[google_maps_flutter_platform_interface] Split CameraUpdate into derived classes to use structured data (flutter#7596)

Platform interface part of flutter/packages#7507

flutter#152928

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] page, which explains my
responsibilities.
- [x] I read and followed the [relevant style guides] and ran the
auto-formatter. (Unlike the flutter/flutter repo, the flutter/packages
repo does use `dart format`.)
- [ ] I signed the [CLA].
- [x] The title of the PR starts with the name of the package surrounded
by square brackets, e.g. `[shared_preferences]`
- [x] I [linked to at least one issue that this PR fixes] in the
description above.
- [x] I updated `pubspec.yaml` with an appropriate new version according
to the [pub versioning philosophy], or this PR is [exempt from version
changes].
- [x] I updated `CHANGELOG.md` to add a description of the change,
[following repository CHANGELOG style], or this PR is [exempt from
CHANGELOG changes].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/packages/blob/main/CONTRIBUTING.md
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md
[relevant style guides]:
https://github.com/flutter/packages/blob/main/CONTRIBUTING.md#style
[CLA]: https://cla.developers.google.com/
[Discord]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Chat.md
[linked to at least one issue that this PR fixes]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#overview
[pub versioning philosophy]: https://dart.dev/tools/pub/versioning
[exempt from version changes]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#version
[following repository CHANGELOG style]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changelog-style
[exempt from CHANGELOG changes]:
https://github.com/flutter/flutter/blob/master/docs/ecosystem/contributing/README.md#changelog
[test-exempt]:
https://github.com/flutter/flutter/blob/master/docs/contributing/Tree-hygiene.md#tests

Author: yaakovschectman

packages/google_maps_flutter/google_maps_flutter_platform_interface/CHANGELOG.md

@@ -1,5 +1,6 @@
-## NEXT
+## 2.9.1
 
+* Splits CameraUpdate into dervied classes for different update cases.
 * Updates minimum supported SDK version to Flutter 3.19/Dart 3.3.
 
 ## 2.9.0

packages/google_maps_flutter/google_maps_flutter_platform_interface/lib/src/types/camera.dart

@@ -110,42 +110,67 @@ class CameraPosition {
       'CameraPosition(bearing: $bearing, target: $target, tilt: $tilt, zoom: $zoom)';
 }
 
+/// Indicates which type of camera update this instance represents.
+enum CameraUpdateType {
+  /// New position for camera
+  newCameraPosition,
+
+  /// New coordinates for camera
+  newLatLng,
+
+  /// New coordinates bounding box
+  newLatLngBounds,
+
+  /// New coordinate with zoom level
+  newLatLngZoom,
+
+  /// Move by a scroll delta
+  scrollBy,
+
+  /// Zoom by a relative change
+  zoomBy,
+
+  /// Zoom to an absolute level
+  zoomTo,
+
+  /// Zoom in
+  zoomIn,
+
+  /// Zoom out
+  zoomOut,
+}
+
 /// Defines a camera move, supporting absolute moves as well as moves relative
 /// the current position.
-class CameraUpdate {
-  const CameraUpdate._(this._json);
+abstract class CameraUpdate {
+  const CameraUpdate._(this.updateType);
+
+  /// Indicates which type of camera update this instance represents.
+  final CameraUpdateType updateType;
 
   /// Returns a camera update that moves the camera to the specified position.
   static CameraUpdate newCameraPosition(CameraPosition cameraPosition) {
-    return CameraUpdate._(
-      <Object>['newCameraPosition', cameraPosition.toMap()],
-    );
+    return CameraUpdateNewCameraPosition(cameraPosition);
   }
 
   /// Returns a camera update that moves the camera target to the specified
   /// geographical location.
   static CameraUpdate newLatLng(LatLng latLng) {
-    return CameraUpdate._(<Object>['newLatLng', latLng.toJson()]);
+    return CameraUpdateNewLatLng(latLng);
   }
 
