feat: InfoWindow anchor configurable

Author: LuisThein

example/pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: apple_maps_flutter
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.2+3"
+    version: "0.1.2+4"
   async:
     dependency: transitive
     description:

lib/src/marker.dart

@@ -2,11 +2,7 @@ part of platform_maps_flutter;
 
 /// Text labels for a [Marker] info window.
 class InfoWindow {
-  const InfoWindow({
-    this.title,
-    this.snippet,
-    this.onTap,
-  });
+  const InfoWindow({this.title, this.snippet, this.onTap, this.anchor});
 
   /// Text labels specifying that no text is to be displayed.
   static const InfoWindow noText = InfoWindow();
@@ -21,18 +17,26 @@ class InfoWindow {
   /// A null value means no additional text.
   final String snippet;
 
+  /// The icon image point that will be the anchor of the info window when
+  /// displayed.
+  ///
+  /// The image point is specified in normalized coordinates: An anchor of
+  /// (0.0, 0.0) means the top left corner of the image. An anchor
+  /// of (1.0, 1.0) means the bottom right corner of the image.
+  final Offset anchor;
+
   /// onTap callback for this [InfoWindow].
   final VoidCallback onTap;
 
   appleMaps.InfoWindow get appleMapsInfoWindow => appleMaps.InfoWindow(
-        anchor: Offset(0, 0),
+        anchor: this.anchor ?? Offset(0, 0),
         onTap: this.onTap,
         snippet: this.snippet,
         title: this.title,
       );
 
   googleMaps.InfoWindow get googleMapsInfoWindow => googleMaps.InfoWindow(
-        anchor: Offset(0, 0),
+        anchor: this.anchor ?? Offset(0, 0),
         onTap: this.onTap,
         snippet: this.snippet,
         title: this.title,
@@ -43,11 +47,13 @@ class InfoWindow {
   InfoWindow copyWith({
     String titleParam,
     String snippetParam,
+    Offset anchorParam,
     VoidCallback onTapParam,
   }) {
     return InfoWindow(
       title: titleParam ?? title,
       snippet: snippetParam ?? snippet,
+      anchor: anchorParam ?? anchor,
       onTap: onTapParam ?? onTap,
     );
   }

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: apple_maps_flutter
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.2+3"
+    version: "0.1.2+4"
   async:
     dependency: transitive
     description:

pubspec.yaml

@@ -14,7 +14,7 @@ dependencies:
 
   google_maps_flutter: ^0.5.28+1
 
-  apple_maps_flutter: ^0.1.2+3
+  apple_maps_flutter: ^0.1.2+4
 
 dev_dependencies:
   flutter_test: