chore: back camera support

Author: thisisabhash

HostApp/HostApp/Views/ExampleLivenessView.swift

@@ -23,6 +23,7 @@ struct ExampleLivenessView: View {
             FaceLivenessDetectorView(
                 sessionID: viewModel.sessionID,
                 region: "us-east-1",
+                cameraPosition: .front,
                 isPresented:  Binding(
                     get: { viewModel.presentationState == .liveness },
                     set: { _ in }

Sources/FaceLiveness/AV/LivenessCaptureDevice.swift

@@ -37,3 +37,8 @@ struct LivenessCaptureDevice {
         }
     }
 }
+
+public enum LivenessCaptureDevicePosition {
+    case front
+    case back
+}

Sources/FaceLiveness/Views/GetReadyPage/CameraPreviewView.swift

@@ -15,7 +15,7 @@ struct CameraPreviewView: View {
 
     @StateObject var model: CameraPreviewViewModel
 
-    init(model: CameraPreviewViewModel = CameraPreviewViewModel()) {
+    init(model: CameraPreviewViewModel = CameraPreviewViewModel(cameraPosition: .front)) {
         self._model = StateObject(wrappedValue: model)
     }
 

Sources/FaceLiveness/Views/GetReadyPage/CameraPreviewViewModel.swift

@@ -16,15 +16,18 @@ class CameraPreviewViewModel: NSObject, ObservableObject {
     @Published var buffer: CVPixelBuffer?
 
     var previewCaptureSession: LivenessCaptureSession?
+    let cameraPosition: LivenessCaptureDevicePosition
 
-    override init() {
+    init(cameraPosition: LivenessCaptureDevicePosition) {
+        self.cameraPosition = cameraPosition
+        
         super.init()
         setupSubscriptions()
 
         let avCaptureDevice = AVCaptureDevice.DiscoverySession(
             deviceTypes: [.builtInWideAngleCamera],
             mediaType: .video,
-            position: .front
+            position: cameraPosition == .front ? .front : .back
         ).devices.first
 
         let outputDelegate = CameraPreviewOutputSampleBufferDelegate { [weak self] buffer in

Sources/FaceLiveness/Views/GetReadyPage/GetReadyPageView.swift

@@ -12,21 +12,24 @@ struct GetReadyPageView: View {
     let beginCheckButtonDisabled: Bool
     let onBegin: () -> Void
     let challenge: Challenge
+    let cameraPosition: LivenessCaptureDevicePosition
 
     init(
         onBegin: @escaping () -> Void,
         beginCheckButtonDisabled: Bool = false,
-        challenge: Challenge
+        challenge: Challenge,
+        cameraPosition: LivenessCaptureDevicePosition
     ) {
         self.onBegin = onBegin
         self.beginCheckButtonDisabled = beginCheckButtonDisabled
         self.challenge = challenge
+        self.cameraPosition = cameraPosition
     }
 
     var body: some View {
         VStack {
             ZStack {
-                CameraPreviewView()
+                CameraPreviewView(model: CameraPreviewViewModel(cameraPosition: cameraPosition))
                 VStack {
                     WarningBox(
                         titleText: LocalizedStrings.get_ready_photosensitivity_title,
@@ -79,6 +82,7 @@ struct GetReadyPageView_Previews: PreviewProvider {
     static var previews: some View {
         GetReadyPageView(onBegin: {}, 
                          challenge: .init(version: "2.0.0",
-                                              type: .faceMovementAndLightChallenge))
+                                              type: .faceMovementAndLightChallenge),
+                         cameraPosition: .front)
     }
 }

Sources/FaceLiveness/Views/Liveness/FaceLivenessDetectionView.swift

@@ -20,6 +20,7 @@ public struct FaceLivenessDetectorView: View {
     @State var displayingCameraPermissionsNeededAlert = false
 
     let disableStartView: Bool
+    let cameraPosition: LivenessCaptureDevicePosition
     let onCompletion: (Result<Void, FaceLivenessDetectionError>) -> Void
 
