fix: Fix the issue of incorrect QR code position detection when Boxfit is …

[ohnobug]

my qrcode scan code:

  @override
  Widget build(BuildContext context) {
    // 二维码的位置
    final overlays = <Widget>[
      if (_barcodeCapture != null && _barcodeCapture!.barcodes.isNotEmpty)
        for (final Barcode barcode in _barcodeCapture!.barcodes)
          if (!barcode.size.isEmpty && barcode.corners.isNotEmpty)
            CustomPaint(
              painter: BarcodePainter2(
                barcodeCorners: barcode.corners,
                barcodeSize: barcode.size,
                boxFit: BoxFit.cover,
                cameraPreviewSize: _barcodeCapture!.size,
                color: const Color.fromARGB(183, 0, 255, 34),
                style: PaintingStyle.fill,
              ),
            ),
    ];

    return BlocBuilder<SystemCubit, SystemState>(
        builder: (context, systemState) {
      return Scaffold(
          primary: false,
          appBar: null,
          body: Stack(
            fit: StackFit.expand,
            children: [
              MobileScanner(
                fit: BoxFit.cover,
                controller: controller,
                // onDetect: _handleBarcode,
              ),

              if (_barcodeCapture != null && _barcodeCapture!.image != null)
                Stack(fit: StackFit.expand, children: [
                  // 扫码后暂停结果
                  Image.memory(
                    _barcodeCapture!.image!,
                    fit: BoxFit.cover,
                    filterQuality: FilterQuality.low,
                    frameBuilder: (
                      BuildContext context,
                      Widget child,
                      int? frame,
                      bool? wasSynchronouslyLoaded,
                    ) {
                      if (wasSynchronouslyLoaded == true || frame != null) {
                        return child;
                      }

                      return SizedBox();
                    },
                  ),
                  ...overlays,
                ]),

before:

fixed after:

[ohnobug]

fix
https://github.com/user-attachments/assets/3123a5ac-c467-4617-8458-0fd4f997e3f2

[ohnobug]

example test video:
https://github.com/user-attachments/assets/a7dbdb13-e212-4f35-a78d-9acb343cc3d6

[navaronbracke]

Can we add unit tests for this function? Then we can assure that the math is right.

[navaronbracke]

What is the meaning of the scp p: in the labels?

[ohnobug]

I don't know what the naming convention for test functions is, I just saw that the previous tests used abbreviations.

[navaronbracke]

I don't know the reasoning behind the existing abbreviations either. I would rather avoid introducing abbreviations altogether. It makes the code harder to reason about.

[navaronbracke]

Just a comment about fixing the test names & a small concern about the test results being duplicated.

[navaronbracke]

Can we use several different sizes, to have the numbers be different for each test?

I'd like to avoid introducing a bug because one test group accidentally had 0.9 / 0.9 several times in tests within the group. If we use different sizes, then the outcomes will also be unique among tests in a test group.

When you define the extra sizes, you can reuse them for landscape as well (since that is just flipping the width/height)

[navaronbracke]

Maybe you can change the inner test group name to already mention portrait / landscape? Then that does not need to be repeated in the tests themselves and the abbreviations can be removed?

group('calculateBoxFitRatio', () {
  group('smaller portrait camera preview size', () {
    test('fit: BoxFit.fill', () { /* ... */ });
    
    // more tests
  });
  
  group('smaller landscape camera preview size', () {
    test('fit: BoxFit.fill', () { /* ... */ });
    
    // more tests  
  });
})