   /// Returns a camera update that transforms the camera so that the specified
   /// geographical bounding box is centered in the map view at the greatest
   /// possible zoom level. A non-zero [padding] insets the bounding box from the
   /// map view's edges. The camera's new tilt and bearing will both be 0.0.
   static CameraUpdate newLatLngBounds(LatLngBounds bounds, double padding) {
-    return CameraUpdate._(<Object>[
-      'newLatLngBounds',
-      bounds.toJson(),
-      padding,
-    ]);
+    return CameraUpdateNewLatLngBounds(bounds, padding);
   }
 
   /// Returns a camera update that moves the camera target to the specified
   /// geographical location and zoom level.
   static CameraUpdate newLatLngZoom(LatLng latLng, double zoom) {
-    return CameraUpdate._(
-      <Object>['newLatLngZoom', latLng.toJson(), zoom],
-    );
+    return CameraUpdateNewLatLngZoom(latLng, zoom);
   }
 
   /// Returns a camera update that moves the camera target the specified screen
@@ -155,49 +180,154 @@ class CameraUpdate {
   /// the camera's target to a geographical location that is 50 to the east and
   /// 75 to the south of the current location, measured in screen coordinates.
   static CameraUpdate scrollBy(double dx, double dy) {
-    return CameraUpdate._(
-      <Object>['scrollBy', dx, dy],
-    );
+    return CameraUpdateScrollBy(dx, dy);
   }
 
   /// Returns a camera update that modifies the camera zoom level by the
   /// specified amount. The optional [focus] is a screen point whose underlying
   /// geographical location should be invariant, if possible, by the movement.
   static CameraUpdate zoomBy(double amount, [Offset? focus]) {
-    if (focus == null) {
-      return CameraUpdate._(<Object>['zoomBy', amount]);
-    } else {
-      return CameraUpdate._(<Object>[
-        'zoomBy',
-        amount,
-        <double>[focus.dx, focus.dy],
-      ]);
-    }
+    return CameraUpdateZoomBy(amount, focus);
   }
 
   /// Returns a camera update that zooms the camera in, bringing the camera
   /// closer to the surface of the Earth.
   ///
   /// Equivalent to the result of calling `zoomBy(1.0)`.
   static CameraUpdate zoomIn() {
-    return const CameraUpdate._(<Object>['zoomIn']);
+    return const CameraUpdateZoomIn();
   }
 
   /// Returns a camera update that zooms the camera out, bringing the camera
   /// further away from the surface of the Earth.
   ///
   /// Equivalent to the result of calling `zoomBy(-1.0)`.
   static CameraUpdate zoomOut() {
-    return const CameraUpdate._(<Object>['zoomOut']);
+    return const CameraUpdateZoomOut();
   }
 
   /// Returns a camera update that sets the camera zoom level.
   static CameraUpdate zoomTo(double zoom) {
-    return CameraUpdate._(<Object>['zoomTo', zoom]);
+    return CameraUpdateZoomTo(zoom);
   }
 
