[DO NOT MERGE] Add BitmapRegistry

packages/google_maps_flutter/google_maps_flutter/example/lib/bitmap_registry.dart

@@ -0,0 +1,136 @@
+// 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.
+
+// ignore_for_file: public_member_api_docs
+
+import 'dart:math';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:google_maps_flutter/google_maps_flutter.dart';
+import 'package:google_maps_flutter_platform_interface/google_maps_flutter_platform_interface.dart';
+
+import 'page.dart';
+
+class BitmapRegistryPage extends GoogleMapExampleAppPage {
+  const BitmapRegistryPage({Key? key})
+      : super(const Icon(Icons.speed), 'Bitmap registry', key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return const _BitmapRegistryBody();
+  }
+}
+
+// How many markers to place on the map.
+const int _numberOfMarkers = 500;
+
+// The name of the bitmap to use for the markers.
+const String _bitmapName = 'assets/checkers.png';
+
+class _BitmapRegistryBody extends StatefulWidget {
+  const _BitmapRegistryBody();
+
+  @override
+  State<_BitmapRegistryBody> createState() => _BitmapRegistryBodyState();
+}
+
+class _BitmapRegistryBodyState extends State<_BitmapRegistryBody> {
+  final Set<Marker> markers = <Marker>{};
+
+  @override
+  Widget build(BuildContext context) {
+    return SingleChildScrollView(
+      child: Column(
+        children: <Widget>[
+          AspectRatio(
+            aspectRatio: 2 / 3,
+            child: GoogleMap(
+              markers: markers,
+              initialCameraPosition: const CameraPosition(
+                target: LatLng(0, 0),
+                zoom: 1.0,
+              ),
+            ),
+          ),
+          MaterialButton(
+            onPressed: _addMarkersWithoutRegistry,
+            child: const Text('Add $_numberOfMarkers markers, no registry'),
+          ),
+          MaterialButton(
+            onPressed: _addMarkersWithRegistry,
+            child: const Text('Add $_numberOfMarkers markers using registry'),
+          ),
+        ],
+      ),
+    );
+  }
+
+  /// Add markers to the map with a custom bitmap as the icon.
+  ///
+  /// To show potential performance issues:
+  /// * large original image is used (800x600px, ~330KB)
+  /// * bitmap is scaled down to 64x64px
+  /// * bitmap is created once and reused for all markers. This doesn't help
+  /// much because the bitmap is still sent to the platform side for each
+  /// marker.
+  ///
+  /// Adding many markers may result in a performance hit, out of memory errors
+  /// or even app crashes.
+  Future<void> _addMarkersWithoutRegistry() async {
+    final ByteData byteData = await rootBundle.load(_bitmapName);
+    final Uint8List bytes = byteData.buffer.asUint8List();
+    final BytesMapBitmap bitmap = BitmapDescriptor.bytes(
+      bytes,
+      width: 64,
+      height: 64,
+    );
+    _updateMarkers(bitmap);
+  }
+
+  /// Add markers to the map with a custom bitmap as the icon placed in the
+  /// bitmap registry beforehand.
+  ///
+  /// Similarly to [_addMarkersWithoutRegistry], this method uses the same
+  /// technique to show potential performance issues, however the bitmap is
+  /// registered in the bitmap registry before creating the markers.
+  Future<void> _addMarkersWithRegistry() async {
+    final ByteData byteData = await rootBundle.load(_bitmapName);
+    final Uint8List bytes = byteData.buffer.asUint8List();
+    final BytesMapBitmap bytesBitmap = BitmapDescriptor.bytes(
+      bytes,
+      width: 64,
+      height: 64,
+    );
+    final int registeredBitmapId =
+        await GoogleMapBitmapRegistry.instance.register(bytesBitmap);
+    final RegisteredMapBitmap registeredBitmap =
+        RegisteredMapBitmap(id: registeredBitmapId);
+    _updateMarkers(registeredBitmap);
+  }
+
+  // Create a set of markers with the given bitmap and update the state with new
+  // markers.
+  void _updateMarkers(BitmapDescriptor bitmap) {
+    final List<Marker> newMarkers = List<Marker>.generate(
+      _numberOfMarkers,
+      (int id) {
+        return Marker(
+          markerId: MarkerId('$id'),
+          icon: bitmap,
+          position: LatLng(
+            Random().nextDouble() * 100 - 50,
+            Random().nextDouble() * 100 - 50,
+          ),
+        );
+      },
+    );
+
+    setState(() {
+      markers
+        ..clear()
+        ..addAll(newMarkers);
+    });
+  }
+}

