[camerax] Implement setZoomLevel (flutter#4950)

Implements `setZoomLevel`.

Fixes flutter#125371.
Fixes flutter#115847.

Author: camsim99

packages/camera/camera_android_camerax/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.0+20
+
+* Implements `setZoomLevel`.
+
 ## 0.5.0+19
 
 * Implements torch flash mode.

packages/camera/camera_android_camerax/README.md

@@ -43,10 +43,6 @@ and thus, the plugin will fall back to 480p if configured with a
 
 `setFocusMode` & `setFocusPoint` are unimplemented.
 
-### Zoom configuration \[[Issue #125371][125371]\]
-
-`setZoomLevel` is unimplemented.
-
 ### Setting maximum duration and stream options for video capture
 
 Calling `startVideoCapturing` with `VideoCaptureOptions` configured with

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

@@ -51,6 +51,29 @@ public void onFailure(Throwable t) {
           },
           ContextCompat.getMainExecutor(context));
     }
+
+    /** Sets the zoom ratio of the specified {@link CameraControl} instance. */
+    @NonNull
+    public void setZoomRatio(
+        @NonNull CameraControl cameraControl,
+        @NonNull Double ratio,
+        @NonNull GeneratedCameraXLibrary.Result<Void> result) {
+      float ratioAsFloat = ratio.floatValue();
+      ListenableFuture<Void> setZoomRatioFuture = cameraControl.setZoomRatio(ratioAsFloat);
+
+      Futures.addCallback(
+          setZoomRatioFuture,
+          new FutureCallback<Void>() {
+            public void onSuccess(Void voidResult) {
+              result.success(null);
+            }
+
+            public void onFailure(Throwable t) {
+              result.error(t);
+            }
+          },
+          ContextCompat.getMainExecutor(context));
+    }
   }
 
   /**
@@ -81,7 +104,8 @@ public CameraControlHostApiImpl(
   }
 
   /**
-   * Sets the context that the {@code ProcessCameraProvider} will use to enable/disable torch mode.
+   * Sets the context that the {@code ProcessCameraProvider} will use to enable/disable torch mode
+   * and set the zoom ratio.
    *
    * <p>If using the camera plugin in an add-to-app context, ensure that a new instance of the
    * {@code CameraControl} is fetched via {@code #enableTorch} anytime the context changes.
@@ -98,4 +122,13 @@ public void enableTorch(
     proxy.enableTorch(
         Objects.requireNonNull(instanceManager.getInstance(identifier)), torch, result);
   }
+
+  @Override
+  public void setZoomRatio(
+      @NonNull Long identifier,
+      @NonNull Double ratio,
+      @NonNull GeneratedCameraXLibrary.Result<Void> result) {
+    proxy.setZoomRatio(
+        Objects.requireNonNull(instanceManager.getInstance(identifier)), ratio, result);
+  }
 }

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

@@ -3237,6 +3237,9 @@ public interface CameraControlHostApi {
     void enableTorch(
         @NonNull Long identifier, @NonNull Boolean torch, @NonNull Result<Void> result);
 
+    void setZoomRatio(
+        @NonNull Long identifier, @NonNull Double ratio, @NonNull Result<Void> result);
+
     /** The codec used by CameraControlHostApi. */
     static @NonNull MessageCodec<Object> getCodec() {
       return new StandardMessageCodec();
@@ -3280,6 +3283,41 @@ public void error(Throwable error) {
           channel.setMessageHandler(null);
         }
       }
+      {
+        BasicMessageChannel<Object> channel =
+            new BasicMessageChannel<>(
+                binaryMessenger,
+                "dev.flutter.pigeon.CameraControlHostApi.setZoomRatio",
+                getCodec());
+        if (api != null) {
+          channel.setMessageHandler(
+              (message, reply) -> {
+                ArrayList<Object> wrapped = new ArrayList<Object>();
+                ArrayList<Object> args = (ArrayList<Object>) message;
+                Number identifierArg = (Number) args.get(0);
+                Double ratioArg = (Double) args.get(1);
+                Result<Void> resultCallback =
+                    new Result<Void>() {
+                      public void success(Void result) {
+                        wrapped.add(0, null);
+                        reply.reply(wrapped);
+                      }
+
+                      public void error(Throwable error) {
+                        ArrayList<Object> wrappedError = wrapError(error);
+                        reply.reply(wrappedError);
+                      }
+                    };
+
+                api.setZoomRatio(
+                    (identifierArg == null) ? null : identifierArg.longValue(),
+                    ratioArg,
+                    resultCallback);
+              });
+        } else {
+          channel.setMessageHandler(null);
+        }
+      }
     }
   }
   /** Generated class from Pigeon that represents Flutter messages that can be called from Java. */

