plugin_api library

API for packages that add their own layers to UnifiedMap, like flutter_map's plugin_api.dart.

A layer is a StatefulWidget placed in UnifiedMap.children (directly or inside other widgets) whose state extends MapLayerState. The order of UnifiedMap.children is the layers' z-order. In MapLayerState.sync it registers native objects with the map:

• markers through a MarkerPublisher: a list of MarkerSpecs is published atomically once all its icons are rasterised, optionally animated by a MarkerTransition (this layer's markers sliding from / to a position while fading) and with the layer's polylines (spiderfy legs), which are sent once those markers are applied;
• polylines alone with MapLayerState.setPolylines;
• flutter_map layer widgets with MapLayerState.setFlutterMapLayers, drawn only where MapLayerHost.supportsFlutterMapLayers (web, Windows, Linux);
• anything else through MapLayerHost.registry (LayerRegistry).

MapLayerState.host gives the camera (MapLayerHost.camera, MapLayerHost.liveCamera on every move, MapLayerHost.idleCamera when settled), the controller, the pixel ratio and the icon cache.

class PinsLayer extends StatefulWidget {
  const PinsLayer({super.key, required this.points});
  final List<LatLng> points;
  @override
  State<PinsLayer> createState() => _PinsLayerState();
}

class _PinsLayerState extends MapLayerState<PinsLayer> {
  late final _publisher = MarkerPublisher(layerId);

  @override
  void sync() => _publisher.publish(host, [
    for (final (i, p) in widget.points.indexed)
      MarkerSpec(id: objectId(null, i), position: p, iconKey: 'pin', child: const Pin(), size: const Size(24, 24)),
  ]);

  @override
  void dispose() {
    _publisher.dispose();
    super.dispose();
  }
}