packages/google_maps_flutter/google_maps_flutter/example/lib/main.dart

@@ -9,6 +9,7 @@ import 'package:google_maps_flutter_android/google_maps_flutter_android.dart';
 import 'package:google_maps_flutter_platform_interface/google_maps_flutter_platform_interface.dart';
 
 import 'animate_camera.dart';
+import 'bitmap_registry.dart';
 import 'clustering.dart';
 import 'heatmap.dart';
 import 'lite_mode.dart';
@@ -47,6 +48,7 @@ final List<GoogleMapExampleAppPage> _allPages = <GoogleMapExampleAppPage>[
   const ClusteringPage(),
   const MapIdPage(),
   const HeatmapPage(),
+  const BitmapRegistryPage(),
 ];
 
 /// MapsDemo is the Main Application.

packages/google_maps_flutter/google_maps_flutter/example/pubspec.yaml

@@ -33,3 +33,8 @@ flutter:
   uses-material-design: true
   assets:
     - assets/
+
+# FOR TESTING AND INITIAL REVIEW ONLY. DO NOT MERGE.
+# See https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-federated-plugins
+dependency_overrides:
+   {google_maps_flutter_android: {path: ../../../../packages/google_maps_flutter/google_maps_flutter_android}, google_maps_flutter_ios: {path: ../../../../packages/google_maps_flutter/google_maps_flutter_ios}, google_maps_flutter_platform_interface: {path: ../../../../packages/google_maps_flutter/google_maps_flutter_platform_interface}, google_maps_flutter_web: {path: ../../../../packages/google_maps_flutter/google_maps_flutter_web}}

packages/google_maps_flutter/google_maps_flutter/lib/google_maps_flutter.dart

@@ -59,3 +59,4 @@ export 'package:google_maps_flutter_platform_interface/google_maps_flutter_platf
 
 part 'src/controller.dart';
 part 'src/google_map.dart';
+part 'src/bitmap_registry.dart';

packages/google_maps_flutter/google_maps_flutter/lib/src/bitmap_registry.dart

@@ -0,0 +1,61 @@
+part of '../google_maps_flutter.dart';
+
+/// A bitmap registry.
+///
+/// Bitmaps can be created before they are used in markers and then registered
+/// with the registry. This allows for more efficient rendering of markers
+/// on the map. For example, if multiple markers use the same bitmap, bitmap
+/// can be registered once and then reused. This eliminates the need to
+/// transfer the bitmap data multiple times to the platform side.
+///
+/// Using bitmap registry is optional.
+///
+/// Bitmap registry can be used after the map is initialized and displayed
+/// on the screen. On Android registry can be also used after map renderer is
+/// initialized without map being displayed on the screen.
+///
+/// Example:
+/// ```dart
+/// // Register a bitmap
+/// final registeredBitmap = await GoogleMapBitmapRegistry.instance.register(
+///   Bitmap.fromAsset('assets/image.png'),
+/// );
+///
+/// // Use the registered bitmap as marker icon
+/// Marker(
+///   markerId: MarkerId('markerId'),
+///   icon: registeredBitmap,
+///   position: LatLng(0, 0)
+///   ),
+/// )
+/// ```
+class GoogleMapBitmapRegistry {
+  GoogleMapBitmapRegistry._();
+
+  /// The singleton instance of [GoogleMapBitmapRegistry].
+  static final GoogleMapBitmapRegistry instance = GoogleMapBitmapRegistry._();
+
+  // The number of registered images. Also used as a unique identifier for each
+  // registered image.
+  int _imageCount = 0;
+
+  /// Registers a [bitmap] with the registry.
+  ///
+  /// Returns a unique identifier for the registered bitmap.
+  Future<int> register(MapBitmap bitmap) async {
+    _imageCount++;
+    final int id = _imageCount;
+    await GoogleMapsFlutterPlatform.instance.registerBitmap(id, bitmap);
+    return id;
+  }
+
+  /// Unregisters a bitmap with the given [id].
+  Future<void> unregister(int id) {
+    return GoogleMapsFlutterPlatform.instance.unregisterBitmap(id);
+  }
+
+  /// Unregister all previously registered bitmaps and clear the cache.
+  Future<void> clear() {
+    return GoogleMapsFlutterPlatform.instance.clearBitmapCache();
+  }
+}

