tempo editing updates

	- a tempo marker may now be set to always continue (clamped)
	  this means that the end tempo of the previous section will
	  track the start tempo during tempo ops.
	  it mimics the behaviour in 5.8, with the gui indicating
	  the curves to be changed.

2 files changed, 146 insertions, 59 deletions

diff --git a/libs/ardour/ardour/tempo.h b/libs/ardour/ardour/tempo.h
index b1c2dc6428..dcf68d7f16 100644
--- a/libs/ardour/ardour/tempo.h
+++ b/libs/ardour/ardour/tempo.h
@@ -201,7 +201,7 @@ class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
 	};
 
 	TempoSection (const double& pulse, const double& minute, Tempo tempo, PositionLockStyle pls, framecnt_t sr)
-		: MetricSection (pulse, minute, pls, true, sr), Tempo (tempo), _c (0.0), _active (true), _locked_to_meter (false)  {}
+		: MetricSection (pulse, minute, pls, true, sr), Tempo (tempo), _c (0.0), _active (true), _locked_to_meter (false), _clamped (false)  {}
 
 	TempoSection (const XMLNode&, const framecnt_t sample_rate);
 
@@ -220,6 +220,9 @@ class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
 	bool locked_to_meter ()  const { return _locked_to_meter; }
 	void set_locked_to_meter (bool yn) { _locked_to_meter = yn; }
 
+	bool clamped ()  const { return _clamped; }
+	void set_clamped (bool yn) { _clamped = yn; }
+
 	Tempo tempo_at_minute (const double& minute) const;
 	double minute_at_ntpm (const double& ntpm, const double& pulse) const;
 
@@ -264,9 +267,11 @@ class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
 	   this enables us to keep the tempo change at the same relative
 	   position within the bar if/when the meter changes.
 	*/
+
 	double _c;
 	bool _active;
 	bool _locked_to_meter;
+	bool _clamped;
 	Timecode::BBT_Time _legacy_bbt;
 	bool _legacy_end;
 };
@@ -501,7 +506,7 @@ class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
 
 	void gui_set_tempo_position (TempoSection*, const framepos_t& frame, const int& sub_num);
 	void gui_set_meter_position (MeterSection*, const framepos_t& frame);
-	bool gui_change_tempo (TempoSection*, const Tempo& bpm, bool change_end);
+	bool gui_change_tempo (TempoSection*, const Tempo& bpm);
 	void gui_stretch_tempo (TempoSection* tempo, const framepos_t frame, const framepos_t end_frame);
 	void gui_stretch_tempo_end (TempoSection* tempo, const framepos_t frame, const framepos_t end_frame);
 	bool gui_twist_tempi (TempoSection* first, const Tempo& bpm, const framepos_t frame, const framepos_t end_frame);
@@ -515,6 +520,9 @@ class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
 
 private:
 
+	TempoSection* previous_tempo_section_locked (const Metrics& metrics, TempoSection*) const;
+	TempoSection* next_tempo_section_locked (const Metrics& metrics, TempoSection*) const;
+
 	double beat_at_minute_locked (const Metrics& metrics, const double& minute) const;
 	double minute_at_beat_locked (const Metrics& metrics, const double& beat) const;
 
diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index e11d28bd98..bb61fb7012 100644
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -90,6 +90,7 @@ TempoSection::TempoSection (const XMLNode& node, framecnt_t sample_rate)
 	, _c (0.0)
 	, _active (true)
 	, _locked_to_meter (false)
+	, _clamped (false)
 	, _legacy_end (false)
 {
 	XMLProperty const * prop;
@@ -147,6 +148,13 @@ TempoSection::TempoSection (const XMLNode& node, framecnt_t sample_rate)
 		}
 	}
 
+	if ((prop = node.property ("clamped")) == 0) {
+		warning << _("TempoSection XML node has no \"clamped\" property") << endmsg;
+		set_clamped (false);
+	} else {
+		set_clamped (string_is_affirmative (prop->value()));
+	}
+
 	/* XX replace old end-beats-per-minute name with note-types-per-minute */
 	if ((prop = node.property ("end-beats-per-minute")) != 0) {
 		if (sscanf (prop->value().c_str(), "%lf", &_end_note_types_per_minute) != 1 || _end_note_types_per_minute < 0.0) {
@@ -223,6 +231,8 @@ TempoSection::get_state() const
 	root->add_property ("beats-per-minute", buf);
 	snprintf (buf, sizeof (buf), "%lf", _note_type);
 	root->add_property ("note-type", buf);
+	snprintf (buf, sizeof (buf), "%s", _clamped?"yes":"no");
+	root->add_property ("clamped", buf);
 	snprintf (buf, sizeof (buf), "%lf", _end_note_types_per_minute);
 	root->add_property ("end-beats-per-minute", buf);
 	snprintf (buf, sizeof (buf), "%s", !initial()?"yes":"no");
@@ -1119,7 +1129,8 @@ TempoMap::replace_tempo (TempoSection& ts, const Tempo& tempo, const double& pul
 		return;
 	}
 
