[camerax] Implements setExposureMode (#6110)

Implements `setExposureMode`.

Fixes https://github.com/flutter/flutter/issues/120468.

~To be landed after (1) https://github.com/flutter/packages/pull/6059 then (2) https://github.com/flutter/packages/pull/6109.~ Done :)

packages/camera/camera_android_camerax/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.0+36
+
+* Implements `setExposureMode`.
+
 ## 0.5.0+35
 
 * Modifies `CameraInitializedEvent` that is sent when the camera is initialized to indicate that the initial focus

packages/camera/camera_android_camerax/README.md

@@ -30,10 +30,6 @@ dependencies:
 and thus, the plugin will fall back to 480p if configured with a
 `ResolutionPreset`.
 
-### Exposure mode configuration \[[Issue #120468][120468]\]
-
-`setExposureMode`is unimplemented.
-
 ### Focus mode configuration \[[Issue #120467][120467]\]
 
 `setFocusMode` is unimplemented.

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/CameraAndroidCameraxPlugin.java

@@ -29,6 +29,9 @@ public final class CameraAndroidCameraxPlugin implements FlutterPlugin, Activity
   @VisibleForTesting @Nullable public SystemServicesHostApiImpl systemServicesHostApiImpl;
   @VisibleForTesting @Nullable public MeteringPointHostApiImpl meteringPointHostApiImpl;
 
+  @VisibleForTesting @Nullable
+  public Camera2CameraControlHostApiImpl camera2CameraControlHostApiImpl;
+
   @VisibleForTesting
   public @Nullable DeviceOrientationManagerHostApiImpl deviceOrientationManagerHostApiImpl;
 
@@ -120,6 +123,11 @@ public final class CameraAndroidCameraxPlugin implements FlutterPlugin, Activity
     cameraControlHostApiImpl =
         new CameraControlHostApiImpl(binaryMessenger, instanceManager, context);
     GeneratedCameraXLibrary.CameraControlHostApi.setup(binaryMessenger, cameraControlHostApiImpl);
+    camera2CameraControlHostApiImpl = new Camera2CameraControlHostApiImpl(instanceManager, context);
+    GeneratedCameraXLibrary.Camera2CameraControlHostApi.setup(
+        binaryMessenger, camera2CameraControlHostApiImpl);
+    GeneratedCameraXLibrary.CaptureRequestOptionsHostApi.setup(
+        binaryMessenger, new CaptureRequestOptionsHostApiImpl(instanceManager));
     GeneratedCameraXLibrary.FocusMeteringActionHostApi.setup(
         binaryMessenger, new FocusMeteringActionHostApiImpl(instanceManager));
     GeneratedCameraXLibrary.FocusMeteringResultHostApi.setup(
@@ -217,6 +225,9 @@ public final class CameraAndroidCameraxPlugin implements FlutterPlugin, Activity
     if (cameraControlHostApiImpl != null) {
       cameraControlHostApiImpl.setContext(context);
     }
+    if (camera2CameraControlHostApiImpl != null) {
+      camera2CameraControlHostApiImpl.setContext(context);
+    }
   }
 
   /** Sets {@code LifecycleOwner} that is used to control the lifecycle of the camera by CameraX. */

packages/camera/camera_android_camerax/android/src/main/java/io/flutter/plugins/camerax/CaptureRequestOptionsHostApiImpl.java

@@ -110,8 +110,8 @@ public class CaptureRequestOptionsHostApiImpl implements CaptureRequestOptionsHo
     Map<CaptureRequestKeySupportedType, Object> decodedOptions =
         new HashMap<CaptureRequestKeySupportedType, Object>();
     for (Map.Entry<Long, Object> option : options.entrySet()) {
-      decodedOptions.put(
+      Integer index = ((Number) option.getKey()).intValue();
-          CaptureRequestKeySupportedType.values()[option.getKey().intValue()], option.getValue());
+      decodedOptions.put(CaptureRequestKeySupportedType.values()[index], option.getValue());
     }
     instanceManager.addDartCreatedInstance(proxy.create(decodedOptions), identifier);
   }

packages/camera/camera_android_camerax/android/src/test/java/io/flutter/plugins/camerax/CameraAndroidCameraxPluginTest.java

