QuickQR Scanner Plugin #

Enterprise-grade QR code and barcode scanner plugin for Flutter with native Vision framework integration for iOS and ML Kit for Android. Designed for production apps requiring high-performance, low-latency scanning with comprehensive error handling.

🌟 Features #

Core Scanning #

Native Performance: Vision framework (iOS) + ML Kit (Android) for optimal speed
Real-time Scanning: Live camera scanning with sub-second detection
Platform Views: Native camera integration with Flutter UI overlay
Multiple Formats: QR Code, Code 128, Code 39, EAN-13, EAN-8, UPC-E
Image Scanning: Scan QR codes from image files without picker dependency

📸 Advanced Camera Control (v1.1.0+) #

Digital Zoom: 1.0x - 10.0x zoom control with smooth adjustment
Macro Mode: Close-up scanning for small QR codes
Focus Control: Auto, manual, infinity, and macro focus modes with point-of-interest
Exposure Control: Automatic and manual exposure with EV compensation
White Balance: Auto, daylight, cloudy, tungsten, and fluorescent modes
Image Stabilization: Hardware-based stabilization where available
HDR Mode: High Dynamic Range for challenging lighting conditions
Frame Rate Control: Adjustable frame rates (15-60fps) for performance
Camera Switching: Front/back camera selection
Preset Configurations: Macro, distant, low-light, and performance presets

Enterprise Features #

Enterprise Error Handling: Comprehensive status reporting and recovery
Permission Management: Graceful camera permission handling
Resource Management: Proper cleanup and memory management
State Management: Real-time access to all camera settings
Capability Detection: Check device support for each feature
Minimal Dependencies: Lightweight with essential libraries only

📱 Supported Platforms #

Platform	Version	Framework	Performance
iOS	12.0+	Vision + AVFoundation	Hardware acceleration on supported devices
Android	API 21+	ML Kit + Camera2 API	Google ML optimization

🚀 Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  quickqr_scanner_plugin: ^1.1.0

Then run:

flutter pub get

iOS Configuration #

Add camera permission to ios/Runner/Info.plist:

<key>NSCameraUsageDescription</key>
<string>This app needs camera access to scan QR codes</string>

Android Configuration #

Add camera permission to android/app/src/main/AndroidManifest.xml:

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" android:required="true" />

💡 Quick Start #

Basic Usage #

import 'package:quickqr_scanner_plugin/quickqr_scanner_plugin.dart';

class QRScannerPage extends StatefulWidget {
  @override
  _QRScannerPageState createState() => _QRScannerPageState();
}

class _QRScannerPageState extends State<QRScannerPage> {
  final _scanner = QuickqrScannerPlugin();
  StreamSubscription<QRScanResult>? _subscription;

  @override
  void initState() {
    super.initState();
    _initializeScanner();
  }

  Future<void> _initializeScanner() async {
    // Check device availability
    final availability = await _scanner.checkAvailability();
    if (!availability['isAvailable']) {
      print('QR scanning not supported on this device');
      return;
    }

    // Check permissions
    final permissions = await _scanner.checkPermissions();
    if (permissions['status'] != 'granted') {
      final requested = await _scanner.requestPermissions();
      if (!requested['granted']) {
        print('Camera permission required');
        return;
      }
    }

    // Initialize scanner
    await _scanner.initialize();
    
    // Listen for scan results
    _subscription = _scanner.onQRDetected.listen((result) {
      print('QR Code detected: ${result.content}');
      print('Format: ${result.format}');
      print('Confidence: ${result.confidence}');
    });

    // Start scanning
    await _scanner.startScanning();
  }

  @override
  void dispose() {
    _subscription?.cancel();
    _scanner.dispose();
    super.dispose();
  }
}

Image-based Scanning #

// Scan QR code from image file
Future<void> scanFromImage(String imagePath) async {
  final scanner = QuickqrScannerPlugin();
  final result = await scanner.scanFromImage(imagePath);
  if (result != null) {
    print('QR Code: ${result.content}');
    print('Format: ${result.format}');
  } else {
    print('No QR code found in image');
  }
}

📸 Advanced Camera Control #

Basic Camera Control #

import 'package:quickqr_scanner_plugin/quickqr_scanner_plugin.dart';

class AdvancedQRScanner extends StatefulWidget {
  @override
  _AdvancedQRScannerState createState() => _AdvancedQRScannerState();
}

class _AdvancedQRScannerState extends State<AdvancedQRScanner> {
  final _scanner = QuickqrScannerPlugin();
  double _currentZoom = 1.0;
  double _maxZoom = 1.0;
  bool _macroMode = false;

  @override
  void initState() {
    super.initState();
    _initializeWithCameraControl();
  }

  Future<void> _initializeWithCameraControl() async {
    // Initialize scanner
    await _scanner.initialize();
    
    // Get camera capabilities
    final capabilities = await _scanner.getCameraCapabilities();
    final zoomInfo = await _scanner.getZoomCapabilities();
    
    setState(() {
      _maxZoom = zoomInfo['maxZoom']?.toDouble() ?? 1.0;
    });
  }

