From 45e21de209431deeecd2e495de739730ff9c61b1 Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Fri, 7 Oct 2022 16:12:27 -0600
Subject: [PATCH] implement and adopt new conventions for AudioClock use

The class now has two separate methods for setting a duration or a point
value. They MUST be used appropriately, because their behavior is different.

When ::set_duration() is used in timecode mode, an extent (inclusive-end
length) is shown rather than a length.

Some objects, such as the TimeInfoBox, now deliberately shown an inclusive end
for their "end" clock, but this not universally followed, pending more feedback
from users and investigating of conventions in other DAWs.
---
 gtk2_ardour/ardour_ui2.cc                |   4 +-
 gtk2_ardour/ardour_ui3.cc                |   8 +-
 gtk2_ardour/ardour_ui_options.cc         |   4 -
 gtk2_ardour/audio_clock.cc               | 247 ++++++++++++-----------
 gtk2_ardour/audio_clock.h                |  13 +-
 gtk2_ardour/big_clock_window.cc          |   2 +-
 gtk2_ardour/edit_note_dialog.cc          |  14 +-
 gtk2_ardour/editor_drag.cc               |   4 +-
 gtk2_ardour/editor_markers.cc            |   2 +-
 gtk2_ardour/editor_ops.cc                |  21 +-
 gtk2_ardour/editor_selection.cc          |   2 +-
 gtk2_ardour/insert_remove_time_dialog.cc |   8 +-
 gtk2_ardour/main_clock.cc                |   6 +-
 gtk2_ardour/main_clock.h                 |   2 +-
 gtk2_ardour/region_editor.cc             |   6 +-
 gtk2_ardour/region_selection.cc          |   2 +-
 gtk2_ardour/region_view.cc               |   6 +-
 gtk2_ardour/sfdb_ui.cc                   |   6 +-
 gtk2_ardour/strip_silence_dialog.cc      |   4 -
 gtk2_ardour/time_axis_view.cc            |   2 +-
 gtk2_ardour/time_fx_dialog.cc            |   3 +-
 gtk2_ardour/time_info_box.cc             |  22 +-
 22 files changed, 189 insertions(+), 199 deletions(-)

diff --git a/gtk2_ardour/ardour_ui2.cc b/gtk2_ardour/ardour_ui2.cc
index df344a5124..37f1a9865a 100644
--- a/gtk2_ardour/ardour_ui2.cc
+++ b/gtk2_ardour/ardour_ui2.cc
@@ -366,8 +366,8 @@ ARDOUR_UI::setup_transport ()
 	set_size_request_to_display_given_text (io_latency_value, "1000 spl", 0, 0);
 
 	/* connect signals */
-	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (primary_clock, &MainClock::set), false, timecnt_t::zero (Temporal::AudioTime)));
-	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (secondary_clock, &MainClock::set), false, timecnt_t::zero (Temporal::AudioTime)));
+	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (primary_clock, &MainClock::set), false));
+	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (secondary_clock, &MainClock::set), false));
 
 	primary_clock->ValueChanged.connect (sigc::mem_fun(*this, &ARDOUR_UI::primary_clock_value_changed));
 	secondary_clock->ValueChanged.connect (sigc::mem_fun(*this, &ARDOUR_UI::secondary_clock_value_changed));
diff --git a/gtk2_ardour/ardour_ui3.cc b/gtk2_ardour/ardour_ui3.cc
index 4cd2ef1585..67c4f69263 100644
--- a/gtk2_ardour/ardour_ui3.cc
+++ b/gtk2_ardour/ardour_ui3.cc
@@ -185,12 +185,12 @@ ARDOUR_UI::update_transport_clocks (samplepos_t p)
 			primary_clock->set (pos);
 			break;
 		case DeltaEditPoint:
-			primary_clock->set (pos, false, timecnt_t (editor->get_preferred_edit_position (EDIT_IGNORE_PHEAD)));
+			primary_clock->set_duration (pos.distance (editor->get_preferred_edit_position (EDIT_IGNORE_PHEAD)), false);
 			break;
 		case DeltaOriginMarker:
 			{
 				Location* loc = _session->locations()->clock_origin_location ();
-				primary_clock->set (pos, false, timecnt_t (loc ? loc->start_sample() : 0));
+				primary_clock->set_duration (pos.distance (loc->start()));
 			}
 			break;
 	}
@@ -200,12 +200,12 @@ ARDOUR_UI::update_transport_clocks (samplepos_t p)
 			secondary_clock->set (pos);
 			break;
 		case DeltaEditPoint:
-			secondary_clock->set (pos, false, timecnt_t (editor->get_preferred_edit_position (EDIT_IGNORE_PHEAD)));
+			secondary_clock->set_duration (pos.distance (editor->get_preferred_edit_position (EDIT_IGNORE_PHEAD)), false);
 			break;
 		case DeltaOriginMarker:
 			{
 				Location* loc = _session->locations()->clock_origin_location ();
-				secondary_clock->set (pos, false, timecnt_t (loc ? loc->start_sample() : 0));
+				secondary_clock->set_duration (pos.distance (loc->start()));
 			}
 			break;
 	}
diff --git a/gtk2_ardour/ardour_ui_options.cc b/gtk2_ardour/ardour_ui_options.cc
index 8b262dbd58..68de11e1df 100644
--- a/gtk2_ardour/ardour_ui_options.cc
+++ b/gtk2_ardour/ardour_ui_options.cc
@@ -380,21 +380,17 @@ ARDOUR_UI::parameter_changed (std::string p)
 		if (editor) editor->toggle_meter_updating();
 	} else if (p == "primary-clock-delta-mode") {
 		if (UIConfiguration::instance().get_primary_clock_delta_mode() != NoDelta) {
-			primary_clock->set_is_duration (true, timepos_t());
 			primary_clock->set_editable (false);
 			primary_clock->set_widget_name ("transport delta");
 		} else {
-			primary_clock->set_is_duration (false, timepos_t());
 			primary_clock->set_editable (true);
 			primary_clock->set_widget_name ("transport");
 		}
 	} else if (p == "secondary-clock-delta-mode") {
 		if (UIConfiguration::instance().get_secondary_clock_delta_mode() != NoDelta) {
-			secondary_clock->set_is_duration (true, timepos_t());
 			secondary_clock->set_editable (false);
 			secondary_clock->set_widget_name ("secondary delta");
 		} else {
-			secondary_clock->set_is_duration (false, timepos_t());
 			secondary_clock->set_editable (true);
 			secondary_clock->set_widget_name ("secondary");
 		}
diff --git a/gtk2_ardour/audio_clock.cc b/gtk2_ardour/audio_clock.cc
index b25e1f6c22..fdd1e795e7 100644
--- a/gtk2_ardour/audio_clock.cc
+++ b/gtk2_ardour/audio_clock.cc
@@ -101,7 +101,6 @@ AudioClock::AudioClock (const string& clock_name, bool transient, const string&
 	, corner_radius (4)
 	, font_size (10240)
 	, editing (false)
-	, bbt_reference_time (timepos_t::from_superclock (-1)) /* needs to be some negative value but SR may not be available at init */
 	, last_pdelta (0)
 	, last_sdelta (0)
 	, dragging (false)
@@ -120,7 +119,7 @@ AudioClock::AudioClock (const string& clock_name, bool transient, const string&
 
