mlkit_scanner

MLKit Scanner

A Flutter plugin to detect barcodes, text, faces, and objects using Google MLKit API for iOS and Android

This Plugin uses Android CameraView library and iOS AVFoundation APIs for detecting objects from device's camera.

Note: This plugin is under development, and some APIs might not be available yet.

Features:

• Display camera preview in a widget.
• Set size of the camera preview.
• Set overlay for camera preview.
• Set area for detect object.
• Pause/Resume camera preview.
• Toogle device flash.
• Set a preview scale
• Use camera Zoom
• Lock autofocus

Installation

First, add mlkit_scanner as a dependency in your pubspec.yaml.

iOS

iOS 11.0 of higher is needed to use the camera plugin.

Add key to the ios/Runner/Info.plist:

<key>NSCameraUsageDescription</key>
<string>...description...</string>

Android

Change the minimum Android sdk version to 21 (or higher) in your android/app/build.gradle file.

minSdkVersion 21

Example

import 'package:mlkit_scanner/mlkit_scanner.dart';

...

return SizedBox(
  height: 200.0                                 // CameraPreview needs height constraints, if you use widget 
                                                // in Column use SizedBox or Container with height.
  child: BarcodeScanner(
    cropOverlay: ScannerCropOverlay             // you can use default ScannerOverlay, create custom, or do not 
                                                // use it at all

    onScannerInitialized: _onScannerInitialized // callback with BarcodeScannerController for control camera 
                                                // and detection when camera preview initialize.
    
    onCameraInitializeError: (error) {          // Handling error if camera can't initialize on device.
      // handleError.
    }
    onScan: (barcode) {                         // Calls on success barcode recognition
      // Do anything with the code.
    },
  ),
);

Future<void> _onScannerInitialized(BarcodeScannerController controller) async {
    await controller.startScan(100)             // Detection starts only after this call.
                                                // 100 - delay in milliseconds between detection for decreasing 
                                                // CPU consumption. Detection happens every 100 milliseconds 
                                                // skipping frames during delay. Use 0 to turn off delay.

    await controller.stopScan()                 // You can stop detection.

    await controller.setDelay(200)              // Or set delay while detection is going.

    await controller.toggleFlash()              // Toggle device flash. Can throw an Exception if device 
                                                // doesn't have flash.

    await controller.pauseCamera()              // Pause camera preview, detection also stops.

    await controller.resumeCamera()             // Resume camera preview, detection resumes too if 
                                                // controller.startScan calls before.
                                                
    await controller.setZoom(0.5)               // Set camera zoom. Values must be in range 0...1                            
}

Contributing:

Contributions are welcome.