tripz-llc/apps/rider/lib/controller/home/decode_polyline_isolate.dart

import 'package:google_maps_flutter/google_maps_flutter.dart';

List<LatLng> decodePolylineIsolate(String encoded) {
  List<LatLng> points = [];
  int index = 0, len = encoded.length;
  int lat = 0, lng = 0;

  while (index < len) {
    int b, shift = 0, result = 0;
    do {
      b = encoded.codeUnitAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lat += dlat;

    shift = 0;
    result = 0;
    do {
      b = encoded.codeUnitAt(index++) - 63;
      result |= (b & 0x1f) << shift;
      shift += 5;
    } while (b >= 0x20);
    int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
    lng += dlng;

    points.add(LatLng(lat / 1E5, lng / 1E5));
  }
  return points;
}
// Helper method for decoding polyline (if not already defined)
// List<LatLng> decodePolyline(String encoded) {
//   List<LatLng> points = [];
//   int index = 0, len = encoded.length;
//   int lat = 0, lng = 0;

//   while (index < len) {
//     int b, shift = 0, result = 0;
//     do {
//       b = encoded.codeUnitAt(index++) - 63;
//       result |= (b & 0x1f) << shift;
//       shift += 5;
//     } while (b >= 0x20);
//     int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
//     lat += dlat;

//     shift = 0;
//     result = 0;
//     do {
//       b = encoded.codeUnitAt(index++) - 63;
//       result |= (b & 0x1f) << shift;
//       shift += 5;
//     } while (b >= 0x20);
//     int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
//     lng += dlng;

//     points.add(LatLng(lat / 1E5, lng / 1E5));
//   }

//   return points;
// }