 	_mode = BBT; /* lie to force mode switch */
 	set_mode (Timecode);
-	AudioClock::set (last_when, true);
+	AudioClock::set (last_when(), true);
 
 	if (!is_transient) {
 		clocks.push_back (this);
@@ -523,7 +522,7 @@ AudioClock::end_edit (bool modify)
 
 			case BBT:
 				if (is_duration) {
-					pos = sample_duration_from_bbt_string (bbt_reference_time, edit_string);
+					pos = sample_duration_from_bbt_string (last_when(), edit_string);
 				} else {
 					pos = samples_from_bbt_string (timepos_t(), edit_string);
 				}
@@ -807,7 +806,7 @@ AudioClock::end_edit_relative (bool add)
 void
 AudioClock::tempo_map_changed ()
 {
-	AudioClock::set (last_when, true);
+	AudioClock::set (last_when(), true);
 }
 
 void
@@ -819,69 +818,71 @@ AudioClock::session_configuration_changed (std::string p)
 	}
 
 	if (p == "sync-source" || p == "external-sync") {
-		AudioClock::set (current_time(), true);
-		return;
-	}
-
-	if (p != "timecode-offset" && p != "timecode-offset-negative") {
-		return;
-	}
-
-	timepos_t current;
-
-	switch (_mode) {
-	case Timecode:
 		if (is_duration) {
-			current = timepos_t (current_duration ());
+			AudioClock::set_duration (current_duration(), true);
 		} else {
-			current = current_time ();
+			AudioClock::set (current_time(), true);
+		}
+		return;
+	}
+
+	if (p == "timecode-offset" && p == "timecode-offset-negative") {
+		switch (_mode) {
+		case Timecode:
+			if (is_duration) {
+				AudioClock::set_duration (current_duration(), true);
+			} else {
+				AudioClock::set (current_time(), true);
+			}
+			break;
+		default:
+			break;
 		}
-		AudioClock::set (current, true);
-		break;
-	default:
-		break;
 	}
 }
 
 void
-AudioClock::set (timepos_t const & w, bool force, timecnt_t const & offset)
+AudioClock::set_duration (Temporal::timecnt_t const & dur, bool force)
 {
-	timepos_t when (w);
+	is_duration = true;
 
 	if ((!force && !get_visible()) || !_session) {
 		return;
 	}
 
-	_offset = offset;
-	if (is_duration) {
-		when = when.earlier (offset);
+	timepos_t when;
+
+	/* extent semantics, not length */
+
+	timecnt_t d;
+
+	/* durations for timecode display should use extent, not length
+	 *
+	 * reminder: length = end - start ; extent = end - start - 1
+	 *
+	 * start + length = end
+	 * start + extent = last_point_inside duration
+	 */
+
+	switch (_mode) {
+	case Timecode:
+		d = dur.is_zero() ? dur : dur.decrement_by_domain ();
+		break;
+	default:
+		d = dur;
+		break;
 	}
 
-	if (when > _limit_pos) {
-		when = _limit_pos;
-	} else if (when < -_limit_pos) {
-		when = -_limit_pos;
+	/* Converting a negative duration to a position throws */
+
+	if (d.is_negative()) {
+		when = timepos_t (d);
+	} else {
+		when = -timepos_t (-d);
 	}
 
-	if (when == last_when && !force) {
-#if 0 // XXX return if no change and no change forced. verify Aug/2014
-		if (_mode != Timecode && _mode != MinSec) {
-			/* may need to force display of TC source
-			 * time, so don't return early.
-			 */
-			/* ^^ Why was that?,  delta times?
-			 * Timecode FPS, pull-up/down, etc changes
-			 * trigger a 'session_property_changed' which
-			 * eventually calls set(last_when, true)
-			 *
-			 * re-rendering the clock every 40ms or so just
-			 * because we can is not ideal.
-			 */
-			return;
-		}
-#else
+	if (when == last_when() && !force) {
 		return;
-#endif
 	}
 
 	bool btn_en = false;
@@ -894,7 +895,7 @@ AudioClock::set (timepos_t const & w, bool force, timecnt_t const & offset)
 			break;
 
 		case BBT:
-			set_bbt (when, offset, force);
+			set_bbt (dur, force);
 			btn_en = true;
 			break;
 
