flutter_zxing

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 capabilities for Flutter applications. Whether you need to scan barcodes from the camera or generate custom QR codes, Flutter ZXing makes it seamless and efficient.

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Table of Contents

• Flutter ZXing
  • Table of Contents
  • Demo Screenshots
  • Features
  • Supported Formats
  • Supported Platforms
  • ZXScanner
    • Features
    • Try ZXScanner
  • Getting Started
    • Cloning the flutter_zxing project
    • Installing dependencies
    • Use with dependency_overrides
  • Usage
    • To read barcode
    • To create barcode
  • License

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Demo Screenshots

Left: Barcode Scanner, Right: QR Code Creator

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Features

• Scan QR codes and barcodes from the camera stream (on mobile platforms only), image file, or URL.
• Scan multiple barcodes at once from the camera stream (on mobile platforms only), image file, or URL.
• Generate QR codes with customizable content and size.
• Return the position points of the scanned barcode.
• Customizable scanner frame size and color, and the ability to enable or disable features like torch and pinch to zoom.

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Supported Formats

Linear product	Linear industrial	Matrix
UPC-A	Code 39	QR Code
UPC-E	Code 93	Micro QR Code ᴿ
EAN-8	Code 128	rMQR Code ᴿ
EAN-13	Codabar	Aztec
DataBar	DataBar Expanded	DataMatrix
DataBar Limited ᴿ	ITF	PDF417
	Telepen ᴿ	MicroPDF417 ᴿ
	DX Film Edge ᴿ	MaxiCode ᴿ

ᴿ read only — these can be scanned but not generated.

Powered by zxing-cpp v3.1.1.

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Supported Platforms

Platform	Status	Notes
Android	✅ Fully Supported	Minimum API level 23 (Android 6.0)
iOS	✅ Fully Supported	Minimum iOS 13.0
MacOS	⚠️ Beta	Minimum macOS 10.15, without camera support
Linux	⚠️ Beta	Without Camera support
Windows	⚠️ Beta	Without Camera support
Web	❌ Not Supported	Dart FFI is not available on the web

Note: Flutter ZXing relies on the Dart FFI feature, making it unsupported on the web. Camera-based scanning is only available on mobile platforms.

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ZXScanner

ZXScanner is a free QR code and barcode scanner app for Android and iOS. It is built using Flutter and the flutter_zxing plugin.

Features

• Fast and reliable QR code and barcode scanning.
• Built-in support for multiple barcode formats.
• Fully open-source and customizable.

Try ZXScanner

To learn more or contribute, visit the ZXScanner repository.

Getting Started

Cloning the flutter_zxing project

To clone the flutter_zxing project from Github which includes submodules, use the following command:

git clone --recursive https://github.com/khoren93/flutter_zxing.git

Installing dependencies

Use Melos to install the dependencies of the flutter_zxing project. Melos is a tool that helps you manage multiple Dart packages in a single repository. To install Melos, use the following command:

flutter pub global activate melos

To install the dependencies of the flutter_zxing project, use the following command:

melos bootstrap

To allow the building on iOS and MacOS, you need to run the following command:

./scripts/update_ios_macos_src.sh

To run the integration tests:

cd example
flutter test integration_test

Now you can run the flutter_zxing example app on your device or emulator.

Use with dependency_overrides

If you want to use a forked version of the flutter_zxing library in your project, you can specify it using dependency_overrides in your pubspec.yaml. However, be aware that flutter_zxing relies on the ZXing C++ code included as a git submodule. When using dependency_overrides with a git repository, these submodules are not automatically included, and the update_ios_macos_src.sh script is not run, which can lead to errors, especially on iOS.

Your project might build but encounter runtime errors due to missing library exports that appear as an error like this: flutter: type 'ArgumentError' is not a subtype of type 'Code' in type cast

Recommended Approach: Using a Git Submodule

To ensure all necessary files are present, it's recommended to add your forked repository as a git submodule, initialize the submodules recursively, and reference it using a local path. Follow these steps:

1. In your project add your fork as a submodule and initialize it recursively.

git submodule add https://github.com/YourUsername/flutter_zxing.git flutter_zxing
git submodule update --init --recursive

2. Add your submodule to your pubspec.yaml file as a path dependency override.

dependency_overrides:
  flutter_zxing:
    path: ./flutter_zxing

3. Run flutter pub get to install the dependencies.
4. Run the scripts/update_ios_macos_src.sh script to update the iOS and MacOS source files. (Or add it to your own projects build process)
5. Run flutter clean to clear the build cache.
6. Build and run your project.

