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Tres Finocchiaro edited this page Apr 26, 2021 · 3 revisions

Compatibility

  • ✅ 2.0 | ⛔ 1.9 | ...

Deprecation Notice

⚠️ This API is deprecated. Please use the 2.1 API here with the latest qz-tray.js, which is fully backwards compatible with the 2.0 version.

Background

These features may not work with many raw printing devices, such as Zebra, Epson, Citizen printers. The data is sent in Pixel Printing format, which is more common for LaserJet or Deskjet printers. The ZDesigner driver from Zebra allows both raw and pixel printing.

To test these features without a physical printer, use a printer emulator

Contents

The following code can be used for Pixel Printing (formerly Postscript Printing) only. If you are unsure what Pixel Printing is, please refer to What is Pixel Printing?

HTML Printing

  1. HTML rendering is done via pure Java in using an embedded webkit browser

    var config = qz.configs.create("Printer Name");
var data = [{
   type: 'html',
   format: 'file', // or 'plain' if the data is raw HTML
   data: 'assets/html_sample.html'
}];
qz.print(config, data).catch(function(e) { console.error(e); });

  2. An options parameter can be supplied to signify things including margins, orientation, size, printer language, encoding, etc.

    Orientation

    var config = qz.configs.create("Printer Name", { margins: 2, orientation: 'landscape'});
var data = [{
   type: 'html',
   format: 'file', // or 'plain' if the data is raw HTML
   data: 'assets/html_sample.html'
}];
qz.print(config, data).catch(function(e) { console.error(e); });

    Page Width

    A print parameter can be supplied to force a particular HTML page width. If you're experiencing layout problems, please see this explanation.

    var config = qz.configs.create("Printer Name");
var data = [{
   type: 'html',
   format: 'file', // or 'plain' if the data is raw HTML
   data: 'assets/html_sample.html',
   options: { pageWidth: 8 }
}];
qz.print(config, data).catch(function(e) { console.error(e); });

    Page Height

    A print parameter can be supplied to force a particular HTML page height. If you're experiencing layout problems, please see this explanation.

    var config = qz.configs.create("Printer Name");
var data = [{
   type: 'html',
   format: 'file', // or 'plain' if the data is raw HTML
   data: 'assets/html_sample.html',
   options: { pageHeight: 11.5 }
}];
qz.print(config, data).catch(function(e) { console.error(e); });

    JavaFX

    • ⚠️ Java 8 + JavaFX is required for high-resolution (>72 dpi) HTML printing.
      • ⚠️ Linux users: By default, JavaFX is NOT included in OpenJDK
    • 💡 We recommend using AdoptOpenJDK 11 for all Operating Systems. We have written an installation tutorial: Upgrading Java

    Legacy HTML

    Since 2.0.6, a legacy parameter can be supplied to force QZ Tray to emulate HTML printing engine from QZ Tray 1.9 and older. For receipt printers, it's recommend to add style="margin-left: 8px;" to mimic the margins from 1.9.

    var config = qz.configs.create("Printer Name", { legacy: true });
var data = [{
   type: 'html',
   format: 'file', // or 'plain' if the data is raw HTML
   data: 'assets/html_sample.html',
}];
qz.print(config, data).catch(function(e) { console.error(e); });

PDF Printing

QZ Tray 2.0 allows printing PDF files directly to a printer using Apache PDFBOX.

  1. How to print a PDF file

    var config = qz.configs.create("Printer Name");
var data = [{ 
      type: 'pdf', 
      data: 'assets/pdf_sample.pdf' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

    Base64 PDF

  2. How to print a base64 PDF

    var config = qz.configs.create("Printer Name");
var data = [{ 
   type: 'pdf',
   format: 'base64',
   data: 'Ck4KcTYwOQpRMjAzLDI2CkI1LDI2LDAsMUEsMyw3LDE1MixCLCIxMjM0IgpBMzEwLDI2LDAsMywx...' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Image Printing

var config = qz.configs.create("Printer Name");
var data = [{ 
   type: 'image', 
   data: 'assets/img/image_sample.png' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Base64 Image

var config = qz.configs.create("Printer Name");
var data = [{ 
   type: 'image', 
   format: 'base64',
   data: 'AAAA...==' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Advanced Printing

Page Size

A page size can be set using the config parameter size.

  • Both standard and metric sizes are supported. Warning, providing a metric page size will assume the density is in a metric format as well.
Dymo LabelWriter

The following example illustrates how to print a 2.25in x 1.25in label to a Dymo LabelWriter printer.

