Update MidiRegion::_start_beats on trimming the front of a MIDI region; reset _start_beats with _start on MidiRegion::fix_negative_start(). May help with #4736.

git-svn-id: svn://localhost/ardour2/branches/3.0@11984 d708f5d6-7413-0410-9779-e7cbd77b26cf

libs/ardour/ardour/midi_region.h

@@ -132,6 +132,7 @@ class MidiRegion : public Region
 
 	void set_position_internal (framepos_t pos, bool allow_bbt_recompute);
 	void set_length_internal (framecnt_t len);
+	void set_start_internal (framecnt_t);
 	void update_length_beats ();
 
 	void model_changed ();

libs/ardour/ardour/region.h

@@ -325,6 +325,7 @@ class Region
 	void post_set (const PBD::PropertyChange&);
 	virtual void set_position_internal (framepos_t pos, bool allow_bbt_recompute);
 	virtual void set_length_internal (framecnt_t);
+	virtual void set_start_internal (framecnt_t);
 	
 	DataType _type;
 

libs/ardour/midi_region.cc

@@ -153,7 +153,7 @@ void
 MidiRegion::post_set (const PropertyChange& pc)
 {
 	Region::post_set (pc);
-	
+
 	if (pc.contains (Properties::length) && !pc.contains (Properties::length_beats)) {
 		update_length_beats ();
 	} else if (pc.contains (Properties::start) && !pc.contains (Properties::start_beats)) {
@@ -424,6 +424,7 @@ MidiRegion::fix_negative_start ()
 
 	model()->insert_silence_at_start (c.from (-_start));
 	_start = 0;
+	_start_beats = 0;
 }
 
 /** Transpose the notes in this region by a given number of semitones */
@@ -433,3 +434,10 @@ MidiRegion::transpose (int semitones)
 	BeatsFramesConverter c (_session.tempo_map(), _start);
 	model()->transpose (c.from (_start), c.from (_start + _length), semitones);
 }
+
+void
+MidiRegion::set_start_internal (framecnt_t s)
+{
+	Region::set_start_internal (s);
+	set_start_beats_from_start_frames ();
+}

libs/ardour/region.cc

@@ -686,7 +686,7 @@ Region::set_start (framepos_t pos)
 			return;
 		}
 
-		_start = pos;
+		set_start_internal (pos);
 		_whole_file = false;
 		first_edit ();
 		invalidate_transients ();
@@ -701,6 +701,7 @@ Region::trim_start (framepos_t new_position)
 	if (locked() || position_locked()) {
 		return;
 	}
+
 	framepos_t new_start;
 	frameoffset_t const start_shift = new_position - _position;
 
@@ -732,7 +733,7 @@ Region::trim_start (framepos_t new_position)
 		return;
 	}
 
-	_start = new_start;
+	set_start_internal (new_start);
 	_whole_file = false;
 	first_edit ();
 
@@ -888,7 +889,7 @@ Region::trim_to_internal (framepos_t position, framecnt_t length)
 	PropertyChange what_changed;
 
 	if (_start != new_start) {
-		_start = new_start;
+		set_start_internal (new_start);
 		what_changed.add (Properties::start);
 	}
 
@@ -1648,3 +1649,8 @@ Region::post_set (const PropertyChange& pc)
 	}
 }
 
+void
+Region::set_start_internal (framecnt_t s)
+{
+	_start = s;
+}

libs/ardour/tempo.cc

@@ -1889,7 +1889,7 @@ TempoMap::framepos_plus_beats (framepos_t pos, Evoral::MusicalTime beats) const
 	return pos;
 }
 
-/** Subtract some (fractional) beats to a frame position, and return the result in frames */
+/** Subtract some (fractional) beats from a frame position, and return the result in frames */
 framepos_t
 TempoMap::framepos_minus_beats (framepos_t pos, Evoral::MusicalTime beats) const
 {