flutter_webrtc_zxing 0.2.0

Barcode scanner and generator for all Flutter platforms. Uses WebRTC for camera and zxing-wasm for web — no platform-specific code required.

Flutter ZXing

Flutter ZXing is a high-performance Flutter plugin for scanning and generating QR codes and barcodes. Built on the powerful ZXing C++ library, it provides fast and reliable barcode processing on all Flutter platforms — mobile, desktop, and web.

Camera access uses flutter_webrtc, so the same scanning widget works on Android, iOS, macOS, Windows, Linux, and Web without any platform-specific code in your app.

Note: This is an experimental fork of khoren93/flutter_zxing that replaces the camera plugin with WebRTC for unified cross-platform camera support. If you don't need web or desktop camera scanning, the original package is simpler and more lightweight.

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pub.dev

https://pub.dev/packages/flutter_webrtc_zxing

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Live Demo

https://konyshevgmbh.github.io/flutter_webrtc_zxing/

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Table of Contents

• Features
• Supported Formats
• Supported Platforms
• Getting Started
• Usage
  • ReaderWidget (recommended)
  • Process frames manually
  • Read from file or URL
  • Generate barcodes
• Web setup
• License

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Features

• Scan QR codes and barcodes from the live camera stream on all platforms (mobile, desktop, and web).
• Scan multiple barcodes at once.
• Read barcodes from an image file or URL.
• Generate QR codes and barcodes with customizable content and size.
• Returns the position and corner points of every detected barcode.
• Drop-in ReaderWidget with built-in scanner overlay, camera toggle, and gallery picker.

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Supported Formats

Linear product	Linear industrial	Matrix
UPC-A	Code 39	QR Code
UPC-E	Code 93	Micro QR Code
EAN-8	Code 128	rMQR Code
EAN-13	Codabar	Aztec
DataBar	DataBar Expanded	DataMatrix
	ITF	PDF417
		MaxiCode (partial)

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Supported Platforms

Platform	Scanning	Generating	Notes
Android	✅	✅	API 21+. Tested.
iOS	⚠️	⚠️	iOS 11+. Not personally tested — should work.
macOS	⚠️	⚠️	Not personally tested — should work.
Windows	✅	✅	Tested.
Linux	⚠️	⚠️	Not personally tested — should work.
Web	✅	✅	Tested. Uses zxing-wasm — first scan has a cold-start delay while the WASM module loads (~300 ms). See Web setup.

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Getting Started

Add as a dependency

dependencies:
  flutter_webrtc_zxing: ^0.1.0

iOS / macOS note: the plugin requires the zxing-cpp C++ sources in ios/ and macos/. Run the setup script once after cloning:

git clone --recursive https://github.com/konyshevgmbh/flutter_webrtc_zxing.git
./flutter_webrtc_zxing/scripts/update_ios_macos_src.sh

Then add a local path override in your app:

dependency_overrides:
  flutter_webrtc_zxing:
    path: ./flutter_webrtc_zxing

Run the example

git clone --recursive https://github.com/konyshevgmbh/flutter_webrtc_zxing.git
cd flutter_webrtc_zxing/example
flutter pub get
flutter run                  # mobile / desktop
flutter run -d chrome        # web

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Usage

ReaderWidget (recommended)

Drop ReaderWidget anywhere in your widget tree — it handles camera initialisation, WebRTC setup, and barcode detection automatically.

import 'package:flutter_webrtc_zxing/flutter_webrtc_zxing.dart';

ReaderWidget(
  onScan: (Code result) {
    debugPrint('Scanned: ${result.text}  format: ${result.format}');
  },
  onScanFailure: (Code result) {
    // called every tick when nothing is found
  },

  // Optional tuning
  codeFormat: Format.any,       // filter to specific format(s)
  tryHarder: false,
  tryInverted: false,
  cropPercent: 0.5,             // centre crop (0 = full frame)
  scanDelay: Duration(milliseconds: 500),
  useFrontCamera: false,
  targetFps: 10,
)

Multi-scan (several codes at once):

ReaderWidget(
  isMultiScan: true,
  onMultiScan: (Codes results) {
    for (final code in results.codes) {
      debugPrint('${code.text}');
    }
  },
)

Process frames manually

Use this when you already have a WebRTC stream and want to scan frames yourself:

await zx.startCameraProcessing();   // starts the processing isolate

// inside your frame callback — encodedBytes is Uint8List from RTCVideoTrack.captureFrame()
final Code result = await zx.processWebRtcFrame(
  encodedBytes,
  DecodeParams(format: Format.qrCode),
  cropPercent: 0.5,
);
if (result.isValid) debugPrint(result.text);

zx.stopCameraProcessing();          // call in dispose

Read from file or URL

// From XFile (e.g. image_picker result)
final Code result = await zx.readBarcodeImagePath(xFile, DecodeParams());

// From local path string
final Code result = await zx.readBarcodeImagePathString('/path/to/image.jpg', DecodeParams());

// From remote URL
final Code result = await zx.readBarcodeImageUrl('https://example.com/qr.png', DecodeParams());

// From raw bytes (native only — use readBarcodeImagePath on web)
final Code result = zx.readBarcode(bytes, DecodeParams(imageFormat: ImageFormat.rgb));

Generate barcodes

import 'package:flutter_webrtc_zxing/flutter_webrtc_zxing.dart';
import 'package:image/image.dart' as imglib;

final Encode result = zx.encodeBarcode(
  contents: 'https://example.com',
  params: EncodeParams(
    format: Format.qrCode,
    width: 256,
    height: 256,
    margin: 10,
    eccLevel: EccLevel.medium,
  ),
);

if (result.isValid && result.data != null) {
  final img = imglib.Image.fromBytes(
    width: result.width!,
    height: result.height!,
    bytes: result.data!.buffer,
    numChannels: 1,
  );
  final Uint8List png = imglib.encodePng(img);
  // display or save png
}

// Or use the built-in widget
WriterWidget(
  onSuccess: (Encode result, Uint8List? bytes) { },
  onError: (String error) { },
)

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Web setup

On web the library loads a pre-built zxing-wasm module from your Flutter asset bundle — no CDN, no external scripts, no index.html changes needed.

The bundled files live in lib/web/ and are declared as Flutter assets in the library's pubspec.yaml. They are served automatically alongside your app.

Updating the WASM bundle

When you want to upgrade to a newer zxing-wasm version:

VERSION=2.2.4   # replace with target version

curl -L https://cdn.jsdelivr.net/npm/zxing-wasm@${VERSION}/dist/es/share.js         -o lib/web/share.js
curl -L https://cdn.jsdelivr.net/npm/zxing-wasm@${VERSION}/dist/es/full/index.js    -o lib/web/zxing/index.js
curl -L https://cdn.jsdelivr.net/npm/zxing-wasm@${VERSION}/dist/full/zxing_full.wasm -o lib/web/zxing/zxing_full.wasm

Then update the version in lib/web/zxing/version.txt.

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License

MIT. See LICENSE.

Original work © 2022 Khoren Markosyan. Modifications © 2025 Igor Konyshev.