-	const bool locked_to_meter = ts.locked_to_meter();
+	bool const locked_to_meter = ts.locked_to_meter();
+	bool const ts_clamped = ts.clamped();
 	TempoSection* new_ts = 0;
 
 	{
@@ -1135,6 +1146,7 @@ TempoMap::replace_tempo (TempoSection& ts, const Tempo& tempo, const double& pul
 			} else {
 				remove_tempo_locked (ts);
 				new_ts = add_tempo_locked (tempo, pulse, minute_at_frame (frame), pls, true, locked_to_meter);
+				new_ts->set_clamped (ts_clamped);
 
 				if (new_ts && new_ts->type() == TempoSection::Constant) {
 					new_ts->set_end_note_types_per_minute (new_ts->note_types_per_minute());
@@ -1162,6 +1174,7 @@ TempoMap::replace_tempo (TempoSection& ts, const Tempo& tempo, const double& pul
 			first.set_minute (minute_at_frame (frame));
 			first.set_position_lock_style (AudioTime);
 			first.set_locked_to_meter (true);
+			first.set_clamped (ts_clamped);
 			{
 				/* cannot move the first tempo section */
 				*static_cast<Tempo*>(&first) = tempo;
@@ -3381,7 +3394,7 @@ TempoMap::gui_set_meter_position (MeterSection* ms, const framepos_t& frame)
 }
 
 bool
-TempoMap::gui_change_tempo (TempoSection* ts, const Tempo& bpm, bool change_end)
+TempoMap::gui_change_tempo (TempoSection* ts, const Tempo& bpm)
 {
 	Metrics future_map;
 	bool can_solve = false;
@@ -3389,27 +3402,39 @@ TempoMap::gui_change_tempo (TempoSection* ts, const Tempo& bpm, bool change_end)
 		Glib::Threads::RWLock::WriterLock lm (lock);
 		TempoSection* tempo_copy = copy_metrics_and_point (_metrics, future_map, ts);
 
-		if (change_end && tempo_copy->type() == TempoSection::Constant) {
+		if (tempo_copy->type() == TempoSection::Constant) {
 			tempo_copy->set_end_note_types_per_minute (bpm.note_types_per_minute());
 			tempo_copy->set_note_types_per_minute (bpm.note_types_per_minute());
-		} else if (change_end) {
-			tempo_copy->set_end_note_types_per_minute (bpm.note_types_per_minute());
 		} else {
 			tempo_copy->set_note_types_per_minute (bpm.note_types_per_minute());
+			tempo_copy->set_end_note_types_per_minute (bpm.end_note_types_per_minute());
+		}
+
+		if (ts->clamped()) {
+			TempoSection* prev = 0;
+			if ((prev = previous_tempo_section_locked (future_map, tempo_copy)) != 0) {
+				prev->set_end_note_types_per_minute (tempo_copy->note_types_per_minute());
+			}
 		}
 
 		recompute_tempi (future_map);
 
 		if (check_solved (future_map)) {
-			if (change_end && ts->type() == TempoSection::Constant) {
+			if (ts->type() == TempoSection::Constant) {
 				ts->set_end_note_types_per_minute (bpm.note_types_per_minute());
 				ts->set_note_types_per_minute (bpm.note_types_per_minute());
-			} else if (change_end) {
-				ts->set_end_note_types_per_minute (bpm.note_types_per_minute());
 			} else {
+				ts->set_end_note_types_per_minute (bpm.end_note_types_per_minute());
 				ts->set_note_types_per_minute (bpm.note_types_per_minute());
 			}
 
+			if (ts->clamped()) {
+				TempoSection* prev = 0;
+				if ((prev = previous_tempo_section_locked (_metrics, ts)) != 0) {
+					prev->set_end_note_types_per_minute (ts->note_types_per_minute());
+				}
+			}
+
 			recompute_map (_metrics);
 			can_solve = true;
 		}
@@ -3457,18 +3482,36 @@ TempoMap::gui_stretch_tempo (TempoSection* ts, const framepos_t frame, const fra
 		framepos_t const min_dframe = 2;
 
 		double new_bpm;
+		if (prev_t->clamped()) {
+			TempoSection* next_t = next_tempo_section_locked (future_map, prev_t);
+			TempoSection* prev_to_prev_t = previous_tempo_section_locked (future_map, prev_t);
+			/* the change in frames is the result of changing the slope of at most 2 previous tempo sections.
+			   constant to constant is straightforward, as the tempo prev to prev_t has constant slope.
+			*/
+			double contribution = 0.0;
+			if (next_t && prev_to_prev_t && prev_to_prev_t->type() == TempoSection::Ramp) {
+				contribution = (prev_t->frame() - prev_to_prev_t->frame()) / (double) (next_t->frame() - prev_to_prev_t->frame());
+			}
+			framepos_t const fr_off = (end_frame - frame);
+			const frameoffset_t prev_t_frame_contribution = fr_off - (contribution * (double) fr_off);
 
-		if (frame > prev_t->frame() + min_dframe && end_frame > prev_t->frame() + min_dframe) {
-
-			new_bpm = prev_t->note_types_per_minute() * ((frame - prev_t->frame())
-										   / (double) (end_frame - prev_t->frame()));
+			if (frame > prev_to_prev_t->frame() + min_dframe && (frame + prev_t_frame_contribution) > prev_to_prev_t->frame() + min_dframe) {
+				new_bpm = prev_t->note_types_per_minute() * ((frame - prev_to_prev_t->frame())
+										     / (double) ((frame + prev_t_frame_contribution) - prev_to_prev_t->frame()));
+			} else {
+				new_bpm = prev_t->note_types_per_minute();
+			}
 		} else {
-			new_bpm = prev_t->note_types_per_minute();
-		}
+			if (frame > prev_t->frame() + min_dframe && end_frame > prev_t->frame() + min_dframe) {
 
-		std::cout << "new bpm : " << new_bpm << std::endl;
-		new_bpm = min (new_bpm, (double) 1000.0);
+				new_bpm = prev_t->note_types_per_minute() * ((frame - prev_t->frame())
+									     / (double) (end_frame - prev_t->frame()));
+			} else {
+				new_bpm = prev_t->note_types_per_minute();
+			}
 
+			new_bpm = min (new_bpm, (double) 1000.0);
+		}
 		/* don't clamp and proceed here.
 		   testing has revealed that this can go negative,
 		   which is an entirely different thing to just being too low.
@@ -3485,6 +3528,13 @@ TempoMap::gui_stretch_tempo (TempoSection* ts, const framepos_t frame, const fra
 			prev_t->set_note_types_per_minute (new_bpm);
 		}
 
+		if (prev_t->clamped()) {
+			TempoSection* prev = 0;
+			if ((prev = previous_tempo_section_locked (future_map, prev_t)) != 0) {
+				prev->set_end_note_types_per_minute (prev_t->note_types_per_minute());
+			}
+		}
+
 		recompute_tempi (future_map);
 		recompute_meters (future_map);
 
@@ -3495,12 +3545,17 @@ TempoMap::gui_stretch_tempo (TempoSection* ts, const framepos_t frame, const fra
 				ts->set_end_note_types_per_minute (new_bpm);
 				ts->set_note_types_per_minute (new_bpm);
 			}
+			if (ts->clamped()) {
+				TempoSection* prev = 0;
+				if ((prev = previous_tempo_section_locked (_metrics, ts)) != 0) {
+					prev->set_end_note_types_per_minute (ts->note_types_per_minute());
+				}
+			}
 			recompute_tempi (_metrics);
 			recompute_meters (_metrics);
 		}
 	}
 
-	MetricPositionChanged (PropertyChange ()); // Emit Signal
 
 out:
 	Metrics::const_iterator d = future_map.begin();
@@ -3508,6 +3563,8 @@ out:
 		delete (*d);
 		++d;
 	}
+	MetricPositionChanged (PropertyChange ()); // Emit Signal
+
 
 }
 void
@@ -3532,31 +3589,17 @@ TempoMap::gui_stretch_tempo_end (TempoSection* ts, const framepos_t frame, const
 
 		TempoSection* prev_t = copy_metrics_and_point (_metrics, future_map, ts);
 