@@ -913,12 +914,61 @@ AudioClock::set (timepos_t const & w, bool force, timecnt_t const & offset)
 	}
 
 	finish_set (when, btn_en);
+	last_time = dur;
 }
 
 void
-AudioClock::set_duration (Temporal::timecnt_t const & d, bool force, Temporal::timecnt_t const & offset)
+AudioClock::set (timepos_t const & w, bool force)
 {
-	set (timepos_t (d), force, offset);
+	is_duration = false;
+
+	timepos_t when (w);
+
+	if ((!force && !get_visible()) || !_session) {
+		return;
+	}
+
+	if (when > _limit_pos) {
+		when = _limit_pos;
+	} else if (when < -_limit_pos) {
+		when = -_limit_pos;
+	}
+
+	if (when == last_when() && !force) {
+		return;
+	}
+
+	bool btn_en = false;
+
+	if (!editing) {
+
+		switch (_mode) {
+		case Timecode:
+			set_timecode (when, force);
+			break;
+
+		case BBT:
+			set_bbt (timecnt_t (when), force);
+			btn_en = true;
+			break;
+
+		case MinSec:
+			set_minsec (when, force);
+			break;
+
+		case Seconds:
+			set_seconds (when, force);
+			break;
+
+		case Samples:
+			set_samples (when, force);
+			break;
+		}
+	}
+
+	finish_set (when, btn_en);
+
+	last_time = timecnt_t (last_time.distance(), when);
 }
 
 void
@@ -947,7 +997,6 @@ AudioClock::finish_set (Temporal::timepos_t const & when, bool btn_en)
 	}
 
 	queue_draw ();
-	last_when = when;
 }
 
 void
@@ -1209,49 +1258,44 @@ AudioClock::set_timecode (timepos_t const & w, bool /*force*/)
 }
 
 void
-AudioClock::set_bbt (timepos_t const & w, timecnt_t const & o, bool /*force*/)
+AudioClock::set_bbt (timecnt_t const & w, bool /*force*/)
 {
-	timepos_t when (w);
-	timecnt_t offset (o);
+	timepos_t pos (w);
 	char buf[64];
 	Temporal::BBT_Time BBT;
 	bool negative = false;
 
-	if (_off || when >= _limit_pos || when < -_limit_pos) {
+	if (_off || pos >= _limit_pos || pos < -_limit_pos) {
 		_layout->set_text (" ---|--|----");
 		_left_btn.set_text ("", false);
 		_right_btn.set_text ("", false);
 		return;
 	}
 
-	if (when.is_negative ()) {
-		when = -when;
+	if (pos.is_negative ()) {
+		pos = -pos;
 		negative = true;
 	}
 
 	/* handle a common case */
 
 	if (is_duration) {
-		if (when.is_zero ()) {
+		if (pos.is_zero ()) {
 			BBT.bars = 0;
 			BBT.beats = 0;
 			BBT.ticks = 0;
 		} else {
 			TempoMap::SharedPtr tmap (TempoMap::use());
 
-			if (offset.is_zero ()) {
-				offset = timecnt_t (bbt_reference_time);
-			}
-
-			const int divisions = tmap->meter_at (timepos_t (offset)).divisions_per_bar();
+			const int divisions = tmap->meter_at (w.position()).divisions_per_bar();
 			Temporal::BBT_Time sub_bbt;
 
 			if (negative) {
-				BBT = tmap->bbt_at (timepos_t (tmap->quarters_at (timepos_t (offset))));
-				sub_bbt = tmap->bbt_at (timepos_t (offset - when));
+				BBT = tmap->bbt_at (timepos_t (tmap->quarters_at (w.position())));
+				sub_bbt = tmap->bbt_at (last_when().earlier (w.position()));
 			} else {
-				BBT = tmap->bbt_at (timepos_t (tmap->quarters_at (when + offset)));
-				sub_bbt = tmap->bbt_at (timepos_t (offset));
+				BBT = tmap->bbt_at (timepos_t (tmap->quarters_at (w.end())));
+				sub_bbt = tmap->bbt_at (w.position());
 			}
 
 			BBT.bars -= sub_bbt.bars;
@@ -1276,7 +1320,7 @@ AudioClock::set_bbt (timepos_t const & w, timecnt_t const & o, bool /*force*/)
 			}
 		}
 	} else {
-		BBT = TempoMap::use()->bbt_at (when);
+		BBT = TempoMap::use()->bbt_at (pos);
 	}
 
 	if (negative) {
@@ -1290,13 +1334,6 @@ AudioClock::set_bbt (timepos_t const & w, timecnt_t const & o, bool /*force*/)
 	_layout->set_text (buf);
 
 	if (_with_info) {
-		timepos_t pos;
-
-		if (bbt_reference_time.is_negative ()) {
-			pos = when;
-		} else {
-			pos = bbt_reference_time;
-		}
 
 		TempoMetric m (TempoMap::use()->metric_at (pos));
 
@@ -1356,7 +1393,7 @@ AudioClock::set_session (Session *s)
 			}
 		}
 
-		AudioClock::set (last_when, true);
+		AudioClock::set (last_when(), true);
 	}
 }
 
@@ -1927,7 +1964,7 @@ AudioClock::get_incremental_step (Field field, timepos_t const & pos)
 timepos_t
 AudioClock::current_time () const
 {
-	return last_when;
+	return last_when();
 }
 
 timecnt_t
@@ -1944,7 +1981,7 @@ AudioClock::current_duration (timepos_t pos) const
 	case MinSec:
 	case Seconds:
 	case Samples:
-		ret = timecnt_t (last_when, pos);
+		ret = timecnt_t (last_when(), pos);
 		break;
 	}
 
@@ -1954,28 +1991,28 @@ AudioClock::current_duration (timepos_t pos) const
 bool
 AudioClock::bbt_validate_edit (string & str)
 {
-	AnyTime any;
+	BBT_Time bbt;
 
