Detach direct camera preview immediately when UI goes to background

tools/chatgui-android/app/src/main/java/com/utun/chat/data/StreamPreview.kt

@@ -46,6 +46,7 @@ class StreamPreview {
     private var target: StreamPreviewTarget? = null
     private var owner: ((StreamPreviewTarget?) -> Unit)? = null
     private var closed = false
+    private var visible = true
     private val mutable = MutableStateFlow(StreamPreviewState())
     val state: StateFlow<StreamPreviewState> = mutable
 
@@ -53,7 +54,7 @@ class StreamPreview {
         val next = StreamPreviewTarget(texture)
         if (closed) { LogManager.addLog("WARN", "video", "direct preview attach after capture stopped"); return next }
         val previous = target
-        target = next.retain(); owner?.invoke(next.retain()); previous?.release()
+        target = next.retain(); owner?.invoke(if (visible) next.retain() else null); previous?.release()
         LogManager.addLog("INFO", "video", "direct preview attached target=${System.identityHashCode(next)} bound=${owner != null}")
         return next // Первую ссылку освобождает UI в onSurfaceTextureDestroyed, возвращая false.
     }
@@ -67,7 +68,15 @@ class StreamPreview {
 
     @Synchronized internal fun bind(listener: (StreamPreviewTarget?) -> Unit) {
         check(!closed && owner == null)
-        owner = listener; listener(target?.retain())
+        owner = listener; listener(if (visible) target?.retain() else null)
+    }
+
+    /** Lifecycle отключает output сразу, даже когда Compose уже приостановил recomposition. */
+    @Synchronized fun setVisible(value: Boolean) {
+        if (visible == value || closed) return
+        visible = value; owner?.invoke(if (visible) target?.retain() else null)
+        if (!visible) mutable.value = mutable.value.copy(active = false)
+        LogManager.addLog("INFO", "video", "direct preview visibility=$visible target=${target?.let(System::identityHashCode)}")
     }
 
     internal fun update(format: StreamPreviewFormat?, active: Boolean = false, failed: Boolean = false) {

tools/chatgui-android/app/src/main/java/com/utun/chat/ui/screens/StreamScreen.kt

@@ -298,13 +298,14 @@ private fun StreamRotationMark(top: Int) {
 private fun LiveStreamView(group: Long, source: Long, epoch: Long, localPreview: StreamPreview?) {
     val owner = LocalLifecycleOwner.current
     var visible by remember(owner) { mutableStateOf(owner.lifecycle.currentState.isAtLeast(Lifecycle.State.STARTED)) }
-    DisposableEffect(owner) {
+    DisposableEffect(owner, localPreview) {
+        localPreview?.setVisible(visible)
         val observer = LifecycleEventObserver { _, event ->
-            if (event == Lifecycle.Event.ON_START) visible = true
-            if (event == Lifecycle.Event.ON_STOP) visible = false
+            if (event == Lifecycle.Event.ON_START) { localPreview?.setVisible(true); visible = true }
+            if (event == Lifecycle.Event.ON_STOP) { localPreview?.setVisible(false); visible = false }
         }
         owner.lifecycle.addObserver(observer)
-        onDispose { owner.lifecycle.removeObserver(observer) }
+        onDispose { owner.lifecycle.removeObserver(observer); localPreview?.setVisible(false) }
     }
     val context = LocalContext.current
     val configuration = LocalConfiguration.current