Enable pinch zoom and bounded panning in Android live viewer

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

@@ -8,6 +8,7 @@ import android.view.Surface
 import android.view.TextureView
 import androidx.compose.foundation.background
 import androidx.compose.foundation.gestures.detectTapGestures
+import androidx.compose.foundation.gestures.detectTransformGestures
 import androidx.compose.foundation.layout.*
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.Close
@@ -18,9 +19,13 @@ import androidx.compose.material3.Text
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clipToBounds
+import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalLifecycleOwner
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.style.TextOverflow
@@ -50,6 +55,8 @@ internal fun StreamViewerScreen(group: Long, source: Long, epoch: Long, title: S
     var aspect by remember { mutableStateOf(0f) }
     var status by remember { mutableStateOf(R.string.stream_connecting) }
     var controls by remember { mutableStateOf(true) }
+    var hideTick by remember { mutableStateOf(0) }
+    val zoom = remember { VideoZoomState() }
 
     DisposableEffect(owner) {
         val observer = LifecycleEventObserver { _, event ->
@@ -90,16 +97,38 @@ internal fun StreamViewerScreen(group: Long, source: Long, epoch: Long, title: S
         }
     }
     LaunchedEffect(status) { controls = true }
-    LaunchedEffect(controls, status, visible) {
+    LaunchedEffect(controls, status, visible, hideTick) {
         if (controls && status == R.string.stream_live && visible) { delay(3000); controls = false }
     }
     LaunchedEffect(controls) { LogManager.addLog("DEBUG", "stream", "viewer controls source=$source visible=$controls") }
+    LaunchedEffect(zoom.scale, zoom.offset) {
+        delay(300)
+        LogManager.addLog("DEBUG", "stream", "viewer zoom source=$source scale=${zoom.scale} offset=${zoom.offset}")
+    }
 
-    Box(Modifier.fillMaxSize().background(Color.Black)) {
-        if (visible) StreamViewerPlayback(group, source, epoch, { aspect = it }, { status = it })
-        Box(Modifier.matchParentSize().pointerInput(status) {
-            detectTapGestures { if (status == R.string.stream_live) controls = !controls else controls = true }
-        })
+    BoxWithConstraints(Modifier.fillMaxSize().background(Color.Black).clipToBounds()) {
+        val ratio = aspect.takeIf { it > 0f } ?: 16f / 9f
+        val width = minOf(maxWidth, maxHeight * ratio)
+        val height = width / ratio
+        val density = LocalDensity.current
+        val videoSize = with(density) { Size(width.toPx(), height.toPx()) }
+        val viewport = with(density) { Size(maxWidth.toPx(), maxHeight.toPx()) }
+        LaunchedEffect(videoSize, viewport) { zoom.constrain(videoSize, viewport) }
+        if (visible) StreamViewerPlayback(group, source, epoch, { aspect = it }, { status = it },
+            Modifier.size(width, height).align(Alignment.Center).graphicsLayer {
+                scaleX = zoom.scale; scaleY = zoom.scale
+                translationX = zoom.offset.x; translationY = zoom.offset.y
+            })
+        Box(Modifier.matchParentSize()
+            .pointerInput(status) {
+                detectTapGestures { if (status == R.string.stream_live) controls = !controls else controls = true }
+            }
+            .pointerInput(videoSize, viewport) {
+                detectTransformGestures { centroid, pan, factor, _ ->
+                    controls = true; hideTick++
+                    zoom.transform(centroid, pan, factor, videoSize, viewport)
+                }
+            })
         if (controls) {
             Row(Modifier.fillMaxWidth().align(Alignment.TopCenter).background(Color.Black.copy(alpha = 0.65f))
                 .windowInsetsPadding(WindowInsets.safeDrawing).padding(start = 16.dp, end = 4.dp, top = 4.dp, bottom = 4.dp),
@@ -117,33 +146,29 @@ internal fun StreamViewerScreen(group: Long, source: Long, epoch: Long, title: S
 
 /** Смена размеров окна и скрытие controls сохраняют TextureView, decoder и сетевой reader. */
 @Composable
-private fun StreamViewerPlayback(group: Long, source: Long, epoch: Long, onAspect: (Float) -> Unit, onStatus: (Int) -> Unit) {
+private fun StreamViewerPlayback(group: Long, source: Long, epoch: Long, onAspect: (Float) -> Unit, onStatus: (Int) -> Unit,
+                                 modifier: Modifier) {
     val engine = remember(group, source, epoch) { StreamPlayerEngine(group, source, epoch) }
     val aspect by engine.aspect.collectAsState()
     val status by engine.status.collectAsState()
     var surface by remember { mutableStateOf<Surface?>(null) }
     LaunchedEffect(aspect, status) { onAspect(aspect); onStatus(status) }
     DisposableEffect(engine) { onDispose { engine.stop() } }
-    BoxWithConstraints(Modifier.fillMaxSize(), contentAlignment = Alignment.Center) {
-        val ratio = aspect.takeIf { it > 0f } ?: 16f / 9f
-        val width = minOf(maxWidth, maxHeight * ratio)
-        val height = width / ratio
-        AndroidView(factory = { context ->
-            TextureView(context).apply {
-                keepScreenOn = true
-                surfaceTextureListener = object : TextureView.SurfaceTextureListener {
-                    override fun onSurfaceTextureAvailable(texture: SurfaceTexture, width: Int, height: Int) {
-                        surface = Surface(texture); engine.start(surface!!)
-                    }
-                    override fun onSurfaceTextureSizeChanged(texture: SurfaceTexture, width: Int, height: Int) {}
-                    override fun onSurfaceTextureDestroyed(texture: SurfaceTexture): Boolean {
-                        engine.stop(); surface?.release(); surface = null; return true
-                    }
-                    override fun onSurfaceTextureUpdated(texture: SurfaceTexture) {}
+    AndroidView(factory = { context ->
+        TextureView(context).apply {
+            keepScreenOn = true
+            surfaceTextureListener = object : TextureView.SurfaceTextureListener {
+                override fun onSurfaceTextureAvailable(texture: SurfaceTexture, width: Int, height: Int) {
+                    surface = Surface(texture); engine.start(surface!!)
                 }
+                override fun onSurfaceTextureSizeChanged(texture: SurfaceTexture, width: Int, height: Int) {}
+                override fun onSurfaceTextureDestroyed(texture: SurfaceTexture): Boolean {
+                    engine.stop(); surface?.release(); surface = null; return true
+                }
+                override fun onSurfaceTextureUpdated(texture: SurfaceTexture) {}
             }
-        }, modifier = Modifier.size(width, height), onRelease = { view ->
-            engine.stop(); view.surfaceTextureListener = null; surface?.release(); surface = null
-        })
-    }
+        }
+    }, modifier = modifier, onRelease = { view ->
+        engine.stop(); view.surfaceTextureListener = null; surface?.release(); surface = null
+    })
 }