-	if (sscanf (str.c_str(), BBT_SCANF_FORMAT, &any.bbt.bars, &any.bbt.beats, &any.bbt.ticks) != 3) {
+	if (sscanf (str.c_str(), BBT_SCANF_FORMAT, &bbt.bars, &bbt.beats, &bbt.ticks) != 3) {
 		return false;
 	}
 
-	if (any.bbt.ticks > Temporal::ticks_per_beat) {
+	if (bbt.ticks > Temporal::ticks_per_beat) {
 		return false;
 	}
 
-	if (!is_duration && any.bbt.bars == 0) {
+	if (!is_duration && bbt.bars == 0) {
 		return false;
 	}
 
-	if (!is_duration && any.bbt.beats == 0) {
+	if (!is_duration && bbt.beats == 0) {
 		/* user could not have mean zero beats because for a
 		 * non-duration clock that's impossible. Assume that they
 		 * mis-entered things and meant Bar|1|ticks
 		 */
 
 		char buf[128];
-		snprintf (buf, sizeof (buf), "%" PRIu32 "|%" PRIu32 "|%" PRIu32, any.bbt.bars, 1, any.bbt.ticks);
+		snprintf (buf, sizeof (buf), "%" PRIu32 "|%" PRIu32 "|%" PRIu32, bbt.bars, 1, bbt.ticks);
 		str = buf;
 	}
 
@@ -2278,7 +2315,7 @@ AudioClock::set_mode (Mode m, bool noemit)
 		break;
 	}
 
-	AudioClock::set (last_when, true);
+	AudioClock::set (last_when(), true);
 
 	if (!is_transient && !noemit) {
 		ModeChanged (); /* EMIT SIGNAL (the static one)*/
@@ -2287,12 +2324,6 @@ AudioClock::set_mode (Mode m, bool noemit)
 	mode_changed (); /* EMIT SIGNAL (the member one) */
 }
 
-void
-AudioClock::set_bbt_reference (timepos_t const & pos)
-{
-	bbt_reference_time = pos;
-}
-
 void
 AudioClock::on_style_changed (const Glib::RefPtr<Gtk::Style>& old_style)
 {
@@ -2319,28 +2350,6 @@ AudioClock::set_editable (bool yn)
 	editable = yn;
 }
 
-void
-AudioClock::set_is_duration (bool yn, timepos_t const & p)
-{
-	if (yn == is_duration) {
-		if (yn) {
-			/* just reset position */
-			duration_position = p;
-		}
-
-		return;
-	}
-
-	is_duration = yn;
-	if (yn) {
-		duration_position = p;
-	} else {
-		duration_position = timepos_t ();
-	}
-
-	set (last_when, true);
-}
-
 void
 AudioClock::set_off (bool yn)
 {
@@ -2350,11 +2359,15 @@ AudioClock::set_off (bool yn)
 
 	_off = yn;
 
-	/* force a redraw. last_when will be preserved, but the clock text will
+	/* force a redraw. last_time will be preserved, but the clock text will
 	 * change
 	 */
 
-	AudioClock::set (last_when, true);
+	if (is_duration) {
+		AudioClock::set_duration (last_time, true);
+	} else {
+		AudioClock::set (last_when(), true);
+	}
 }
 
 void
diff --git a/gtk2_ardour/audio_clock.h b/gtk2_ardour/audio_clock.h
index f671d8c6b9..48f30dae89 100644
--- a/gtk2_ardour/audio_clock.h
+++ b/gtk2_ardour/audio_clock.h
@@ -73,14 +73,14 @@ class AudioClock : public CairoWidget, public ARDOUR::SessionHandlePtr
 
 	void focus ();
 
-	virtual void set (Temporal::timepos_t const &, bool force = false, Temporal::timecnt_t const & offset = Temporal::timecnt_t());
-	void set_duration (Temporal::timecnt_t const &, bool force = false, Temporal::timecnt_t const & offset = Temporal::timecnt_t());
+	/* overriden by MainClock */
+	virtual void set (Temporal::timepos_t const &, bool force = false);
+	void set_duration (Temporal::timecnt_t const &, bool force = false);
 
 	void set_from_playhead ();
 	void locate ();
 	void set_mode (Mode, bool noemit = false);
 	void set_bbt_reference (Temporal::timepos_t const &);
-	void set_is_duration (bool, Temporal::timepos_t const &);
 
 	void copy_text_to_clipboard () const;
 
@@ -199,8 +199,9 @@ class AudioClock : public CairoWidget, public ARDOUR::SessionHandlePtr
 	std::string pre_edit_string;
 	std::string input_string;
 
-	Temporal::timepos_t bbt_reference_time;
-	Temporal::timepos_t last_when;
+	Temporal::timecnt_t last_time;
+	Temporal::timepos_t last_when() const { return last_time.position(); }
+
 	bool last_pdelta;
 	bool last_sdelta;
 
@@ -221,7 +222,7 @@ class AudioClock : public CairoWidget, public ARDOUR::SessionHandlePtr
 
 	void set_slave_info ();
 	void set_timecode (Temporal::timepos_t const &, bool);
-	void set_bbt (Temporal::timepos_t const &, Temporal::timecnt_t const &, bool);
+	void set_bbt (Temporal::timecnt_t const &, bool);
 	void set_minsec (Temporal::timepos_t const &, bool);
 	void set_seconds (Temporal::timepos_t const &, bool);
 	void set_samples (Temporal::timepos_t const &, bool);
diff --git a/gtk2_ardour/big_clock_window.cc b/gtk2_ardour/big_clock_window.cc
index ecb3c12492..dfabc440f7 100644
--- a/gtk2_ardour/big_clock_window.cc
+++ b/gtk2_ardour/big_clock_window.cc
@@ -39,7 +39,7 @@ BigClockWindow::BigClockWindow (AudioClock& c)
 	: ArdourWindow (_("Big Clock"))
 	, clock (c)
 {
-	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (clock, &AudioClock::set), false, Temporal::timecnt_t()));
+	ARDOUR_UI::Clock.connect (sigc::bind (sigc::mem_fun (clock, &AudioClock::set), false));
 
 	clock.set_corner_radius (0.0);
 
diff --git a/gtk2_ardour/edit_note_dialog.cc b/gtk2_ardour/edit_note_dialog.cc
index 13ab3930d6..8e11ccebea 100644
--- a/gtk2_ardour/edit_note_dialog.cc
+++ b/gtk2_ardour/edit_note_dialog.cc
@@ -97,9 +97,7 @@ EditNoteDialog::EditNoteDialog (MidiRegionView* rv, set<NoteBase*> n)
 	_time_clock.set_session (_region_view->get_time_axis_view().session ());
 	_time_clock.set_mode (AudioClock::BBT);
 
-	timecnt_t dur = _region_view->source_relative_distance (timecnt_t ((*_events.begin())->note()->time(), timepos_t()), BeatTime);
-	timepos_t pos = _region_view->region()->source_position() + dur;
-
+	const timepos_t pos (_region_view->region_relative_distance (timecnt_t ((*_events.begin())->note()->time (), timepos_t()), BeatTime));
 	_time_clock.set (pos, true);
 
 	l = manage (left_aligned_label (_("Length")));
@@ -110,15 +108,7 @@ EditNoteDialog::EditNoteDialog (MidiRegionView* rv, set<NoteBase*> n)
 
 	_length_clock.set_session (_region_view->get_time_axis_view().session ());
 	_length_clock.set_mode (AudioClock::BBT);
-
-	dur = _region_view->region_relative_distance (timecnt_t ((*_events.begin())->note()->end_time (), timepos_t()), BeatTime);
-	pos = _region_view->region()->position() + dur;
-	timecnt_t offset;
-	dur = _region_view->region_relative_distance (timecnt_t ((*_events.begin())->note()->time (), timepos_t()), BeatTime);
-	offset = timecnt_t (_region_view->region()->position(), timepos_t()) + dur;
-
-	_length_clock.set_is_duration (true, pos);
-	_length_clock.set (pos, true, offset);
+	_length_clock.set_duration (timecnt_t ((*_events.begin())->note()->length()), true);
 
 	/* Set up `set all notes...' buttons' sensitivity */
 
diff --git a/gtk2_ardour/editor_drag.cc b/gtk2_ardour/editor_drag.cc
index 48d3ca6fcd..4af0414758 100644
--- a/gtk2_ardour/editor_drag.cc
+++ b/gtk2_ardour/editor_drag.cc
@@ -4333,7 +4333,7 @@ MarkerDrag::start_grab (GdkEvent* event, Gdk::Cursor* cursor)
 		s = min (s, e);
 		e = max (s, e);
 		if (e < timepos_t::max (e.time_domain())) {
-			e.increment();
+			e.increment_by_domain();
 		}
 		_editor->session()->locations()->find_all_between (s, e, ll, Location::Flags (0));
 		for (Locations::LocationList::iterator i = ll.begin(); i != ll.end(); ++i) {
@@ -6632,7 +6632,7 @@ EditorRubberbandSelectDrag::select_things (int button_state, timepos_t const & x
 
 	_editor->begin_reversible_selection_op (X_("rubberband selection"));
 
-	_editor->select_all_within (x1, x2.decrement(), y1, y2, _editor->track_views, op, false);
+	_editor->select_all_within (x1, x2.decrement_by_domain(), y1, y2, _editor->track_views, op, false);
 
 	_editor->commit_reversible_selection_op ();
 }
diff --git a/gtk2_ardour/editor_markers.cc b/gtk2_ardour/editor_markers.cc
index f4cdf6a6f1..092a30979f 100644
--- a/gtk2_ardour/editor_markers.cc
+++ b/gtk2_ardour/editor_markers.cc
@@ -1310,7 +1310,7 @@ Editor::marker_menu_select_all_selectables_using_range ()
 	bool is_start;
 
 	if (((l = find_location_from_marker (marker, is_start)) != 0) && (l->end() > l->start())) {
-		select_all_within (l->start(), l->end().decrement(), 0,  DBL_MAX, track_views, Selection::Set, false);
+		select_all_within (l->start(), l->end(), 0,  DBL_MAX, track_views, Selection::Set, false);
 	}
 
 }
diff --git a/gtk2_ardour/editor_ops.cc b/gtk2_ardour/editor_ops.cc
index f2dd50629c..82639bc66c 100644
--- a/gtk2_ardour/editor_ops.cc
+++ b/gtk2_ardour/editor_ops.cc
@@ -350,7 +350,7 @@ Editor::move_range_selection_start_or_end_to_region_boundary (bool move_end, boo
 
 	/* so we don't find the current region again */
 	if (dir > 0 || pos.is_positive()) {
-		pos = pos.increment ();
+		pos = pos.increment_by_domain ();
 	}
 
 	timepos_t const target = get_region_boundary (pos, dir, true, false);
@@ -835,7 +835,7 @@ Editor::build_region_boundary_cache ()
 			}
 		}
 
-		pos = lpos.increment();
+		pos = lpos.increment_by_domain();
 	}
 
 	/* finally sort to be sure that the order is correct */
@@ -976,7 +976,7 @@ Editor::cursor_to_region_boundary (bool with_selection, int32_t dir)
 
 	// so we don't find the current region again..
 	if (dir > 0 || pos > 0) {
-		pos = pos.increment();
+		pos = pos.increment_by_domain();
 	}
 
 	if ((target = get_region_boundary (pos, dir, with_selection, false)) < 0) {
@@ -1012,7 +1012,7 @@ Editor::cursor_to_region_point (EditorCursor* cursor, RegionPoint point, int32_t
 
