From 4cdac290290d24265089c3ffa0379a500b5d15dc Mon Sep 17 00:00:00 2001
From: Paul Davis <paul@linuxaudiosystems.com>
Date: Fri, 21 Jul 2023 13:48:50 -0600
Subject: [PATCH] attempt to follow time domain changes in playlists when
 tracks change

---
 libs/ardour/playlist.cc | 10 ++++++++++
 libs/ardour/region.cc   |  9 +++++++++
 libs/ardour/track.cc    | 17 +++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index b251f1c5a5..066bf72dbe 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -3516,6 +3516,16 @@ Playlist::globally_change_time_domain (Temporal::TimeDomain from, Temporal::Time
 void
 Playlist::time_domain_changed ()
 {
+	using namespace Temporal;
+
 	TimeDomainProvider::time_domain_changed ();
+
+	Temporal::TimeDomain to = time_domain();
+	Temporal::TimeDomain from = (to == AudioTime ? BeatTime : AudioTime);
+
+	for (auto & region  : regions) {
+		region->change_time_domain (from, to);
+	}
+
 }
 
diff --git a/libs/ardour/region.cc b/libs/ardour/region.cc
index f7c91592eb..1b341293ab 100644
--- a/libs/ardour/region.cc
+++ b/libs/ardour/region.cc
@@ -2205,3 +2205,12 @@ Region::globally_change_time_domain (Temporal::TimeDomain from, Temporal::TimeDo
 		std::cerr << "new domain after GCTD " << _length.val() << std::endl;
 	}
 }
+
+void
+Region::change_time_domain (Temporal::TimeDomain from, Temporal::TimeDomain to)
+{
+	if (_length.val().time_domain() == from) {
+		timecnt_t& l (_length.non_const_val());
+		l.set_time_domain (to);
+	}
+}
diff --git a/libs/ardour/track.cc b/libs/ardour/track.cc
index ced688a030..37b42ac807 100644
--- a/libs/ardour/track.cc
+++ b/libs/ardour/track.cc
@@ -712,12 +712,29 @@ Track::use_playlist (DataType dt, std::shared_ptr<Playlist> p, bool set_orig)
 		if (rl->size () > 0) {
 			Region::RegionsPropertyChanged (rl, Properties::hidden);
 		}
+		/* we don't know for certain that we controlled the old
+		 * playlist's time domain, but it's a pretty good guess. If it
+		 * has an actual parent, revert to using its parent's domain
+		 */
+		if (old->time_domain_parent()) {
+			old->clear_time_domain ();
+		}
 	}
+
 	if (p) {
 		std::shared_ptr<RegionList> rl (new RegionList (p->region_list_property ().rlist ()));
 		if (rl->size () > 0) {
 			Region::RegionsPropertyChanged (rl, Properties::hidden);
 		}
+
+		/* If the playlist has no time domain parent or its parent is
+		 * the session, reset to the explicit time domain of this
+		 * track.
+		 */
+
+		if (!p->time_domain_parent() || p->time_domain_parent() == &_session) {
+			p->set_time_domain (time_domain());
+		}
 	}
 
 	_session.set_dirty ();