google_maps_flutter how to display Polyline in its entirety

Question

I want to display my motion on the google_maps_flutter, I know I can use the polylines feature, but how do I set initialCameraPosition so that all the lines are displayed on the current window? Here's how I look now, with some lines outside the window. enter image description here

    // 运动轨迹
    if((is_load == false) && (UI_Data.current_file!.movement_trajectory!.isNotEmpty))
    {
      for (var i = 0; i < UI_Data.current_file!.movement_trajectory!.length; i++)
      {
        MovementTrajectory data = UI_Data.current_file!.movement_trajectory![i];
        point_list.add(LatLng(data.latitude, data.longitude));
      }
    }

    // 连线
    final Polyline polyline = Polyline(
      polylineId: PolylineId("polyline_id_1"),
      consumeTapEvents: true,
      color: Colors.orange,
      width: 2,
      points: point_list,
      onTap: () {
      },
    );
    polylines[PolylineId("polyline_id_1")] = polyline;

   GoogleMap(
                  gestureRecognizers: <Factory<OneSequenceGestureRecognizer>>{
                    Factory<OneSequenceGestureRecognizer>(
                          () => EagerGestureRecognizer(),
                    ),
                  },
                  initialCameraPosition: CameraPosition(
                    target: LatLng(point_list[0].latitude, point_list[0].longitude),
                    zoom: 15,
                  ),
                  myLocationEnabled: false,
                  zoomControlsEnabled: false,
                  // cameraTargetBounds: CameraTargetBounds(
                  //   LatLngBounds(
                  //     southwest: LatLng(22.731377, 113.800997),
                  //     northeast: LatLng(22.750079, 113.836433),
                  //   ),
                  // ),
                  polylines: Set<Polyline>.of(polylines.values),
                  markers: Set<Marker>.of(markers.values),
                ),

I tried using cameraTargetBounds, but I found that this option had something to do with zoom, and it sometimes showed up fine, but sometimes it didn't.