Why Not Use a Direct Git Reference?

Referencing your forked repo as a direct git reference in the depenency_overrides section of the pubspec.yaml does not include submodules or run the update_ios_macos_src.sh script. Manually running these steps in the .pub-cache directory is not practical, since the path changes with each commit.

Usage

To read barcode

flutter_zxing re-exports the camera types that appear in its own API (CameraImage, XFile, CameraController, ...), so a single import is enough.

import 'package:flutter_zxing/flutter_zxing.dart';

// Use ReaderWidget to quickly read barcode from camera image
@override
Widget build(BuildContext context) {
  return Scaffold(
    body: ReaderWidget(
      onScan: (result) async {
        // Do something with the result
      },
    ),
  );
}

// Or use flutter_zxing plugin methods
// To read barcode from camera image directly
await zx.startCameraProcessing(); // Call this in initState

cameraController?.startImageStream((image) async {
    final Code result = await zx.processCameraImage(
        image,
        DecodeParams(
            imageFormat: ImageFormat.lum, // the luminance plane of a YUV420/NV21 frame
            format: Format.any,
            width: image.width,
            height: image.height,
        ),
    );
    if (result.isValid) {
        debugPrint(result.text);
    }
});

zx.stopCameraProcessing(); // Call this in dispose

// To read a barcode from an XFile, a path, a URL or raw bytes.
// Every method takes a DecodeParams; the defaults are a good starting point.
XFile xFile = XFile('Your image path');
Code resultFromXFile = await zx.readBarcodeImagePath(xFile, DecodeParams());

String path = 'Your local image path';
Code resultFromPath = await zx.readBarcodeImagePathString(path, DecodeParams());

String url = 'Your remote image url';
Code resultFromUrl = await zx.readBarcodeImageUrl(url, DecodeParams());

// `readBarcode` is synchronous and takes already-decoded pixels, so the image
// dimensions and pixel format have to be described explicitly.
Uint8List bytes = Uint8List.fromList(yourImageBytes);
Code resultFromBytes = zx.readBarcode(
    bytes,
    DecodeParams(imageFormat: ImageFormat.rgb, width: width, height: height),
);

// The reading methods never throw: a failure is reported on the result.
if (!resultFromPath.isValid) {
    debugPrint(resultFromPath.error);
}

// Every method above has a `readBarcodes...` counterpart that returns `Codes`
// with every symbol found in the image.
Codes allCodes = await zx.readBarcodesImagePath(xFile, DecodeParams());

To create barcode

import 'dart:typed_data';

import 'package:flutter_zxing/flutter_zxing.dart';

// Use WriterWidget to quickly create barcode
@override
Widget build(BuildContext context) {
  return Scaffold(
    body: WriterWidget(
      onSuccess: (result, bytes) {
        // Do something with the result
      },
      onError: (error) {
        // Do something with the error
      },
    ),
  );
}

// Or use FlutterZxing to create barcode directly
final Encode result = zx.encodeBarcode(
    contents: 'Text to encode',
    params: EncodeParams(
        format: Format.qrCode,
        width: 120,
        height: 120,
        margin: 10,
        eccLevel: EccLevel.low,
    ),
);
if (result.isValid && result.data != null) {
    // `result.data` holds one byte per pixel. Always render it with the size
    // the encoder reports: when the symbol does not fit the requested box,
    // zxing enlarges it, so `result.width`/`result.height` may differ from the
    // width and height that were asked for.
    final Uint8List encodedBytes = pngFromBytes(
        result.data!,
        result.width!,
        result.height!,
    );
    // use encodedBytes as you wish, for example Image.memory(encodedBytes)
} else {
    debugPrint(result.error);
}

License

MIT License. See LICENSE.