Make sure at least one position change event is emitted after

a timeline drag (with frequent=false), even if lots have been sent
with frequent=true.

Otherwise the code in the CHNAGE_TYPE_DONE branch of Butler::player_change
never gets to seek (since frequent is true, it ignores the signal).
Without the seek things go wrong.

Believed to fix #1534.

4 files changed, 13 insertions, 8 deletions

diff --git a/src/lib/content.cc b/src/lib/content.cc
index ca76b01a6..2ca029d5a 100644
--- a/src/lib/content.cc
+++ b/src/lib/content.cc
@@ -211,7 +211,7 @@ Content::signal_change (ChangeType c, int p)
 }
 
 void
-Content::set_position (shared_ptr<const Film> film, DCPTime p)
+Content::set_position (shared_ptr<const Film> film, DCPTime p, bool force_emit)
 {
 	/* video and audio content can modify its position */
 
@@ -227,7 +227,7 @@ Content::set_position (shared_ptr<const Film> film, DCPTime p)
 
 	{
 		boost::mutex::scoped_lock lm (_mutex);
-		if (p == _position) {
+		if (p == _position && !force_emit) {
 			cc.abort ();
 			return;
 		}
diff --git a/src/lib/content.h b/src/lib/content.h
index 96359fadb..4c1d55765 100644
--- a/src/lib/content.h
+++ b/src/lib/content.h
@@ -135,7 +135,7 @@ public:
 		return _digest;
 	}
 
-	void set_position (boost::shared_ptr<const Film> film, DCPTime);
+	void set_position (boost::shared_ptr<const Film> film, DCPTime, bool force_emit = false);
 
 	/** DCPTime that this content starts; i.e. the time that the first
 	 *  bit of the content (trimmed or not) will happen.
diff --git a/src/wx/timeline.cc b/src/wx/timeline.cc
index 1c1da708e..de5f05ae7 100644
--- a/src/wx/timeline.cc
+++ b/src/wx/timeline.cc
@@ -568,7 +568,12 @@ Timeline::left_up_select (wxMouseEvent& ev)
 	}
 
 	_content_panel->set_selection (selected_content ());
-	set_position_from_event (ev);
+	/* Since we may have just set change signals back to `not-frequent', we have to
+	   make sure this position change is signalled, even if the position value has
+	   not changed since the last time it was set (with frequent=true).  This is
+	   a bit of a hack.
+	*/
+	set_position_from_event (ev, true);
 
 	/* Clear up up the stuff we don't do during drag */
 	assign_tracks ();
@@ -704,7 +709,7 @@ Timeline::maybe_snap (DCPTime a, DCPTime b, optional<DCPTime>& nearest_distance)
 }
 
 void
-Timeline::set_position_from_event (wxMouseEvent& ev)
+Timeline::set_position_from_event (wxMouseEvent& ev, bool force_emit)
 {
 	if (!_pixels_per_second) {
 		return;
@@ -763,7 +768,7 @@ Timeline::set_position_from_event (wxMouseEvent& ev)
 		new_position = DCPTime ();
 	}
 
-	_down_view->content()->set_position (film, new_position);
+	_down_view->content()->set_position (film, new_position, force_emit);
 
 	film->set_sequence (false);
 }
diff --git a/src/wx/timeline.h b/src/wx/timeline.h
index 89fd94179..a7f345863 100644
--- a/src/wx/timeline.h
+++ b/src/wx/timeline.h
@@ -1,5 +1,5 @@
 /*
-    Copyright (C) 2013-2018 Carl Hetherington <cth@carlh.net>
+    Copyright (C) 2013-2019 Carl Hetherington <cth@carlh.net>
 
     This file is part of DCP-o-matic.
 
@@ -95,7 +95,7 @@ private:
 	void film_content_change (ChangeType type, int, bool frequent);
 	void resized ();
 	void assign_tracks ();
-	void set_position_from_event (wxMouseEvent &);
+	void set_position_from_event (wxMouseEvent& ev, bool force_emit = false);
 	void clear_selection ();
 	void recreate_views ();
 	void setup_scrollbars ();