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -41,3 +41,8 @@ topics:
 # The example deliberately includes limited-use secrets.
 false_secrets:
   - /example/web/index.html
+
+# FOR TESTING AND INITIAL REVIEW ONLY. DO NOT MERGE.
+# See https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changing-federated-plugins
+dependency_overrides:
+   {google_maps_flutter_android: {path: ../../../packages/google_maps_flutter/google_maps_flutter_android}, google_maps_flutter_ios: {path: ../../../packages/google_maps_flutter/google_maps_flutter_ios}, google_maps_flutter_platform_interface: {path: ../../../packages/google_maps_flutter/google_maps_flutter_platform_interface}, google_maps_flutter_web: {path: ../../../packages/google_maps_flutter/google_maps_flutter_web}}

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/Convert.java

@@ -61,17 +61,55 @@ class Convert {
   public static final String HEATMAP_GRADIENT_COLOR_MAP_SIZE_KEY = "colorMapSize";
 
   private static BitmapDescriptor toBitmapDescriptor(
-      Messages.PlatformBitmap platformBitmap, AssetManager assetManager, float density) {
+      Messages.PlatformBitmap platformBitmap, AssetManager assetManager, float density,
+      ImageRegistry imageRegistry) {
     return toBitmapDescriptor(
-        platformBitmap, assetManager, density, new BitmapDescriptorFactoryWrapper());
+        platformBitmap, assetManager, density, new BitmapDescriptorFactoryWrapper(),
+        imageRegistry);
   }
 
-  private static BitmapDescriptor toBitmapDescriptor(
+  public static BitmapDescriptor createBitmapDescriptor(
       Messages.PlatformBitmap platformBitmap,
       AssetManager assetManager,
       float density,
       BitmapDescriptorFactoryWrapper wrapper) {
     Object bitmap = platformBitmap.getBitmap();
+
+    if (bitmap instanceof Messages.PlatformBitmapAsset) {
+      Messages.PlatformBitmapAsset typedBitmap = (Messages.PlatformBitmapAsset) bitmap;
+      final String assetPath = typedBitmap.getName();
+      final String assetPackage = typedBitmap.getPkg();
+      if (assetPackage == null) {
+        return BitmapDescriptorFactory.fromAsset(
+            FlutterInjector.instance().flutterLoader().getLookupKeyForAsset(assetPath));
+      } else {
+        return BitmapDescriptorFactory.fromAsset(
+            FlutterInjector.instance()
+                .flutterLoader()
+                .getLookupKeyForAsset(assetPath, assetPackage));
+      }
+    }
+    if (bitmap instanceof Messages.PlatformBitmapAssetMap) {
+      Messages.PlatformBitmapAssetMap typedBitmap = (Messages.PlatformBitmapAssetMap) bitmap;
+      return getBitmapFromAsset(
+          typedBitmap, assetManager, density, wrapper, new FlutterInjectorWrapper());
+    }
+    if (bitmap instanceof Messages.PlatformBitmapBytesMap) {
+      Messages.PlatformBitmapBytesMap typedBitmap = (Messages.PlatformBitmapBytesMap) bitmap;
+      return getBitmapFromBytes(typedBitmap, density, wrapper);
+    }
+    // TODO support for legacy Messages.PlatformBitmapAssetImage and Messages.PlatformBitmapBytes
+
+    throw new IllegalArgumentException("PlatformBitmap did not contain a supported subtype.");
+  }
+
+  private static BitmapDescriptor toBitmapDescriptor(
+      Messages.PlatformBitmap platformBitmap,
+      AssetManager assetManager,
+      float density,
+      BitmapDescriptorFactoryWrapper wrapper,
+      ImageRegistry imageRegistry) {
+    Object bitmap = platformBitmap.getBitmap();
     if (bitmap instanceof Messages.PlatformBitmapDefaultMarker) {
       Messages.PlatformBitmapDefaultMarker typedBitmap =
           (Messages.PlatformBitmapDefaultMarker) bitmap;
@@ -115,6 +153,11 @@ private static BitmapDescriptor toBitmapDescriptor(
       Messages.PlatformBitmapBytesMap typedBitmap = (Messages.PlatformBitmapBytesMap) bitmap;
       return getBitmapFromBytes(typedBitmap, density, wrapper);
     }
+    if (bitmap instanceof Messages.PlatformBitmapRegisteredMapBitmap) {
+      Messages.PlatformBitmapRegisteredMapBitmap typedBitmap =
+          (Messages.PlatformBitmapRegisteredMapBitmap) bitmap;
+      return getBitmapFromRegisteredBitmap(imageRegistry, typedBitmap);
+    }
     throw new IllegalArgumentException("PlatformBitmap did not contain a supported subtype.");
   }
 
