Scan autofocus does not work on my (expensive) phone

[teolemon]

Story: Scan autofocus does not work on my (expensive) phone (I could scan a barcode seconds before, but with less depth). Is that something anyone else is experiencing ? Is that related to our current scanner, or the settings we give it ?

[M123-dev]

For me it is similar. The plugin we are using now uses two native libraries, MTBBarcodeScanner (iOS) and ZXing (Android), the first one is completely archived and the android one is in Maintenance Mode Only. Therefore, it is probably more due to these.

The maintainer of the Flutter plugin is already ( inactively ) working on a new version which will use the Google ML Kit. However, it looks like it will take a rather long time before this one is ready.

[monsieurtanuki]

Regarding a possible additional set-up of QRView, I'm afraid there's not much we can do:

const QRView({
  required Key key, // we already use it
  required this.onQRViewCreated, // we already use it
  this.overlay, // we already use it
  this.overlayMargin = EdgeInsets.zero, // we don't set it; wouldn't probably be helpful
  this.cameraFacing = CameraFacing.back, // we don't set it; wouldn't probably be helpful
  this.onPermissionSet, // we don't set it; wouldn't probably be helpful
  this.formatsAllowed = const <BarcodeFormat>[], // we don't set it; setting it to [BarcodeFormat.ean13] would make sense but wouldn't probably be helpful enough
}) : super(key: key);

/// [onQRViewCreated] gets called when the view is created
final QRViewCreatedCallback onQRViewCreated;

/// Use [overlay] to provide an overlay for the view.
/// This can be used to create a certain scan area.
final QrScannerOverlayShape? overlay;

/// Use [overlayMargin] to provide a margin to [overlay]
final EdgeInsetsGeometry overlayMargin;

/// Set which camera to use on startup.
///
/// [cameraFacing] can either be CameraFacing.front or CameraFacing.back.
/// Defaults to CameraFacing.back
final CameraFacing cameraFacing;

/// Calls the provided [onPermissionSet] callback when the permission is set.
final PermissionSetCallback? onPermissionSet;

/// Use [formatsAllowed] to specify which formats needs to be scanned.
final List<BarcodeFormat> formatsAllowed;

@teolemon If you download the first scan app on google play (or if you use the default scanner on your phone), do you experience the same problem on barcodes / on close-up pictures?

Perhaps it would make sense to challenge again (cf. #106) the choice of the scan library, focusing on active libraries only.

[teolemon]

We also discussed a bit about it with @M123-dev.

• I felt it was related about the lack of provision for autofocus (and manual focus by touching the screen).
• I'm not sure why we gave up on ML Kit (unmaintained 3rd party wrapper ?)
• How about using the default camera package + https://pub.dev/packages/google_ml_kit (last updated 56 days ago) ?
• How about refreshing this benchmark ?
• https://docs.google.com/document/d/1nxjyZD8NKM28w1J5LPhMybIRiw1t-31gB3mq39XtFxw/edit

[M123-dev]

Happy new year to you all 🎉
I'm going to update the list with all now still interesting scanners.

[M123-dev]

Done, see https://docs.google.com/document/d/1nxjyZD8NKM28w1J5LPhMybIRiw1t-31gB3mq39XtFxw/edit#heading=h.kdyjt7lwfz85

Looks like we either decide against ML-Kit or keep the old scanner for F-Droid,

[M123-dev]

As discussed, implementing alternative ml-kit for testing

[monsieurtanuki]

@M123-dev Could make sense to put the choice of ml-kit in dev mode.

[M123-dev]

Already in there locally 😁

[M123-dev]

Fixed by #893