 	// so we don't find the current region again..
 	if (dir > 0 || pos.is_positive())
-		pos = pos.increment();
+		pos = pos.increment_by_domain();
 
 	if (!selection->tracks.empty()) {
 
@@ -1155,7 +1155,7 @@ Editor::selected_marker_to_region_boundary (bool with_selection, int32_t dir)
 
 	// so we don't find the current region again..
 	if (dir > 0 || pos.is_positive()) {
-		pos = pos.increment();
+		pos = pos.increment_by_domain();
 	}
 
 	if ((target = get_region_boundary (pos, dir, with_selection, false)) < 0) {
@@ -1199,7 +1199,7 @@ Editor::selected_marker_to_region_point (RegionPoint point, int32_t dir)
 
 	// so we don't find the current region again..
 	if (dir > 0 || pos > 0) {
-		pos = pos.increment();
+		pos = pos.increment_by_domain();
 	}
 
 	if (!selection->tracks.empty()) {
@@ -3428,7 +3428,7 @@ Editor::separate_under_selected_regions ()
 		}
 
 		//Partition on the region bounds
-		playlist->partition ((*rl)->position().decrement(), (*rl)->end(), true);
+		playlist->partition ((*rl)->position().decrement_by_domain(), (*rl)->end(), true);
 
 		//Re-add region that was just removed due to the partition operation
 		playlist->add_region ((*rl), (*rl)->position());
@@ -3553,7 +3553,7 @@ Editor::region_fill_track ()
 
 	timepos_t const end (_session->current_end_sample ());
 
-	if (regions.empty () || regions.end_time().increment() >= end) {
+	if (regions.empty () || regions.end_time().increment_by_domain() >= end) {
 		return;
 	}
 
@@ -3972,7 +3972,8 @@ Editor::trim_to_region(bool forward)
 				continue;
 			}
 
-			region->trim_end (next_region->position().decrement());
+			/* new end is 1 domain unit before the next region */
+			region->trim_end (next_region->position().decrement_by_domain());
 			arv->region_changed (PropertyChange (ARDOUR::Properties::length));
 		}
 		else {
@@ -9634,7 +9635,7 @@ Editor::effective_ripple_mark_start (boost::shared_ptr<Playlist> target_playlist
 	}
 
 	if (last_region_end_before_at < pos) {
-		pos = last_region_end_before_at.increment();
+		pos = last_region_end_before_at.increment_by_domain();
 	}
 #endif
 
diff --git a/gtk2_ardour/editor_selection.cc b/gtk2_ardour/editor_selection.cc
index 0f57542e97..cdcccf8d74 100644
--- a/gtk2_ardour/editor_selection.cc
+++ b/gtk2_ardour/editor_selection.cc
@@ -2186,7 +2186,7 @@ Editor::select_all_selectables_using_edit (bool after, bool from_context_menu)
 	} else {
 		if ((end = get_preferred_edit_position(EDIT_IGNORE_NONE, from_context_menu)) > 1) {
 			start = timepos_t ();
-			end = end.decrement();
+			end = end.decrement_by_domain();
 		} else {
 			return;
 		}
diff --git a/gtk2_ardour/insert_remove_time_dialog.cc b/gtk2_ardour/insert_remove_time_dialog.cc
index 55883cc7ac..89136865d5 100644
--- a/gtk2_ardour/insert_remove_time_dialog.cc
+++ b/gtk2_ardour/insert_remove_time_dialog.cc
@@ -74,14 +74,10 @@ InsertRemoveTimeDialog::InsertRemoveTimeDialog (PublicEditor& e, bool remove)
 
 	//if a Range is selected, assume the user wants to insert/remove the length of the range
 	if ( _editor.get_selection().time.length() != 0 ) {
-		position_clock.set (_editor.get_selection().time.start_time(), true);
-		duration_clock.set (_editor.get_selection().time.end_time(), true,  timecnt_t (_editor.get_selection().time.start_time()));
-		duration_clock.set_bbt_reference (_editor.get_selection().time.start_time());
+		duration_clock.set_duration (_editor.get_selection().time.start_time().distance (_editor.get_selection().time.start_time()), true);
 	} else {
 		timepos_t const pos = _editor.get_preferred_edit_position (EDIT_IGNORE_MOUSE);
-		position_clock.set (pos, true);
-		duration_clock.set_bbt_reference (pos);
-		duration_clock.set (timepos_t());
+		duration_clock.set_duration (timecnt_t (pos));
 	}
 
 	if (!remove) {
diff --git a/gtk2_ardour/main_clock.cc b/gtk2_ardour/main_clock.cc
index 1ffd903ab2..d098240bdb 100644
--- a/gtk2_ardour/main_clock.cc
+++ b/gtk2_ardour/main_clock.cc
@@ -108,7 +108,7 @@ MainClock::absolute_time () const
 }
 
