问颤振相机捏缩变焦

EN

class CameraPreviewPage extends StatefulWidget {
  final CameraDescription camera;

  CameraPreviewPage({required this.camera});

  @override
  _CameraPreviewPageState createState() => _CameraPreviewPageState();
}

class _CameraPreviewPageState extends State<CameraPreviewPage> {
  late CameraController _cameraController;
  late Future<void> _initializeCameraControllerFuture;
  double zoom = 1.0;
  double _scaleFactor = 1.0;

  @override
  void initState() {
    super.initState();

    _cameraController =
        CameraController(widget.camera, ResolutionPreset.ultraHigh);

    _initializeCameraControllerFuture = _cameraController.initialize();
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
      children: <Widget>[
       FutureBuilder(
            future: _initializeCameraControllerFuture,
            builder: (context, snapshot) {
              //The gestureDetector doesn't work
              if (snapshot.connectionState == ConnectionState.done) {
                return
                  GestureDetector(
                    behavior: HitTestBehavior.translucent,
                    onScaleStart: (details) {
                       zoom = _scaleFactor;
                    },
                    onScaleUpdate: (details) {
                       _scaleFactor = zoom * details.scale;
                       _cameraController.setZoomLevel(_scaleFactor);
                       debugPrint('Gesture updated');
                    },
                    child:CameraPreview(_cameraController));
              } else {
                return Center(child: CircularProgressIndicator());
              }
            },
          ),

        SafeArea(
            child: Scaffold(
          backgroundColor: Colors.transparent,
          floatingActionButton:
              Column(mainAxisSize: MainAxisSize.min, children: <Widget>[
            FloatingActionButton(
              heroTag: "FABZoomIn",
              child: Icon(
                Icons.zoom_in,
                color: Colors.white,
              ),
              onPressed: () {
                if (zoom < 8) {
                  zoom = zoom + 1;
                }
                _cameraController.setZoomLevel(zoom);
              },
              backgroundColor: Colors.cyan,
            ),
            SizedBox(
              height: 10,
            ),
            FloatingActionButton(
              heroTag: "FABZoomOut",
              child: Icon(
                Icons.zoom_out,
                color: Colors.white,
              ),
              onPressed: () {
                if (zoom > 1) {
                  zoom = zoom - 1;
                }
                _cameraController.setZoomLevel(zoom);
              },
              backgroundColor: Colors.red,
            ),
            SizedBox(
              height: 10,
            ),
            FloatingActionButton(
                heroTag: "FABCamera",
                child: Icon(Icons.camera, color: Colors.white),
                backgroundColor: Colors.green,
                onPressed: () {
                  _takePicture(context);
                })
          ]),
        ))
      ],
    );
  }

  @override
  void dispose() {
    _cameraController.dispose();
    super.dispose();
  }
}