[google_maps_flutter] Maps snapshot

packages/google_maps_flutter/android/gradle.properties

@@ -1 +1 @@
-org.gradle.jvmargs=-Xmx1536M
+#org.gradle.jvmargs=-Xmx1536M

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

@@ -17,6 +17,7 @@
 import android.app.Application;
 import android.content.Context;
 import android.content.pm.PackageManager;
+import android.graphics.Bitmap;
 import android.graphics.Point;
 import android.os.Bundle;
 import android.util.Log;
@@ -38,6 +39,7 @@
 import io.flutter.plugin.common.MethodChannel;
 import io.flutter.plugin.common.PluginRegistry;
 import io.flutter.plugin.platform.PlatformView;
+import java.io.ByteArrayOutputStream;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
@@ -61,6 +63,7 @@ final class GoogleMapController
         OnMapReadyCallback,
         GoogleMap.OnMapClickListener,
         GoogleMap.OnMapLongClickListener,
+        GoogleMap.SnapshotReadyCallback,
         GoogleMap.OnMarkerDragListener,
         PlatformView {
 
@@ -229,6 +232,11 @@ public void onMethodCall(MethodCall call, MethodChannel.Result result) {
           }
           break;
         }
+      case "map#snapshot":
+        {
+          googleMap.snapshot(this);
+          result.success(null);
+        }
       case "map#getScreenCoordinate":
         {
           if (googleMap != null) {
@@ -464,6 +472,15 @@ public void onCircleClick(Circle circle) {
     circlesController.onCircleTap(circle.getId());
   }
 
+  @Override
+  public void onSnapshotReady(Bitmap bitmap) {
+    ByteArrayOutputStream stream = new ByteArrayOutputStream();
+    bitmap.compress(Bitmap.CompressFormat.PNG, 100, stream);
+    byte[] byteArray = stream.toByteArray();
+    bitmap.recycle();
+    methodChannel.invokeMethod("map#onSnapshot", byteArray);
+  }
+
   @Override
   public void dispose() {
     if (disposed) {

packages/google_maps_flutter/example/android/gradle.properties

@@ -1,4 +1,4 @@
-org.gradle.jvmargs=-Xmx1536M
+#org.gradle.jvmargs=-Xmx1536M
 android.enableR8=true
 android.useAndroidX=true
 android.enableJetifier=true

packages/google_maps_flutter/example/lib/map_ui.dart

@@ -4,6 +4,8 @@
 
 // ignore_for_file: public_member_api_docs
 
+import 'dart:typed_data';
+import 'dart:ui' as ui;
 import 'package:flutter/material.dart';
 import 'package:google_maps_flutter/google_maps_flutter.dart';
 import 'package:flutter/services.dart' show rootBundle;
@@ -92,38 +94,29 @@ class MapUiBodyState extends State<MapUiBody> {
   Widget _latLngBoundsToggler() {
     return FlatButton(
       child: Text(
-        _cameraTargetBounds.bounds == null
-            ? 'bound camera target'
-            : 'release camera target',
+        _cameraTargetBounds.bounds == null ? 'bound camera target' : 'release camera target',
       ),
       onPressed: () {
         setState(() {
-          _cameraTargetBounds = _cameraTargetBounds.bounds == null
-              ? CameraTargetBounds(sydneyBounds)
-              : CameraTargetBounds.unbounded;
+          _cameraTargetBounds = _cameraTargetBounds.bounds == null ? CameraTargetBounds(sydneyBounds) : CameraTargetBounds.unbounded;
         });
       },
     );
   }
 
   Widget _zoomBoundsToggler() {
     return FlatButton(
-      child: Text(_minMaxZoomPreference.minZoom == null
-          ? 'bound zoom'
-          : 'release zoom'),
+      child: Text(_minMaxZoomPreference.minZoom == null ? 'bound zoom' : 'release zoom'),
       onPressed: () {
         setState(() {
-          _minMaxZoomPreference = _minMaxZoomPreference.minZoom == null
-              ? const MinMaxZoomPreference(12.0, 16.0)
-              : MinMaxZoomPreference.unbounded;
+          _minMaxZoomPreference = _minMaxZoomPreference.minZoom == null ? const MinMaxZoomPreference(12.0, 16.0) : MinMaxZoomPreference.unbounded;
         });
       },
     );
   }
 
   Widget _mapTypeCycler() {
-    final MapType nextType =
-        MapType.values[(_mapType.index + 1) % MapType.values.length];
+    final MapType nextType = MapType.values[(_mapType.index + 1) % MapType.values.length];
     return FlatButton(
       child: Text('change map type to $nextType'),
       onPressed: () {
@@ -191,8 +184,7 @@ class MapUiBodyState extends State<MapUiBody> {
 
   Widget _myLocationToggler() {
     return FlatButton(
-      child: Text(
-          '${_myLocationButtonEnabled ? 'disable' : 'enable'} my location button'),
+      child: Text('${_myLocationButtonEnabled ? 'disable' : 'enable'} my location button'),
       onPressed: () {
         setState(() {
           _myLocationEnabled = !_myLocationEnabled;
@@ -203,8 +195,7 @@ class MapUiBodyState extends State<MapUiBody> {
 
