🇨🇭 QR Bill Validator App

A modern, privacy-first React Native app for validating Swiss QR bills with real-time camera scanning and advanced image processing.

• Local Processing Only: All QR code detection happens on your device
• No Cloud Dependencies: No data sent to external servers
• Zero Data Collection: Complete privacy protection

• Dark Theme: Sophisticated Material Design 3 Dark Theme
• Swiss Branding: Custom Swiss cross logo and red accent colors
• iOS Navigation: Native iOS-style navigation and interactions

• Real-Time Camera Scanning: Instant QR code detection with live camera feed
• Flashlight Support: Built-in flashlight for low-light conditions
• ZXing Image Processing: Industry-standard Zebra Crossing library for image analysis
• Multi-Strategy Detection: 5 different image processing approaches for maximum success rate

• High-Resolution Upscaling: Automatically enhances images up to 1600px for better detection
• Multiple Processing Strategies:
  1. Original image processing
  2. Enhanced contrast (1.5x)
  3. Reduced contrast (0.7x) for overexposed images
  4. Grayscale conversion with contrast boost
  5. Edge sharpening with binary conversion

• Complete Validation: Full Swiss QR bill format compliance
• Payment Information: Displays amount, currency, and payment details
• Creditor & Debtor Info: Shows complete payment party information
• Reference Validation: Validates Swiss QR reference numbers
• Optional Fields: Proper handling of optional street address fields

• Node.js 18+ and npm
• Expo CLI
• iOS Simulator or Android Emulator (or physical device with Expo Go)

1. Clone the repository

   git clone https://github.com/kukshaus/qr-bill-validator.git
   cd qr-bill-validator/qr-bill-validator-app

2. Install dependencies

   npm install

3. Start the development server

   npx expo start

4. Run on your device

   • iOS: Press i to open iOS simulator
   • Android: Press a to open Android emulator
   • Physical Device: Scan QR code with Expo Go app

qr-bill-validator/
├── qr-bill-validator-app/          # React Native app
│   ├── src/
│   │   ├── components/              # React components
│   │   │   └── RealZXingProcessor.tsx  # ZXing image processing
│   │   ├── screens/                 # App screens
│   │   │   ├── HomeScreen.tsx       # Main landing screen
│   │   │   ├── ScannerScreen.tsx    # QR code camera scanner
│   │   │   └── ValidationScreen.tsx # QR bill validation results
│   │   ├── services/                # Business logic
│   │   │   ├── QRBillValidator.ts   # Swiss QR bill validation
│   │   │   └── ImageProcessingService.ts # Image processing service
│   │   └── types/                   # TypeScript type definitions
│   ├── App.tsx                      # Main app component
│   └── package.json                 # Dependencies and scripts
├── PRD/                             # Product Requirements
└── REQ/                             # Requirements and Documentation

• Framework: React Native with Expo SDK 52
• Language: TypeScript
• UI Library: React Native Paper (Material Design 3)
• Camera: Expo Camera with CameraView
• Image Processing: Expo Image Manipulator + ZXing
• QR Detection: ZXing (Zebra Crossing) library via WebView
• Navigation: Custom navigation with state management

Advanced QR code detection using ZXing library with:

• High-resolution image processing
• Multiple detection strategies
• Error handling and timeouts
• Privacy-focused local processing

Swiss QR bill validation with:

• Complete format compliance checking
• Payment information extraction
• Reference number validation
• Optional field handling

Real-time camera scanning with:

• Live QR code detection
• Flashlight toggle
• Smooth camera permissions handling
• Instant feedback

1. Launch the app and tap "📷 Scan QR Code" for real-time scanning
2. Or upload an image with "📷 Upload Image" for advanced processing
3. Choose processing method when uploading:
   • 🦓 ZXing Processing: Advanced image analysis with 5 strategies
   • 📱 Camera Scanner: Switch to real-time camera scanning
4. View validation results with complete QR bill information
5. Scan another or return to home screen

• No Network Requests: All processing happens locally on your device
• No Data Storage: No QR code data is saved or cached
• No Analytics: No tracking or usage analytics
• Open Source: Full transparency of all code and functionality

Fully compliant with Swiss QR bill standards:

• ✅ QR-IBAN validation
• ✅ Swiss franc (CHF) and Euro (EUR) support
• ✅ Structured and unstructured reference support
• ✅ Complete creditor and debtor information
• ✅ Additional information and alternative procedures

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

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

• ZXing (Zebra Crossing): Industry-standard barcode scanning library
• Expo Team: Excellent React Native development platform
• Swiss QR Bill Standard: Official Swiss payment standard documentation
• React Native Paper: Beautiful Material Design components

Built with ❤️ for Swiss QR bill validation