  // Zoom control
  Future<void> _setZoom(double zoomLevel) async {
    final result = await _scanner.setZoomLevel(zoomLevel);
    if (result['success'] == true) {
      setState(() {
        _currentZoom = result['currentZoom']?.toDouble() ?? zoomLevel;
      });
    }
  }

  // Macro mode for close-up scanning
  Future<void> _toggleMacroMode() async {
    final result = await _scanner.setMacroMode(!_macroMode);
    if (result['success'] == true) {
      setState(() {
        _macroMode = result['enabled'] ?? !_macroMode;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Advanced QR Scanner')),
      body: Column(
        children: [
          // Zoom control
          if (_maxZoom > 1.0)
            Slider(
              value: _currentZoom,
              min: 1.0,
              max: _maxZoom,
              divisions: (_maxZoom * 10).round() - 10,
              label: '${_currentZoom.toStringAsFixed(1)}x',
              onChanged: _setZoom,
            ),
          
          // Macro mode toggle
          SwitchListTile(
            title: Text('Macro Mode'),
            subtitle: Text('For small QR codes'),
            value: _macroMode,
            onChanged: (_) => _toggleMacroMode(),
          ),
          
          // Camera preview would go here
          Expanded(
            child: Container(
              color: Colors.black,
              child: Center(
                child: Text(
                  'Camera Preview',
                  style: TextStyle(color: Colors.white),
                ),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

Preset Configurations #

// Macro configuration for close-up scanning
final macroConfig = CameraControlConfig.macro();
await scanner.applyCameraControlConfig(macroConfig);

// Distant configuration for far-range scanning
final distantConfig = CameraControlConfig.distant();
await scanner.applyCameraControlConfig(distantConfig);

// Low light configuration
final lowLightConfig = CameraControlConfig.lowLight();
await scanner.applyCameraControlConfig(lowLightConfig);

// Performance optimized configuration
final performanceConfig = CameraControlConfig.performance();
await scanner.applyCameraControlConfig(performanceConfig);

Manual Camera Control #

// Set specific focus mode with point of interest
await scanner.setFocusMode(FocusMode.manual, FocusPoint(0.5, 0.5));

// Adjust exposure compensation
await scanner.setExposureMode(ExposureMode.manual, -0.5);

// Set white balance for specific lighting
await scanner.setWhiteBalanceMode(WhiteBalanceMode.tungsten);

// Enable image stabilization
await scanner.setImageStabilization(true);

// Set frame rate for performance optimization
await scanner.setFrameRate(30);

// Enable HDR mode for challenging lighting
await scanner.setHDRMode(true);

State Monitoring #

// Get current camera state
final zoomState = await scanner.getZoomCapabilities();
final focusState = await scanner.getFocusState();
final exposureState = await scanner.getExposureState();
final macroState = await scanner.getMacroModeState();

print('Current zoom: ${zoomState['currentZoom']}x');
print('Focus mode: ${focusState['focusMode']}');
print('Macro enabled: ${macroState['enabled']}');

// Get comprehensive camera capabilities
final capabilities = await scanner.getCameraCapabilities();
final features = capabilities['features'] as Map<String, dynamic>;

if (features['macroMode'] == true) {
  print('Macro mode supported');
}
if (features['stabilization'] == true) {
  print('Image stabilization available');
}

📖 API Reference #

QuickqrScannerPlugin #

Main plugin class providing QR scanning functionality.

Properties

static instance - Singleton instance
onQRDetected - Broadcast Stream for real-time scan results
- Emits QR/barcode detection events during active scanning
- Supports multiple listeners with automatic error recovery
- ⚠️ Remember to cancel subscriptions in dispose() to prevent memory leaks

Methods

Device Information

Future<Map<String, dynamic>> checkAvailability()

Returns device scanning capabilities and supported formats.

Future<Map<String, dynamic>> checkPermissions()

Checks current camera permission status.

Future<Map<String, dynamic>> requestPermissions()

Requests camera permissions from user.

Scanner Control

Future<Map<String, dynamic>> initialize([QRScanConfig? config])

Initializes the scanner with optional configuration.

Future<void> startScanning()

Starts real-time QR code scanning.

Future<void> stopScanning()

Stops the scanning process.

Future<void> dispose()

Releases all resources and cleans up.

Additional Features

Future<Map<String, dynamic>> toggleFlashlight()

Toggles device flashlight (if available).

Future<QRScanResult?> scanFromImage(String imagePath)

Scans QR code from image file.

Camera Control (v1.1.0+)

Future<Map<String, dynamic>> setZoomLevel(double zoomLevel)

Sets digital zoom level (1.0x - 10.0x).

Future<Map<String, dynamic>> getZoomCapabilities()

Gets current zoom level and capabilities.

Future<Map<String, dynamic>> setMacroMode(bool enabled)

Enables/disables macro mode for close-up scanning.

Future<Map<String, dynamic>> setFocusMode(FocusMode focusMode, [FocusPoint? focusPoint])

Sets focus mode with optional point of interest.

Future<Map<String, dynamic>> setExposureMode(ExposureMode exposureMode, [double? exposureCompensation])

Sets exposure mode with optional EV compensation.

