 图像转换为 dithering 图像，使用 php 代码
$photo_url="";
if(isset($_GET['photo'])){
$photo_url=$_GET['photo'];
}
function image2grf($filename='$photo_url', $targetname = 'R:IMAGE.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) . $hexString;
}
// Usage:
print "^XA N ^XZ" . PHP_EOL;
print image2grf($photo_url, 'R:SAMPLE.GRF');
//print "^XA^FO20,20^XGR:SAMPLE.GRF,1,1^FS^XZ" . PHP_EOL;
我正在连接我的应用程序并使用下面的 javascript 代码将参数传递给打印机
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 occured 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.");
};
// new Date().toLocaleTimeString('en-US', { hour12: false,
// hour: "numeric",
// minute: "numeric"});
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("~DYE:SAMPLE.GRF,A,GRF,5000,030"+test+",A"); selected_printer.send("^XA^FX^CFA,30^FO10,70^FDVisitorName:"+$("#user").val()+"^FS^FO10,120^FDCompany:"+$("#compName").val()+"^FS ^FO10,170^FDTo Meet:"+$("#toMeet").val()+"^FS ^FO10,220^FDPurpose:"+$("#reason").val()+"^FS ^FO10,270^FDAuthorise^FS ^FO10,320^FDto Carry:"+mob+" "+lap+"^FS^FO250,70^XG R:SAMPLE.GRF,1,1^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();
$('#error_div').hide();
setup_web_print();
//hideLoading();
}
在下面的函数中，我发送了打印所需的参数
selected_printer.send("^XA^FX^CFA,30^FO10,70^FDVisitorName:"+$("#user").val()+"^FS^FO10,120^FDCompany:"+$("#compName").val()+"^FS ^FO10,170^FDTo Meet:"+$("#toMeet").val()+"^FS ^FO10,220^FDPurpose:"+$("#reason").val()+"^FS ^FO10,270^FDAuthorise^FS ^FO10,320^FDto Carry:"+mob+" "+lap+"^FS^FO250,70^XG R:SAMPLE.GRF,1,1^FS^XZ");
在上面的函数中图像数据存储在^FO250,70^XG R:SAMPLE.GRF,1,1^FS
当我将数据发送到打印机时，它正确打印了所有文本，但打印的图像如第二张图片所示，但预期的打印图像如第一张图片所示。如果我对在 labelary 网站上完成的图像转换进行硬编码，我就可以打印第一张图像。如果我实时点击图像并打印它会给出第二张图像。
看看这个库 GDIndexedColorConverter 这是一个将图像转换为索引颜色模式的简单库。
require 'GDIndexedColorConverter.php';
// create an image
$image = imagecreatefromjpeg('image.jpg');
// create a gd indexed color converter
$converter = new GDIndexedColorConverter();
// the color palette
$palette = array(
array(0, 0, 0),
array(255, 255, 255),
array(0, 0, 0),
array(0, 0, 0),
array(0, 0, 0)
);
// convert the image to indexed color mode
$new_image = $converter->convertToIndexedColor($image, $palette, 0.25);
// save the new image
imagepng($new_image, 'example_indexed_color.png', 0);
这是输入：
这是输出：
我正在开发一个基于桌面的 PHP 应用程序，我们需要在其中捕获人物图像并使用 Zebra GC420t 打印机将其打印在标签上
预期的图像应如下图所示。
当我尝试打印时，它给出了如下图所示的输出。
rgb 图像转换为 dithering 图像，使用 php 代码
$photo_url="";
if(isset($_GET['photo'])){
$photo_url=$_GET['photo'];
}
function image2grf($filename='$photo_url', $targetname = 'R:IMAGE.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) . $hexString;
}
// Usage:
print "^XA N ^XZ" . PHP_EOL;
print image2grf($photo_url, 'R:SAMPLE.GRF');
//print "^XA^FO20,20^XGR:SAMPLE.GRF,1,1^FS^XZ" . PHP_EOL;
我正在连接我的应用程序并使用下面的 javascript 代码将参数传递给打印机
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 occured 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.");
};
// new Date().toLocaleTimeString('en-US', { hour12: false,
// hour: "numeric",
// minute: "numeric"});
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("~DYE:SAMPLE.GRF,A,GRF,5000,030"+test+",A"); selected_printer.send("^XA^FX^CFA,30^FO10,70^FDVisitorName:"+$("#user").val()+"^FS^FO10,120^FDCompany:"+$("#compName").val()+"^FS ^FO10,170^FDTo Meet:"+$("#toMeet").val()+"^FS ^FO10,220^FDPurpose:"+$("#reason").val()+"^FS ^FO10,270^FDAuthorise^FS ^FO10,320^FDto Carry:"+mob+" "+lap+"^FS^FO250,70^XG R:SAMPLE.GRF,1,1^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();
$('#error_div').hide();
setup_web_print();
//hideLoading();
}
在下面的函数中，我发送了打印所需的参数
selected_printer.send("^XA^FX^CFA,30^FO10,70^FDVisitorName:"+$("#user").val()+"^FS^FO10,120^FDCompany:"+$("#compName").val()+"^FS ^FO10,170^FDTo Meet:"+$("#toMeet").val()+"^FS ^FO10,220^FDPurpose:"+$("#reason").val()+"^FS ^FO10,270^FDAuthorise^FS ^FO10,320^FDto Carry:"+mob+" "+lap+"^FS^FO250,70^XG R:SAMPLE.GRF,1,1^FS^XZ");
在上面的函数中图像数据存储在^FO250,70^XG R:SAMPLE.GRF,1,1^FS
当我将数据发送到打印机时，它正确打印了所有文本，但打印的图像如第二张图片所示，但预期的打印图像如第一张图片所示。如果我对在 labelary 网站上完成的图像转换进行硬编码，我就可以打印第一张图像。如果我实时点击图像并打印它会给出第二张图像。
看看这个库 GDIndexedColorConverter 这是一个将图像转换为索引颜色模式的简单库。
require 'GDIndexedColorConverter.php';
// create an image
$image = imagecreatefromjpeg('image.jpg');
// create a gd indexed color converter
$converter = new GDIndexedColorConverter();
// the color palette
$palette = array(
array(0, 0, 0),
array(255, 255, 255),
array(0, 0, 0),
array(0, 0, 0),
array(0, 0, 0)
);
// convert the image to indexed color mode
$new_image = $converter->convertToIndexedColor($image, $palette, 0.25);
// save the new image
imagepng($new_image, 'example_indexed_color.png', 0);
这是输入：
这是输出：