@@ -169,6 +169,8 @@ public class CameraAndroidCameraxPluginTest {
         mock(ImageAnalysisHostApiImpl.class);
     final CameraControlHostApiImpl mockCameraControlHostApiImpl =
         mock(CameraControlHostApiImpl.class);
+    final Camera2CameraControlHostApiImpl mockCamera2CameraControlHostApiImpl =
+        mock(Camera2CameraControlHostApiImpl.class);
 
     when(flutterPluginBinding.getApplicationContext()).thenReturn(mockContext);
 
@@ -180,6 +182,7 @@ public class CameraAndroidCameraxPluginTest {
     plugin.imageAnalysisHostApiImpl = mockImageAnalysisHostApiImpl;
     plugin.cameraControlHostApiImpl = mockCameraControlHostApiImpl;
     plugin.liveDataHostApiImpl = mock(LiveDataHostApiImpl.class);
+    plugin.camera2CameraControlHostApiImpl = mockCamera2CameraControlHostApiImpl;
 
     plugin.onAttachedToEngine(flutterPluginBinding);
     plugin.onDetachedFromActivityForConfigChanges();
@@ -191,6 +194,7 @@ public class CameraAndroidCameraxPluginTest {
     verify(mockImageCaptureHostApiImpl).setContext(mockContext);
     verify(mockImageAnalysisHostApiImpl).setContext(mockContext);
     verify(mockCameraControlHostApiImpl).setContext(mockContext);
+    verify(mockCamera2CameraControlHostApiImpl).setContext(mockContext);
   }
 
   @Test
@@ -259,6 +263,8 @@ public class CameraAndroidCameraxPluginTest {
         mock(CameraControlHostApiImpl.class);
     final DeviceOrientationManagerHostApiImpl mockDeviceOrientationManagerHostApiImpl =
         mock(DeviceOrientationManagerHostApiImpl.class);
+    final Camera2CameraControlHostApiImpl mockCamera2CameraControlHostApiImpl =
+        mock(Camera2CameraControlHostApiImpl.class);
     final MeteringPointHostApiImpl mockMeteringPointHostApiImpl =
         mock(MeteringPointHostApiImpl.class);
     final ArgumentCaptor<PermissionsRegistry> permissionsRegistryCaptor =
@@ -277,6 +283,7 @@ public class CameraAndroidCameraxPluginTest {
     plugin.deviceOrientationManagerHostApiImpl = mockDeviceOrientationManagerHostApiImpl;
     plugin.meteringPointHostApiImpl = mockMeteringPointHostApiImpl;
     plugin.liveDataHostApiImpl = mock(LiveDataHostApiImpl.class);
+    plugin.camera2CameraControlHostApiImpl = mockCamera2CameraControlHostApiImpl;
 
     plugin.onAttachedToEngine(flutterPluginBinding);
     plugin.onReattachedToActivityForConfigChanges(activityPluginBinding);
@@ -294,6 +301,7 @@ public class CameraAndroidCameraxPluginTest {
     verify(mockImageCaptureHostApiImpl).setContext(mockActivity);
     verify(mockImageAnalysisHostApiImpl).setContext(mockActivity);
     verify(mockCameraControlHostApiImpl).setContext(mockActivity);
+    verify(mockCamera2CameraControlHostApiImpl).setContext(mockActivity);
 
     // Check permissions registry reference is set.
     verify(mockSystemServicesHostApiImpl)
@@ -347,6 +355,8 @@ public class CameraAndroidCameraxPluginTest {
     final ImageCaptureHostApiImpl mockImageCaptureHostApiImpl = mock(ImageCaptureHostApiImpl.class);
     final CameraControlHostApiImpl mockCameraControlHostApiImpl =
         mock(CameraControlHostApiImpl.class);
+    final Camera2CameraControlHostApiImpl mockCamera2CameraControlHostApiImpl =
+        mock(Camera2CameraControlHostApiImpl.class);
     final ArgumentCaptor<PermissionsRegistry> permissionsRegistryCaptor =
         ArgumentCaptor.forClass(PermissionsRegistry.class);
 
@@ -360,6 +370,7 @@ public class CameraAndroidCameraxPluginTest {
     plugin.imageAnalysisHostApiImpl = mockImageAnalysisHostApiImpl;
     plugin.cameraControlHostApiImpl = mockCameraControlHostApiImpl;
     plugin.liveDataHostApiImpl = mock(LiveDataHostApiImpl.class);
+    plugin.camera2CameraControlHostApiImpl = mockCamera2CameraControlHostApiImpl;
 
     plugin.onAttachedToEngine(flutterPluginBinding);
     plugin.onDetachedFromActivity();
@@ -371,5 +382,6 @@ public class CameraAndroidCameraxPluginTest {
     verify(mockImageCaptureHostApiImpl).setContext(mockContext);
     verify(mockImageAnalysisHostApiImpl).setContext(mockContext);
     verify(mockCameraControlHostApiImpl).setContext(mockContext);
+    verify(mockCamera2CameraControlHostApiImpl).setContext(mockContext);
   }
 }

packages/camera/camera_android_camerax/example/lib/main.dart

@@ -393,8 +393,10 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                 children: <Widget>[
                   TextButton(
                     style: styleAuto,
-                    onPressed:
+                    onPressed: controller != null
-                        () {}, // TODO(camsim99): Add functionality back here.
+                        ? () =>
+                            onSetExposureModeButtonPressed(ExposureMode.auto)
+                        : null,
                     onLongPress: () {
                       if (controller != null) {
                         CameraPlatform.instance
@@ -406,8 +408,10 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                   ),
                   TextButton(
                     style: styleLocked,
-                    onPressed:
+                    onPressed: controller != null
-                        () {}, // TODO(camsim99): Add functionality back here.
+                        ? () =>
+                            onSetExposureModeButtonPressed(ExposureMode.locked)
+                        : null,
                     child: const Text('LOCKED'),
                   ),
                   TextButton(

packages/camera/camera_android_camerax/lib/src/android_camera_camerax.dart

@@ -14,12 +14,14 @@ import 'package:stream_transform/stream_transform.dart';
 
 import 'analyzer.dart';
 import 'camera.dart';
+import 'camera2_camera_control.dart';
 import 'camera_control.dart';
 import 'camera_info.dart';
 import 'camera_selector.dart';
 import 'camera_state.dart';
 import 'camerax_library.g.dart';
 import 'camerax_proxy.dart';
+import 'capture_request_options.dart';
 import 'device_orientation_manager.dart';
 import 'exposure_state.dart';
 import 'fallback_strategy.dart';
@@ -545,6 +547,27 @@ class AndroidCameraCameraX extends CameraPlatform {
         point: point, meteringMode: FocusMeteringAction.flagAf);
   }
 
+  /// Sets the exposure mode for taking pictures.
+  ///
+  /// Setting [ExposureMode.locked] will lock current exposure point until it
+  /// is unset by setting [ExposureMode.auto].
+  ///
+  /// [cameraId] is not used.
+  @override
+  Future<void> setExposureMode(int cameraId, ExposureMode mode) async {
+    final Camera2CameraControl camera2Control =
+        proxy.getCamera2CameraControl(cameraControl);
+    final bool lockExposureMode = mode == ExposureMode.locked;
+
+    final CaptureRequestOptions captureRequestOptions = proxy
+        .createCaptureRequestOptions(<(
+      CaptureRequestKeySupportedType,
+      Object?
+    )>[(CaptureRequestKeySupportedType.controlAeLock, lockExposureMode)]);
+
+    await camera2Control.addCaptureRequestOptions(captureRequestOptions);
+  }
+
   /// Gets the maximum supported zoom level for the selected camera.
   ///
   /// [cameraId] not used.

packages/camera/camera_android_camerax/lib/src/camerax_proxy.dart

@@ -5,10 +5,13 @@
 import 'dart:ui' show Size;
 
 import 'analyzer.dart';
+import 'camera2_camera_control.dart';
+import 'camera_control.dart';
 import 'camera_info.dart';
 import 'camera_selector.dart';
 import 'camera_state.dart';
 import 'camerax_library.g.dart';
+import 'capture_request_options.dart';
 import 'device_orientation_manager.dart';
 import 'fallback_strategy.dart';
 import 'focus_metering_action.dart';
@@ -52,6 +55,8 @@ class CameraXProxy {
         _startListeningForDeviceOrientationChange,
     this.setPreviewSurfaceProvider = _setPreviewSurfaceProvider,
     this.getDefaultDisplayRotation = _getDefaultDisplayRotation,
+    this.getCamera2CameraControl = _getCamera2CameraControl,
+    this.createCaptureRequestOptions = _createCaptureRequestOptions,
     this.createMeteringPoint = _createMeteringPoint,
     this.createFocusMeteringAction = _createFocusMeteringAction,
   });
@@ -142,6 +147,15 @@ class CameraXProxy {
   /// rotation constants.
   Future<int> Function() getDefaultDisplayRotation;
 
+  /// Get [Camera2CameraControl] instance from [cameraControl].
+  Camera2CameraControl Function(CameraControl cameraControl)
+      getCamera2CameraControl;
+
+  /// Create [CapureRequestOptions] with specified options.
+  CaptureRequestOptions Function(
+          List<(CaptureRequestKeySupportedType, Object?)> options)
+      createCaptureRequestOptions;
+
   /// Returns a [MeteringPoint] with the specified coordinates based on
   /// [cameraInfo].
   MeteringPoint Function(double x, double y, CameraInfo cameraInfo)
@@ -255,6 +269,16 @@ class CameraXProxy {
     return DeviceOrientationManager.getDefaultDisplayRotation();
   }
 
+  static Camera2CameraControl _getCamera2CameraControl(
+      CameraControl cameraControl) {
+    return Camera2CameraControl(cameraControl: cameraControl);
+  }
+
+  static CaptureRequestOptions _createCaptureRequestOptions(
+      List<(CaptureRequestKeySupportedType, Object?)> options) {
+    return CaptureRequestOptions(requestedOptions: options);
+  }
+
   static MeteringPoint _createMeteringPoint(
       double x, double y, CameraInfo cameraInfo) {
     return MeteringPoint(x: x, y: y, cameraInfo: cameraInfo);

packages/camera/camera_android_camerax/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera_android_camerax
 description: Android implementation of the camera plugin using the CameraX library.
 repository: https://github.com/flutter/packages/tree/main/packages/camera/camera_android_camerax
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+camera%22
-version: 0.5.0+35
+version: 0.5.0+36
 
 environment:
   sdk: ^3.1.0

packages/camera/camera_android_camerax/test/android_camera_camerax_test.dart

@@ -9,6 +9,7 @@ import 'package:async/async.dart';
 import 'package:camera_android_camerax/camera_android_camerax.dart';
 import 'package:camera_android_camerax/src/analyzer.dart';
 import 'package:camera_android_camerax/src/camera.dart';
+import 'package:camera_android_camerax/src/camera2_camera_control.dart';
 import 'package:camera_android_camerax/src/camera_control.dart';
 import 'package:camera_android_camerax/src/camera_info.dart';
 import 'package:camera_android_camerax/src/camera_selector.dart';
@@ -16,6 +17,7 @@ import 'package:camera_android_camerax/src/camera_state.dart';
 import 'package:camera_android_camerax/src/camera_state_error.dart';
 import 'package:camera_android_camerax/src/camerax_library.g.dart';
 import 'package:camera_android_camerax/src/camerax_proxy.dart';
+import 'package:camera_android_camerax/src/capture_request_options.dart';
 import 'package:camera_android_camerax/src/device_orientation_manager.dart';
 import 'package:camera_android_camerax/src/exposure_state.dart';
 import 'package:camera_android_camerax/src/fallback_strategy.dart';
@@ -78,6 +80,7 @@ import 'test_camerax_library.g.dart';
   MockSpec<TestInstanceManagerHostApi>(),
   MockSpec<TestSystemServicesHostApi>(),
   MockSpec<ZoomState>(),
+  MockSpec<Camera2CameraControl>(),
 ])
 @GenerateMocks(<Type>[], customMocks: <MockSpec<Object>>[
   MockSpec<LiveData<CameraState>>(as: #MockLiveCameraState),
@@ -2010,6 +2013,59 @@ void main() {
     expect(camera.captureOrientationLocked, isFalse);
   });
 