-  final Object _json;
-
   /// Converts this object to something serializable in JSON.
-  Object toJson() => _json;
+  Object toJson();
+}
+
+/// Defines a camera move to a new position.
+class CameraUpdateNewCameraPosition extends CameraUpdate {
+  /// Creates a camera move.
+  const CameraUpdateNewCameraPosition(this.cameraPosition)
+      : super._(CameraUpdateType.newCameraPosition);
+
+  /// The new camera position.
+  final CameraPosition cameraPosition;
+  @override
+  Object toJson() => <Object>['newCameraPosition', cameraPosition.toMap()];
+}
+
+/// Defines a camera move to a latitude and longitude.
+class CameraUpdateNewLatLng extends CameraUpdate {
+  /// Creates a camera move to latitude and longitude.
+  const CameraUpdateNewLatLng(this.latLng)
+      : super._(CameraUpdateType.newLatLng);
+
+  /// New latitude and longitude of the camera..
+  final LatLng latLng;
+  @override
+  Object toJson() => <Object>['newLatLng', latLng.toJson()];
+}
+
+/// Defines a camera move to a new bounding latitude and longitude range.
+class CameraUpdateNewLatLngBounds extends CameraUpdate {
+  /// Creates a camera move to a bounding range.
+  const CameraUpdateNewLatLngBounds(this.bounds, this.padding)
+      : super._(CameraUpdateType.newLatLngBounds);
+
+  /// The northeast and southwest bounding coordinates.
+  final LatLngBounds bounds;
+
+  /// The amount of padding by which the view is inset.
+  final double padding;
+  @override
+  Object toJson() => <Object>['newLatLngZoom', bounds.toJson(), padding];
+}
+
+/// Defines a camera move to new coordinates with a zoom level.
+class CameraUpdateNewLatLngZoom extends CameraUpdate {
+  /// Creates a camera move with coordinates and zoom level.
+  const CameraUpdateNewLatLngZoom(this.latLng, this.zoom)
+      : super._(CameraUpdateType.newLatLngZoom);
+
+  /// New coordinates of the camera.
+  final LatLng latLng;
+
+  /// New zoom level of the camera.
+  final double zoom;
+  @override
+  Object toJson() => <Object>['newLatLngZoom', latLng.toJson(), zoom];
+}
+
+/// Defines a camera scroll by a certain delta.
+class CameraUpdateScrollBy extends CameraUpdate {
+  /// Creates a camera scroll.
+  const CameraUpdateScrollBy(this.dx, this.dy)
+      : super._(CameraUpdateType.scrollBy);
+
+  /// Scroll delta x.
+  final double dx;
+
+  /// Scroll delta y.
+  final double dy;
+  @override
+  Object toJson() => <Object>['scrollBy', dx, dy];
+}
+
+/// Defines a relative camera zoom.
+class CameraUpdateZoomBy extends CameraUpdate {
+  /// Creates a relative camera zoom.
+  const CameraUpdateZoomBy(this.amount, [this.focus])
+      : super._(CameraUpdateType.zoomBy);
+
+  /// Change in camera zoom amount.
+  final double amount;
+
+  /// Optional point around which the zoom is focused.
+  final Offset? focus;
+  @override
+  Object toJson() => (focus == null)
+      ? <Object>['zoomBy', amount]
+      : <Object>[
+          'zoomBy',
+          amount,
+          <double>[focus!.dx, focus!.dy]
+        ];
+}
+
+/// Defines a camera zoom in.
+class CameraUpdateZoomIn extends CameraUpdate {
+  /// Zooms in the camera.
+  const CameraUpdateZoomIn() : super._(CameraUpdateType.zoomIn);
+  @override
+  Object toJson() => <Object>['zoomIn'];
+}
+
+/// Defines a camera zoom out.
+class CameraUpdateZoomOut extends CameraUpdate {
+  /// Zooms out the camera.
+  const CameraUpdateZoomOut() : super._(CameraUpdateType.zoomOut);
+  @override
+  Object toJson() => <Object>['zoomOut'];
+}
+
+/// Defines a camera zoom to an absolute zoom.
+class CameraUpdateZoomTo extends CameraUpdate {
+  /// Creates a zoom to an absolute zoom level.
+  const CameraUpdateZoomTo(this.zoom) : super._(CameraUpdateType.zoomTo);
+
+  /// New zoom level of the camera.
+  final double zoom;
+  @override
+  Object toJson() => <Object>['zoomTo', zoom];
 }

packages/google_maps_flutter/google_maps_flutter_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/google_maps_f
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+maps%22
 # 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: 2.9.0
+version: 2.9.1
 
 environment:
   sdk: ^3.3.0

packages/google_maps_flutter/google_maps_flutter_platform_interface/test/types/camera_test.dart

