decodeEncodedPolyline method

List<PointLatLng> decodeEncodedPolyline(String encoded)

decode the google encoded string using Encoded Polyline Algorithm Format for more info about the algorithm check https://developers.google.com/maps/documentation/utilities/polylinealgorithm

return List

Implementation

List<PointLatLng> decodeEncodedPolyline(String encoded) {
  List<PointLatLng> poly = [];
  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;
    PointLatLng p =
        PointLatLng((lat / 1E5).toDouble(), (lng / 1E5).toDouble());
    poly.add(p);
  }
  return poly;
}