Layering - the return of "later is higher".

    Currently we don't do anything special on layering prefs change
    (relayer only occurs when each playlist is first edited). The idea here is
    that "undo" is still available to restore previous layering in case of any
    surprises.

4 files changed, 46 insertions, 4 deletions

diff --git a/libs/ardour/ardour/rc_configuration_vars.h b/libs/ardour/ardour/rc_configuration_vars.h
index 832cb8e958..52c3309b65 100644
--- a/libs/ardour/ardour/rc_configuration_vars.h
+++ b/libs/ardour/ardour/rc_configuration_vars.h
@@ -90,6 +90,7 @@ CONFIG_VARIABLE (bool, use_osc, "use-osc", false)
 
 /* editing related */
 
+CONFIG_VARIABLE (LayerModel, layer_model, "layer-model", Manual)
 CONFIG_VARIABLE (bool, automation_follows_regions, "automation-follows-regions", true)
 CONFIG_VARIABLE (bool, region_boundaries_from_selected_tracks, "region-boundaries-from-selected-tracks", true)
 CONFIG_VARIABLE (bool, region_boundaries_from_onscreen_tracks, "region-boundaries-from-onscreen_tracks", true)
diff --git a/libs/ardour/ardour/types.h b/libs/ardour/ardour/types.h
index a43eb0125d..b1b4388a74 100644
--- a/libs/ardour/ardour/types.h
+++ b/libs/ardour/ardour/types.h
@@ -441,6 +441,11 @@ namespace ARDOUR {
 		MixerOrdered
 	};
 
+	enum LayerModel {
+		LaterHigher,
+		Manual
+	};
+
 	enum ListenPosition {
 		AfterFaderListen,
 		PreFaderListen
@@ -633,6 +638,7 @@ std::istream& operator>>(std::istream& o, ARDOUR::PFLPosition& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::AFLPosition& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::RemoteModel& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::ListenPosition& sf);
+std::istream& operator>>(std::istream& o, ARDOUR::LayerModel& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::InsertMergePolicy& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::SyncSource& sf);
 std::istream& operator>>(std::istream& o, ARDOUR::ShuttleBehaviour& sf);
@@ -652,6 +658,7 @@ std::ostream& operator<<(std::ostream& o, const ARDOUR::PFLPosition& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::AFLPosition& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::RemoteModel& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::ListenPosition& sf);
+std::ostream& operator<<(std::ostream& o, const ARDOUR::LayerModel& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::InsertMergePolicy& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::SyncSource& sf);
 std::ostream& operator<<(std::ostream& o, const ARDOUR::ShuttleBehaviour& sf);
diff --git a/libs/ardour/enums.cc b/libs/ardour/enums.cc
index b5a7447ab8..a1cf8d090c 100644
--- a/libs/ardour/enums.cc
+++ b/libs/ardour/enums.cc
@@ -74,6 +74,7 @@ setup_enum_writer ()
 	AFLPosition _AFLPosition;
 	RemoteModel _RemoteModel;
 	DenormalModel _DenormalModel;
+	LayerModel _LayerModel;
 	InsertMergePolicy _InsertMergePolicy;
 	ListenPosition _ListenPosition;
 	SampleFormat _SampleFormat;
@@ -298,7 +299,11 @@ setup_enum_writer ()
 	*/
 	enum_writer.add_to_hack_table ("EditorOrdered", "MixerOrdered");
 
-        REGISTER_ENUM (InsertMergeReject);
+	REGISTER_ENUM (LaterHigher);
+	REGISTER_ENUM (Manual);
+	REGISTER (_LayerModel);
+
+	REGISTER_ENUM (InsertMergeReject);
         REGISTER_ENUM (InsertMergeRelax);
         REGISTER_ENUM (InsertMergeReplace);
         REGISTER_ENUM (InsertMergeTruncateExisting);
@@ -805,6 +810,19 @@ std::ostream& operator<<(std::ostream& o, const ListenPosition& var)
 	std::string s = enum_2_string (var);
 	return o << s;
 }
+std::istream& operator>>(std::istream& o, LayerModel& var)
+{
+	std::string s;
+	o >> s;
+	var = (LayerModel) string_2_enum (s, var);
+	return o;
+}
+
+std::ostream& operator<<(std::ostream& o, const LayerModel& var)
+{
+	std::string s = enum_2_string (var);
+	return o << s;
+}
 
 std::istream& operator>>(std::istream& o, InsertMergePolicy& var)
 {
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index d121ee04ff..20a2ef0197 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -2333,7 +2333,10 @@ struct RelayerSort {
 void
 Playlist::set_layer (boost::shared_ptr<Region> region, double new_layer)
 {
-	/* Remove the layer we are setting from our region list, and sort it */
+	/* Remove the layer we are setting from our region list, and sort it
+	*  using the layer indeces.
+	*/
+
 	RegionList copy = regions.rlist();
 	copy.remove (region);
 	copy.sort (RelayerSort ());
@@ -2362,6 +2365,12 @@ Playlist::setup_layering_indices (RegionList const & regions)
 	}
 }
 
+struct LaterHigherSort {
+	bool operator () (boost::shared_ptr<Region> a, boost::shared_ptr<Region> b) {
+		return a->position() < b->position();
+	}
+};
+
 /** Take the layering indices of each of our regions, compute the layers
  *  that they should be on, and write the layers back to the regions.
  */
@@ -2396,9 +2405,16 @@ Playlist::relayer ()
 	vector<vector<RegionList> > layers;
 	layers.push_back (vector<RegionList> (divisions));
 
-	/* Sort our regions into layering index order */
+	/* Sort our regions into layering index order (for manual layering) or position order (for later is higher)*/
 	RegionList copy = regions.rlist();
-	copy.sort (RelayerSort ());
+	switch (Config->get_layer_model()) {
+		case LaterHigher:
+			copy.sort (LaterHigherSort ());
+			break;
+		case Manual:
+			copy.sort (RelayerSort ());
+			break;
+	}
 
 	DEBUG_TRACE (DEBUG::Layering, "relayer() using:\n");
 	for (RegionList::iterator i = copy.begin(); i != copy.end(); ++i) {