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

@@ -97,6 +97,57 @@ public void enableTorch_turnsTorchModeOnAndOffAsExpected() {
     }
   }
 
+  @Test
+  public void setZoomRatio_setsZoomAsExpected() {
+    try (MockedStatic<Futures> mockedFutures = Mockito.mockStatic(Futures.class)) {
+      final CameraControlHostApiImpl cameraControlHostApiImpl =
+          new CameraControlHostApiImpl(testInstanceManager, mock(Context.class));
+      final Long cameraControlIdentifier = 33L;
+      final Double zoomRatio = 0.2D;
+
+      @SuppressWarnings("unchecked")
+      final ListenableFuture<Void> setZoomRatioFuture = mock(ListenableFuture.class);
+
+      testInstanceManager.addDartCreatedInstance(cameraControl, cameraControlIdentifier);
+
+      when(cameraControl.setZoomRatio(zoomRatio.floatValue())).thenReturn(setZoomRatioFuture);
+
+      @SuppressWarnings("unchecked")
+      final ArgumentCaptor<FutureCallback<Void>> futureCallbackCaptor =
+          ArgumentCaptor.forClass(FutureCallback.class);
+
+      // Test successful behavior.
+      @SuppressWarnings("unchecked")
+      final GeneratedCameraXLibrary.Result<Void> successfulMockResult =
+          mock(GeneratedCameraXLibrary.Result.class);
+      cameraControlHostApiImpl.setZoomRatio(
+          cameraControlIdentifier, zoomRatio, successfulMockResult);
+      mockedFutures.verify(
+          () -> Futures.addCallback(eq(setZoomRatioFuture), futureCallbackCaptor.capture(), any()));
+      mockedFutures.clearInvocations();
+
+      FutureCallback<Void> successfulSetZoomRatioCallback = futureCallbackCaptor.getValue();
+
+      successfulSetZoomRatioCallback.onSuccess(mock(Void.class));
+      verify(successfulMockResult).success(null);
+
+      // Test failed behavior.
+      @SuppressWarnings("unchecked")
+      final GeneratedCameraXLibrary.Result<Void> failedMockResult =
+          mock(GeneratedCameraXLibrary.Result.class);
+      final Throwable testThrowable = new Throwable();
+      cameraControlHostApiImpl.setZoomRatio(cameraControlIdentifier, zoomRatio, failedMockResult);
+      mockedFutures.verify(
+          () -> Futures.addCallback(eq(setZoomRatioFuture), futureCallbackCaptor.capture(), any()));
+      mockedFutures.clearInvocations();
+
+      FutureCallback<Void> failedSetZoomRatioCallback = futureCallbackCaptor.getValue();
+
+      failedSetZoomRatioCallback.onFailure(testThrowable);
+      verify(failedMockResult).error(testThrowable);
+    }
+  }
+
   @Test
   public void flutterApiCreate_makesCallToCreateInstanceOnDartSide() {
     final CameraControlFlutterApiImpl spyFlutterApi =

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

@@ -392,12 +392,8 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                     style: styleAuto,
                     onPressed:
                         () {}, // TODO(camsim99): Add functionality back here.
-                    onLongPress: () {
-                      if (controller != null) {
-                        controller!.setExposurePoint(null);
-                        showInSnackBar('Resetting exposure point');
-                      }
-                    },
+                    onLongPress:
+                        () {}, // TODO(camsim99): Add functionality back here.,
                     child: const Text('AUTO'),
                   ),
                   TextButton(
@@ -470,12 +466,8 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                     style: styleAuto,
                     onPressed:
                         () {}, // TODO(camsim99): Add functionality back here.
-                    onLongPress: () {
-                      if (controller != null) {
-                        controller!.setFocusPoint(null);
-                      }
-                      showInSnackBar('Resetting focus point');
-                    },
+                    onLongPress:
+                        () {}, // TODO(camsim99): Add functionality back here.
                     child: const Text('AUTO'),
                   ),
                   TextButton(

