[google_maps_flutter] Add pointForMeters to plugin in iOS

packages/google_maps_flutter/google_maps_flutter/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.5.28
+
+* Support projection method pointForMeters to get the distance in meters to content size
+  from the specified LatLng in the map.
+
 ## 0.5.27+3
 
 * iOS: Update the gesture recognizer blocking policy to "WaitUntilTouchesEnded", which fixes the camera idle callback not triggered issue.

packages/google_maps_flutter/google_maps_flutter/example/test_driver/google_maps_e2e.dart

@@ -4,6 +4,7 @@
 
 import 'dart:async';
 import 'dart:io';
+import 'dart:math';
 import 'dart:typed_data';
 
 import 'package:e2e/e2e.dart';
@@ -832,6 +833,39 @@ void main() {
     expect(topLeft, const ScreenCoordinate(x: 0, y: 0));
   });
 
+  testWidgets('testGetPointsForMeters', (WidgetTester tester) async {
+    final Key key = GlobalKey();
+    final Completer<GoogleMapController> controllerCompleter =
+        Completer<GoogleMapController>();
+
+    await tester.pumpWidget(Directionality(
+      textDirection: TextDirection.ltr,
+      child: GoogleMap(
+        key: key,
+        initialCameraPosition: _kInitialCameraPosition,
+        onMapCreated: (GoogleMapController controller) {
+          controllerCompleter.complete(controller);
+        },
+      ),
+    ));
+    final GoogleMapController controller = await controllerCompleter.future;
+
+    await tester.pumpAndSettle();
+    // TODO(cyanglaz): Remove this after we added `mapRendered` callback, and `mapControllerCompleter.complete(controller)` above should happen
+    // in `mapRendered`.
+    // https://github.com/flutter/flutter/issues/54758
+    await Future.delayed(Duration(seconds: 1));
+
+    final double points =
+        await controller.getPointsForMeters(1, _kInitialCameraPosition.target);
+    // Formula is from Chris Broadfoot's comment : https://groups.google.com/d/msg/google-maps-js-api-v3/hDRO4oHVSeM/osOYQYXg2oUJ
+    final double meters_per_pixel = 156543.03392 *
+        cos(_kInitialCameraPosition.target.latitude * pi / 180) /
+        pow(2, _kInitialZoomLevel);
+    final double points_per_meter = 1 / meters_per_pixel;
+    expect(points, moreOrLessEquals(points_per_meter, epsilon: 1e-5));
+  }, skip: !Platform.isIOS);
+
   testWidgets('testResizeWidget', (WidgetTester tester) async {
     final Completer<GoogleMapController> controllerCompleter =
         Completer<GoogleMapController>();

packages/google_maps_flutter/google_maps_flutter/ios/Classes/GoogleMapController.m

@@ -192,6 +192,18 @@ - (void)onMethodCall:(FlutterMethodCall*)call result:(FlutterResult)result {
                                  message:@"getLatLng called prior to map initialization"
                                  details:nil]);
     }
+  } else if ([call.method isEqualToString:@"projection#getPointsForMeters"]) {
+    if (_mapView != nil) {
+      CLLocationDistance meter = ToDouble(call.arguments[@"meter"]);
+      CLLocationCoordinate2D location =
+          [FLTGoogleMapJsonConversions toLocation:call.arguments[@"location"]];
+      CGFloat points = [_mapView.projection pointsForMeters:meter atCoordinate:location];
+      result(@(points));
+    } else {
+      result([FlutterError errorWithCode:@"GoogleMap uninitialized"
+                                 message:@"getPointsForMeters called prior to map initialization"
+                                 details:nil]);
+    }
   } else if ([call.method isEqualToString:@"map#waitForMap"]) {
     result(nil);
   } else if ([call.method isEqualToString:@"map#takeSnapshot"]) {

packages/google_maps_flutter/google_maps_flutter/lib/src/controller.dart

@@ -254,6 +254,12 @@ class GoogleMapController {
     return _googleMapsFlutterPlatform.getZoomLevel(mapId: mapId);
   }
 
+  /// Converts a distance in meters to content size.
+  Future<double> getPointsForMeters(double meters, LatLng latLng) {
+    return _googleMapsFlutterPlatform.getPointsForMeters(meters, latLng,
+        mapId: mapId);
+  }
+
   /// Returns the image bytes of the map
   Future<Uint8List> takeSnapshot() {
     return _googleMapsFlutterPlatform.takeSnapshot(mapId: mapId);

packages/google_maps_flutter/google_maps_flutter/pubspec.yaml

@@ -1,13 +1,14 @@
 name: google_maps_flutter
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_maps_flutter/google_maps_flutter
-version: 0.5.27+3
+version: 0.5.28
 
 dependencies:
   flutter:
     sdk: flutter
   flutter_plugin_android_lifecycle: ^1.0.0
-  google_maps_flutter_platform_interface: ^1.0.1
+  google_maps_flutter_platform_interface:
+    path: ../google_maps_flutter_platform_interface
 
 dev_dependencies:
   flutter_test:

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 1.1.0
+
+* Support projection method pointForMeters, to get the distance in meters to content size from the specified LatLng in the map for iOS.
+
 ## 1.0.2
 
 * Update lower bound of dart dependency to 2.1.0.

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

@@ -437,6 +437,14 @@ class MethodChannelGoogleMapsFlutter extends GoogleMapsFlutterPlatform {
     return channel(mapId).invokeMethod<double>('map#getZoomLevel');
   }
 
+  /// Converts a distance in meters to content size.
+  Future<double> getPointsForMeters(double meters, LatLng latLng,
+      {@required int mapId}) {
+    assert(meters != null && latLng != null);
+    return channel(mapId).invokeMethod<double>('projection#getPointsForMeters',
+        <String, dynamic>{"meter": meters, "location": latLng.toJson()});
+  }
+
   /// Returns the image bytes of the map
   @override
   Future<Uint8List> takeSnapshot({

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

@@ -239,6 +239,12 @@ abstract class GoogleMapsFlutterPlatform extends PlatformInterface {
     throw UnimplementedError('getZoomLevel() has not been implemented.');
   }
 
+  /// Converts a distance in meters to content size.
+  Future<double> getPointsForMeters(double meters, LatLng latLng,
+      {@required int mapId}) {
+    throw UnimplementedError('getPointsForMeters() has not been implemented.');
+  }
+
   /// Returns the image bytes of the map
   Future<Uint8List> takeSnapshot({
     @required int mapId,

packages/google_maps_flutter/google_maps_flutter_platform_interface/pubspec.yaml

@@ -3,7 +3,7 @@ description: A common platform interface for the google_maps_flutter plugin.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_maps_flutter/google_maps_flutter_platform_interface
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 1.0.2
+version: 1.1.0
 
 dependencies:
   flutter: