pos_kozen_printer

Flutter plugin for KOZEN printers on TUU/Haulmer POS PRO2 devices. Easily print text and images on thermal printers.

Features

✅ Print text with multiple styles (bold, italic, underline, inverted)
✅ Print images (PNG, JPEG)
✅ Support for text columns (2 or 3 columns)
✅ Alignment control (left, center, right)
✅ Print event management (start, finish, errors)
✅ Printer status verification
✅ Simple and well-documented API

Requirements

Flutter SDK: >=3.0.0
Dart SDK: ^3.8.0
Android: minSdk 21 (Android 5.0)
TUU/Haulmer POS PRO2 device with KOZEN printer

Installation

Add the package to your pubspec.yaml:

dependencies:
  pos_kozen_printer: ^0.0.1

Then run:

flutter pub get

Note: The KOZEN library is already included in the plugin. You don't need to add any additional files to your app.

Basic usage

Import the package

import 'package:pos_kozen_printer/pos_kozen_printer.dart';

Simple example

final printer = PosKozenPrinter();

// 1. Open printer connection
await printer.open();

// 2. Add content
await printer.addTextLine(
  TextPrintLine.bold(
    'Hello World!',
    alignment: PrintAlignment.center,
    fontSize: 28,
  ),
);
await printer.addBlankLines(3);

// 3. Print with listener
await printer.beginPrint(
  SimplePrinterListener(
    onStart: () => print('Printing started'),
    onFinish: () async {
      await printer.cleanCache();
      await printer.close();
      print('Print complete');
    },
    onError: (error, message) async {
      await printer.cleanCache();
      await printer.close();
      print('Error: ${error.description}');
    },
  ),
);

Print complete receipt

final printer = PosKozenPrinter();
await printer.open();

// Header
await printer.addTextLine(
  TextPrintLine.bold('MY STORE', alignment: PrintAlignment.center, fontSize: 32),
);
await printer.addTextLine(
  TextPrintLine.simple('123 Main Street', alignment: PrintAlignment.center),
);
await printer.addBlankLines(2);

// Items in columns
await printer.addTextColumns([
  TextPrintLine.simple('Product 1', alignment: PrintAlignment.left),
  TextPrintLine.simple('\$10.00', alignment: PrintAlignment.right),
]);
await printer.addTextColumns([
  TextPrintLine.simple('Product 2', alignment: PrintAlignment.left),
  TextPrintLine.simple('\$25.50', alignment: PrintAlignment.right),
]);

await printer.addBlankLines(1);

// Total
await printer.addTextColumns([
  TextPrintLine.bold('TOTAL:', alignment: PrintAlignment.left, fontSize: 28),
  TextPrintLine.bold('\$35.50', alignment: PrintAlignment.right, fontSize: 28),
]);

await printer.addBlankLines(5);

// Print
await printer.beginPrint(
  SimplePrinterListener(
    onFinish: () async {
      await printer.cleanCache();
      await printer.close();
    },
    onError: (error, msg) async {
      await printer.cleanCache();
      await printer.close();
    },
  ),
);

Print images

import 'dart:typed_data';
import 'package:flutter/services.dart';

final printer = PosKozenPrinter();
await printer.open();

// Load image from assets
final ByteData data = await rootBundle.load('assets/logo.png');
final Uint8List bytes = data.buffer.asUint8List();

// Add centered image
await printer.addBitmapLine(
  BitmapPrintLine(
    imageBytes: bytes,
    alignment: PrintAlignment.center,
  ),
);

await printer.addBlankLines(3);
await printer.beginPrint(/* ... */);

Main API