 void
-MainClock::set (timepos_t const & when, bool force, timecnt_t const & /*offset*/)
+MainClock::set (timepos_t const & when, bool force)
 {
 	ClockDeltaMode mode;
 	if (_primary) {
@@ -126,12 +126,12 @@ MainClock::set (timepos_t const & when, bool force, timecnt_t const & /*offset*/
 			AudioClock::set (when, force);
 			break;
 		case DeltaEditPoint:
-			AudioClock::set (when, force, timecnt_t (PublicEditor::instance().get_preferred_edit_position (Editing::EDIT_IGNORE_PHEAD)));
+			AudioClock::set_duration (when.distance (PublicEditor::instance().get_preferred_edit_position (Editing::EDIT_IGNORE_PHEAD)), force);
 			break;
 		case DeltaOriginMarker:
 			{
 				Location* loc = AudioEngine::instance()->session()->locations()->clock_origin_location ();
-				AudioClock::set (when, force, loc ? timecnt_t (loc->start()) : timecnt_t());
+				AudioClock::set_duration (when.distance (loc ? loc->start() : timepos_t (when.time_domain())), force);
 			}
 			break;
 	}
diff --git a/gtk2_ardour/main_clock.h b/gtk2_ardour/main_clock.h
index c8e89fd549..a87ca600c5 100644
--- a/gtk2_ardour/main_clock.h
+++ b/gtk2_ardour/main_clock.h
@@ -31,7 +31,7 @@ public:
 	MainClock (const std::string& clock_name, const std::string& widget_name, bool primary);
 	Temporal::timepos_t absolute_time () const;
 	void set_session (ARDOUR::Session *s);
-	void set (Temporal::timepos_t const &, bool force = false, Temporal::timecnt_t const & offset = Temporal::timecnt_t ());
+	void set (Temporal::timepos_t const &, bool force = false);
 
 private:
 
diff --git a/gtk2_ardour/region_editor.cc b/gtk2_ardour/region_editor.cc
index b7c5f6e717..242e537984 100644
--- a/gtk2_ardour/region_editor.cc
+++ b/gtk2_ardour/region_editor.cc
@@ -334,7 +334,11 @@ RegionEditor::length_clock_changed ()
 		in_command = true;
 
 		_region->clear_changes ();
-		_region->trim_end (_region->position() + len.decrement());
+		/* new end is actually 1 domain unit before the clock duration
+		 * would otherwise indicate
+		 */
+		const timepos_t new_end = (_region->position() + len).decrement_by_domain ();
+		_region->trim_end (new_end);
 		_session->add_command(new StatefulDiffCommand (_region));
 	}
 
diff --git a/gtk2_ardour/region_selection.cc b/gtk2_ardour/region_selection.cc
index 7f3309eade..913d642b3c 100644
--- a/gtk2_ardour/region_selection.cc
+++ b/gtk2_ardour/region_selection.cc
@@ -316,7 +316,7 @@ RegionSelection::end_time () const
 	timepos_t e (timepos_t::zero (front()->region()->position().time_domain()));
 
 	for (RegionSelection::const_iterator i = begin(); i != end(); ++i) {
-		e = max (e, (*i)->region()->end ());
+		e = max (e, (*i)->region()->nt_last ());
 	}
 
 	return e;
diff --git a/gtk2_ardour/region_view.cc b/gtk2_ardour/region_view.cc
index 143d49f019..7f7e43af83 100644
--- a/gtk2_ardour/region_view.cc
+++ b/gtk2_ardour/region_view.cc
@@ -1008,7 +1008,7 @@ RegionView::update_coverage_frame (LayerDisplay d)
 
 	while (t < end) {
 
-		t = t.increment ();
+		t = t.increment_by_domain ();
 
 		/* is this region is on top at time t? */
 		bool const new_me = pl->region_is_audible_at (_region, t);
@@ -1086,7 +1086,7 @@ RegionView::trim_front (timepos_t const & new_bound, bool no_overlap)
 
 		/* Only trim region on the left if the first sample has gone beyond the left region's last sample. */
 		if (region_left && (region_left->nt_last() > _region->position() || regions_touching)) {
-			region_left->trim_end (_region->position().decrement());
+			region_left->trim_end (_region->position().decrement_by_domain());
 		}
 	}
 
@@ -1113,7 +1113,7 @@ RegionView::trim_end (timepos_t const & new_bound, bool no_overlap)
 
 		bool regions_touching = false;
 
-		if (region_right && (last == region_right->position().decrement())) {
+		if (region_right && (last == region_right->position().decrement_by_domain())) {
 			regions_touching = true;
 		}
 
diff --git a/gtk2_ardour/sfdb_ui.cc b/gtk2_ardour/sfdb_ui.cc
index dd50cefa8d..ea3e8eef63 100644
--- a/gtk2_ardour/sfdb_ui.cc
+++ b/gtk2_ardour/sfdb_ui.cc
@@ -218,7 +218,6 @@ SoundFileBox::SoundFileBox (bool /*persistent*/)
 	table.attach (timecode_clock,  1, 2, row, row+1, FILL, FILL);  row+=1;
 	table.attach (tempomap_value,  1, 2, row, row+1, FILL, FILL);  row+=1;
 
-	length_clock.set_is_duration (true, timepos_t());
 	length_clock.set_mode (ARDOUR_UI::instance()->primary_clock->mode());
 	timecode_clock.set_mode (AudioClock::Timecode);
 
@@ -380,7 +379,7 @@ SoundFileBox::setup_labels (const string& filename)
 			}
 		} else {
 			channels_value.set_text ("");
-			length_clock.set (timepos_t());
+			length_clock.set_duration (timecnt_t());
 			tempomap_value.set_text (_("No tempo data"));
 		}
 
@@ -401,7 +400,7 @@ SoundFileBox::setup_labels (const string& filename)
 		samplerate_value.set_text ("");
 		tags_entry.get_buffer()->set_text ("");
 
-		length_clock.set (timepos_t());
+		length_clock.set_duration (timecnt_t());
 		timecode_clock.set (timepos_t());
 
 		tags_entry.set_sensitive (false);
@@ -433,7 +432,6 @@ SoundFileBox::setup_labels (const string& filename)
 	samplecnt_t const nfr = _session ? _session->nominal_sample_rate() : 25;
 	double src_coef = (double) nfr / sf_info.samplerate;
 