-/*
-		TempoSection* next_t = 0;
-		for (Metrics::const_iterator i = future_map.begin(); i != future_map.end(); ++i) {
-			if ((*i)->is_tempo() && (*i)->minute() >  prev_t->minute()) {
-				next_t = static_cast<TempoSection*> (*i);
-				break;
-			}
-		}
-
-		if (!next_t) {
-			return;
-		}
-*/
 		if (!prev_t) {
 			return;
 		}
 
-
 		/* minimum allowed measurement distance in frames */
 		framepos_t const min_dframe = 2;
 		double new_bpm;
 
 		if (frame > prev_t->frame() + min_dframe && end_frame > prev_t->frame() + min_dframe) {
-			new_bpm = prev_t->end_note_types_per_minute() * ((frame - prev_t->frame())
-										 / (double) (end_frame - prev_t->frame()));
+			new_bpm = prev_t->end_note_types_per_minute() * ((prev_t->frame() - frame)
+										 / (double) (prev_t->frame() - end_frame));
 		} else {
 			new_bpm = prev_t->end_note_types_per_minute();
 		}
@@ -3569,18 +3612,31 @@ TempoMap::gui_stretch_tempo_end (TempoSection* ts, const framepos_t frame, const
 
 		prev_t->set_end_note_types_per_minute (new_bpm);
 
+		TempoSection* next = 0;
+		if ((next = next_tempo_section_locked (future_map, prev_t)) != 0) {
+			if (next->clamped()) {
+				next->set_note_types_per_minute (prev_t->end_note_types_per_minute());
+			}
+		}
+
 		recompute_tempi (future_map);
 		recompute_meters (future_map);
 
 		if (check_solved (future_map)) {
 			ts->set_end_note_types_per_minute (new_bpm);
 
+			TempoSection* true_next = 0;
+			if ((true_next = next_tempo_section_locked (_metrics, ts)) != 0) {
+				if (true_next->clamped()) {
+					true_next->set_note_types_per_minute (ts->end_note_types_per_minute());
+				}
+			}
+
 			recompute_tempi (_metrics);
 			recompute_meters (_metrics);
 		}
 	}
 
-	MetricPositionChanged (PropertyChange ()); // Emit Signal
 
 out:
 	Metrics::const_iterator d = future_map.begin();
@@ -3589,7 +3645,9 @@ out:
 		++d;
 	}
 
+	MetricPositionChanged (PropertyChange ()); // Emit Signal
 }
+
 bool
 TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t frame, const framepos_t end_frame)
 {
@@ -3638,7 +3696,6 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 		}
 
 		if (!next_to_next_t) {
-			std::cout << "no next to next t" << std::endl;
 			return false;
 		}
 
@@ -3651,10 +3708,8 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 		const frameoffset_t tempo_copy_frame_contribution = fr_off - (prev_contribution * (double) fr_off);
 
 
-		framepos_t old_tc_pos = tempo_copy->frame();
-		framepos_t old_next_pos = next_t->frame();
+		framepos_t old_tc_minute = tempo_copy->minute();
 		double old_next_minute = next_t->minute();
-		framepos_t old_next_to_next_pos = next_to_next_t->frame();
 		double old_next_to_next_minute = next_to_next_t->minute();
 
 		double new_bpm;
@@ -3682,6 +3737,7 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 		if (tempo_copy->type() == TempoSection::Constant) {
 			tempo_copy->set_end_note_types_per_minute (new_bpm);
 		}
+
 		recompute_tempi (future_map);
 
 		if (check_solved (future_map)) {
@@ -3689,11 +3745,14 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 			if (!next_t) {
 				return false;
 			}
+
 			ts->set_note_types_per_minute (new_bpm);
 			if (ts->type() == TempoSection::Constant) {
 				ts->set_end_note_types_per_minute (new_bpm);
 			}
+
 			recompute_map (_metrics);
+
 			can_solve = true;
 		}
 
@@ -3701,7 +3760,7 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 			if (frame > tempo_copy->frame() + min_dframe && end_frame > tempo_copy->frame() + min_dframe) {
 
 				new_next_bpm = next_t->note_types_per_minute() * ((next_to_next_t->minute() - old_next_minute)
-											/ (double) ((old_next_to_next_minute) - old_next_minute));
+										  / (double) ((old_next_to_next_minute) - old_next_minute));
 
