toGeoJsonWithExtentCalculated<T extends GeoJson<Geometry>> method

T? toGeoJsonWithExtentCalculated<T extends GeoJson<Geometry>>({
  1. required int x0,
  2. required int y0,
  3. required int size,
})

Get GeoJson data from this feature

x0, y0, size: is tile numbers and tile zoom that already calculated with layer extent x0, y0, size was used to calculate lon/lat pairs

Return generic GeoJson type, there are two ways to to read data returned from this method:

  • Explicit given a generic type: 
     var geojson = feature.toGeoJson<GeoJsonPoint>(3262, 1923, 12);
 var coordinates = geojson.geometry.coordinates;
  • Cast to specific GeoJson type after got returned data: 
     var geojson = feature.toGeoJson(3262, 1923, 12);
 var coordinates = (geojson as GeoJsonPoint).geometry.coordinates;

Implementation

T? toGeoJsonWithExtentCalculated<T extends GeoJson>(
    {required int x0, required int y0, required int size}) {
  if (this.geometry == null) {
    this.decodeGeometry();
  }

  switch (this.geometryType) {
    case GeometryType.Point:
      final geometryPoint = this.geometry as GeometryPoint;

      geometryPoint.coordinates =
          this._projectPoint(size, x0, y0, geometryPoint.coordinates);

      return GeoJsonPoint(
        geometry: geometryPoint,
        properties: this.properties,
      ) as T;
    case GeometryType.MultiPoint:
      final geometryMultiPoint = this.geometry as GeometryMultiPoint;

      geometryMultiPoint.coordinates =
          this._project(size, x0, y0, geometryMultiPoint.coordinates);

      return GeoJsonMultiPoint(
        geometry: geometryMultiPoint,
        properties: this.properties,
      ) as T;
    case GeometryType.LineString:
      final geometryLineString = this.geometry as GeometryLineString;

      geometryLineString.coordinates =
          this._project(size, x0, y0, geometryLineString.coordinates);

      return GeoJsonLineString(
        geometry: geometryLineString,
        properties: this.properties,
      ) as T;

    case GeometryType.MultiLineString:
      final geometryLineString = this.geometry as GeometryMultiLineString;

      geometryLineString.coordinates = geometryLineString.coordinates
          .map((line) => this._project(size, x0, y0, line))
          .toList(growable: false);

      return GeoJsonMultiLineString(
        geometry: geometryLineString,
        properties: this.properties,
      ) as T;
    case GeometryType.Polygon:
      final geometryPolygon = this.geometry as GeometryPolygon;

      geometryPolygon.coordinates = geometryPolygon.coordinates
          .map((line) => this._project(size, x0, y0, line))
          .toList(growable: false);

      return GeoJsonPolygon(
        geometry: geometryPolygon,
        properties: this.properties,
      ) as T;
    case GeometryType.MultiPolygon:
      final geometryMultiPolygon = this.geometry as GeometryMultiPolygon;

      geometryMultiPolygon.coordinates = geometryMultiPolygon.coordinates
          ?.map((polygon) => polygon
              .map((ring) => this._project(size, x0, y0, ring))
              .toList(growable: false))
          .toList(growable: false);

      return GeoJsonMultiPolygon(
        geometry: geometryMultiPolygon,
        properties: this.properties,
      ) as T;
    default:
  }

  return null;
}