     let sessionTask: Task<FaceLivenessSession, Error>
@@ -29,11 +30,13 @@ public struct FaceLivenessDetectorView: View {
         credentialsProvider: AWSCredentialsProvider? = nil,
         region: String,
         disableStartView: Bool = false,
+        cameraPosition: LivenessCaptureDevicePosition,
         isPresented: Binding<Bool>,
         onCompletion: @escaping (Result<Void, FaceLivenessDetectionError>) -> Void
     ) {        
         self.disableStartView = disableStartView
         self._isPresented = isPresented
+        self.cameraPosition = cameraPosition
         self.onCompletion = onCompletion
 
         self.sessionTask = Task {
@@ -60,7 +63,7 @@ public struct FaceLivenessDetectorView: View {
         let avCpatureDevice = AVCaptureDevice.DiscoverySession(
             deviceTypes: [.builtInWideAngleCamera],
             mediaType: .video,
-            position: .front
+            position: cameraPosition == .front ? .front : .back
         ).devices.first
 
         let captureSession = LivenessCaptureSession(
@@ -89,13 +92,15 @@ public struct FaceLivenessDetectorView: View {
         credentialsProvider: AWSCredentialsProvider? = nil,
         region: String,
         disableStartView: Bool = false,
+        cameraPosition: LivenessCaptureDevicePosition,
         isPresented: Binding<Bool>,
         onCompletion: @escaping (Result<Void, FaceLivenessDetectionError>) -> Void,
         captureSession: LivenessCaptureSession
     ) {
         self.disableStartView = disableStartView
         self._isPresented = isPresented
         self.onCompletion = onCompletion
+        self.cameraPosition = cameraPosition
 
         self.sessionTask = Task {
             let session = try await AWSPredictionsPlugin.startFaceLivenessSession(
@@ -166,21 +171,22 @@ public struct FaceLivenessDetectorView: View {
                         do {
                             let newState = disableStartView
                             ? DisplayState.displayingLiveness
-                            : DisplayState.displayingGetReadyView(challenge)
+                            : DisplayState.displayingGetReadyView(challenge, cameraPosition)
                             guard self.displayState != newState else { return }
                             self.displayState = newState
                         }
                     }
                 }
 
-        case .displayingGetReadyView(let challenge):
+        case .displayingGetReadyView(let challenge, let cameraPosition):
             GetReadyPageView(
                 onBegin: {
                     guard displayState != .displayingLiveness else { return }
                     displayState = .displayingLiveness
                 },
                 beginCheckButtonDisabled: false,
-                challenge: challenge
+                challenge: challenge,
+                cameraPosition: cameraPosition
             )
             .onAppear {
                 DispatchQueue.main.async {
@@ -276,7 +282,7 @@ public struct FaceLivenessDetectorView: View {
 enum DisplayState: Equatable {
     case awaitingChallengeType
     case awaitingLivenessSession(Challenge)
-    case displayingGetReadyView(Challenge)
+    case displayingGetReadyView(Challenge, LivenessCaptureDevicePosition)
     case displayingLiveness
     case awaitingCameraPermission
 
@@ -286,8 +292,8 @@ enum DisplayState: Equatable {
             return true
         case (let .awaitingLivenessSession(c1), let .awaitingLivenessSession(c2)):
             return c1.type == c2.type && c1.version == c2.version
-        case (let .displayingGetReadyView(c1), let .displayingGetReadyView(c2)):
-            return c1.type == c2.type && c1.version == c2.version
+        case (let .displayingGetReadyView(c1, position1), let .displayingGetReadyView(c2, position2)):
+            return c1.type == c2.type && c1.version == c2.version && position1 == position2
         case (.displayingLiveness, .displayingLiveness):
             return true
         case (.awaitingCameraPermission, .awaitingCameraPermission):

Tests/FaceLivenessTests/CredentialsProviderTestCase.swift

@@ -66,6 +66,7 @@ final class CredentialsProviderTestCase: XCTestCase {
             sessionID: UUID().uuidString,
             credentialsProvider: credentialsProvider,
             region: "us-east-1",
+            cameraPosition: .front,
             isPresented: .constant(true),
             onCompletion: { _ in }
         )
@@ -102,6 +103,7 @@ final class CredentialsProviderTestCase: XCTestCase {
             sessionID: UUID().uuidString,
             credentialsProvider: credentialsProvider,
             region: "us-east-1",
+            cameraPosition: .front,
             isPresented: .constant(true),
             onCompletion: { _ in }
         )