+  test('setExposureMode sets expected controlAeLock value via Camera2 interop',
+      () async {
+    final AndroidCameraCameraX camera = AndroidCameraCameraX();
+    const int cameraId = 78;
+    final MockCameraControl mockCameraControl = MockCameraControl();
+    final MockCamera2CameraControl mockCamera2CameraControl =
+        MockCamera2CameraControl();
+
+    // Set directly for test versus calling createCamera.
+    camera.camera = MockCamera();
+    camera.cameraControl = mockCameraControl;
+
+    // Tell plugin to create detached Camera2CameraControl and
+    // CaptureRequestOptions instances for testing.
+    camera.proxy = CameraXProxy(
+      getCamera2CameraControl: (CameraControl cameraControl) =>
+          cameraControl == mockCameraControl
+              ? mockCamera2CameraControl
+              : Camera2CameraControl.detached(cameraControl: cameraControl),
+      createCaptureRequestOptions:
+          (List<(CaptureRequestKeySupportedType, Object?)> options) =>
+              CaptureRequestOptions.detached(requestedOptions: options),
+    );
+
+    // Test auto mode.
+    await camera.setExposureMode(cameraId, ExposureMode.auto);
+
+    VerificationResult verificationResult =
+        verify(mockCamera2CameraControl.addCaptureRequestOptions(captureAny));
+    CaptureRequestOptions capturedCaptureRequestOptions =
+        verificationResult.captured.single as CaptureRequestOptions;
+    List<(CaptureRequestKeySupportedType, Object?)> requestedOptions =
+        capturedCaptureRequestOptions.requestedOptions;
+    expect(requestedOptions.length, equals(1));
+    expect(requestedOptions.first.$1,
+        equals(CaptureRequestKeySupportedType.controlAeLock));
+    expect(requestedOptions.first.$2, equals(false));
+
+    // Test locked mode.
+    clearInteractions(mockCamera2CameraControl);
+    await camera.setExposureMode(cameraId, ExposureMode.locked);
+
+    verificationResult =
+        verify(mockCamera2CameraControl.addCaptureRequestOptions(captureAny));
+    capturedCaptureRequestOptions =
+        verificationResult.captured.single as CaptureRequestOptions;
+    requestedOptions = capturedCaptureRequestOptions.requestedOptions;
+    expect(requestedOptions.length, equals(1));
+    expect(requestedOptions.first.$1,
+        equals(CaptureRequestKeySupportedType.controlAeLock));
+    expect(requestedOptions.first.$2, equals(true));
+  });
+
   test(
       'setExposurePoint clears current auto-exposure metering point as expected',
       () async {

packages/camera/camera_android_camerax/test/android_camera_camerax_test.mocks.dart

@@ -8,11 +8,14 @@ import 'dart:typed_data' as _i29;
 
 import 'package:camera_android_camerax/src/analyzer.dart' as _i15;
 import 'package:camera_android_camerax/src/camera.dart' as _i9;
+import 'package:camera_android_camerax/src/camera2_camera_control.dart' as _i38;
 import 'package:camera_android_camerax/src/camera_control.dart' as _i3;
 import 'package:camera_android_camerax/src/camera_info.dart' as _i2;
 import 'package:camera_android_camerax/src/camera_selector.dart' as _i22;
 import 'package:camera_android_camerax/src/camera_state.dart' as _i18;
 import 'package:camera_android_camerax/src/camerax_library.g.dart' as _i7;
+import 'package:camera_android_camerax/src/capture_request_options.dart'
+    as _i39;
 import 'package:camera_android_camerax/src/exposure_state.dart' as _i5;
 import 'package:camera_android_camerax/src/fallback_strategy.dart' as _i23;
 import 'package:camera_android_camerax/src/focus_metering_action.dart' as _i21;
@@ -1317,6 +1320,38 @@ class MockZoomState extends _i1.Mock implements _i19.ZoomState {
       ) as double);
 }
 
+/// A class which mocks [Camera2CameraControl].
+///
+/// See the documentation for Mockito's code generation for more information.
+// ignore: must_be_immutable
+class MockCamera2CameraControl extends _i1.Mock
+    implements _i38.Camera2CameraControl {
+  @override
+  _i3.CameraControl get cameraControl => (super.noSuchMethod(
+        Invocation.getter(#cameraControl),
+        returnValue: _FakeCameraControl_1(
+          this,
+          Invocation.getter(#cameraControl),
+        ),
+        returnValueForMissingStub: _FakeCameraControl_1(
+          this,
+          Invocation.getter(#cameraControl),
+        ),
+      ) as _i3.CameraControl);
+
+  @override
+  _i16.Future<void> addCaptureRequestOptions(
+          _i39.CaptureRequestOptions? captureRequestOptions) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #addCaptureRequestOptions,
+          [captureRequestOptions],
+        ),
+        returnValue: _i16.Future<void>.value(),
+        returnValueForMissingStub: _i16.Future<void>.value(),
+      ) as _i16.Future<void>);
+}
+
 /// A class which mocks [LiveData].
 ///
 /// See the documentation for Mockito's code generation for more information.