-	length_clock.set_is_duration (true, timepos_t());
 	length_clock.set_duration (timecnt_t (samplecnt_t (llrint (sf_info.length * src_coef + 0.5))), true);
 	timecode_clock.set (timepos_t (samplepos_t (llrint (sf_info.timecode * src_coef + 0.5))), true);
 
diff --git a/gtk2_ardour/strip_silence_dialog.cc b/gtk2_ardour/strip_silence_dialog.cc
index 1222e2f2f2..88108ed071 100644
--- a/gtk2_ardour/strip_silence_dialog.cc
+++ b/gtk2_ardour/strip_silence_dialog.cc
@@ -63,9 +63,6 @@ StripSilenceDialog::StripSilenceDialog (Session* s, list<RegionView*> const & v)
 		views.push_back (ViewInterval (*r));
 	}
 
-	_minimum_length->set_is_duration (true, views.front().view->region()->position());
-	_fade_length->set_is_duration (true, views.front().view->region()->position());
-
 	Gtk::HBox* hbox = Gtk::manage (new Gtk::HBox);
 
 	Gtk::Table* table = Gtk::manage (new Gtk::Table (3, 3));
@@ -106,7 +103,6 @@ StripSilenceDialog::StripSilenceDialog (Session* s, list<RegionView*> const & v)
 
 	_fade_length->set_session (s);
 	_fade_length->set_mode (AudioClock::Samples);
-	_fade_length->set_is_duration (true, timepos_t());
 	_fade_length->set_duration (timecnt_t (_fade_length_value), true);
 
 	hbox->pack_start (*table);
diff --git a/gtk2_ardour/time_axis_view.cc b/gtk2_ardour/time_axis_view.cc
index aed370613e..99301ccfda 100644
--- a/gtk2_ardour/time_axis_view.cc
+++ b/gtk2_ardour/time_axis_view.cc
@@ -895,7 +895,7 @@ TimeAxisView::show_selection (TimeSelection& ts)
 		rect = get_selection_rect ((*i).id);
 
 		x1 = _editor.time_to_pixel (start);
-		x2 = _editor.time_to_pixel (end.decrement());
+		x2 = _editor.time_to_pixel (end.decrement_by_domain());
 		y2 = current_height() - 1;
 
 		if (dynamic_cast<AudioTimeAxisView*>(this)) {
diff --git a/gtk2_ardour/time_fx_dialog.cc b/gtk2_ardour/time_fx_dialog.cc
index aa83b5181d..bdd9296442 100644
--- a/gtk2_ardour/time_fx_dialog.cc
+++ b/gtk2_ardour/time_fx_dialog.cc
@@ -148,9 +148,8 @@ TimeFXDialog::TimeFXDialog (Editor& e, bool pitch, timecnt_t const & oldlen, tim
 		vector<string> strings;
 		duration_clock = manage (new AudioClock (X_("stretch"), true, X_("stretch"), true, false, true, false, true));
 		duration_clock->set_session (e.session());
-		duration_clock->set (timepos_t (new_length), true);
 		duration_clock->set_mode (AudioClock::BBT);
-		duration_clock->set_bbt_reference (position);
+		duration_clock->set_duration (timecnt_t (new_length, position));
 
 		Gtk::Alignment* clock_align = manage (new Gtk::Alignment);
 		clock_align->add (*duration_clock);
diff --git a/gtk2_ardour/time_info_box.cc b/gtk2_ardour/time_info_box.cc
index df472e28e0..82c47b4a19 100644
--- a/gtk2_ardour/time_info_box.cc
+++ b/gtk2_ardour/time_info_box.cc
@@ -242,8 +242,8 @@ TimeInfoBox::region_selection_changed ()
 	selection_end->set_off (false);
 	selection_length->set_off (false);
 	selection_start->set (s);
-	selection_end->set (e);
-	selection_length->set_duration (timecnt_t (e), false, timecnt_t (s));
+	selection_end->set (e.decrement_by_domain());
+	selection_length->set_duration (s.distance (e), true);
 }
 
 void
@@ -273,8 +273,7 @@ TimeInfoBox::selection_changed ()
 					selection_end->set_off (false);
 					selection_length->set_off (false);
 					selection_start->set (selection.time.start_time());
-					selection_end->set (selection.time.end_time());
-					selection_length->set_is_duration (true, selection.time.start_time());
+					selection_end->set (selection.time.end_time().decrement_by_domain());
 					selection_length->set_duration (selection.time.start_time().distance (selection.time.end_time()));
 				} else {
 					selection_start->set_off (true);
@@ -293,9 +292,8 @@ TimeInfoBox::selection_changed ()
 				selection_end->set_off (false);
 				selection_length->set_off (false);
 				selection_start->set (s);
-				selection_end->set (e);
-				selection_length->set_is_duration (true, s);
-				selection_length->set (e, false, timecnt_t (s));
+				selection_end->set (e.decrement_by_domain());
+				selection_length->set_duration (s.distance (e), false);
 			}
 		} else {
 			/* this is more efficient than tracking changes per region in large selections */
@@ -326,9 +324,8 @@ TimeInfoBox::selection_changed ()
 				selection_end->set_off (false);
 				selection_length->set_off (false);
 				selection_start->set (s);
-				selection_end->set (e);
-				selection_length->set_is_duration (true, s);
-				selection_length->set (e, false, timecnt_t (s));
+				selection_end->set (e.decrement_by_domain());
+				selection_length->set_duration(s.distance (e));
 			} else {
 				selection_start->set_off (true);
 				selection_end->set_off (true);
@@ -339,9 +336,8 @@ TimeInfoBox::selection_changed ()
 			selection_end->set_off (false);
 			selection_length->set_off (false);
 			selection_start->set (selection.time.start_time());
-			selection_end->set (selection.time.end_time());
-			selection_length->set_is_duration (true, selection.time.start_time());
-			selection_length->set_duration (selection.time.start_time().distance (selection.time.end_time()));
+			selection_end->set (selection.time.end_time().decrement_by_domain());
+			selection_length->set_duration (selection.time.length());
 		}
 		break;