@@ -20,4 +20,82 @@ void main() {
 
     expect(cameraPosition, cameraPositionFromJson);
   });
+
+  test('CameraUpdate.newCameraPosition', () {
+    const CameraPosition cameraPosition = CameraPosition(
+        target: LatLng(10.0, 15.0), bearing: 0.5, tilt: 30.0, zoom: 1.5);
+    final CameraUpdate cameraUpdate =
+        CameraUpdate.newCameraPosition(cameraPosition);
+    expect(cameraUpdate.runtimeType, CameraUpdateNewCameraPosition);
+    expect(cameraUpdate.updateType, CameraUpdateType.newCameraPosition);
+    cameraUpdate as CameraUpdateNewCameraPosition;
+    expect(cameraUpdate.cameraPosition, cameraPosition);
+  });
+
+  test('CameraUpdate.newLatLng', () {
+    const LatLng latLng = LatLng(1.0, 2.0);
+    final CameraUpdate cameraUpdate = CameraUpdate.newLatLng(latLng);
+    expect(cameraUpdate.runtimeType, CameraUpdateNewLatLng);
+    expect(cameraUpdate.updateType, CameraUpdateType.newLatLng);
+    cameraUpdate as CameraUpdateNewLatLng;
+    expect(cameraUpdate.latLng, latLng);
+  });
+
+  test('CameraUpdate.newLatLngBounds', () {
+    final LatLngBounds latLngBounds = LatLngBounds(
+        northeast: const LatLng(1.0, 2.0), southwest: const LatLng(-2.0, -3.0));
+    const double padding = 1.0;
+    final CameraUpdate cameraUpdate =
+        CameraUpdate.newLatLngBounds(latLngBounds, padding);
+    expect(cameraUpdate.runtimeType, CameraUpdateNewLatLngBounds);
+    expect(cameraUpdate.updateType, CameraUpdateType.newLatLngBounds);
+    cameraUpdate as CameraUpdateNewLatLngBounds;
+    expect(cameraUpdate.bounds, latLngBounds);
+    expect(cameraUpdate.padding, padding);
+  });
+
+  test('CameraUpdate.newLatLngZoom', () {
+    const LatLng latLng = LatLng(1.0, 2.0);
+    const double zoom = 2.0;
+    final CameraUpdate cameraUpdate = CameraUpdate.newLatLngZoom(latLng, zoom);
+    expect(cameraUpdate.runtimeType, CameraUpdateNewLatLngZoom);
+    expect(cameraUpdate.updateType, CameraUpdateType.newLatLngZoom);
+    cameraUpdate as CameraUpdateNewLatLngZoom;
+    expect(cameraUpdate.latLng, latLng);
+    expect(cameraUpdate.zoom, zoom);
+  });
+
+  test('CameraUpdate.scrollBy', () {
+    const double dx = 2.0;
+    const double dy = 5.0;
+    final CameraUpdate cameraUpdate = CameraUpdate.scrollBy(dx, dy);
+    expect(cameraUpdate.runtimeType, CameraUpdateScrollBy);
+    expect(cameraUpdate.updateType, CameraUpdateType.scrollBy);
+    cameraUpdate as CameraUpdateScrollBy;
+    expect(cameraUpdate.dx, dx);
+    expect(cameraUpdate.dy, dy);
+  });
+
+  test('CameraUpdate.zoomBy', () {
+    const double amount = 1.5;
+    const Offset focus = Offset(-1.0, -2.0);
+    final CameraUpdate cameraUpdate = CameraUpdate.zoomBy(amount, focus);
+    expect(cameraUpdate.runtimeType, CameraUpdateZoomBy);
+    expect(cameraUpdate.updateType, CameraUpdateType.zoomBy);
+    cameraUpdate as CameraUpdateZoomBy;
+    expect(cameraUpdate.amount, amount);
+    expect(cameraUpdate.focus, focus);
+  });
+
+  test('CameraUpdate.zoomIn', () {
+    final CameraUpdate cameraUpdate = CameraUpdate.zoomIn();
+    expect(cameraUpdate.runtimeType, CameraUpdateZoomIn);
+    expect(cameraUpdate.updateType, CameraUpdateType.zoomIn);
+  });
+
+  test('CameraUpdate.zoomOut', () {
+    final CameraUpdate cameraUpdate = CameraUpdate.zoomOut();
+    expect(cameraUpdate.runtimeType, CameraUpdateZoomOut);
+    expect(cameraUpdate.updateType, CameraUpdateType.zoomOut);
+  });
 }