Add mirror parameter to VideoRenderer (#218)

@@ -7,6 +7,7 @@
     </inspection_tool>
     <inspection_tool class="PreviewApiLevelMustBeValid" enabled="true" level="ERROR" enabled_by_default="true">
       <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
     </inspection_tool>
     <inspection_tool class="PreviewDimensionRespectsLimit" enabled="true" level="WARNING" enabled_by_default="true">
       <option name="composableFile" value="true" />
@@ -14,6 +15,7 @@
     </inspection_tool>
     <inspection_tool class="PreviewFontScaleMustBeGreaterThanZero" enabled="true" level="ERROR" enabled_by_default="true">
       <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
     </inspection_tool>
     <inspection_tool class="PreviewMultipleParameterProviders" enabled="true" level="ERROR" enabled_by_default="true">
       <option name="composableFile" value="true" />
@@ -29,6 +31,7 @@
     </inspection_tool>
     <inspection_tool class="PreviewNotSupportedInUnitTestFiles" enabled="true" level="ERROR" enabled_by_default="true">
       <option name="composableFile" value="true" />
+      <option name="previewFile" value="true" />
     </inspection_tool>
     <inspection_tool class="PreviewPickerAnnotation" enabled="true" level="ERROR" enabled_by_default="true">
       <option name="composableFile" value="true" />

 package io.livekit.android.compose
 
+import android.graphics.Matrix
 import androidx.compose.runtime.*
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.onGloballyPositioned
@@ -18,12 +19,20 @@ import io.livekit.android.room.track.video.ComposeVisibility
 fun VideoRenderer(
     room: Room,
     videoTrack: VideoTrack,
-    modifier: Modifier = Modifier
+    modifier: Modifier = Modifier,
+    mirror: Boolean = false,
 ) {
 
     val videoSinkVisibility = remember(room, videoTrack) { ComposeVisibility() }
     var boundVideoTrack by remember { mutableStateOf<VideoTrack?>(null) }
     var view: TextureViewRenderer? by remember { mutableStateOf(null) }
+    var videoScale by remember { mutableStateOf(1f) }
+
+    videoScale = if (mirror) {
+        -1f
+    } else {
+        1f
+    }
 
     fun cleanupVideoTrack() {
         view?.let { boundVideoTrack?.removeRenderer(it) }
@@ -45,6 +54,11 @@ fun VideoRenderer(
         }
     }
 
+    DisposableEffect(view, videoScale) {
+        view?.scaleX = videoScale
+        onDispose { }
+    }
+
     DisposableEffect(room, videoTrack) {
         onDispose {
             videoSinkVisibility.onDispose()

@@ -13,28 +13,42 @@ import io.livekit.android.room.participant.Participant
 import io.livekit.android.room.track.Track
 import io.livekit.android.room.track.VideoTrack
 import io.livekit.android.util.flow
-import kotlinx.coroutines.flow.*
 
 /**
- * This widget primarily serves as a way to observe changes in [videoTracks].
+ * This widget primarily serves as a way to observe changes in [Participant.videoTracks].
  */
 @Composable
 fun VideoItemTrackSelector(
     room: Room,
     participant: Participant,
-    modifier: Modifier = Modifier
+    modifier: Modifier = Modifier,
+    mirror: Boolean = false,
 ) {
     val videoTrackMap by participant::videoTracks.flow.collectAsState(initial = emptyList())
     val videoPubs = videoTrackMap.filter { (pub) -> pub.subscribed }
         .map { (pub) -> pub }
-    val videoTrack = videoPubs.firstOrNull { pub -> pub.source == Track.Source.SCREEN_SHARE }?.track as? VideoTrack
-        ?: videoPubs.firstOrNull { pub -> pub.source == Track.Source.CAMERA }?.track as? VideoTrack
-        ?: videoPubs.firstOrNull()?.track as? VideoTrack
 
-    if (videoTrack != null) {
+    // Find the most appropriate video stream to show
+    // Prioritize screen share, then camera, then any video stream.
+    val videoPub = videoPubs.firstOrNull { pub -> pub.source == Track.Source.SCREEN_SHARE }
+        ?: videoPubs.firstOrNull { pub -> pub.source == Track.Source.CAMERA }
+        ?: videoPubs.firstOrNull()
+
+    val videoTrack = videoPub?.track as? VideoTrack
+    val videoMuted by
+    if (videoPub != null) {
+        videoPub::muted.flow.collectAsState()
+    } else {
+        remember(videoPub) {
+            derivedStateOf { false }
+        }
+    }
+
+    if (videoTrack != null && !videoMuted) {
         VideoRenderer(
             room = room,
             videoTrack = videoTrack,
+            mirror = mirror,
             modifier = modifier
         )
     } else {