[camera] zoom feature

packages/camera/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.5.7
+
+* Add zoom feature.
+
 ## 0.5.6+4
 
 * Android: Use CameraDevice.TEMPLATE_RECORD to improve image streaming.

packages/camera/android/src/main/java/io/flutter/plugins/camera/Camera.java

@@ -7,6 +7,7 @@
 import android.app.Activity;
 import android.content.Context;
 import android.graphics.ImageFormat;
+import android.graphics.Rect;
 import android.graphics.SurfaceTexture;
 import android.hardware.camera2.CameraAccessException;
 import android.hardware.camera2.CameraCaptureSession;
@@ -61,6 +62,10 @@ public class Camera {
   private CamcorderProfile recordingProfile;
   private int currentOrientation = ORIENTATION_UNKNOWN;
 
+  public float zoomLevel = 1f;
+  private Rect zoom;
+  protected CameraCharacteristics cameraCharacteristics;
+
   // Mirrors camera.dart
   public enum ResolutionPreset {
     low,
@@ -106,6 +111,8 @@ public void onOrientationChanged(int i) {
         characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
     //noinspection ConstantConditions
     sensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);
+    cameraCharacteristics = characteristics;
+
     //noinspection ConstantConditions
     isFrontFacing =
         characteristics.get(CameraCharacteristics.LENS_FACING) == CameraMetadata.LENS_FACING_FRONT;
@@ -249,6 +256,7 @@ public void takePicture(String filePath, @NonNull final Result result) {
           cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
       captureBuilder.addTarget(pictureImageReader.getSurface());
       captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getMediaOrientation());
+      setScalerCropRegion(captureBuilder, zoom);
 
       cameraCaptureSession.capture(
           captureBuilder.build(),
@@ -320,6 +328,7 @@ public void onConfigured(@NonNull CameraCaptureSession session) {
               cameraCaptureSession = session;
               captureRequestBuilder.set(
                   CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
+              setScalerCropRegion(captureRequestBuilder, zoom);
               cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
               if (onSuccessCallback != null) {
                 onSuccessCallback.run();
@@ -510,6 +519,41 @@ public void dispose() {
     orientationEventListener.disable();
   }
 
+  public void zoom(int step) throws CameraAccessException {
+    changeZoom(step);
+  }
+
+  private void changeZoom(int step) throws CameraAccessException {
+    calculateZoom(step);
+    setScalerCropRegion(captureRequestBuilder, zoom);
+    cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
+  }
+
+  private void calculateZoom(int step) {
+    zoomLevel += step;
+
+    if (zoomLevel < 1f) {
+      zoomLevel = 1f;
+      return;
+    }
+
+    Rect rect = cameraCharacteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);
+
+    float ratio = (float) 1 / zoomLevel;
+    int croppedWidth = rect.width() - Math.round((float) rect.width() * ratio);
+    int croppedHeight = rect.height() - Math.round((float) rect.height() * ratio);
+    zoom =
+        new Rect(
+            croppedWidth / 2,
+            croppedHeight / 2,
+            rect.width() - croppedWidth / 2,
+            rect.height() - croppedHeight / 2);
+  }
+
+  private void setScalerCropRegion(CaptureRequest.Builder captureRequestBuilder, Rect zoom) {
+    captureRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoom);
+  }
+
   private int getMediaOrientation() {
     final int sensorOrientationOffset =
         (currentOrientation == ORIENTATION_UNKNOWN)

packages/camera/android/src/main/java/io/flutter/plugins/camera/MethodCallHandlerImpl.java

@@ -77,6 +77,36 @@ public void onMethodCall(@NonNull MethodCall call, @NonNull final Result result)
           camera.takePicture(call.argument("path"), result);
           break;
         }
+      case "zoom":
+        {
+          try {
+            camera.zoom(call.argument("step"));
+            result.success(null);
+          } catch (CameraAccessException e) {
+            result.error("CameraAccess", e.getMessage(), null);
+          }
+          break;
+        }
+      case "zoomIn":
+        {
+          try {
+            camera.zoom(1);
+            result.success(null);
+          } catch (CameraAccessException e) {
+            result.error("CameraAccess", e.getMessage(), null);
+          }
+          break;
+        }
+      case "zoomOut":
+        {
+          try {
+            camera.zoom(-1);
+            result.success(null);
+          } catch (CameraAccessException e) {
+            result.error("CameraAccess", e.getMessage(), null);
+          }
+          break;
+        }
       case "prepareForVideoRecording":
         {
           // This optimization is not required for Android.

packages/camera/example/lib/main.dart

@@ -235,7 +235,17 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
                   controller.value.isRecordingVideo
               ? onStopButtonPressed
               : null,
-        )
+        ),
+        IconButton(
+          icon: const Icon(Icons.zoom_in),
+          color: Colors.blue,
+          onPressed: controller != null ? onZoomInButtonPressed : null,
+        ),
+        IconButton(
+          icon: const Icon(Icons.zoom_out),
+          color: Colors.blue,
+          onPressed: controller != null ? onZoomOutButtonPressed : null,
+        ),
       ],
     );
   }
@@ -329,6 +339,20 @@ class _CameraExampleHomeState extends State<CameraExampleHome>
     });
   }
 
