tabris-plugin-barcode-scanner

Tabris.js Barcode Scanner Plugin

A barcode scanner widget for Tabris.js, allowing to scan various types of barcodes.

General usage

The plugin provides a BarcodeScannerView which can be embedded into the Tabris.js view hierarchy like any other view. Once embedded it shows a blank screen until the start() method is called. At that point the device camera is displayed in the view bounds and barcode detection is activated. The detect event will fire when a barcode is detected in the camera view. The callback might fire multiple times for the same barcode. Barcode scanning continues until stop() is called which also deactivates the camera. It is recommended to stop barcode detection when not needed as it draws considerable power.

Supported barcode formats

The plugin supports the following barcode formats.

Barcode	Name	iOS	Android
UPC-A	upcA	✓	✓
UPC-E	upcE	✓	✓
Code 39	code39	✓	✓
Code 39 Mod 43	code39Mod43	✓
Code93	code93	✓	✓
Code128	code128	✓	✓
EAN-8	ean8	✓	✓
EAN-13	ean13	✓	✓
PDF417	pdf417	✓	✓
QR	qr	✓	✓
Aztec	aztec	✓	✓
Interleaved 2 of 5	interleaved2of5	✓
ITF14	itf	✓	✓
DataMatrix	dataMatrix	✓	✓
Codabar	codabar		✓

Example

The following snippet shows how the tabris-plugin-barcode-scanner plugin can be used in a Tabris.js app:

let scanner = new esbarcodescanner.BarcodeScannerView({
  left: 0, right: 0, top: 0, bottom: 0
}).on('detect', (e) => console.log(`Detected ${e.format} code with data ${e.data}`))
  .on('error', (e) => console.log(e.error))
  .appendTo(tabris.ui.contentView);
scanner.start(['qr', 'ean13']);

A more elaborate example can be found in the example folder. It provides a Tabris.js project that demonstrates the various features of the tabris-plugin-barcode-scanner widget. Consult the README of the example for build instructions.

Integrating the plugin

The Tabris.js website provides detailed information on how to integrate custom widgets in your Tabris.js app. To add the plugin to your app add the following entry in your apps config.xml:

<plugin name="tabris-plugin-barcode-scanner" spec="1.x" />

To fetch the latest development version use the GitHub URL:

<plugin name="tabris-plugin-barcode-scanner" spec="https://github.com/eclipsesource/tabris-plugin-barcode-scanner.git" />

iOS

The plugin requires key-value entry. NSCameraUsageDescription with description has to be added to the Info.plist file of your app to work correctly. Please include this configuration in your config.xml file.

<edit-config target="NSCameraUsageDescription" file="*-Info.plist" mode="merge">
  <string>Your custom description.</string>
</edit-config>

API

The widget api consists of the object esbarcodescanner.BarcodeScannerView with the following properties, events and methods.

Properties

The following properties can be applied in addition to the [common Tabris.js widget properties](https://tabrisjs .com/documentation/latest/api/Widget#properties):

camera : string, supported values: front, back, default: back

The camera to use when scanning for barcodes. Has to be set in the constructor of the BarcodeScannerView.

scaleMode : string, supported values: fit, fill, default: fit

How to scale the camera frame inside the bounds of the BarcodeScannerView. Setting the scaleMode to fit shows the full camera frame while potentially leaving blank space on the sides. Setting the scaleMode to fill will make the camera frame cover the view bounds while potentially clipping some of the camera frame edges.

active : boolean, readonly

Calling start() sets the active property to true. Calling stop() sets the active property to false. When an error occurs or the widget is disposed the active state is also set tofalse.

Events

detect

Fired when a barcode has been detected. The rate of detect events varies from platform to platform. It is very likely to receive duplicate events for the same barcode.

Event parameter

• format: string
  • The format of the detected barcode
• data: string
  • The data contained in the barcode

error

Fired when an error during the BarcodeScannerViews lifecycle happened. After an an error occurred no further detect event will be fired and the widget becomes unusable.

Event parameter

• error: string
  • A message providing details about the error

activeChanged

Fired when the active state of the widget changes. Either by calling start()/stop(), receiving an error event or disposing the widget.

Methods

start([formats])

Enables the camera and starts scanning for barcodes. When started, the barcode scanner continuously fires the detect event as soon as it finds a barcode in its view. To end barcode detection stop() should be called or the widget should be disposed. Not disabling the barcode scanner will consume a lot of unnecessary processing power. The given formats array can be used to narrow down the detected barcodes.

Example:

scanner.start(['qr']);

Parameter

• formats : string[]
  • The optional formats array allows to limit the detection of barcodes to only the given formats. The supported barcode names can be obtained from the list of supported barcodes. If formats is omitted all barcodes supported on the platform will be detected.

stop()

Stops the barcode scanning and disables the camera.

Example:

scanner.stop();

Compatibility

Compatible with Tabris.js 3.2.0

Supported platforms

• Android
• iOS

Development of the widget

While not required by the consumer or the widget, this repository provides a project folder that contains platform specific development artifacts. These artifacts allow to more easily consume the native source code when developing the native parts of the widget.

Android

The project provides a gradle based build configuration, which also allows to import the project into Android Studio.

In order to reference the Tabris.js specific APIs, the environment variable TABRIS_ANDROID_PLATFORM has to point to the Tabris.js Android Cordova platform root directory.

export TABRIS_ANDROID_PLATFORM=/home/user/tabris-android-cordova

The environment variable is consumed in the gradle projects build.gradle file.

Copyright

See LICENSE notice.