Feature: iOS rectOfInterest implementation

docs/RNCamera.md

@@ -293,6 +293,10 @@ By default a `Camera not authorized` message will be displayed when access to th
 
 By default a <ActivityIndicator> will be displayed while the component is waiting for the user to grant/deny access to the camera, if set displays the passed react element instead of the default one.
 
+#### `iOS` `rectOfInterest`
+
+An `{x: , y:, width:, height: }` object which defines the rect of interst as normalized coordinates from `(0,0)` top left corner to `(1,1)` bottom right corner.
+
 ### `iOS` `videoStabilizationMode`
 
 The video stabilization mode used for a video recording. The possible values are:

ios/RN/RNCamera.h

@@ -40,6 +40,7 @@
 @property(nonatomic, assign) BOOL canReadText;
 @property(nonatomic, assign) BOOL canDetectFaces;
 @property(nonatomic, assign) BOOL canDetectBarcodes;
+@property(nonatomic, assign) CGRect rectOfInterest;
 @property(assign, nonatomic) AVVideoCodecType videoCodecType;
 @property(assign, nonatomic)
     AVCaptureVideoStabilizationMode videoStabilizationMode;
@@ -61,6 +62,7 @@
 - (void)updateFaceDetectionMode:(id)requestedMode;
 - (void)updateFaceDetectionLandmarks:(id)requestedLandmarks;
 - (void)updateFaceDetectionClassifications:(id)requestedClassifications;
+- (void)updateRectOfInterest;
 // google Barcode props
 - (void)updateGoogleVisionBarcodeType:(id)requestedTypes;
 

ios/RN/RNCamera.m

@@ -62,6 +62,7 @@ - (id)initWithBridge:(RCTBridge *)bridge
         self.previewLayer.needsDisplayOnBoundsChange = YES;
 #endif
         self.paused = NO;
+        self.rectOfInterest = CGRectMake(0, 0, 1.0, 1.0);
         [self changePreviewOrientation:[UIApplication sharedApplication].statusBarOrientation];
         [self initializeCaptureSessionInput];
         [self startSession];
@@ -857,6 +858,14 @@ - (void)setupOrDisableBarcodeScanner
     [self _updateMetadataObjectsToRecognize];
 }
 
+- (void)updateRectOfInterest
+{
+    if (_metadataOutput == nil) {
+        return;
+    }
+    [_metadataOutput setRectOfInterest: _rectOfInterest];
+}
+
 - (void)_setupOrDisableMetadataOutput
 {
     if ([self isReadingBarCodes] && (_metadataOutput == nil || ![self.session.outputs containsObject:_metadataOutput])) {
@@ -889,6 +898,7 @@ - (void)_updateMetadataObjectsToRecognize
     }
 
     [_metadataOutput setMetadataObjectTypes:availableRequestedObjectTypes];
+    [self updateRectOfInterest];
 }
 
 - (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects

ios/RN/RNCameraManager.m

@@ -269,6 +269,12 @@ + (NSDictionary *)barcodeDetectorConstants
     [view setupOrDisableTextDetector];
 }
 
+RCT_CUSTOM_VIEW_PROPERTY(rectOfInterest, CGRect, RNCamera)
+{
+    [view setRectOfInterest: [RCTConvert CGRect:json]];
+    [view updateRectOfInterest];
+}
+
 RCT_CUSTOM_VIEW_PROPERTY(defaultVideoQuality, NSInteger, RNCamera)
 {
     [view setDefaultVideoQuality: [NSNumber numberWithInteger:[RCTConvert NSInteger:json]]];

src/RNCamera.js

@@ -231,6 +231,13 @@ type EventCallbackArgumentsType = {
   nativeEvent: Object,
 };
 
+type Rect = {
+  x: number,
+  y: number,
+  width: number,
+  height: number,
+};
+
 type PropsType = typeof View.props & {
   zoom?: number,
   ratio?: string,
@@ -260,6 +267,7 @@ type PropsType = typeof View.props & {
   playSoundOnCapture?: boolean,
   videoStabilizationMode?: number | string,
   pictureSize?: string,
+  rectOfInterest: Rect,
 };
 
 type StateType = {
@@ -401,6 +409,7 @@ export default class Camera extends React.Component<PropsType, StateType> {
     videoStabilizationMode: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
     pictureSize: PropTypes.string,
     mirrorVideo: PropTypes.bool,
+    rectOfInterest: PropTypes.any,
     defaultVideoQuality: PropTypes.oneOfType([PropTypes.string, PropTypes.number]),
   };