feat: taking a screenshot of a video track (#714)

* track screenshot

* vale fix

* vale fix

Author: Brazol

.styles/config/vocabularies/Base/accept.txt

@@ -34,6 +34,7 @@ lecle_yoyo_player
 stream_video
 stream_video_push_notification
 screensharing
+[Ss]creen[Ss]hare
 Livestreaming
 livestreaming
 callee

docusaurus/docs/Flutter/05-advanced/06-screenshots.mdx

@@ -0,0 +1,17 @@
+---
+slug: /screenshots
+title: Screenshots
+---
+You can take a picture of a VideoTrack at highest possible resolution. This can be useful for example if you want to take a screenshot of a screenshare at full resolution.
+
+```dart
+final participant = call.state.value.otherParticipants.first;
+final screenshot = call.takeScreenshot(participant);
+```
+
+In case you want to take a screenshot of a screen-sharing track, you can specify which track type you want to capture:
+
+```dart
+final participant = call.state.value.otherParticipants.first;
+final screenshot = call.takeScreenshot(participant, trackType: SfuTrackType.screenShare);
+```

packages/stream_video/lib/src/call/call.dart

@@ -1,6 +1,7 @@
 // ignore_for_file: deprecated_member_use_from_same_package
 
 import 'dart:async';
+import 'dart:typed_data';
 
 import 'package:collection/collection.dart';
 import 'package:flutter/foundation.dart';
@@ -1058,6 +1059,16 @@ class Call {
     return [...?_session?.getTracks(trackIdPrefix)];
   }
 
+  Future<ByteBuffer?> takeScreenshot(
+    CallParticipantState participant, {
+    SfuTrackType? trackType,
+  }) async {
+    final track =
+        getTrack(participant.trackIdPrefix, trackType ?? SfuTrackType.video);
+
+    return track?.captureScreenshot();
+  }
+
   Future<void> _applyCallSettingsToConnectOptions(CallSettings settings) async {
     // Apply defaul audio output and input devices
     final mediaDevicesResult =

packages/stream_video/lib/src/webrtc/rtc_track/rtc_track.dart

@@ -1,3 +1,5 @@
+import 'dart:typed_data';
+
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 import 'package:meta/meta.dart';
 
@@ -65,6 +67,14 @@ abstract class RtcTrack {
     }
   }
 
+  Future<ByteBuffer?> captureScreenshot() async {
+    if (isVideoTrack) {
+      return mediaStream.getVideoTracks().first.captureFrame();
+    }
+
+    return null;
+  }
+
   Future<void> start();
 
   Future<void> stop();