@@ -185,6 +228,12 @@ public static BitmapDescriptor getBitmapFromBytes(
     }
   }
 
+  public static BitmapDescriptor getBitmapFromRegisteredBitmap(
+      ImageRegistry imageRegistry,
+      Messages.PlatformBitmapRegisteredMapBitmap registeredBitmap) {
+    return imageRegistry.getBitmap(registeredBitmap.getId());
+  }
+
   /**
    * Creates a BitmapDescriptor object from asset, using given details and density.
    *
@@ -588,13 +637,15 @@ static void interpretMarkerOptions(
       MarkerOptionsSink sink,
       AssetManager assetManager,
       float density,
-      BitmapDescriptorFactoryWrapper wrapper) {
+      BitmapDescriptorFactoryWrapper wrapper,
+      ImageRegistry imageRegistry) {
     sink.setAlpha(marker.getAlpha().floatValue());
     sink.setAnchor(marker.getAnchor().getX().floatValue(), marker.getAnchor().getY().floatValue());
     sink.setConsumeTapEvents(marker.getConsumeTapEvents());
     sink.setDraggable(marker.getDraggable());
     sink.setFlat(marker.getFlat());
-    sink.setIcon(toBitmapDescriptor(marker.getIcon(), assetManager, density, wrapper));
+    sink.setIcon(toBitmapDescriptor(marker.getIcon(), assetManager, density, wrapper,
+        imageRegistry));
     interpretInfoWindowOptions(sink, marker.getInfoWindow());
     sink.setPosition(toLatLng(marker.getPosition().toList()));
     sink.setRotation(marker.getRotation().floatValue());
@@ -642,11 +693,12 @@ static String interpretPolylineOptions(
       Messages.PlatformPolyline polyline,
       PolylineOptionsSink sink,
       AssetManager assetManager,
+      ImageRegistry imageRegistry,
       float density) {
     sink.setConsumeTapEvents(polyline.getConsumesTapEvents());
     sink.setColor(polyline.getColor().intValue());
-    sink.setEndCap(capFromPigeon(polyline.getEndCap(), assetManager, density));
-    sink.setStartCap(capFromPigeon(polyline.getStartCap(), assetManager, density));
+    sink.setEndCap(capFromPigeon(polyline.getEndCap(), assetManager, imageRegistry, density));
+    sink.setStartCap(capFromPigeon(polyline.getStartCap(), assetManager, imageRegistry, density));
     sink.setGeodesic(polyline.getGeodesic());
     sink.setJointType(jointTypeFromPigeon(polyline.getJointType()));
     sink.setVisible(polyline.getVisible());
@@ -817,7 +869,8 @@ private static List<PatternItem> patternFromPigeon(
   }
 
   private static Cap capFromPigeon(
-      Messages.PlatformCap cap, AssetManager assetManager, float density) {
+      Messages.PlatformCap cap, AssetManager assetManager, ImageRegistry imageRegistry,
+      float density) {
     switch (cap.getType()) {
       case BUTT_CAP:
         return new ButtCap();
@@ -830,7 +883,7 @@ private static Cap capFromPigeon(
           throw new IllegalArgumentException("A Custom Cap must specify a refWidth value.");
         }
         return new CustomCap(
-            toBitmapDescriptor(cap.getBitmapDescriptor(), assetManager, density),
+            toBitmapDescriptor(cap.getBitmapDescriptor(), assetManager, density, imageRegistry),
             cap.getRefWidth().floatValue());
     }
     throw new IllegalArgumentException("Unrecognized PlatformCap type: " + cap.getType());

packages/google_maps_flutter/google_maps_flutter_android/android/src/main/java/io/flutter/plugins/googlemaps/GoogleMapBuilder.java

@@ -36,9 +36,11 @@ GoogleMapController build(
       int id,
       Context context,
       BinaryMessenger binaryMessenger,
-      LifecycleProvider lifecycleProvider) {
+      LifecycleProvider lifecycleProvider,
+      ImageRegistry imageRegistry) {
     final GoogleMapController controller =
-        new GoogleMapController(id, context, binaryMessenger, lifecycleProvider, options);
+        new GoogleMapController(id, context, binaryMessenger, lifecycleProvider, options,
+            imageRegistry);
     controller.init();
     controller.setMyLocationEnabled(myLocationEnabled);
     controller.setMyLocationButtonEnabled(myLocationButtonEnabled);