How Can I print bangla? When I print bangla it not print properly.

[MohsinP07]

Hey @rudroanik I am also facing the same issue, Did you solved this?

[rudroanik]

@MohsinP07 Yes, I found the solution

[MohsinP07]

@rudroanik How did you solved it can you suggest me?

[rudroanik]

@MohsinP07 You could not print direct bangla text in thermal printer. You have to convert text to image. Here is method for convert string to image.

Future<Uint8List> generateImageFromString(
    String text,double xOffset,{bool isUnderline = false,double fontSize=22}) async {
  PictureRecorder recorder = PictureRecorder();
  Canvas canvas = Canvas(
      recorder,
      Rect.fromCenter(
        center: Offset(0, 0),
        width: 550,
        height: 550, // cheated value, will will clip it later...
      ));
  TextSpan span = TextSpan(
    style: TextStyle(
      color: Colors.black,
      fontSize: fontSize,
      decoration:TextDecoration.none,
    ),
    text: text,
  );
  TextPainter tp = TextPainter(
      text: span,
      maxLines: 8,
      textDirection: TextDirection.ltr);
  tp.layout(minWidth: 400, maxWidth: 500);
  tp.paint(canvas,  Offset(xOffset, 0.0));
  final picture = recorder.endRecording();
  final pngBytes = await picture.toImage(
    tp.size.width.toInt(),
    tp.size.height.toInt(), // decrease padding
  );
  final byteData = await pngBytes.toByteData(format: ImageByteFormat.png);
  return byteData!.buffer.asUint8List();
}

[MohsinP07]

@rudroanik Hey Brother I tried but i am getting error as Failed to handle method call E/MethodChannel#bluetooth_thermal_printer( 7453): java.lang.ClassCastException: byte[] cannot be cast to java.util.List E/MethodChannel#bluetooth_thermal_printer( 7453): at com.peoplewareinnovations.bluetooth_thermal_printer.BluetoothThermalPrinterPlugin.onMethodCall(BluetoothThermalPrinterPlugin.kt:106) E/MethodChannel#bluetooth_thermal_printer( 7453): at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:258) E/MethodChannel#bluetooth_thermal_printer( 7453): at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:295) E/MethodChannel#bluetooth_thermal_printer( 7453): at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$DartMessenger(DartMessenger.java:322) E/MethodChannel#bluetooth_thermal_printer( 7453): at io.flutter.embedding.engine.dart.-$$Lambda$DartMessenger$2j2MERcK825A5j1fv5sZ7xB2Iuo.run(Unknown Source:12) E/MethodChannel#bluetooth_thermal_printer( 7453): at android.os.Handler.handleCallback(Handler.java:938) E/MethodChannel#bluetooth_thermal_printer( 7453): at android.os.Handler.dispatchMessage(Handler.java:99) E/MethodChannel#bluetooth_thermal_printer( 7453): at android.os.Looper.loop(Looper.java:246) E/MethodChannel#bluetooth_thermal_printer( 7453): at android.app.ActivityThread.main(ActivityThread.java:8653) E/MethodChannel#bluetooth_thermal_printer( 7453): at java.lang.reflect.Method.invoke(Native Method) E/MethodChannel#bluetooth_thermal_printer( 7453): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602) E/MethodChannel#bluetooth_thermal_printer( 7453): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130) I/flutter ( 7453): Failed to write bytes: 'byte[] cannot be cast to java.util.List'.

Here is my code

`Future<void> printTicket(
      CollectionItem collectionItem, Map _depositor) async {
    String? isConnected = await BluetoothThermalPrinter.connectionStatus;
    print('printing connection status');

    print(isConnected);
    if (isConnected == "true") {
      List<int> bytes = await generateImageFromString();
      final result = await BluetoothThermalPrinter.writeBytes(bytes);
      print("Print $result");
    } else {
      await BluetoothThermalPrinter.connect(
          bluetoothBox.get('printerCredentials')['macAddr']);
      List<int> bytes = await generateImageFromString();
      final result = await BluetoothThermalPrinter.writeBytes(bytes);
      print("Print $result");
      //Hadnle Not Connected Senario
    }
  }

  Future<Uint8List> generateImageFromString() async {
    ui.PictureRecorder recorder = ui.PictureRecorder();
    Canvas canvas = Canvas(
        recorder,
        Rect.fromCenter(
          center: Offset(0, 0),
          width: 550,
          height: 550, // cheated value, will will clip it later...
        ));
    TextSpan span = TextSpan(
      style: TextStyle(
        color: Colors.black,
        fontSize: 14,
        decoration: TextDecoration.none,
      ),
      text: "मराठी",
    );
    TextPainter tp = TextPainter(
        text: span, maxLines: 8, textDirection: ui.TextDirection.ltr);
    tp.layout(minWidth: 400, maxWidth: 500);
    tp.paint(canvas, Offset(4, 0.0));
    final picture = recorder.endRecording();
    final pngBytes = await picture.toImage(
      tp.size.width.toInt(),
      tp.size.height.toInt(), // decrease padding
    );
    final byteData = await pngBytes.toByteData(format: ui.ImageByteFormat.png);
    return byteData!.buffer.asUint8List();
  }` 

[rudroanik]

@MohsinP07

static Future<List<int>> thermalPrint(Pass your parameter) async {
    List<int> bytes = [];
    CapabilityProfile profile = await CapabilityProfile.load();
    final generator = Generator(PaperSize.mm58, profile);

    final imageBytes = await generateImageFromString("রশিদ", 90.0, fontSize: 26);

    bytes += generator.image(decodeImage(imageBytes)!, align: PosAlign.right);

    bytes += generator.cut();
    return bytes;
  }

final List<int> bytes = await thermalPrint(Pass your parameter);
 await BluetoothThermalPrinter.writeBytes(bytes);

Use this package for Generator https://pub.dev/packages/esc_pos_utils

[MohsinP07]

@rudroanik Thanks a lot bro solved this issue!. One more thing how can i remove the unwanted padding which i am getting at the start and end of the content which is basically wasting the paper at large extend how can keep height according to content i changed this height
Canvas canvas = Canvas( recorder, Rect.fromCenter( center: Offset(0, 0), width: 550, height: 550, // cheated value, will will clip it later... ));

but still the issue occurs that i am getting unwanted spaces at start and end of the content.

[MohsinP07]

Hey @rudroanik, any solution for this??