QR Code Dart Decoder

A Flutter/Dart package for decoding QR codes and other barcode formats from images and camera streams. Built on top of the ZXing library, this package provides a simple API for barcode recognition in Dart applications.

Features

• Decode QR codes and multiple barcode formats from image files
• Process camera streams for real-time barcode detection
• Support for various barcode formats including:
  • QR Code
  • Aztec
  • Data Matrix
  • PDF417
  • Code 39
  • Code 93
  • Code 128
  • EAN-8
  • EAN-13
  • ITF

Getting started

Add the package to your pubspec.yaml:

Usage

import 'dart:typed_data';
import 'package:qr_code_dart_decoder/qr_code_dart_decoder.dart';

Future<void> decodeQrFromImage(Uint8List imageBytes) async {
  // Create decoder instance
  final decoder = QrCodeDartDecoder(
    formats: [BarcodeFormat.qrCode],
  );
  
  // Decode the image
  final result = await decoder.decodeFile(imageBytes);
  if (result != null) {
    print('Decoded text: ${result.text}');
  } else {
    print('No QR code found');
  }
}

Future<void> decodeQrFromCamera(CamperaImage image) async {
  // Create decoder instance
  final decoder = QrCodeDartDecoder(
    formats: [BarcodeFormat.qrCode],
  );

  List<Yuv420Planes> yuv420Planes = image.planes
        .map((e) => Yuv420Planes(
              bytes: e.bytes,
              bytesPerRow: e.bytesPerRow,
              bytesPerPixel: e.bytesPerPixel,
              width: e.width,
              height: e.height,
            ))
        .toList();
  
  // Decode the image
  final result = await decoder.decodeCameraImage(yuv420Planes);
  if (result != null) {
    print('Decoded text: ${result.text}');
  } else {
    print('No QR code found');
  }
}

Result

Both decodeFile and decodeCameraImage return a ScanResult? — null when nothing was decoded. zxing_lib is an implementation detail and never appears in the public API, so your app does not need a dependency on it.

class ScanResult {
  final String text;              // Text encoded in the barcode
  final BarcodeFormat format;     // Format that was decoded
  final DateTime timestamp;       // When it was decoded
  final Uint8List? rawBytes;      // Raw bytes, when the format provides them
  final List<Point<double>> corners; // Bounding quadrilateral, empty if unknown
}

corners uses dart:math's Point so this package stays pure Dart. In Flutter, package:qr_code_dart_scan provides toOffset/toOffsets to bridge them to Offset.

Camera Stream Processing

For real-time barcode detection from camera streams, the package provides: