chrome.printing

Description

Permissions

Availability

All chrome.printing methods and events require you to declare the "printing" permission in the extension manifest. For example:

{
  "name": "My extension",
  ...
  "permissions": [
    "printing"
  ],
  ...
}

Examples

The examples below demonstrate using each of the methods in the printing namespace. This code is copied from or based on the api-samples/printing in the extensions-samples Github repo.

cancelJob()

This example uses the onJobStatusChanged handler to hide a 'cancel' button when the jobStatus is neither PENDING or IN_PROGRESS. Note that on some networks or when a Chromebook is connected directly to the printer, these states may pass too quickly for the cancel button to be visible long enough to be called. This is greatly simplified printing example.

chrome.printing.onJobStatusChanged.addListener((jobId, status) => {
  const cancelButton = document.getElementById("cancelButton");
  cancelButton.addEventListener('click', () => {
    chrome.printing.cancelJob(jobId).then((response) => {
      if (response !== undefined) {
        console.log(response.status);
      }
      if (chrome.runtime.lastError !== undefined) {
        console.log(chrome.runtime.lastError.message);
      }
    });
  });
  if (status !== "PENDING" && status !== "IN_PROGRESS") {
    cancelButton.style.visibility = 'hidden';
  } else {
    cancelButton.style.visibility = 'visible';
  }
}

getPrinters() and getPrinterInfo()

A single example is used for these functions because getting printer information requires a printer ID, which is retrieved by calling getPrinters(). This example logs the name and description of the default printer to the console. This is a simplified version of the printing example.

​​const printers = await chrome.printing.getPrinters();
const defaultPrinter = printers.find((printer) => {
  const printerInfo = await chrome.printing.getPrinterInfo(printer.id);
  return printerInfo.isDefault;
}
console.log(`Default printer: ${defaultPrinter.name}.\n\t${defaultPrinter.description}`);

submitJob()

The submitJob() method requires three things.

• A ticket structure specifying which capabilities of the printer are to be used. If the user needs to select from available capabilities, you can retrieve them for a specific printer using getPrinterInfo().
• A SubmitJobRequest structure, which specifies the printer to use, and the file or date to print. This structure contains a reference to the ticket structure.
• A blob of the file or data to print.

Calling submitJob() triggers a dialog box asking the user to confirm printing. Use the PrintingAPIExtensionsAllowlist to bypass confirmation.

This is a simplified version of the printing example. Notice that the ticket is attached to the SubmitJobRequest structure (line 8) and that the data to print is converted to a blob (line 10). Getting the ID of the printer (line 1) is more complicated in the sample than is shown here.

const defaultPrinter = getDefaultPrinter();
const ticket = getPrinterTicket(defaultPrinter);
const arrayBuffer = getPrintData();
const submitJobRequest = {
  job: {
    printerId: defaultPrinter,
    title: 'test job',
    ticket: ticket,
    contentType: 'application/pdf',
    document: new Blob([new Uint8Array(arrayBuffer)], {
      type: 'application/pdf'
    });
  }
};

chrome.printing.submitJob(submitJobRequest, (response) => {
  if (response !== undefined) {
    console.log(response.status);
  }
  if (chrome.runtime.lastError !== undefined) {
    console.log(chrome.runtime.lastError.message);
  }
});

Roll printing

This example shows how to build a printer ticket for continuous (or roll) printing, which is often used with receipt printing. The submitJobRequest object for roll printing is the same as that shown for the submitJob() example.

If you need to change the default value for paper cutting, use the vendor_ticket_item key. (The default varies from printer to printer.) To change the value, provide an array with one member: an object whose id is 'finishings'. The value can either be 'trim' for printers that cut the roll at the end of printing or 'none' for printers that require the print job to be torn off.

const ticket = {
  version: '1.0',
  print: {
    vendor_ticket_item: [{id: 'finishings', value: 'trim'}],
    color: {type: 'STANDARD_MONOCHROME'},
    duplex: {type: 'NO_DUPLEX'},
    page_orientation: {type: 'PORTRAIT'},
    copies: {copies: 1},
    dpi: {horizontal_dpi: 300, vertical_dpi: 300},
    media_size: {
      width_microns: 72320,
      height_microns: 100000
    },
    collate: {collate: false}
  }
};

Some printers do not support the "finishings" option. To determine if your printer does, call getPrinterInfo() and look for a "display_name" of "finishings/11".

"vendor_capability": [
  {
    "display_name": "finishings/11",
    "id": "finishings/11",
    "type": "TYPED_VALUE",
    "typed_value_cap": {
      "value_type": "BOOLEAN"
    }
  },
  ...
]

The values in a ticket's media_size key are specific to each printer. To select an appropriate size call getPrinterInfo(). The returned GetPrinterResponse contains an array of supported media sizes at "media_size"."option". Choose an option whose "is_continuous_feed" value is true. Use its height and width values for the ticket.

"media_size": {
  "option": [
  {
    "custom_display_name": "",
    "is_continuous_feed": true,
    "max_height_microns": 2000000,
    "min_height_microns": 25400,
    "width_microns": 50800
  },
  ...
  ]
}

chrome.printing.cancelJob(
  jobId: string,
  callback?: function,
)

chrome.printing.getPrinterInfo(
  printerId: string,
  callback?: function,
)

chrome.printing.getPrinters(
  callback?: function,
)

chrome.printing.submitJob(
  request: SubmitJobRequest,
  callback?: function,
)

chrome.printing.onJobStatusChanged.addListener(
  callback: function,
)