From ff65370cbcd816abf0b84b5959643606da096af3 Mon Sep 17 00:00:00 2001
From: Hiroshi Horie <548776+hiroshihorie@users.noreply.github.com>
Date: Tue, 17 May 2022 10:51:38 +0900
Subject: [PATCH] Automatic `mirrorMode` for VideoView (#119)

* update protos

* impl 1

* re-compute when options update

* minor fix
---
 lib/src/internal/events.dart             | 12 ++++++++
 lib/src/track/local/local.dart           |  7 +++++
 lib/src/widget/video_track_renderer.dart | 39 +++++++++++++++++++++---
 3 files changed, 54 insertions(+), 4 deletions(-)

diff --git a/lib/src/internal/events.dart b/lib/src/internal/events.dart
index 7b223a0..ed051f1 100644
--- a/lib/src/internal/events.dart
+++ b/lib/src/internal/events.dart
@@ -4,6 +4,8 @@ import 'package:meta/meta.dart';
 import '../events.dart';
 import '../proto/livekit_models.pb.dart' as lk_models;
 import '../proto/livekit_rtc.pb.dart' as lk_rtc;
+import '../track/local/local.dart';
+import '../track/options.dart';
 import '../track/track.dart';
 import '../types/other.dart';
 
@@ -59,6 +61,16 @@ class TrackStreamUpdatedEvent with TrackEvent, InternalEvent {
   });
 }
 
+@internal
+class LocalTrackOptionsUpdatedEvent with TrackEvent, InternalEvent {
+  final LocalTrack track;
+  final LocalTrackOptions options;
+  const LocalTrackOptionsUpdatedEvent({
+    required this.track,
+    required this.options,
+  });
+}
+
 // Used to notify muted state from Track to TrackPublication.
 @internal
 class InternalTrackMuteUpdatedEvent with TrackEvent, InternalEvent {
diff --git a/lib/src/track/local/local.dart b/lib/src/track/local/local.dart
index 69e4aa5..3e1b1a8 100644
--- a/lib/src/track/local/local.dart
+++ b/lib/src/track/local/local.dart
@@ -5,6 +5,7 @@ import 'package:meta/meta.dart';
 import '../../events.dart';
 import '../../exceptions.dart';
 import '../../extensions.dart';
+import '../../internal/events.dart';
 import '../../logger.dart';
 import '../../participant/remote.dart';
 import '../../proto/livekit_models.pb.dart' as lk_models;
@@ -172,6 +173,12 @@ abstract class LocalTrack extends Track {
 
     // mark as started
     await start();
+
+    // notify so VideoView can re-compute mirror mode if necessary
+    events.emit(LocalTrackOptionsUpdatedEvent(
+      track: this,
+      options: currentOptions,
+    ));
   }
 
   @internal
diff --git a/lib/src/widget/video_track_renderer.dart b/lib/src/widget/video_track_renderer.dart
index 51b579c..66dc156 100644
--- a/lib/src/widget/video_track_renderer.dart
+++ b/lib/src/widget/video_track_renderer.dart
@@ -7,15 +7,24 @@ import '../internal/events.dart';
 import '../managers/event.dart';
 import '../track/local/local.dart';
 import '../track/local/video.dart';
+import '../track/options.dart';
+
+enum VideoViewMirrorMode {
+  auto,
+  off,
+  mirror,
+}
 
 /// Widget that renders a [VideoTrack].
 class VideoTrackRenderer extends StatefulWidget {
   final VideoTrack track;
   final rtc.RTCVideoViewObjectFit fit;
+  final VideoViewMirrorMode mirrorMode;
 
   const VideoTrackRenderer(
     this.track, {
     this.fit = rtc.RTCVideoViewObjectFit.RTCVideoViewObjectFitContain,
+    this.mirrorMode = VideoViewMirrorMode.auto,
     Key? key,
   }) : super(key: key);
 
@@ -56,9 +65,13 @@ class _VideoTrackRendererState extends State<VideoTrackRenderer> {
     await _listener?.dispose();
     _listener = widget.track.createListener()
       ..on<TrackStreamUpdatedEvent>((event) {
-        if (mounted) {
-          _renderer.srcObject = event.stream;
-        }
+        if (!mounted) return;
+        _renderer.srcObject = event.stream;
+      })
+      ..on<LocalTrackOptionsUpdatedEvent>((event) {
+        if (!mounted) return;
+        // force recompute of mirror mode
+        setState(() {});
       });
   }
 
@@ -89,10 +102,28 @@ class _VideoTrackRendererState extends State<VideoTrackRenderer> {
             });
             return rtc.RTCVideoView(
               _renderer,
-              mirror: widget.track is LocalVideoTrack,
+              mirror: _shouldMirror(),
               filterQuality: FilterQuality.medium,
               objectFit: widget.fit,
             );
           },
         );
+
+  bool _shouldMirror() {
+    // on
+    if (widget.mirrorMode == VideoViewMirrorMode.mirror) return true;
+    // auto
+    if (widget.mirrorMode == VideoViewMirrorMode.auto) {
+      final track = widget.track;
+      if (track is LocalVideoTrack) {
+        final options = track.currentOptions;
+        if (options is CameraCaptureOptions) {
+          // mirror if front camera
+          return options.cameraPosition == CameraPosition.front;
+        }
+      }
+    }
+    // default to false
+    return false;
+  }
 }