[google_maps_flutter_platform_interface] Platform interface changes to support heatmaps (#7312)

Prequel to:
- #7313
- #7314
- #7315
- #3257

Author: Rexios80

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.9.0
+
+* Adds support for heatmap layers.
+
 ## 2.8.0
 
 * Deprecates `BitmapDescriptor.fromAssetImage` in favor of `BitmapDescriptor.asset` and `AssetMapBitmap.create`.

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/method_channel/method_channel_google_maps_flutter.dart

@@ -14,6 +14,7 @@ import 'package:stream_transform/stream_transform.dart';
 import '../../google_maps_flutter_platform_interface.dart';
 import '../types/tile_overlay_updates.dart';
 import '../types/utils/map_configuration_serialization.dart';
+import 'serialization.dart';
 
 /// Error thrown when an unknown map ID is provided to a method channel API.
 class UnknownMapIDError extends Error {
@@ -363,6 +364,17 @@ class MethodChannelGoogleMapsFlutter extends GoogleMapsFlutterPlatform {
     );
   }
 
+  @override
+  Future<void> updateHeatmaps(
+    HeatmapUpdates heatmapUpdates, {
+    required int mapId,
+  }) {
+    return channel(mapId).invokeMethod<void>(
+      'heatmaps#update',
+      serializeMapsObjectUpdates(heatmapUpdates, serializeHeatmap),
+    );
+  }
+
   @override
   Future<void> updateTileOverlays({
     required Set<TileOverlay> newTileOverlays,
@@ -542,6 +554,7 @@ class MethodChannelGoogleMapsFlutter extends GoogleMapsFlutterPlatform {
       'polygonsToAdd': serializePolygonSet(mapObjects.polygons),
       'polylinesToAdd': serializePolylineSet(mapObjects.polylines),
       'circlesToAdd': serializeCircleSet(mapObjects.circles),
+      'heatmapsToAdd': serializeHeatmapSet(mapObjects.heatmaps),
       'tileOverlaysToAdd': serializeTileOverlaySet(mapObjects.tileOverlays),
     };
 

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/method_channel/serialization.dart

