expo-brother-printer-sdk

Expo module to connect to Brother printers

Installation in managed Expo projects

For managed Expo projects, please follow the installation instructions in the API documentation for the latest stable release. If you follow the link and there is no documentation available then this library is not yet usable within managed projects — it is likely to be included in an upcoming Expo SDK release.

Installation in bare React Native projects

For bare React Native projects, you must ensure that you have installed and configured the expo package before continuing.

Add the package to your npm dependencies

npm install expo-brother-printer-sdk

Native Configuration

1. Add the config plugin to app.json to add the necessary native configurations.

   {
    "expo": {
      ...
      "plugins": [
        ...,
        "expo-brother-printer-sdk"
      ],
    }
   }

2. Run npx expo prebuild --clean to update the app configuration.

Searching for printers

The SDK supports connecting to printers via both Bluetooth & via WiFi.

Connect via Bluetooth:

NOTE: Connecting via Bluetooth does not work in the Simulator. You will need a physical device for this feature.

1. Connect the printer to the iPhone or Android device via the Bluetooth devices page in settings.
2. Then use the searchBluetoothPrinters function to enumerate all Brother printers connected via Bluetooth.

   const blChannels = await BrotherPrinterSDK.searchBluetoothPrinters();

Connect via WiFi

NOTE: Connecting via WiFi works in both the Simulator and physical devices.

1. Connect the printer to a WiFi network.
2. Ensure the phone (or the mac running the Simulator) is connected to the same WiFi network.
3. Use the searchNetworkPrinters function to enumerate all Brother printers detected on the same WiFi network. Note that this method requires you to specify the model(s) of printers to search for.

   const wifiChannels = await BrotherPrinterSDK.searchNetworkPrinters({
     printerList: ['QL-820NWB'], // iOS only
     isTethering: false,         // Android only
     searchDuration: 2000,       // optional; defaults to 1000ms
   });

Printing Images

Once a printer channel is acquired, you can send a print job to it by specifying a URL to an image.

NOTE: The image URL must be a local file URL. Passing a remote URL will fail silently.

Use the printImage function to send a print job to the chosen printer channel.

const imageUri = 'file:///path/to/local/image.png'; // PNG & JPEG formats are supported

const channel  = /* channel obtained using Bluetooth or WiFi search methods above. */

// all settings are optional. see BPrintSettings documentation for details
const settings: BPPrintSettings = {
  labelSize: BPQLLabelSize.RollW62,
  autoCutForEachPageCount: 1,
  autoCut: true,
  cutAtEnd: true,
  resolution: BPResolution.Normal,
  halftone: BPHalftone.PatternDither,
};

await BrotherPrinterSDK.printImage(imageUri, channel, settings);

Printing PDFs

The SDK also supports printing PDFs. The functionality is very similar to when printing images.

Use the printPDF function to send a PDF print job.

const pdfUri = 'file:///path/to/local/doc.pdf'; // local PDF file URL

const channel  = /* channel obtained using Bluetooth or WiFi search methods above. */

// all settings are optional. see BPrintSettings documentation for details
const settings: BPPrintSettings = {
  labelSize: BPQLLabelSize.RollW62,
  autoCutForEachPageCount: 1,
  autoCut: true,
  cutAtEnd: true,
  resolution: BPResolution.Normal,
  halftone: BPHalftone.PatternDither,
};

await BrotherPrinterSDK.printPDF(pdfUri, channel, settings);

Contributing

Contributions are very welcome! Please refer to guidelines described in the contributing guide.