Pause video feed while the computer is locked

IPCamAppBar/CameraView.Designer.cs

@@ -28,10 +28,13 @@
         /// </summary>
         private void InitializeComponent()
         {
+            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(CameraView));
             this.ConnectingLabel = new System.Windows.Forms.Label();
             this.StreamView = new System.Windows.Forms.PictureBox();
             this.IssueLabel = new System.Windows.Forms.Label();
+            this.PausedOverlay = new System.Windows.Forms.PictureBox();
             ((System.ComponentModel.ISupportInitialize)(this.StreamView)).BeginInit();
+            ((System.ComponentModel.ISupportInitialize)(this.PausedOverlay)).BeginInit();
             this.SuspendLayout();
             // 
             // ConnectingLabel
@@ -71,17 +74,30 @@
             this.IssueLabel.TextAlign = System.Drawing.ContentAlignment.MiddleCenter;
             this.IssueLabel.Visible = false;
             // 
+            // PausedOverlay
+            // 
+            this.PausedOverlay.BackColor = System.Drawing.Color.Transparent;
+            this.PausedOverlay.Image = ((System.Drawing.Image)(resources.GetObject("PausedOverlay.Image")));
+            this.PausedOverlay.Location = new System.Drawing.Point(19, 40);
+            this.PausedOverlay.Name = "PausedOverlay";
+            this.PausedOverlay.Size = new System.Drawing.Size(64, 64);
+            this.PausedOverlay.TabIndex = 3;
+            this.PausedOverlay.TabStop = false;
+            this.PausedOverlay.Visible = false;
+            // 
             // CameraView
             // 
             this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
             this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
             this.BackColor = System.Drawing.Color.Gray;
+            this.Controls.Add(this.PausedOverlay);
             this.Controls.Add(this.IssueLabel);
             this.Controls.Add(this.StreamView);
             this.Controls.Add(this.ConnectingLabel);
             this.Margin = new System.Windows.Forms.Padding(0);
             this.Name = "CameraView";
             ((System.ComponentModel.ISupportInitialize)(this.StreamView)).EndInit();
+            ((System.ComponentModel.ISupportInitialize)(this.PausedOverlay)).EndInit();
             this.ResumeLayout(false);
 
         }
@@ -91,5 +107,6 @@
         private System.Windows.Forms.Label ConnectingLabel;
         private System.Windows.Forms.PictureBox StreamView;
         private System.Windows.Forms.Label IssueLabel;
+        private System.Windows.Forms.PictureBox PausedOverlay;
     }
 }

IPCamAppBar/CameraView.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Drawing;
 using System.Drawing.Drawing2D;
+using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
@@ -11,25 +12,40 @@ namespace IPCamAppBar
 {
     public partial class CameraView : UserControl, IRetryableCameraObserver
     {
+        private readonly ICamera camera;
         private readonly bool overlayDateTime;
         private Bitmap viewBitmap;
+        private CancellationTokenSource streamCancellationTokenSource;
 
         public CameraView(ICamera camera, bool overlayDateTime)
         {
+            this.camera = camera;
             this.overlayDateTime = overlayDateTime;
             InitializeComponent();
 
-            var streamCancellationTokenSource = new CancellationTokenSource();
+            StartCamera();
+            
+            Disposed += (_, _) =>
+            {
+                StopCamera();
+            };
+        }
+
+        private void StartCamera()
+        {
+            streamCancellationTokenSource = new CancellationTokenSource();
+            
             Task.Run(async () =>
             {
                 var retryableCamera = new RetryableCamera(camera);
                 await retryableCamera.Fetch(this, streamCancellationTokenSource.Token);
             });
+        }
 
-            Disposed += (_, _) =>
+
+        private void StopCamera()
         {
             streamCancellationTokenSource.Cancel();
-            };
         }
 
 
@@ -37,6 +53,9 @@ namespace IPCamAppBar
         
         public Task OnFrame(Image image)
         {
+            if (streamCancellationTokenSource.IsCancellationRequested)
+                return Task.CompletedTask;
+            
             if (overlayDateTime || image is not Bitmap bitmap || image.Width != Width || image.Height != Height)
             {
                 resizedBitmap ??= new Bitmap(Width, Height);
@@ -100,6 +119,7 @@ namespace IPCamAppBar
             ConnectingLabel.Visible = false;
             StreamView.Visible = true;
             IssueLabel.Visible = false;
+            PausedOverlay.Visible = false;
 
 
             if (viewBitmap == null)
@@ -130,12 +150,28 @@ namespace IPCamAppBar
         
         private void InvokeDisconnected(Exception exception, TimeSpan retryDelay)
         {
-            if (IsDisposed)
+            if (IsDisposed || streamCancellationTokenSource.IsCancellationRequested)
                 return;
 
