Restore the current preview when reopening stream controls

tools/chatgui/src/stream_publish_engine.cpp

@@ -133,6 +133,13 @@ bool StreamPublishEngine::active() const { return m->id != 0; }
 bool StreamPublishEngine::running() const { return m->running.load(); }
 uint64_t StreamPublishEngine::group() const { return m->group; }
 StreamPublishConfig StreamPublishEngine::config() const { std::lock_guard<std::mutex> guard(m->lock); return m->wanted; }
+QVariant StreamPublishEngine::previewFrame() const {
+#ifdef HAVE_STREAM_CAPTURE
+    std::lock_guard<std::mutex> guard(m->lock); return QVariant::fromValue(m->previewFrame);
+#else
+    return {};
+#endif
+}
 QList<int> StreamPublishEngine::codecs() const { std::lock_guard<std::mutex> guard(m->lock); return m->codecs; }
 bool StreamPublishEngine::muted() const { return m->muted.load(); }
 void StreamPublishEngine::setMuted(bool muted) {

tools/chatgui/src/stream_publish_engine.h

@@ -48,6 +48,7 @@ public:
     bool running() const;
     uint64_t group() const;
     StreamPublishConfig config() const;
+    QVariant previewFrame() const;
     QList<int> codecs() const;
     static QList<StreamVideoSource> sources();
     static bool supported();

tools/chatgui/src/stream_publish_window.cpp

@@ -38,6 +38,7 @@ StreamPublishWindow::StreamPublishWindow(StreamPublishEngine* engine, uint64_t g
 #ifdef HAVE_STREAM_CAPTURE
     auto* preview = new QVideoWidget(this); m_preview = preview;
     preview->setMinimumHeight(160); preview->setAspectRatioMode(Qt::KeepAspectRatio);
+    preview->videoSink()->setVideoFrame(engine->previewFrame().value<QVideoFrame>());
     connect(engine, &StreamPublishEngine::previewVideoChanged, this, [this, preview](const QVariant& frame) {
         auto video = frame.value<QVideoFrame>();
         if (!video.isValid() || isVisible()) preview->videoSink()->setVideoFrame(video);