# Barcode/QR Scanner Quick Start Guide

## ✨ What's New?

The POS system now uses **ZXing WebAssembly** - a powerful, industry-standard barcode scanning library that provides:
- 🎯 **Better accuracy** for both 1D barcodes and 2D QR codes
- 🚀 **Faster scanning** with WebAssembly performance
- 📱 **Enhanced mobile support** with automatic rear camera selection
- 🔧 **All-in-one solution** - no need for multiple libraries

## 🚀 How to Use

### 1. Open the Scanner

Choose any method:

**Method A: Click Camera Button**
- Look for the camera icon 📷 next to the product code field
- Click it to open the scanner

**Method B: Keyboard Shortcut**
- Press `Ctrl + K` (Windows/Linux) or `Cmd + K` (Mac)

**Method C: Mobile Search**
- On mobile, the camera button appears in the search modal

### 2. Scan Your Code

1. **Position the barcode/QR code** within the frame
2. **Hold steady** - the scanner will automatically detect it
3. **Wait for confirmation** - you'll see a green checkmark ✓
4. **Product added!** - the item is automatically added to your cart

### 3. Tips for Best Results

✅ **DO:**
- Use good lighting
- Hold device steady
- Keep barcode flat and clear
- Position within the scanning frame

❌ **DON'T:**
- Scan in very dim light
- Move too quickly
- Use damaged/torn barcodes
- Hold at extreme angles

## 🎯 Supported Formats

### 1D Barcodes (Linear)
- **EAN-13** / **EAN-8** - Retail products
- **UPC-A** / **UPC-E** - North American products
- **Code 128** - Most common in warehouses
- **Code 39** / **Code 93** - Industrial use
- **ITF** - Shipping containers
- **Codabar** - Libraries, medical

### 2D Codes (Matrix)
- **QR Code** - Most popular (URLs, product info)
- **Data Matrix** - Small items
- **Aztec** - Transport tickets
- **PDF417** - ID cards

## 🔧 Troubleshooting

### Scanner Won't Open?
1. Check browser permissions (click 🔒 in address bar)
2. Ensure you're using HTTPS (required for camera)
3. Refresh the page
4. Try a different browser (Chrome/Firefox recommended)

### Not Detecting Codes?
1. Improve lighting
2. Clean camera lens
3. Hold barcode flat (not at an angle)
4. Try different distances (6-12 inches usually best)
5. Ensure barcode is not damaged

### Camera Permission Denied?
1. Click the 🔒 lock icon in browser address bar
2. Allow camera access
3. Refresh the page
4. On mobile: Check device settings → Apps → Browser → Permissions

## 🎮 Keyboard Shortcuts

| Shortcut | Action |
|----------|--------|
| `Ctrl/Cmd + K` | Open scanner |
| `Esc` | Close scanner |
| `Enter` | Search manually by code |

## 📱 Mobile Features

- **Auto rear camera** - Automatically uses back camera on mobile
- **Switch camera** - Toggle between front/back cameras
- **Touch optimized** - Large buttons for easy use
- **Responsive UI** - Adapts to screen size

## 🔐 Privacy & Security

- ✅ Camera access is **local only** - no data sent to external servers
- ✅ Video stream is **not recorded** or saved
- ✅ Scans are processed **in your browser** using WebAssembly
- ✅ Product search happens via your **own database**

## 💡 Pro Tips

1. **Batch Scanning**: Scan multiple items quickly - the scanner reopens after each successful scan
2. **Product Cache**: Recently scanned products load instantly from cache
3. **Audio Feedback**: Enable sound for beep confirmation on successful scans
4. **Keyboard Focus**: After scanning, focus returns to product input for manual entry

## 🆘 Need Help?

**Common Issues:**

**"Library not loaded"**
→ Refresh the page to reload ZXing library

**"Camera not supported"**
→ Use a modern browser (Chrome 57+, Firefox 52+, Safari 11+)

**"Permission denied"**
→ Grant camera permission in browser settings

**Slow scanning?**
→ Improve lighting, clean lens, or use a newer device

## 📊 Performance

| Device Type | Scan Speed | Accuracy |
|-------------|------------|----------|
| Modern Mobile | 10-30 FPS | 95%+ |
| Desktop Webcam | 15-25 FPS | 90%+ |
| Older Devices | 5-15 FPS | 85%+ |

## 🌐 Browser Compatibility

| Browser | Desktop | Mobile |
|---------|---------|--------|
| Chrome | ✅ 57+ | ✅ 57+ |
| Firefox | ✅ 52+ | ✅ 52+ |
| Safari | ✅ 11+ | ✅ 11+ |
| Edge | ✅ 79+ | ✅ 79+ |
| Opera | ✅ 44+ | ✅ 44+ |

## 🎓 Learn More

For detailed technical documentation, see:
- [Full ZXing Implementation Guide](ZXING_SCANNER_README.md)
- [API Reference Documentation](ZXING_SCANNER_README.md#api-reference)

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**Quick Access**: Press `Ctrl/Cmd + K` to scan now! 📷

**Version**: 2.0.0 (ZXing WebAssembly)  
**Last Updated**: November 9, 2025