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

@@ -439,6 +439,17 @@ class AndroidCameraCameraX extends CameraPlatform {
     return zoomState.minZoomRatio;
   }
 
+  /// Set the zoom level for the selected camera.
+  ///
+  /// The supplied [zoom] value should be between the minimum and the maximum
+  /// supported zoom level returned by `getMinZoomLevel` and `getMaxZoomLevel`.
+  /// Throws a `CameraException` when an illegal zoom level is supplied.
+  @override
+  Future<void> setZoomLevel(int cameraId, double zoom) async {
+    final CameraControl cameraControl = await camera!.getCameraControl();
+    await cameraControl.setZoomRatio(zoom);
+  }
+
   /// The ui orientation changed.
   @override
   Stream<DeviceOrientationChangedEvent> onDeviceOrientationChanged() {

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

@@ -32,9 +32,22 @@ class CameraControl extends JavaObject {
   late final _CameraControlHostApiImpl _api;
 
   /// Enables or disables the torch of related [Camera] instance.
+  ///
+  /// If the torch mode was unable to be changed, an error message will be
+  /// added to [SystemServices.cameraErrorStreamController].
   Future<void> enableTorch(bool torch) async {
     return _api.enableTorchFromInstance(this, torch);
   }
+
+  /// Sets zoom of related [Camera] by ratio.
+  ///
+  /// Ratio should be between what the `minZoomRatio` and `maxZoomRatio` of the
+  /// [ZoomState] of the [CameraInfo] instance that is retrievable from the same
+  /// [Camera] instance; otherwise, an error message will be added to
+  /// [SystemServices.cameraErrorStreamController].
+  Future<void> setZoomRatio(double ratio) async {
+    return _api.setZoomRatioFromInstance(this, ratio);
+  }
 }
 
 /// Host API implementation of [CameraControl].
@@ -69,6 +82,18 @@ class _CameraControlHostApiImpl extends CameraControlHostApi {
           .add(e.message ?? 'The camera was unable to change torch modes.');
     }
   }
+
+  /// Sets zoom of specified [CameraControl] instance by ratio.
+  Future<void> setZoomRatioFromInstance(
+      CameraControl instance, double ratio) async {
+    final int identifier = instanceManager.getIdentifier(instance)!;
+    try {
+      await setZoomRatio(identifier, ratio);
+    } on PlatformException catch (e) {
+      SystemServices.cameraErrorStreamController.add(e.message ??
+          'Zoom ratio was unable to be set. If ratio was not out of range, newer value may have been set; otherwise, the camera may be closed.');
+    }
+  }
 }
 
 /// Flutter API implementation of [CameraControl].

packages/camera/camera_android_camerax/lib/src/camerax_library.g.dart

@@ -2685,6 +2685,28 @@ class CameraControlHostApi {
       return;
     }
   }
+
+  Future<void> setZoomRatio(int arg_identifier, double arg_ratio) async {
+    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+        'dev.flutter.pigeon.CameraControlHostApi.setZoomRatio', codec,
+        binaryMessenger: _binaryMessenger);
+    final List<Object?>? replyList = await channel
+        .send(<Object?>[arg_identifier, arg_ratio]) as List<Object?>?;
+    if (replyList == null) {
+      throw PlatformException(
+        code: 'channel-error',
+        message: 'Unable to establish connection on channel.',
+      );
+    } else if (replyList.length > 1) {
+      throw PlatformException(
+        code: replyList[0]! as String,
+        message: replyList[1] as String?,
+        details: replyList[2],
+      );
+    } else {
+      return;
+    }
+  }
 }
 
 abstract class CameraControlFlutterApi {

packages/camera/camera_android_camerax/pigeons/camerax_library.dart

@@ -424,6 +424,9 @@ abstract class FallbackStrategyHostApi {
 abstract class CameraControlHostApi {
   @async
   void enableTorch(int identifier, bool torch);
+
+  @async
+  void setZoomRatio(int identifier, double ratio);
 }
 
 @FlutterApi()