  • size is provided in inches. Alternatively 57.15mm x 31.75mm can be provided if metric units are desired.
  • interpolation is provided to prevent barcode blurring.
  • colorType is provided to maximize driver quality compatibility/300dpi dithering.
   function printStuff() {
      var config = qz.configs.create("Printer Name", {
         size: {width: 2.25, height: 1.25}, units: 'in', 
         colorType: 'grayscale', 
         interpolation: "nearest-neighbor" 
      });

      var data = [{ 
         type: 'image', 
         data: 'assets/img/image_sample.png' 
      }];

      qz.print(config, data).catch(function(e) { console.error(e); });
   }

Margins

A config parameter margins can be provided to change the default page margins around the content.

 var config = qz.configs.create("Printer Name", { margins: { top: 0.25, right: 0.25, bottom: 0.25, left: 0.25 } 
 });
 var data = [{ 
   type: 'image', 
   data: 'assets/img/image_sample.png'
 }];
 qz.print(config, data).catch(function(e) { console.error(e); });

Image Interpolation

A config parameter interpolation can be provided to change the pixel blending technique used when scaling an image.

var config = qz.configs.create("Printer Name", { interpolation: "nearest-neighbor" });
var data = [{ 
   type: 'image', 
   data: 'assets/img/image_sample.png'
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Density

Not providing a density will cause printing to use the default value for the printer. A config parameter density can be provided to change the DPI, dots/mm or dots/cm respectively. Since 2.0.2, multiple density values can be provided in an array and the first compatible density will be chosen.

var config = qz.configs.create("Printer Name", { units: "in", density: "600" });  // force 600dpi
var data = [{ 
   type: 'pdf', 
   data: 'assets/pdf_sample.pdf' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Copies

A config parameter copies can be provided to send the specified raw commands multiple times. This is a convenience function as most raw languages already have an internal copies command.

function copies() {
var config = qz.configs.create("Printer Name", { copies: 4 });

var data = [{ 
   type: 'pdf', 
   data: 'assets/pdf_sample.pdf' 
}];

qz.print(config, data).catch(function(e) { console.error(e); });
}

Custom Job Name

A config parameter jobName can be provided to change the name listed in the print queue.

var config = qz.configs.create("Printer Name", { jobName: "Receipt #123456" });
var data = [{ 
   type: 'image', 
   data: 'assets/img/image_sample.png' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Disable Autoscale

By default, content is automatically scaled to the destination page size. This is done as a courtesy to take out the guesswork in fitting the content to the media. A config parameter scaleContent can be forced to prevent auto-scaling.

var config = qz.configs.create("Printer Name", { scaleContent: "false" });  // do not stretch image to page width
var data = [{ 
   type: 'image', 
   data: 'assets/image_sample.png' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Rasterize

In some cases, rather than rasterizing print output, the vector version is preferred. This can have both quality as well as performance benefits during the printing process. A config parameter rasterize can be forced to prevent software rasterization prior to printing.

var config = qz.configs.create("Printer Name", { rasterize: "false" });  // use vector rendering
var data = [{ 
   type: 'pdf', 
   data: 'assets/pdf_sample.pdf' 
}];
qz.print(config, data).catch(function(e) { console.error(e); });

Chaining Requests

Print requests can be chained together to print several documents at once, or to print to several different printers.

var config = qz.configs.create();
var data = [{ type: 'image', data: null, }];

data.data = 'assets/img/my_first_image.png';       ////// First document
config.setPrinter('First Printer');                ////// First printer
qz.print(config, data)

.then(function() {
   data.data = 'assets/img/my_second_image.png';   ////// Second document
   config.setPrinter('Second Printer');            ////// Second printer
   return qz.print(config, data);
})

.then(function() {
   data.data = 'assets/img/my_third_image.png';    ////// Third document
   config.setPrinter('Third Printer');             ////// Third printer
   return qz.print(config, data);
})

.catch(function(e) {
   console.error(e);                // Exceptions throw all the way up the stack
});

Promise Loop

Using a Promise Loop, we can defer items (printers, data)

  • So that different chunks of data can be sent to different printers
  • So that an arbitrary (non-fixed) amount of data can be sent to a printer
function promiseLoop() {
    var data = [
        { "type": "pdf", "data": "assets/sample_pdf1.pdf" },
        { "type": "pdf", "data": "assets/sample_pdf2.pdf" },
        { "type": "pdf", "data": "assets/sample_pdf3.pdf" },
        { "type": "pdf", "data": "assets/sample_pdf3.pdf" },
        { "type": "pdf", "data": "assets/sample_pdf5.pdf" }
    ];
    var configs = [
        { "printer": "HP LaserJet M605" },
        { "printer": "HP LaserJet M605" },
        { "printer": "HP LaserJet M605" },
        { "printer": "HP LaserJet M605" },
        { "printer": "HP LaserJet M605" }
    ];
    var chain = [];

    for(var i = 0; i < data.length; i++) {
        (function(i_) {
            //setup this chain link
            var link = function() {
                return qz.printers.find(configs[i_].printer).then(function(found) {
                    return qz.print(qz.configs.create(found), [data[i_]]);
                });
            };

            chain.push(link);
        })(i);
        //closure ensures this promise's concept of `i` doesn't change
    }

    //can be .connect or `Promise.resolve()`, etc
    var firstLink = new RSVP.Promise(function(r, e) { r(); });

    var lastLink = null;
    chain.reduce(function(sequence, link) {
        lastLink = sequence.then(link);
        return lastLink;
    }, firstLink);

    //this will be the very last link in the chain
    lastLink.catch(function(err) {
        console.error(err);
    });
}
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