[BUG] White QRCode with other Background Color cannot be scanned.

[derjohng]

Describe the bug
White QRCode with other Background Color cannot be scanned.

Flutter information
[✓] Flutter (Channel master, 2.5.0-7.0.pre.185, on macOS 11.5.2 20G95 darwin-x64, locale en-GB)
• Flutter version 2.5.0-7.0.pre.185
• Upstream repository https://github.com/flutter/flutter.git
• Framework revision 2526cb07cb (11 hours ago), 2021-08-21 23:42:01 -0400
• Engine revision 4783663ee4
• Dart version 2.15.0 (build 2.15.0-41.0.dev)

Device (please complete the following information):

• Device: Google Pixel 3a
• OS: Android11
  PS: iPhone/iOS will not have this issue.

Screenshots
Left part of below image CANNOT be scanned with qr_code_scanner v0.5.2.
In my case, white QRCode with blue background cannot be scanned also.
Right part is ok.

Additional context
...

[goshander]

same issue

[UsamaKarim]

Confirming. Scanner problems on different colors

[deepak-0811]

In my case qr code has blue background.

And not scanning only in Androd in iOS working fine.

Any solution for this?

[jodafm]

same issue

[gokhancvs]

I have the exact same issue. Any solution?

[vikneshgopinathan]

i have the same issue, any solutions?

[goshander]

i have the same issue, any solutions?

For now, I found only one solution. I use other lib: qrscan, which use input image buffer for recognize. I use camera package to get image buffer, then apply grayscale and invert filter before send to qrscan lib. It worked, but it slow, and I had to come simply tricky frame skip code

recognize snippet

    Timer.periodic(new Duration(seconds: 2), (timer) {
      timerP = timer;
      if (image == null) return;
      scanner
          .scanBytes(Uint8List.fromList(jpgOut.encodeImage(
              invert(grayscale(jpg.decodeImage(image!.planes[0].bytes))))))
          .then((barcode) {
        barcode = barcode.trim();
        if (barcode != '') {
         // do something
        }
      }).catchError((err) {});
    });

get image snippet

availableCameras().then((cameras) {
      controller = CameraController(cameras[0], ResolutionPreset.medium,
          imageFormatGroup: ImageFormatGroup.jpeg);
      controller!.initialize().then((cam) {
        if (!mounted) {
          return;
        }
        controller!.startImageStream((image) {
          this.image = image;
        });
        setState(() {});
      });
    });

I wait, when this library can recognize qr automatically, it will awesome, for now this trick)

[UsamaKarim]

i have the same issue, any solutions?

For now, I found only one solution. I use other lib: qrscan, which use input image buffer for recognize. I use camera package to get image buffer, then apply grayscale and invert filter before send to qrscan lib. It worked, but it slow, and I had to come simply tricky frame skip code

It does only support Android 😐