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dxBarcode

1. Overview​

This module is part of the official system module library of dejaOS, used for barcode scanning and decoding functionality. It includes comprehensive barcode scanning features:

  • Initialize/deinitialize barcode scanner
  • Real-time barcode detection and decoding
  • Support for various barcode formats (QR, Code128, Code39, etc.)
  • Event-driven callback system
  • Singleton pattern for system-wide barcode scanning

2. Files​

  • dxBarcode.js
  • libvbar-m-dxbarcode.so
  • Ensure these 2 files are included in the dxmodules subdirectory under your project root directory

3. Dependencies​

  • dxLogger

4. Compatible Devices​

Compatible with all devices running dejaOS v2.0+. Device must have a scanner camera.

5. Usage​

Basic Usage​

import dxbarcode from "./dxmodules/dxBarcode.js";

// Initialize the barcode scanner
dxbarcode.init();

// Set callback for barcode detection
dxbarcode.setCallbacks({
  onBarcodeDetected: function (data, type, quality, timestamp) {
    // data is ArrayBuffer containing the barcode data
    let str = common.utf8HexToStr(common.arrayBufferToHexString(data));
    log.info("Barcode data :", str);
    log.info("Barcode type:", type);
    log.info("Quality:", quality);
    log.info("Timestamp:", timestamp);
  },
});

// Start processing barcode events (call periodically)
setInterval(() => {
  dxbarcode.loop();
}, 50); // Process events every 50ms

6. API Reference​

dxbarcode.init()​

Initializes the barcode scanner. Must be called before any other operation.

Returns: void

dxbarcode.deinit()​

Deinitializes the barcode scanner and releases resources.

Returns: void

dxbarcode.setCallbacks(callbacks)​

Sets the callback function for barcode detection events.

Parameters:

  • callbacks (Object): The callback functions object
    • onBarcodeDetected (Function): The callback function to handle barcode detection
      • data (ArrayBuffer): The barcode data as ArrayBuffer. This preserves binary data integrity and prevents encoding issues.
      • type (Number): The barcode type identifier. Refer to [Supported Formats and Type Values]
      • quality (Number): The quality score of the decoded barcode.
      • timestamp (Number): The timestamp when the barcode was detected.

Returns: void

dxbarcode.loop()​

Processes events from the barcode event queue. Should be called periodically (e.g. in setInterval).

Returns: void

dxbarcode.getNative()​

Gets the native barcode client object.

Returns: Object|null - The native client object, or null if not initialized.

  • dxCode: Deprecated,replaced by dxBarcode
  • dxCapturer: Image capture functionality
  • dxDecoder: Barcode decoding functionality

8. Example​

Source Code

For complete working examples, refer to the demo files in the source repository.

9. Supported Formats and Type Values​

1D Barcode Standards:​

  • UPC-A (Universal Product Code A): Type 2 UPC-A

  • UPC-E (Universal Product Code E): Type 2 UPC-E

  • CODE128 (Code 128)：Type 7 CODE128

  • CODE93 (Code 93)：Type 6 CODE93

  • CODE39 (Code 39)：Type 5 CODE39

  • EAN-8 (European Article Number 8-digit): Type 2 EAN-8

  • EAN-13 (European Article Number 13-digit): Type 2 EAN-13

2D Barcode Standards:​

  • QR Code (Quick Response Code): Type 1 QR Code

  • PDF417 (Portable Data File 417): Type 10 PDF417

  • AZTEC (Aztec Code): Type 16 AZTEC

  • Micro QR Code: Type 1 Micro QR Code

10. Long Text QR Code Example​

Long QR Code