Refactor Webcam initialization and navigation logic

Co-authored-by: toniolo.luca <toniolo.luca@outlook.com>

Author: cursoragent

src/Captura/Pages/SettingsPage.xaml.cs

@@ -5,15 +5,18 @@ namespace Captura
 {
     public partial class SettingsPage
     {
+        bool _webcamPageNavigated;
+
         public SettingsPage()
         {
             InitializeComponent();
 
             Loaded += (s, e) =>
             {
-                // Navigate to WebcamPlacementPreviewPage singleton instance for the WebCam tab
-                if (WebcamTabFrame != null)
+                // Navigate to WebcamPlacementPreviewPage singleton instance for the WebCam tab (only once)
+                if (WebcamTabFrame != null && !_webcamPageNavigated)
                 {
+                    _webcamPageNavigated = true;
                     WebcamTabFrame.Navigate(ServiceProvider.Get<WebcamPlacementPreviewPage>());
                 }
             };

src/Captura/Pages/WebcamPlacementPreviewPage.xaml.cs

@@ -69,14 +69,27 @@ async Task UpdateBackground()
         }
 
         IReadOnlyReactiveProperty<IWebcamCapture> _webcamCapture;
+        bool _setupComplete;
 
         void SetupPreview()
         {
+            if (_setupComplete)
+                return;
+
+            _setupComplete = true;
+
             IsVisibleChanged += (S, E) =>
             {
                 if (IsVisible && _webcamCapture == null)
                 {
-                    InitializeWebcam();
+                    _webcamCapture = _webcamModel.InitCapture();
+
+                    if (_webcamCapture.Value is { } capture)
+                    {
+                        _reactor.WebcamSize.OnNext(new WSize(capture.Width, capture.Height));
+
+                        UpdateWebcamPreview();
+                    }
                 }
                 else if (!IsVisible && _webcamCapture != null)
                 {
@@ -97,16 +110,7 @@ void OnRegionChange()
 
             _webcamModel
                 .ObserveProperty(M => M.SelectedCam)
-                .Subscribe(M =>
-                {
-                    // Release previous capture and reinitialize when camera changes
-                    if (_webcamCapture != null && IsVisible)
-                    {
-                        _webcamModel.ReleaseCapture();
-                        _webcamCapture = null;
-                        InitializeWebcam();
-                    }
-                });
+                .Subscribe(M => UpdateWebcamPreview());
 
             _reactor.Location
                 .CombineLatest(_reactor.Size, (M, N) =>
@@ -116,24 +120,21 @@ void OnRegionChange()
                 })
                 .Subscribe();
 
-            // If page is already visible, initialize webcam immediately
-            if (IsVisible)
+            // If page is already visible when setup is first called, initialize webcam
+            // (IsVisibleChanged won't fire if page is already visible)
+            if (IsVisible && _webcamCapture == null)
             {
-                InitializeWebcam();
-            }
-        }
-
-        void InitializeWebcam()
-        {
-            if (_webcamCapture != null)
-                return;
+                _webcamCapture = _webcamModel.InitCapture();
 
-            _webcamCapture = _webcamModel.InitCapture();
-
-            if (_webcamCapture.Value is { } capture)
+                if (_webcamCapture.Value is { } capture)
+                {
+                    _reactor.WebcamSize.OnNext(new WSize(capture.Width, capture.Height));
+                    // UpdateWebcamPreview will be called by the Location/Size subscription
+                }
+            }
+            else
             {
-                _reactor.WebcamSize.OnNext(new WSize(capture.Width, capture.Height));
-
+                // Just update preview position if webcam already exists
                 UpdateWebcamPreview();
             }
         }