fix iOS snapshot orientation when device orientation is locked

ios/RCTCameraManager.m

@@ -9,6 +9,13 @@
 #import <AssetsLibrary/ALAssetsLibrary.h>
 #import <AVFoundation/AVFoundation.h>
 #import <ImageIO/ImageIO.h>
+#import <CoreMotion/CoreMotion.h>
+
+@interface RCTCameraManager ()
+
+@property (strong, nonatomic) CMMotionManager * motionManager;
+
+@end
 
 @implementation RCTCameraManager
 
@@ -458,7 +465,8 @@ RCT_EXPORT_METHOD(hasFlash:(RCTPromiseResolveBlock)resolve reject:(RCTPromiseRej
       NSData *imageData = UIImageJPEGRepresentation(image, 1.0);
       [self saveImage:imageData target:target metadata:nil resolve:resolve reject:reject];
 #else
-      [[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] setVideoOrientation:self.previewLayer.connection.videoOrientation];
+      [self getDeviceOrientation:^(UIInterfaceOrientation orientation) {
+          [[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] setVideoOrientation:[self convertToAVCaptureVideoOrientation: orientation]];
 
       [self.stillImageOutput captureStillImageAsynchronouslyFromConnection:[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
 
@@ -521,6 +529,7 @@ RCT_EXPORT_METHOD(hasFlash:(RCTPromiseResolveBlock)resolve reject:(RCTPromiseRej
           reject(RCTErrorUnspecified, nil, RCTErrorWithMessage(error.description));
         }
       }];
+      }];
 #endif
   });
 }
@@ -863,4 +872,63 @@ didFinishRecordingToOutputFileAtURL:(NSURL *)outputFileURL
     }
 }
 
+- (void)getDeviceOrientation:(void(^)(UIInterfaceOrientation orientation))callback
+{
+    self.motionManager = [[CMMotionManager alloc] init];
+    self.motionManager.accelerometerUpdateInterval = DBL_MAX; // infinite delay, never update
+    self.motionManager.gyroUpdateInterval = DBL_MAX;
+    
+    __weak CMMotionManager * weakMotionManager = self.motionManager;
+    __weak __typeof(self) weakSelf = self;
+    
+    [self.motionManager startAccelerometerUpdatesToQueue:[NSOperationQueue new]
+                                             withHandler:^(CMAccelerometerData  *accelerometerData, NSError *error) {
+                                                 // stop after the first sample
+                                                 [weakMotionManager stopAccelerometerUpdates];
+                                                 
+                                                 UIInterfaceOrientation deviceOrientation = UIInterfaceOrientationUnknown;
+                                                 if (!error) {
+                                                     deviceOrientation = [weakSelf getOrientationBy:accelerometerData.acceleration];
+                                                 }
+                                                 
+                                                 if (callback) {
+                                                     callback(deviceOrientation);
+                                                 }
+                                             }];
+    
+}
+
+- (UIInterfaceOrientation)getOrientationBy:(CMAcceleration)acceleration
+{
+    if(acceleration.x >= 0.75) {
+        return UIInterfaceOrientationLandscapeLeft;
+    }
+    if(acceleration.x <= -0.75) {
+        return UIInterfaceOrientationLandscapeRight;
+    }
+    if(acceleration.y >= -0.75) {
+        return UIInterfaceOrientationPortrait;
+    }
+    if(acceleration.y >= 0.75) {
+        return UIInterfaceOrientationPortraitUpsideDown;
+    }
+    return [[UIApplication sharedApplication] statusBarOrientation];
+}
+
+- (AVCaptureVideoOrientation)convertToAVCaptureVideoOrientation:(UIInterfaceOrientation)orientation
+{
+    switch (orientation) {
+        case UIInterfaceOrientationPortrait:
+            return AVCaptureVideoOrientationPortrait;
+        case UIInterfaceOrientationPortraitUpsideDown:
+            return AVCaptureVideoOrientationPortraitUpsideDown;
+        case UIInterfaceOrientationLandscapeLeft:
+            return AVCaptureVideoOrientationLandscapeLeft;
+        case UIInterfaceOrientationLandscapeRight:
+            return AVCaptureVideoOrientationLandscapeRight;
+        default:
+            return 0; // unknown
+    }
+}
+
 @end