+  void onZoomInButtonPressed() {
+    if (controller == null) {
+      return;
+    }
+    controller.zoomIn();
+  }
+
+  void onZoomOutButtonPressed() {
+    if (controller == null) {
+      return;
+    }
+    controller.zoomOut();
+  }
+
   void onPauseButtonPressed() {
     pauseVideoRecording().then((_) {
       if (mounted) setState(() {});

packages/camera/ios/Classes/CameraPlugin.m

@@ -197,6 +197,7 @@ - (instancetype)initWithCameraName:(NSString *)cameraName
                        enableAudio:(BOOL)enableAudio
                      dispatchQueue:(dispatch_queue_t)dispatchQueue
                              error:(NSError **)error;
+@property(nonatomic, assign) int zoom;
 
 - (void)start;
 - (void)stop;
@@ -205,6 +206,7 @@ - (void)stopVideoRecordingWithResult:(FlutterResult)result;
 - (void)startImageStreamWithMessenger:(NSObject<FlutterBinaryMessenger> *)messenger;
 - (void)stopImageStream;
 - (void)captureToFile:(NSString *)filename result:(FlutterResult)result;
+- (void)zoom:(NSUInteger *)step;
 @end
 
 @implementation FLTCam {
@@ -219,6 +221,8 @@ - (instancetype)initWithCameraName:(NSString *)cameraName
                      dispatchQueue:(dispatch_queue_t)dispatchQueue
                              error:(NSError **)error {
   self = [super init];
+  _zoom = 1;
+
   NSAssert(self, @"super init cannot be nil");
   @try {
     _resolutionPreset = getResolutionPresetForString(resolutionPreset);
@@ -272,6 +276,19 @@ - (void)stop {
   [_captureSession stopRunning];
 }
 
+- (void)zoom:(NSUInteger *)step {
+  _zoom += step;
+
+  if (_zoom < 1) {
+    _zoom = 1;
+    return;
+  }
+
+  [_captureDevice lockForConfiguration:NULL];
+  [_captureDevice setVideoZoomFactor:_zoom];
+  [_captureDevice unlockForConfiguration];
+}
+
 - (void)captureToFile:(NSString *)path result:(FlutterResult)result {
   AVCapturePhotoSettings *settings = [AVCapturePhotoSettings photoSettings];
   if (_resolutionPreset == max) {
@@ -871,6 +888,16 @@ - (void)handleMethodCallAsync:(FlutterMethodCall *)call result:(FlutterResult)re
   } else if ([@"stopImageStream" isEqualToString:call.method]) {
     [_camera stopImageStream];
     result(nil);
+  } else if ([@"zoomIn" isEqualToString:call.method]) {
+    [_camera zoom:1];
+    result(nil);
+  } else if ([@"zoomOut" isEqualToString:call.method]) {
+    [_camera zoom:-1];
+    result(nil);
+  } else if ([@"zoom" isEqualToString:call.method]) {
+    NSUInteger step = ((NSNumber *)call.arguments[@"step"]).unsignedIntegerValue;
+    [_camera zoom:step];
+    result(nil);
   } else if ([@"pauseVideoRecording" isEqualToString:call.method]) {
     [_camera pauseVideoRecording];
     result(nil);

packages/camera/lib/camera.dart

@@ -585,4 +585,20 @@ class CameraController extends ValueNotifier<CameraValue> {
       await _eventSubscription?.cancel();
     }
   }
+
+  Future<void> zoomIn() async {
+    await _channel.invokeMethod<void>('zoomIn');
+  }
+
+  ///
+  /// change zoom by specific [step].
+  /// with a negative step, the zoom will be 1
+  ///
+  Future<void> zoom(int step) async {
+    await _channel.invokeMethod<void>('zoom', <String, dynamic>{'step': step});
+  }
+
+  Future<void> zoomOut() async {
+    await _channel.invokeMethod<void>('zoomOut');
+  }
 }

packages/camera/pubspec.yaml

@@ -2,7 +2,7 @@ name: camera
 description: A Flutter plugin for getting information about and controlling the
   camera on Android and iOS. Supports previewing the camera feed, capturing images, capturing video,
   and streaming image buffers to dart.
-version: 0.5.6+3
+version: 0.5.7
 
 authors:
   - Flutter Team <flutter-dev@googlegroups.com>

packages/connectivity/ios/Classes/ConnectivityPlugin.m

@@ -155,7 +155,9 @@ - (NSString*)convertCLAuthorizationStatusToString:(CLAuthorizationStatus)status
     case kCLAuthorizationStatusAuthorizedWhenInUse: {
       return @"authorizedWhenInUse";
     }
-    default: { return @"unknown"; }
+    default: {
+      return @"unknown";
+    }
   }
 }