fix: pause dynamic video background when main window is minimized

src/Starward/Features/Background/AppBackground.xaml.cs

@@ -361,6 +361,14 @@ private async Task ChangeBackgroundImageAsync(string file, CancellationToken can
 
     private SemaphoreSlim _videoSemaphore = new SemaphoreSlim(1, 1);
 
+    private bool _windowHidden;
+
+    private bool _windowMinimized;
+
+    private bool _sessionLocked;
+
+    private bool ShouldPauseVideo => _windowHidden || _windowMinimized || _sessionLocked;
+
 
     private void StartMediaPlayer(string file)
     {
@@ -402,6 +410,11 @@ private void StartMediaPlayer(string file)
         _mediaPlayer.VideoFrameAvailable += MediaPlayer_VideoFrameAvailable;
         _mediaPlayer.MediaFailed += MediaPlayer_MediaFailed;
         _mediaPlayer.Play();
+        // 若窗口当前不处于可播放状态（最小化、隐藏或锁屏），暂停新建的播放器
+        if (ShouldPauseVideo)
+        {
+            _mediaPlayer.Pause();
+        }
     }
 
 
@@ -592,16 +605,37 @@ private void OnMainWindowStateChanged(object _, MainWindowStateChangedMessage me
     {
         try
         {
+            // 各暂停条件由对应窗口消息独立维护，播放或暂停由聚合状态统一决定
+            if (message.Hide)
+            {
+                _windowHidden = true;
+            }
+            if (message.Activate)
+            {
+                // 激活只代表窗口回到屏幕前，不改变最小化和锁屏状态
+                _windowHidden = false;
+            }
+            if (message.Minimized is bool minimized)
+            {
+                _windowMinimized = minimized;
+            }
+            if (message.SessionLock)
+            {
+                _sessionLocked = true;
+            }
+            if (message.SessionUnlock)
+            {
+                _sessionLocked = false;
+            }
             if (_mediaPlayer is not null)
             {
-                var state = _mediaPlayer.PlaybackSession.PlaybackState;
-                if (message.Activate && state is not MediaPlaybackState.Playing)
+                if (ShouldPauseVideo)
                 {
-                    _mediaPlayer.Play();
+                    _mediaPlayer.Pause();
                 }
-                else if (message.Hide || message.SessionLock)
+                else if (_mediaPlayer.PlaybackSession.PlaybackState is not MediaPlaybackState.Playing)
                 {
-                    _mediaPlayer.Pause();
+                    _mediaPlayer.Play();
                 }
             }
         }

src/Starward/Features/ViewHost/MainWindow.xaml.cs

@@ -178,6 +178,9 @@ public override void Hide()
     private DateTimeOffset _lastActivatedTime = DateTimeOffset.Now;
 
 
+    private bool _isMinimized;
+
+
     protected override nint WindowSubclassProc(HWND hWnd, uint uMsg, nint wParam, nint lParam, nuint uIdSubclass, nint dwRefData)
     {
         if (uMsg == (uint)User32.WindowMessage.WM_ACTIVATE || uMsg == (uint)User32.WindowMessage.WM_POINTERACTIVATE)
@@ -205,6 +208,19 @@ protected override nint WindowSubclassProc(HWND hWnd, uint uMsg, nint wParam, ni
                 return IntPtr.Zero;
             }
         }
+        else if (uMsg == (uint)User32.WindowMessage.WM_SIZE)
+        {
+            // 窗口最小化或还原，通知动态背景暂停或恢复
+            if (wParam is 0 or 1 or 2)
+            {
+                bool minimized = wParam is 1;
+                if (minimized != _isMinimized)
+                {
+                    _isMinimized = minimized;
+                    WeakReferenceMessenger.Default.Send(new MainWindowStateChangedMessage { Minimized = minimized, CurrentTime = DateTimeOffset.Now });
+                }
+            }
+        }
         else if (uMsg == (uint)User32.WindowMessage.WM_WTSSESSION_CHANGE)
         {
             if (wParam == 0x7)
@@ -215,7 +231,8 @@ protected override nint WindowSubclassProc(HWND hWnd, uint uMsg, nint wParam, ni
             }
             else if (wParam == 0x8)
             {
-                // WTS_SESSION_UNLOCK 
+                // WTS_SESSION_UNLOCK
+                WeakReferenceMessenger.Default.Send(new MainWindowStateChangedMessage { SessionUnlock = true, CurrentTime = DateTimeOffset.Now });
             }
         }
         else if (uMsg == (uint)User32.WindowMessage.WM_DEVICECHANGE)

src/Starward/Features/ViewHost/MainWindowStateChangedMessage.cs

@@ -17,6 +17,12 @@ internal class MainWindowStateChangedMessage
     public bool SessionLock { get; set; }
 
 
+    public bool SessionUnlock { get; set; }
+
+
+    public bool? Minimized { get; set; }
+
+
     public DateTimeOffset CurrentTime { get; set; }