Question 273156 in Flutter Question posted in
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Flutter – how to print text in more than one row on a thermal printer?

I have a flutter application that makes use of a thermal printer, when the following format is printed:

C. Order
1 Order one description long too and more
2 Order two description long too and more

If the column order is quite long, only the part where it reaches the row is printed.
I am using the following packages for printing:

  • print_bluetooth_thermal: ^1.0.9
  • esc_pos_utils: ^1.1.0
    This piece of code is where the print command is added.
final Generator ticket = Generator(paper, profile);
List<int> bytes = [];
String product = _cleanText(detail['product'].toString());
bytes += ticket.row([
        PosColumn(text: detail['amount'].toString(), width: 1),
        PosColumn(text: product, width: 11)
]);

It is required that if the order does not reach the row, it is printed on the next line.
The result should be like this:

C. Order
1 Order one description long
too and more
2 Order two description long
too and more
Tags:

2

Answers


  1. 0

    To print text in more than one row on a thermal printer in a Flutter application, you might need to split the text into multiple lines manually and then print each line separately. You can create a function to handle the splitting of the text based on the maximum width of the text that the printer can handle on a single line.

    Here’s how you could modify your code:

    import 'package:esc_pos_utils/esc_pos_utils.dart';
import 'package:print_bluetooth_thermal/print_bluetooth_thermal.dart';

// Function to split the text into multiple lines
List<String> splitText(String text, int maxWidth) {
  List<String> lines = [];
  while (text.length > maxWidth) {
    int index = text.lastIndexOf(' ', maxWidth);
    if (index == -1) index = maxWidth;
    lines.add(text.substring(0, index));
    text = text.substring(index).trim();
  }
  lines.add(text);
  return lines;
}

// Printing function
void printOrder(Map detail, CapabilityProfile profile) {
  const PaperSize paper = PaperSize.mm80;
  final Generator ticket = Generator(paper, profile);
  List<int> bytes = [];
  
  String product = _cleanText(detail['product'].toString());
  List<String> productLines = splitText(product, 20); // assuming max 20 chars per line
  
  bytes += ticket.text('${detail['amount']}');
  for (String line in productLines) {
    bytes += ticket.text(line);
  }
  
  // Send bytes to the printer
  // ... your printing code goes here ...
}
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  2. 0

    use log instead of print. Remember to import import ‘dart:developer’ as developer.

     import 'dart:developer' as developer;
    
    void main() {
      var myCustomObject = MyCustomObject();
    
      developer.log(
        'log me',
        name: 'my.app.category',
        error: jsonEncode(myCustomObject),
      );
    }
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