   Widget _myLocationButtonToggler() {
     return FlatButton(
-      child: Text(
-          '${_myLocationButtonEnabled ? 'disable' : 'enable'} my location button'),
+      child: Text('${_myLocationButtonEnabled ? 'disable' : 'enable'} my location button'),
       onPressed: () {
         setState(() {
           _myLocationButtonEnabled = !_myLocationButtonEnabled;
@@ -213,6 +204,14 @@ class MapUiBodyState extends State<MapUiBody> {
     );
   }
 
+  Widget _snapshotter() {
+    return FlatButton(
+        child: const Text('make snapshot'),
+        onPressed: () {
+          _controller.snapshot();
+        });
+  }
+
   Future<String> _getFileData(String path) async {
     return await rootBundle.loadString(path);
   }
@@ -261,6 +260,7 @@ class MapUiBodyState extends State<MapUiBody> {
       myLocationEnabled: _myLocationEnabled,
       myLocationButtonEnabled: _myLocationButtonEnabled,
       onCameraMove: _updateCameraPosition,
+      onSnapshot: _snapshot,
     );
 
     final List<Widget> columnChildren = <Widget>[
@@ -282,8 +282,7 @@ class MapUiBodyState extends State<MapUiBody> {
           child: ListView(
             children: <Widget>[
               Text('camera bearing: ${_position.bearing}'),
-              Text(
-                  'camera target: ${_position.target.latitude.toStringAsFixed(4)},'
+              Text('camera target: ${_position.target.latitude.toStringAsFixed(4)},'
                   '${_position.target.longitude.toStringAsFixed(4)}'),
               Text('camera zoom: ${_position.zoom}'),
               Text('camera tilt: ${_position.tilt}'),
@@ -300,6 +299,7 @@ class MapUiBodyState extends State<MapUiBody> {
               _indoorViewToggler(),
               _myLocationToggler(),
               _myLocationButtonToggler(),
+              _snapshotter(),
               _nightModeToggler(),
             ],
           ),
@@ -320,9 +320,35 @@ class MapUiBodyState extends State<MapUiBody> {
   }
 
   void onMapCreated(GoogleMapController controller) {
+    _controller = controller;
     setState(() {
       _controller = controller;
       _isMapCreated = true;
     });
   }
+
+  void _snapshot(Uint8List argument) async {
+    final ui.Codec codec = await ui.instantiateImageCodec(argument);
+    final ui.FrameInfo frame = await codec.getNextFrame();
+    final ui.Image img = frame.image;
+    print('${argument.length} bytes, ${img.width} x ${img.height} px');
+    await showDialog<void>(
+      context: context,
+      builder: (BuildContext context) {
+        return AlertDialog(
+            actions: <Widget>[
+              FlatButton(
+                child: const Text('OK'),
+                onPressed: () => Navigator.of(context).pop(),
+              )
+            ],
+            content: Padding(
+                padding: const EdgeInsets.symmetric(vertical: 66),
+                child: Row(
+                  mainAxisAlignment: MainAxisAlignment.spaceAround,
+                  children: <Widget>[Image.memory(argument)],
+                )));
+      },
+    );
+  }
 }

packages/google_maps_flutter/ios/Classes/GoogleMapController.m

@@ -138,6 +138,14 @@ - (void)onMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
   } else if ([call.method isEqualToString:@"map#update"]) {
     InterpretMapOptions(call.arguments[@"options"], self);
     result(PositionToJson([self cameraPosition]));
+  } else if ([call.method isEqualToString:@"map#snapshot"]) {
+    UIGraphicsBeginImageContextWithOptions(_mapView.frame.size, NO, [UIScreen mainScreen].scale);
+    [_mapView.layer renderInContext:UIGraphicsGetCurrentContext()];
+    UIImage* screenShotImage = UIGraphicsGetImageFromCurrentImageContext();
+    NSData* imageData = UIImagePNGRepresentation(screenShotImage);
+    UIGraphicsEndImageContext();
+    result(nil);
+    [_channel invokeMethod:@"map#onSnapshot" arguments:imageData];
   } else if ([call.method isEqualToString:@"map#getVisibleRegion"]) {
     if (_mapView != nil) {
       GMSVisibleRegion visibleRegion = _mapView.projection.visibleRegion;