             IssueLabel.Text = (exception?.Message ?? "Camera disconnected") + $", retrying in {retryDelay.TotalSeconds} seconds";
             IssueLabel.Visible = true;
             IssueLabel.BringToFront();
         }
+
+        
+        public void SetPaused(bool pause)
+        {
+            if (pause)
+            {
+                StopCamera();
+
+                PausedOverlay.Left = (Width - PausedOverlay.Width) / 2;
+                PausedOverlay.Top = (Height - PausedOverlay.Height) / 2;
+                PausedOverlay.Visible = true;
+                PausedOverlay.BringToFront();
+            }
+            else
+                StartCamera();
+        }
     }
 }

IPCamAppBar/CameraView.resx

@@ -117,4 +117,18 @@
   <resheader name="writer">
     <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
   </resheader>
+  <assembly alias="System.Drawing" name="System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
+  <data name="PausedOverlay.Image" type="System.Drawing.Bitmap, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+    <value>
+        iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHeAAAABGdBTUEAALGPC/xhBQAAABl0RVh0U29m
+        dHdhcmUAQWRvYmUgSW1hZ2VSZWFkeXHJZTwAAAF8SURBVHhetc8xCsAAEALB/P/TF9PaSZiBrcXnvG/j
+        TxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+
+        tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHo
+        Q2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+I
+        PrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB
+        6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQf
+        iD60RvGB6ENrFB+IPrRG8YHoQ2sUH4g+tEbxgehDaxQfiD60RvGB6ENrFB+IPrQG3b1Awcd2Z2RJDQAA
+        AABJRU5ErkJggg==
+</value>
+  </data>
 </root>

IPCamAppBar/MainForm.cs

@@ -5,6 +5,7 @@ using System.Reflection;
 using System.Windows.Forms;
 using IPCamLib;
 using IPCamLib.Concrete;
+using Microsoft.Win32;
 using Newtonsoft.Json;
 
 namespace IPCamAppBar
@@ -13,6 +14,7 @@ namespace IPCamAppBar
     {
         private readonly Config config;
         private readonly AppBar appBar;
+        private bool paused = false;
 
 
         public MainForm()
@@ -39,6 +41,9 @@ namespace IPCamAppBar
                     : FlowDirection.LeftToRight;
             
             config.Cameras?.ForEach(AddCamera);
+            
+            
+            SystemEvents.SessionSwitch += SystemEventsOnSessionSwitch;
         }
 
 
@@ -65,15 +70,14 @@ namespace IPCamAppBar
 
         private static AppBarPosition GetAppBarPosition(ConfigSide side)
         {
-            switch (side)
+            return side switch
             {
-                case ConfigSide.Top: return AppBarPosition.Top;
+                ConfigSide.Top => AppBarPosition.Top,
-                case ConfigSide.Bottom: return AppBarPosition.Bottom;
+                ConfigSide.Bottom => AppBarPosition.Bottom,
-                case ConfigSide.Left: return AppBarPosition.Left;
+                ConfigSide.Left => AppBarPosition.Left,
-                case ConfigSide.Right: return AppBarPosition.Right;
+                ConfigSide.Right => AppBarPosition.Right,
-                default:
+                _ => throw new ArgumentOutOfRangeException(nameof(side), side, @"Invalid side value")
-                    throw new ArgumentOutOfRangeException(nameof(side), side, @"Invalid side value");
+            };
-            }
         }
 
 
@@ -113,5 +117,31 @@ namespace IPCamAppBar
         {
             Close();
         }
+
+        
+        private void SystemEventsOnSessionSwitch(object sender, SessionSwitchEventArgs e)
+        {
+            if (InvokeRequired)
+            {
+                Invoke(new Action(() => SystemEventsOnSessionSwitch(sender, e)));
+                return;
+            }
+
+            var pause = e.Reason == SessionSwitchReason.ConsoleDisconnect ||
+                        e.Reason == SessionSwitchReason.RemoteDisconnect ||
+                        e.Reason == SessionSwitchReason.SessionLock ||
+                        e.Reason == SessionSwitchReason.SessionLogoff;
+
+            if (pause == paused)
+                return;
+
+            foreach (var control in CameraViewContainer.Controls)
+            {
+                if (control is CameraView cameraView)
+                    cameraView.SetPaused(pause);
+            }
+            
+            paused = pause;
+        }
     }
 }