@@ -0,0 +1,159 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import '../../google_maps_flutter_platform_interface.dart';
+
+String _objectsToAddKey(String name) => '${name}sToAdd';
+String _objectsToChangeKey(String name) => '${name}sToChange';
+String _objectIdsToRemoveKey(String name) => '${name}IdsToRemove';
+const String _heatmapIdKey = 'heatmapId';
+const String _heatmapDataKey = 'data';
+const String _heatmapDissipatingKey = 'dissipating';
+const String _heatmapGradientKey = 'gradient';
+const String _heatmapMaxIntensityKey = 'maxIntensity';
+const String _heatmapOpacityKey = 'opacity';
+const String _heatmapRadiusKey = 'radius';
+const String _heatmapMinimumZoomIntensityKey = 'minimumZoomIntensity';
+const String _heatmapMaximumZoomIntensityKey = 'maximumZoomIntensity';
+const String _heatmapGradientColorsKey = 'colors';
+const String _heatmapGradientStartPointsKey = 'startPoints';
+const String _heatmapGradientColorMapSizeKey = 'colorMapSize';
+
+void _addIfNonNull(Map<String, Object?> map, String fieldName, Object? value) {
+  if (value != null) {
+    map[fieldName] = value;
+  }
+}
+
+/// Serialize [MapsObjectUpdates]
+Object serializeMapsObjectUpdates<T extends MapsObject<T>>(
+  MapsObjectUpdates<T> updates,
+  Object Function(T) serialize,
+) {
+  final Map<String, Object> json = <String, Object>{};
+
+  _addIfNonNull(
+    json,
+    _objectsToAddKey(updates.objectName),
+    updates.objectsToAdd.map(serialize).toList(),
+  );
+  _addIfNonNull(
+    json,
+    _objectsToChangeKey(updates.objectName),
+    updates.objectsToChange.map(serialize).toList(),
+  );
+  _addIfNonNull(
+    json,
+    _objectIdsToRemoveKey(updates.objectName),
+    updates.objectIdsToRemove
+        .map<String>((MapsObjectId<T> m) => m.value)
+        .toList(),
+  );
+
+  return json;
+}
+
+/// Serialize [Heatmap]
+Object serializeHeatmap(Heatmap heatmap) {
+  final Map<String, Object> json = <String, Object>{};
+
+  _addIfNonNull(json, _heatmapIdKey, heatmap.heatmapId.value);
+  _addIfNonNull(
+    json,
+    _heatmapDataKey,
+    heatmap.data.map(serializeWeightedLatLng).toList(),
+  );
+  _addIfNonNull(json, _heatmapDissipatingKey, heatmap.dissipating);
+
+  final HeatmapGradient? gradient = heatmap.gradient;
+  if (gradient != null) {
+    _addIfNonNull(
+        json, _heatmapGradientKey, serializeHeatmapGradient(gradient));
+  }
+  _addIfNonNull(json, _heatmapMaxIntensityKey, heatmap.maxIntensity);
+  _addIfNonNull(json, _heatmapOpacityKey, heatmap.opacity);
+  _addIfNonNull(json, _heatmapRadiusKey, heatmap.radius.radius);
+  _addIfNonNull(
+      json, _heatmapMinimumZoomIntensityKey, heatmap.minimumZoomIntensity);
+  _addIfNonNull(
+      json, _heatmapMaximumZoomIntensityKey, heatmap.maximumZoomIntensity);
+
+  return json;
+}
+
+/// Serialize [WeightedLatLng]
+Object serializeWeightedLatLng(WeightedLatLng wll) {
+  return <Object>[serializeLatLng(wll.point), wll.weight];
+}
+
+/// Deserialize [WeightedLatLng]
+WeightedLatLng? deserializeWeightedLatLng(Object? json) {
+  if (json == null) {
+    return null;
+  }
+  assert(json is List && json.length == 2);
+  final List<dynamic> list = json as List<dynamic>;
+  final LatLng latLng = deserializeLatLng(list[0])!;
+  return WeightedLatLng(latLng, weight: list[1] as double);
+}
+
+/// Serialize [LatLng]
+Object serializeLatLng(LatLng latLng) {
+  return <Object>[latLng.latitude, latLng.longitude];
+}
+
+/// Deserialize [LatLng]
+LatLng? deserializeLatLng(Object? json) {
+  if (json == null) {
+    return null;
+  }
+  assert(json is List && json.length == 2);
+  final List<Object?> list = json as List<Object?>;
+  return LatLng(list[0]! as double, list[1]! as double);
+}
+
+/// Serialize [HeatmapGradient]
+Object serializeHeatmapGradient(HeatmapGradient gradient) {
+  final Map<String, Object> json = <String, Object>{};
+
+  _addIfNonNull(
+    json,
+    _heatmapGradientColorsKey,
+    gradient.colors.map((HeatmapGradientColor e) => e.color.value).toList(),
+  );
+  _addIfNonNull(
+    json,
+    _heatmapGradientStartPointsKey,
+    gradient.colors.map((HeatmapGradientColor e) => e.startPoint).toList(),
+  );
+  _addIfNonNull(json, _heatmapGradientColorMapSizeKey, gradient.colorMapSize);
+
+  return json;
+}
+
+/// Deserialize [HeatmapGradient]
+HeatmapGradient? deserializeHeatmapGradient(Object? json) {
+  if (json == null) {
+    return null;
+  }
+  assert(json is Map);
+  final Map<String, Object?> map = (json as Map<Object?, Object?>).cast();
+  final List<Color> colors = (map[_heatmapGradientColorsKey]! as List<Object?>)
+      .whereType<int>()
+      .map((int e) => Color(e))
+      .toList();
+  final List<double> startPoints =
+      (map[_heatmapGradientStartPointsKey]! as List<Object?>)
+          .whereType<double>()
+          .toList();
+  final List<HeatmapGradientColor> gradientColors = <HeatmapGradientColor>[];
+  for (int i = 0; i < colors.length; i++) {
+    gradientColors.add(HeatmapGradientColor(colors[i], startPoints[i]));
+  }
+  return HeatmapGradient(
+    gradientColors,
+    colorMapSize: map[_heatmapGradientColorMapSizeKey] as int? ?? 256,
+  );
+}