packages/google_maps_flutter/lib/src/controller.dart

@@ -24,8 +24,7 @@ class GoogleMapController {
     _GoogleMapState googleMapState,
   ) async {
     assert(id != null);
-    final MethodChannel channel =
-        MethodChannel('plugins.flutter.io/google_maps_$id');
+    final MethodChannel channel = MethodChannel('plugins.flutter.io/google_maps_$id');
     await channel.invokeMethod<void>('map#waitForMap');
     return GoogleMapController._(
       channel,
@@ -65,8 +64,7 @@ class GoogleMapController {
         _googleMapState.onMarkerTap(call.arguments['markerId']);
         break;
       case 'marker#onDragEnd':
-        _googleMapState.onMarkerDragEnd(call.arguments['markerId'],
-            LatLng._fromJson(call.arguments['position']));
+        _googleMapState.onMarkerDragEnd(call.arguments['markerId'], LatLng._fromJson(call.arguments['position']));
         break;
       case 'infoWindow#onTap':
         _googleMapState.onInfoWindowTap(call.arguments['markerId']);
@@ -84,8 +82,10 @@ class GoogleMapController {
         _googleMapState.onTap(LatLng._fromJson(call.arguments['position']));
         break;
       case 'map#onLongPress':
-        _googleMapState
-            .onLongPress(LatLng._fromJson(call.arguments['position']));
+        _googleMapState.onLongPress(LatLng._fromJson(call.arguments['position']));
+        break;
+      case 'map#onSnapshot':
+        _googleMapState.onSnaphot(call.arguments);
         break;
       default:
         throw MissingPluginException();
@@ -198,8 +198,7 @@ class GoogleMapController {
   /// and [Android](https://developers.google.com/maps/documentation/android-sdk/style-reference)
   /// style reference for more information regarding the supported styles.
   Future<void> setMapStyle(String mapStyle) async {
-    final List<dynamic> successAndError =
-        await channel.invokeMethod<List<dynamic>>('map#setStyle', mapStyle);
+    final List<dynamic> successAndError = await channel.invokeMethod<List<dynamic>>('map#setStyle', mapStyle);
     final bool success = successAndError[0];
     if (!success) {
       throw MapStyleException(successAndError[1]);
@@ -208,22 +207,25 @@ class GoogleMapController {
 
   /// Return [LatLngBounds] defining the region that is visible in a map.
   Future<LatLngBounds> getVisibleRegion() async {
-    final Map<String, dynamic> latLngBounds =
-        await channel.invokeMapMethod<String, dynamic>('map#getVisibleRegion');
+    final Map<String, dynamic> latLngBounds = await channel.invokeMapMethod<String, dynamic>('map#getVisibleRegion');
     final LatLng southwest = LatLng._fromJson(latLngBounds['southwest']);
     final LatLng northeast = LatLng._fromJson(latLngBounds['northeast']);
 
     return LatLngBounds(northeast: northeast, southwest: southwest);
   }
 
+  /// Ask for a snapshot to be returned via onSnapshot event
+  Future<void> snapshot() async {
+    await channel.invokeMethod<void>('map#snapshot');
+  }
+
   /// Return [ScreenCoordinate] of the [LatLng] in the current map view.
   ///
   /// A projection is used to translate between on screen location and geographic coordinates.
   /// Screen location is in screen pixels (not display pixels) with respect to the top left corner
   /// of the map, not necessarily of the whole screen.
   Future<ScreenCoordinate> getScreenCoordinate(LatLng latLng) async {
-    final Map<String, int> point = await channel.invokeMapMethod<String, int>(
-        'map#getScreenCoordinate', latLng._toJson());
+    final Map<String, int> point = await channel.invokeMapMethod<String, int>('map#getScreenCoordinate', latLng._toJson());
     return ScreenCoordinate(x: point['x'], y: point['y']);
   }
 
@@ -232,8 +234,7 @@ class GoogleMapController {
   /// Returned [LatLng] corresponds to a screen location. The screen location is specified in screen
   /// pixels (not display pixels) relative to the top left of the map, not top left of the whole screen.
   Future<LatLng> getLatLng(ScreenCoordinate screenCoordinate) async {
-    final List<dynamic> latLng = await channel.invokeMethod<List<dynamic>>(
-        'map#getLatLng', screenCoordinate._toJson());
+    final List<dynamic> latLng = await channel.invokeMethod<List<dynamic>>('map#getLatLng', screenCoordinate._toJson());
     return LatLng(latLng[0], latLng[1]);
   }
 }

packages/google_maps_flutter/lib/src/google_map.dart

@@ -54,6 +54,7 @@ class GoogleMap extends StatefulWidget {
     this.onCameraIdle,
     this.onTap,
     this.onLongPress,
+    this.onSnapshot,
   })  : assert(initialCameraPosition != null),
         super(key: key);
 
@@ -136,6 +137,9 @@ class GoogleMap extends StatefulWidget {
   /// Called every time a [GoogleMap] is long pressed.
   final ArgumentCallback<LatLng> onLongPress;
 
+  /// Called when a snapshot has completed
+  final ArgumentCallback<Uint8List> onSnapshot;
+
   /// True if a "My Location" layer should be shown on the map.
   ///
   /// This layer includes a location indicator at the current device location,
@@ -375,6 +379,13 @@ class _GoogleMapState extends State<GoogleMap> {
       widget.onLongPress(position);
     }
   }
+
+  void onSnaphot(Uint8List imgData) {
+    assert(imgData != null);
+    if (widget.onSnapshot != null) {
+      widget.onSnapshot(imgData);
+    }
+  }
 }
 
 /// Configuration options for the GoogleMaps user interface.