CODEWITHSUNDEEP
flutterqr-codethermal-printer
Geoffrey Lee
Geoffrey Lee

Reputation: 407

Flutter Print Qr Code Image in Flutter to Thermal Printer

I try to print out qr code to thermal printer by using flutter_bluetooth_serial.

I generate the qr code by using following guide https://medium.com/flutter-community/building-flutter-qr-code-generator-scanner-and-sharing-app-703e73b228d3

I manage to convert the image into Uint8List and send to the printer.

Future<Uint8List> _getQrByte() async {
    RenderRepaintBoundary boundary =
        globalKey.currentContext.findRenderObject();
    var image = await boundary.toImage();
    var byteData = await image.toByteData();
    return byteData.buffer.asUint8List();
  }

and I call function in flutter_bluetooth_serial

await _bluetooth.writeBytes(bytes);

I expect to print a perfect qr code, but the printout is random char and very long.

In android, I manage to print out by sending byte array from bitmap class to the printer

Upvotes: 1

Views: 3870

Answers (2)

Bruno Santos
Bruno Santos

Reputation: 35

You can use this:

final profile = await CapabilityProfile.load(name: 'XP-N160I');

final generator = Generator(PaperSize.mm80, profile);

  bytes += generator.qrcode(
    'https://github.com/BrunoSantosCosta',
    size: const QRSize(30),
  );

Upvotes: 0

Jean DuPont
Jean DuPont

Reputation: 451

Have you tried esc_pos_bluetooth for a Bluetooth printer (or esc_pos_printer for a WiFi/network printer)? Both packages can print QR codes

Upvotes: 1

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