 			} else {
 				new_next_bpm = next_t->note_types_per_minute();
@@ -3730,20 +3789,22 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 			double copy_frame_ratio = 1.0;
 
 			if (next_to_next_t) {
-				next_frame_ratio =  (next_to_next_t->frame() - old_next_pos) / (double) (old_next_to_next_pos -  old_next_pos);
+				next_frame_ratio = (next_to_next_t->minute() - old_next_minute) / (old_next_to_next_minute -  old_next_minute);
 
-				copy_frame_ratio =   ((old_tc_pos - next_t->frame()) / (double) (old_tc_pos - old_next_pos));
-
-			} else {
-				//next_frame_ratio = (((next_to_next_pos - fr_off) - next_t->frame()) / (double) ((next_to_next_pos) - next_t->frame()));
-				//next_pulse_ratio = (start_pulse / end_pulse);
+				copy_frame_ratio = ((old_tc_minute - next_t->minute()) / (double) (old_tc_minute - old_next_minute));
 			}
 
 			new_next_bpm = next_t->note_types_per_minute() * next_frame_ratio;
-			new_copy_end_bpm =  tempo_copy->end_note_types_per_minute() * copy_frame_ratio;
+			new_copy_end_bpm = tempo_copy->end_note_types_per_minute() * copy_frame_ratio;
 
-			next_t->set_note_types_per_minute (new_next_bpm);
 			tempo_copy->set_end_note_types_per_minute (new_copy_end_bpm);
+
+			if (next_t->clamped()) {
+				next_t->set_note_types_per_minute (new_copy_end_bpm);
+			} else {
+				next_t->set_note_types_per_minute (new_next_bpm);
+			}
+
 			recompute_tempi (future_map);
 
 			if (check_solved (future_map)) {
@@ -3757,7 +3818,13 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 				if (!next_t) {
 					return false;
 				}
-				next_t->set_note_types_per_minute (new_next_bpm);
+
+				if (next_t->clamped()) {
+					next_t->set_note_types_per_minute (new_copy_end_bpm);
+				} else {
+					next_t->set_note_types_per_minute (new_next_bpm);
+				}
+
 				ts->set_end_note_types_per_minute (new_copy_end_bpm);
 				recompute_map (_metrics);
 				can_solve = true;
@@ -3770,9 +3837,8 @@ TempoMap::gui_twist_tempi (TempoSection* ts, const Tempo& bpm, const framepos_t
 		delete (*d);
 		++d;
 	}
-	if (can_solve) {
-		MetricPositionChanged (PropertyChange ()); // Emit Signal
-	}
+
+	MetricPositionChanged (PropertyChange ()); // Emit Signal
 
 	return can_solve;
 }
@@ -4288,15 +4354,22 @@ TempoMap::tempo_section_at_beat_locked (const Metrics& metrics, const double& be
 TempoSection*
 TempoMap::previous_tempo_section (TempoSection* ts) const
 {
+	Glib::Threads::RWLock::ReaderLock lm (lock);
+
+	return previous_tempo_section_locked (_metrics, ts);
+
+}
+
+TempoSection*
+TempoMap::previous_tempo_section_locked (const Metrics& metrics, TempoSection* ts) const
+{
 	if (!ts) {
 		return 0;
 	}
 
-	Glib::Threads::RWLock::ReaderLock lm (lock);
-
 	TempoSection* prev = 0;
 
-	for (Metrics::const_iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
+	for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
 
 		if ((*i)->is_tempo()) {
 			TempoSection* t = static_cast<TempoSection*> (*i);
@@ -4325,15 +4398,21 @@ TempoMap::previous_tempo_section (TempoSection* ts) const
 TempoSection*
 TempoMap::next_tempo_section (TempoSection* ts) const
 {
+	Glib::Threads::RWLock::ReaderLock lm (lock);
+
+	return next_tempo_section_locked (_metrics, ts);
+}
+
+TempoSection*
+TempoMap::next_tempo_section_locked (const Metrics& metrics, TempoSection* ts) const
+{
 	if (!ts) {
 		return 0;
 	}
 
-	Glib::Threads::RWLock::ReaderLock lm (lock);
-
 	TempoSection* prev = 0;
 
-	for (Metrics::const_iterator i = _metrics.begin(); i != _metrics.end(); ++i) {
+	for (Metrics::const_iterator i = metrics.begin(); i != metrics.end(); ++i) {
 
 		if ((*i)->is_tempo()) {
 			TempoSection* t = static_cast<TempoSection*> (*i);