offset linked regions to compensate for negative start after trim drag.

	- should fix 7105

4 files changed, 35 insertions, 1 deletions

diff --git a/libs/ardour/ardour/midi_model.h b/libs/ardour/ardour/midi_model.h
index cdf7b3fd3b..fb71f69085 100644
--- a/libs/ardour/ardour/midi_model.h
+++ b/libs/ardour/ardour/midi_model.h
@@ -275,6 +275,7 @@ public:
 	int set_state(const XMLNode&) { return 0; }
 
 	PBD::Signal0<void> ContentsChanged;
+	PBD::Signal1<void, double> ContentsShifted;
 
 	boost::shared_ptr<const MidiSource> midi_source ();
 	void set_midi_source (boost::shared_ptr<MidiSource>);
diff --git a/libs/ardour/ardour/midi_region.h b/libs/ardour/ardour/midi_region.h
index b41f620e87..e6357746f7 100644
--- a/libs/ardour/ardour/midi_region.h
+++ b/libs/ardour/ardour/midi_region.h
@@ -153,6 +153,7 @@ class LIBARDOUR_API MidiRegion : public Region
 	void update_length_beats (const int32_t sub_num);
 
 	void model_changed ();
+	void model_shifted (double qn_distance);
 	void model_automation_state_changed (Evoral::Parameter const &);
 
 	void set_start_beats_from_start_frames ();
@@ -160,8 +161,10 @@ class LIBARDOUR_API MidiRegion : public Region
 
 	std::set<Evoral::Parameter> _filtered_parameters; ///< parameters that we ask our source not to return when reading
 	PBD::ScopedConnection _model_connection;
+	PBD::ScopedConnection _model_shift_connection;
 	PBD::ScopedConnection _source_connection;
 	PBD::ScopedConnection _model_contents_connection;
+	bool _ignore_shift;
 };
 
 } /* namespace ARDOUR */
diff --git a/libs/ardour/midi_model.cc b/libs/ardour/midi_model.cc
index 4da2dc3396..d4c690c55b 100644
--- a/libs/ardour/midi_model.cc
+++ b/libs/ardour/midi_model.cc
@@ -1979,6 +1979,8 @@ MidiModel::insert_silence_at_start (TimeType t)
 
 		apply_command_as_subcommand (s->session(), c);
 	}
+
+	ContentsShifted (t.to_double());
 }
 
 void
diff --git a/libs/ardour/midi_region.cc b/libs/ardour/midi_region.cc
index 9826fa5641..2ce234b634 100644
--- a/libs/ardour/midi_region.cc
+++ b/libs/ardour/midi_region.cc
@@ -80,6 +80,7 @@ MidiRegion::MidiRegion (const SourceList& srcs)
 	: Region (srcs)
 	, _start_beats (Properties::start_beats, 0.0)
 	, _length_beats (Properties::length_beats, midi_source(0)->length_beats().to_double())
+	, _ignore_shift (false)
 {
 	register_properties ();
 	midi_source(0)->ModelChanged.connect_same_thread (_source_connection, boost::bind (&MidiRegion::model_changed, this));
@@ -92,6 +93,7 @@ MidiRegion::MidiRegion (boost::shared_ptr<const MidiRegion> other)
 	: Region (other)
 	, _start_beats (Properties::start_beats, other->_start_beats)
 	, _length_beats (Properties::length_beats, other->_length_beats)
+	, _ignore_shift (false)
 {
 	//update_length_beats ();
 	register_properties ();
@@ -585,6 +587,24 @@ MidiRegion::model_changed ()
 	midi_source()->AutomationStateChanged.connect_same_thread (
 		_model_connection, boost::bind (&MidiRegion::model_automation_state_changed, this, _1)
 		);
+
+	model()->ContentsShifted.connect_same_thread (_model_shift_connection, boost::bind (&MidiRegion::model_shifted, this, _1));
+}
+void
+MidiRegion::model_shifted (double qn_distance)
+{
+	if (!model()) {
+		return;
+	}
+
+	if (!_ignore_shift) {
+		_start_beats += qn_distance;
+		framepos_t const new_start = _session.tempo_map().frames_between_quarter_notes (_quarter_note - _start_beats, _quarter_note);
+		_start = new_start;
+		send_change (Properties::start);
+	} else {
+		_ignore_shift = false;
+	}
 }
 
 void
@@ -620,7 +640,10 @@ MidiRegion::fix_negative_start ()
 {
 	BeatsFramesConverter c (_session.tempo_map(), _position);
 
-	model()->insert_silence_at_start (c.from (-_start));
+	_ignore_shift = true;
+
+	model()->insert_silence_at_start (Evoral::Beats (- _start_beats));
+
 	_start = 0;
 	_start_beats = 0.0;
 }
@@ -629,6 +652,11 @@ void
 MidiRegion::set_start_internal (framecnt_t s, const int32_t sub_num)
 {
 	Region::set_start_internal (s, sub_num);
+
+	if (_start_beats < 0.0) {
+		fix_negative_start();
+	}
+
 	set_start_beats_from_start_frames ();
 }