Future<Map<String, dynamic>> setCameraResolution(CameraResolution resolution)

Sets camera resolution preference.

Future<Map<String, dynamic>> switchCamera(CameraPosition position)

Switches between front and back camera.

Future<Map<String, dynamic>> setImageStabilization(bool enabled)

Enables/disables image stabilization.

Future<Map<String, dynamic>> setWhiteBalanceMode(WhiteBalanceMode whiteBalanceMode)

Sets white balance mode.

Future<Map<String, dynamic>> setFrameRate(int frameRate)

Sets preferred frame rate.

Future<Map<String, dynamic>> setHDRMode(bool enabled)

Enables/disables HDR mode.

Future<Map<String, dynamic>> getCameraCapabilities()

Gets comprehensive camera capabilities.

Future<Map<String, dynamic>> applyCameraControlConfig(CameraControlConfig config)

Applies complete camera configuration.

Camera State (v1.1.0+)

Future<Map<String, dynamic>> getMacroModeState()

Gets current macro mode state.

Future<Map<String, dynamic>> getFocusState()

Gets current focus mode and settings.

Future<Map<String, dynamic>> getExposureState()

Gets current exposure settings.

Future<Map<String, dynamic>> getCameraResolutionState()

Gets current resolution settings.

Future<Map<String, dynamic>> getImageStabilizationState()

Gets current stabilization state.

Future<Map<String, dynamic>> getWhiteBalanceState()

Gets current white balance settings.

Future<Map<String, dynamic>> getFrameRateState()

Gets current frame rate settings.

Future<Map<String, dynamic>> getHDRState()

Gets current HDR state.

Data Models #

QRScanResult

class QRScanResult {
  final String content;     // QR code content
  final String format;      // Barcode format (qr, code128, etc.)
  final int timestamp;      // Detection timestamp (milliseconds)
  final double confidence;  // Detection confidence (0.0-1.0)
}

CameraControlConfig (v1.1.0+)

class CameraControlConfig {
  final double zoomLevel;              // Digital zoom level (1.0-10.0)
  final bool enableMacroMode;          // Enable macro mode
  final FocusMode focusMode;           // Focus mode setting
  final FocusPoint? focusPoint;        // Manual focus point
  final ExposureMode exposureMode;     // Exposure mode
  final double? exposureCompensation;  // EV compensation
  final CameraResolution resolution;   // Resolution preference
  final CameraPosition position;       // Camera position
  final bool enableStabilization;      // Image stabilization
  final WhiteBalanceMode whiteBalance; // White balance mode
  final int? preferredFrameRate;       // Frame rate preference
  final bool enableHDR;                // HDR mode

  // Preset factory constructors
  factory CameraControlConfig.macro();       // Close-up scanning
  factory CameraControlConfig.distant();     // Far-range scanning
  factory CameraControlConfig.lowLight();    // Low light conditions
  factory CameraControlConfig.performance(); // Performance optimized
}

Enums

enum FocusMode { auto, manual, infinity, macro }
enum ExposureMode { auto, manual }
enum CameraResolution { low, medium, high, ultra }
enum CameraPosition { back, front }
enum WhiteBalanceMode { auto, daylight, cloudy, tungsten, fluorescent }

class FocusPoint {
  final double x; // Normalized coordinates (0.0-1.0)
  final double y; // Normalized coordinates (0.0-1.0)
}

📱 Example App #

A comprehensive example app is included in the example/ directory demonstrating:

Device capability detection
Permission handling
Real-time scanning with visual feedback
Image-based scanning
Error handling and recovery
Scan result management
Flashlight control

To run the example:

cd example
flutter run

🛠 Performance Notes #

iOS (VisionKit) #

High Performance: Native system integration
Low Battery Usage: Optimized Apple Vision framework
System UI: Consistent with iOS design patterns
Neural Engine: Hardware acceleration on supported devices

Android (ML Kit) #

Google ML: Powered by Google's machine learning
On-device Processing: No internet connection required
Broad Compatibility: Works on API level 21+
Efficient Detection: Optimized for mobile devices

🚨 Troubleshooting #

Common Issues #

"Camera permission denied"

Ensure camera permission is added to platform manifests
Check that user has granted permission in device settings
Use checkPermissions() and requestPermissions() methods

"Scanner not initialized"

Call initialize() before starting scanning
Ensure initialization completes successfully before calling other methods
Check device compatibility with checkAvailability()

"No camera available"

Verify device has camera hardware
Check that camera isn't being used by another app
Try restarting the app or device

Debug Mode #

Enable detailed logging in debug builds:

// Add to main.dart for debugging
void main() {
  if (kDebugMode) {
    print('QuickQR Scanner Plugin Debug Mode Enabled');
  }
  runApp(MyApp());
}

📄 License #

This project is licensed under the MIT License - see the LICENSE file for details.

🤝 Contributing #

We welcome contributions! Please see CONTRIBUTING.md for details on how to get started.

📞 Support #

Documentation: API Reference
Examples: More Examples
Issues: GitHub Issues
Discussions: GitHub Discussions

Made with ❤️ for the Flutter community

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