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/platform_interface/google_maps_flutter_platform.dart

@@ -49,13 +49,13 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     throw UnimplementedError('init() has not been implemented.');
   }
 
-  /// Updates configuration options of the map user interface - deprecated, use
-  /// updateMapConfiguration instead.
+  /// Updates configuration options of the map user interface.
   ///
   /// Change listeners are notified once the update has been made on the
   /// platform side.
   ///
   /// The returned [Future] completes after listeners have been notified.
+  @Deprecated('Use updateMapConfiguration instead.')
   Future<void> updateMapOptions(
     Map<String, dynamic> optionsUpdate, {
     required int mapId,
@@ -129,6 +129,19 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     throw UnimplementedError('updateCircles() has not been implemented.');
   }
 
+  /// Updates heatmap configuration.
+  ///
+  /// Change listeners are notified once the update has been made on the
+  /// platform side.
+  ///
+  /// The returned [Future] completes after listeners have been notified.
+  Future<void> updateHeatmaps(
+    HeatmapUpdates heatmapUpdates, {
+    required int mapId,
+  }) {
+    throw UnimplementedError('updateHeatmaps() has not been implemented.');
+  }
+
   /// Updates tile overlay configuration.
   ///
   /// Change listeners are notified once the update has been made on the
@@ -387,8 +400,8 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     return null;
   }
 
-  /// Returns a widget displaying the map view - deprecated, use
-  /// [buildViewWithConfiguration] instead.
+  /// Returns a widget displaying the map view.
+  @Deprecated('Use buildViewWithConfiguration instead.')
   Widget buildView(
     int creationId,
     PlatformViewCreatedCallback onPlatformViewCreated, {
@@ -407,8 +420,7 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     throw UnimplementedError('buildView() has not been implemented.');
   }
 
-  /// Returns a widget displaying the map view - deprecated, use
-  /// [buildViewWithConfiguration] instead.
+  /// Returns a widget displaying the map view.
   ///
   /// This method is similar to [buildView], but contains a parameter for
   /// platforms that require a text direction.
@@ -417,6 +429,7 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
   /// [buildView]. This is for backward compatibility with existing
   /// implementations. Platforms that use the text direction should override
   /// this as the primary implementation, and delegate to it from buildView.
+  @Deprecated('Use buildViewWithConfiguration instead.')
   Widget buildViewWithTextDirection(
     int creationId,
     PlatformViewCreatedCallback onPlatformViewCreated, {

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/platform_interface/google_maps_inspector_platform.dart

@@ -116,6 +116,22 @@ abstract class GoogleMapsInspectorPlatform extends PlatformInterface {
     throw UnimplementedError('getTileOverlayInfo() has not been implemented.');
   }
 
+  /// If the platform supports getting information about heatmaps.
+  bool supportsGettingHeatmapInfo() {
+    throw UnimplementedError(
+      'supportsGettingHeatmapInfo() has not been implemented.',
+    );
+  }
+
+  /// Returns information about the heatmap with the given ID.
+  ///
+  /// The returned object will be synthesized from platform data, so will not
+  /// be the same Dart object as the original [Heatmap] provided to the
+  /// platform interface with that ID, and not all fields will be populated.
+  Future<Heatmap?> getHeatmapInfo(HeatmapId heatmapId, {required int mapId}) {
+    throw UnimplementedError('getHeatmapInfo() has not been implemented.');
+  }
+
   /// Returns current clusters from [ClusterManager].
   Future<List<Cluster>> getClusters(
       {required int mapId, required ClusterManagerId clusterManagerId}) {