Optimise the feel of some GUI functions by doing the seek after

many content changes in an idle handler, rather than blocking
the UI update until the seek and image redisplay have finished.

2 files changed, 16 insertions, 7 deletions

diff --git a/src/wx/film_viewer.cc b/src/wx/film_viewer.cc
index a2b055934..edb451e74 100644
--- a/src/wx/film_viewer.cc
+++ b/src/wx/film_viewer.cc
@@ -231,17 +231,22 @@ FilmViewer::refresh_view ()
 	_state_timer.unset ();
 }
 
+/** @param lazy true if it is *not* important that the display be updated as quickly as possible.
+ *  If lazy is true we will try to return from this method quickly and postpone any time-consuming
+ *  work until the UI is next idle.  Otherwise we will block here and try to get the image on
+ *  screen as soon as possible.
+ */
 void
-FilmViewer::get ()
+FilmViewer::get (bool lazy)
 {
 	DCPOMATIC_ASSERT (_butler);
 	++_gets;
 
 	do {
 		Butler::Error e;
-		_player_video = _butler->get_video (&e);
+		_player_video = _butler->get_video (!lazy, &e);
 		if (!_player_video.first && e == Butler::AGAIN) {
-			signal_manager->when_idle (boost::bind(&FilmViewer::get, this));
+			signal_manager->when_idle (boost::bind(&FilmViewer::get, this, lazy));
 			return;
 		}
 	} while (
@@ -257,7 +262,11 @@ FilmViewer::get ()
 		error_dialog (_video_view->get(), e.what());
 	}
 
-	display_player_video ();
+	if (lazy) {
+		signal_manager->when_idle (boost::bind(&FilmViewer::display_player_video, this));
+	} else {
+		display_player_video ();
+	}
 }
 
 void
@@ -322,7 +331,7 @@ FilmViewer::timer ()
 		return;
 	}
 
-	get ();
+	get (false);
 	PositionChanged ();
 	DCPTime const next = _video_position + one_video_frame();
 
@@ -541,7 +550,7 @@ FilmViewer::seek (DCPTime t, bool accurate)
 
 	_closed_captions_dialog->clear ();
 	_butler->seek (t, accurate);
-	get ();
+	get (true);
 
 	if (was_running) {
 		start ();
diff --git a/src/wx/film_viewer.h b/src/wx/film_viewer.h
index 5ddb12baf..298e9dd00 100644
--- a/src/wx/film_viewer.h
+++ b/src/wx/film_viewer.h
@@ -151,7 +151,7 @@ private:
 	void timer ();
 	void calculate_sizes ();
 	void player_change (ChangeType type, int, bool);
-	void get ();
+	void get (bool lazy);
 	void display_player_video ();
 	void film_change (ChangeType, Film::Property);
 	void recreate_butler ();