I need accurate screen cordinates to pass for magnifer widget in Flutter

Question

This is with the magic numbers This is without magic numbers I am trying to add raw magnifier widget on the google map marker which activates when marker is dragged, i cannot wrap the marker as it is not a flutter widget i tried passing cordinates to the widget using google controller screen cordinates they worked but they are not accurate and varries from device to device , then i tried gesture detector but after using it dosent allow me to navigate on map or drag the marker also tried hit behviour translucent , next i tries listener but it is also not accurate and dosent work while dragging is THERE ANY OTHER WAY WHICH MIGHT WORK?

Future<void> _handleDrag(LatLng newPosition) async {
    _lastMarkerPosition = newPosition;
    GoogleMapController controller = await _controller.future;
    ScreenCoordinate screenCoordinate =
        await controller.getScreenCoordinate(newPosition);
    print(
        'Screen coordinates: x=${screenCoordinate.x}, y=${screenCoordinate.y}');

    // Update state with new screen coordinates
    setState(() {
      _left = screenCoordinate.x.toDouble() / 1.9 - 60;
      _top = screenCoordinate.y.toDouble() / 1.9 - 45;
    });
  }

`

: Stack(children: [
            GoogleMap(
              mapType: MapType.hybrid,
              initialCameraPosition: gblFactoryLocation,
              compassEnabled: false,
              myLocationButtonEnabled: true,
              myLocationEnabled: true,
              polylines: _polyline,
              // If empty, returns error

              //CODE//
              onTap: (position) {
                if (isAddingPlot) {
                  int index_element = 0;
                  setState(() {
                    Marker newMarker = Marker(
                        markerId: MarkerId(position.toString()),
                        position: position,
                        draggable: true,
                        onDrag: _handleDrag,
                        // rotation: 180,
                        icon: BitmapDescriptor.defaultMarkerWithHue(
                            BitmapDescriptor.hueCyan),
                        consumeTapEvents: false,
                        onDragStart: (oldPosition) {
                          isMagnifierVisible = true;
                          // Finding nearest marker (Since its not accurate)
                          double distance = calculateDistance(
                              oldPosition.latitude,
                              oldPosition.longitude,
                              new_polygon.points[0].latitude,
                              new_polygon.points[0].longitude);

                          for (var i = 0;
                              i < new_polygon.points.length;
                              i++) {
                            double dist = calculateDistance(
                                oldPosition.latitude,
                                oldPosition.longitude,
                                new_polygon.points[i].latitude,
                                new_polygon.points[i].longitude);
                            if (dist < distance) {
                              index_element = i;
                              distance = dist;
                            }
                          }
                        },
                        onDragEnd: (position) {
                          isMagnifierVisible = false;
                          new_polygon.points.removeAt(index_element);
                          new_polygon.points.insert(
                              index_element,
                              LatLng(
                                  position.latitude, position.longitude));

                           // CODE//
                               
            Positioned(
              left: _left,
              top: _top,
              child: isMagnifierVisible
                  ? const RawMagnifier(
                      decoration: MagnifierDecoration(
                        shape: CircleBorder(
                          side: BorderSide(color: Colors.pink, width: 3),
                        ),
                      ),
                      size: Size(140, 140),
                      magnificationScale: 2,
                    )
                  : SizedBox.shrink(),
            ),`