avatarmanipulation: fix recent regression in avatar preview

The recent 990ffe00 commit did not
make changes needed for avatarmanipulation due to recent LRC change
in video threading.  This fixes the regression, and makes the avatar
preview behave similarly to the 'Settings > Media' video preview, and
reuses an existing renderer when possible (e.g. when in an ongoing
call).

Change-Id: I1dfa386318acd7178c1840b79fa173c85128f901

src/avatarmanipulation.cpp

@@ -90,6 +90,8 @@ struct _AvatarManipulationPrivate
      */
     gboolean video_started_by_avatar_manipulation;
 
+    QMetaObject::Connection local_renderer_connection;
+
     GtkWidget *crop_area;
 
     lrc::api::AVModel* avModel_;
@@ -123,6 +125,8 @@ avatar_manipulation_dispose(GObject *object)
         priv->video_widget = NULL;
     }
 
+    QObject::disconnect(priv->local_renderer_connection);
+
     G_OBJECT_CLASS(avatar_manipulation_parent_class)->dispose(object);
 }
 
@@ -257,8 +261,10 @@ set_state(AvatarManipulation *self, AvatarManipulationState state)
             gtk_widget_set_visible(priv->button_box_edit,    false);
 
             /* make sure video widget and camera is not running */
-            if (priv->video_started_by_avatar_manipulation)
+            if (priv->video_started_by_avatar_manipulation) {
                 priv->avModel_->stopPreview();
+                QObject::disconnect(priv->local_renderer_connection);
+            }
             if (priv->video_widget) {
                 gtk_container_remove(GTK_CONTAINER(priv->frame_video), priv->video_widget);
                 priv->video_widget = NULL;
@@ -278,22 +284,39 @@ set_state(AvatarManipulation *self, AvatarManipulationState state)
 
 
             // local renderer, but set as "remote" so that it takes up the whole screen
+            const lrc::api::video::Renderer* prenderer = nullptr;
             try {
-                const lrc::api::video::Renderer* previewRenderer =
-                    &priv->avModel_->getRenderer(
+                prenderer = &priv->avModel_->getRenderer(
                     lrc::api::video::PREVIEW_RENDERER_ID);
-                video_widget_add_new_renderer(VIDEO_WIDGET(priv->video_widget),
-                    priv->avModel_,
-                    previewRenderer, VIDEO_RENDERER_REMOTE);
-
-                if (!previewRenderer->isRendering()) {
-                    priv->video_started_by_avatar_manipulation = TRUE;
-                    priv->avModel_->startPreview();
-                } else {
-                    priv->video_started_by_avatar_manipulation = FALSE;
-                }
-            } catch (const std::out_of_range& e) {
-                g_warning("Cannot start preview");
+            } catch (const std::out_of_range& e) {}
+
+            priv->video_started_by_avatar_manipulation =
+                prenderer && prenderer->isRendering();
+            if (priv->video_started_by_avatar_manipulation) {
+                video_widget_add_new_renderer(
+                    VIDEO_WIDGET(priv->video_widget),
+                    priv->avModel_, prenderer,
+                    VIDEO_RENDERER_REMOTE);
+            } else {
+                priv->video_started_by_avatar_manipulation = true;
+                priv->local_renderer_connection = QObject::connect(
+                    &*priv->avModel_,
+                    &lrc::api::AVModel::rendererStarted,
+                    [=](const QString& id) {
+                        if (id != lrc::api::video::PREVIEW_RENDERER_ID)
+                            return;
+                        try {
+                            const auto* prenderer =
+                                &priv->avModel_->getRenderer(id);
+                            video_widget_add_new_renderer(
+                                VIDEO_WIDGET(priv->video_widget),
+                                priv->avModel_, prenderer,
+                                VIDEO_RENDERER_REMOTE);
+                        }  catch (const std::out_of_range& e) {
+                            g_warning("Cannot start preview");
+                        }
+                    });
+                priv->avModel_->startPreview();
             }
 
             /* available actions: take snapshot, return*/