From b243af48c756813eda6af6f519e138447591cbde Mon Sep 17 00:00:00 2001
From: nick_m <mainsbridge@gmail.com>
Date: Thu, 18 Aug 2016 05:36:24 +1000
Subject: [PATCH] Add methods for plugin APIs to obtsin quarter pulses ('beats'
 for AU) from the tempo map.

---
 libs/ardour/ardour/tempo.h |  5 ++++
 libs/ardour/tempo.cc       | 60 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/libs/ardour/ardour/tempo.h b/libs/ardour/ardour/tempo.h
index 1db1f65149..c134f450fb 100644
--- a/libs/ardour/ardour/tempo.h
+++ b/libs/ardour/ardour/tempo.h
@@ -429,6 +429,7 @@ class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
 	Timecode::BBT_Time bbt_at_beat (const double& beats);
 
 	double pulse_at_bbt (const Timecode::BBT_Time& bbt);
+	double pulse_at_bbt_rt (const Timecode::BBT_Time& bbt);
 	Timecode::BBT_Time bbt_at_pulse (const double& pulse);
 
 	framecnt_t bbt_duration_at (framepos_t, const Timecode::BBT_Time&, int dir);
@@ -448,6 +449,10 @@ class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
 	framepos_t framepos_minus_beats (framepos_t, Evoral::Beats) const;
 	Evoral::Beats framewalk_to_beats (framepos_t pos, framecnt_t distance) const;
 
+	double quarter_note_at_frame (const framepos_t frame);
+	double quarter_note_at_frame_rt (const framepos_t frame);
+	framepos_t frame_at_quarter_note (const double quarter_note);
+
 	void gui_move_tempo (TempoSection*, const framepos_t& frame, const int& sub_num);
 	void gui_move_meter (MeterSection*, const framepos_t& frame);
 	bool gui_change_tempo (TempoSection*, const Tempo& bpm);
diff --git a/libs/ardour/tempo.cc b/libs/ardour/tempo.cc
index 754b60f249..d8db6a5616 100644
--- a/libs/ardour/tempo.cc
+++ b/libs/ardour/tempo.cc
@@ -1861,6 +1861,18 @@ TempoMap::pulse_at_bbt (const Timecode::BBT_Time& bbt)
 	return pulse_at_bbt_locked (_metrics, bbt);
 }
 
+double
+TempoMap::pulse_at_bbt_rt (const Timecode::BBT_Time& bbt)
+{
+	Glib::Threads::RWLock::ReaderLock lm (lock);
+
+	if (!lm.locked()) {
+		throw std::logic_error ("TempoMap::pulse_at_bbt_rt() could not lock tempo map");
+	}
+
+	return pulse_at_bbt_locked (_metrics, bbt);
+}
+
 double
 TempoMap::pulse_at_bbt_locked (const Metrics& metrics, const Timecode::BBT_Time& bbt) const
 {
@@ -1975,7 +1987,7 @@ TempoMap::bbt_at_frame_rt (framepos_t frame)
 	Glib::Threads::RWLock::ReaderLock lm (lock, Glib::Threads::TRY_LOCK);
 
 	if (!lm.locked()) {
-		throw std::logic_error ("TempoMap::bbt_time_rt() could not lock tempo map");
+		throw std::logic_error ("TempoMap::bbt_at_frame_rt() could not lock tempo map");
 	}
 
 	return bbt_at_frame_locked (_metrics, frame);
@@ -2077,6 +2089,52 @@ TempoMap::frame_at_bbt_locked (const Metrics& metrics, const BBT_Time& bbt) cons
 	return ret;
 }
 
+/**
+ * Returns the distance from 0 in quarter pulses at the supplied frame.
+ *
+ * Plugin APIs don't count ticks in the same way PROGRAM_NAME does.
+ * We use ticks per beat whereas the rest of the world uses ticks per quarter note.
+ * This is more or less the VST's ppqPos (a scalar you use to obtain tick position
+ * in whatever ppqn you're using).
+ *
+ * @param frame The distance in frames relative to session 0 whose quarter note distance you would like.
+ * @return The quarter note (quarter pulse) distance from session 0 to the supplied frame. Ignores meter.
+*/
+
+double
+TempoMap::quarter_note_at_frame (const framepos_t frame)
+{
+	Glib::Threads::RWLock::ReaderLock lm (lock, Glib::Threads::TRY_LOCK);
+
+	const double ret = pulse_at_frame_locked (_metrics, frame) * 4.0;
+
+	return ret;
+}
+
+double
+TempoMap::quarter_note_at_frame_rt (const framepos_t frame)
+{
+	Glib::Threads::RWLock::ReaderLock lm (lock, Glib::Threads::TRY_LOCK);
+
+	if (!lm.locked()) {
+		throw std::logic_error ("TempoMap::quarter_note_at_frame_rt() could not lock tempo map");
+	}
+
+	const double ret = pulse_at_frame_locked (_metrics, frame) * 4.0;
+
+	return ret;
+}
+
+framepos_t
+TempoMap::frame_at_quarter_note (const double quarter_note)
+{
+	Glib::Threads::RWLock::ReaderLock lm (lock, Glib::Threads::TRY_LOCK);
+
+	const framepos_t ret = frame_at_pulse_locked (_metrics, quarter_note / 4.0);
+
+	return ret;
+}
+
 bool
 TempoMap::check_solved (const Metrics& metrics) const
 {