Added scanning barcodes with a camera

quagga2/quagga2-1.12.1/docs/how-to-guides/configure-readers.md

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+# Configure Barcode Readers {#configure-readers}
+
+This guide explains how to configure which barcode formats Quagga2 will detect.
+
+## Basic Configuration {#basic-configuration}
+
+Specify readers in the `decoder.readers` array:
+
+```javascript
+Quagga.init({
+  decoder: {
+    readers: ["code_128_reader", "ean_reader"]
+  }
+});
+```
+
+## Available Readers {#available-readers}
+
+| Reader | Format | Common Uses |
+|--------|--------|-------------|
+| `code_128_reader` | Code 128 | Shipping, packaging |
+| `ean_reader` | EAN-13 | Retail products |
+| `ean_8_reader` | EAN-8 | Small products |
+| `upc_reader` | UPC-A | North American retail |
+| `upc_e_reader` | UPC-E | Small products |
+| `code_39_reader` | Code 39 | Industrial |
+| `code_39_vin_reader` | Code 39 VIN | Vehicle identification |
+| `codabar_reader` | Codabar | Libraries, blood banks |
+| `i2of5_reader` | Interleaved 2 of 5 | Warehouse |
+| `2of5_reader` | Standard 2 of 5 | Industrial |
+| `code_93_reader` | Code 93 | Logistics |
+| `code_32_reader` | Code 32 | Italian pharmaceuticals |
+
+## Reader Priority {#reader-priority}
+
+Readers are processed in order. Put most likely formats first:
+
+```javascript
+decoder: {
+  readers: [
+    "ean_reader",     // Most common - checked first
+    "upc_reader",     // Second most common
+    "code_128_reader" // Fallback
+  ]
+}
+```
+
+## EAN Supplements {#ean-supplements}
+
+To read EAN-2 or EAN-5 extension supplements:
+
+```javascript
+decoder: {
+  readers: [
+    "ean_reader",  // Regular EAN without supplements
+    {
+      format: "ean_reader",
+      config: {
+        supplements: ["ean_5_reader", "ean_2_reader"]
+      }
+    }
+  ]
+}
+```
+
+## Best Practices {#best-practices}
+
+1. **Only enable needed readers** - More readers = slower performance
+2. **Order by frequency** - Put most common formats first
+3. **Test thoroughly** - Some formats can conflict
+
+## Related {#related}
+
+- [Supported Barcode Types](../reference/readers.md) - Complete reader documentation
+- [Configuration Reference](../reference/configuration.md) - All configuration options
+
+---
+
+[← Back to How-To Guides](index.md)