major chunk of the region layering editor from 2.X, fwd-ported to 3.0

git-svn-id: svn://localhost/ardour2/branches/3.0@7689 d708f5d6-7413-0410-9779-e7cbd77b26cf

2 files changed, 19 insertions, 3 deletions

diff --git a/libs/ardour/ardour/playlist.h b/libs/ardour/ardour/playlist.h
index 624f0a3da1..6473211126 100644
--- a/libs/ardour/ardour/playlist.h
+++ b/libs/ardour/ardour/playlist.h
@@ -144,6 +144,7 @@ public:
 	const RegionListProperty& region_list () const { return regions; }
 
 	RegionList*                regions_at (framepos_t frame);
+        uint32_t                   count_regions_at (framepos_t);
 	RegionList*                regions_touched (framepos_t start, framepos_t end);
 	RegionList*                regions_to_read (framepos_t start, framepos_t end);
 	boost::shared_ptr<Region>  find_region (const PBD::ID&) const;
@@ -326,7 +327,7 @@ public:
 	bool add_region_internal (boost::shared_ptr<Region>, framepos_t position);
 
 	int remove_region_internal (boost::shared_ptr<Region>);
-	RegionList *find_regions_at (framepos_t frame);
+	RegionList *find_regions_at (framepos_t);
 	void copy_regions (RegionList&) const;
 	void partition_internal (framepos_t start, framepos_t end, bool cutting, RegionList& thawlist);
 
diff --git a/libs/ardour/playlist.cc b/libs/ardour/playlist.cc
index 93cfbab1fc..9c980ff735 100644
--- a/libs/ardour/playlist.cc
+++ b/libs/ardour/playlist.cc
@@ -1665,6 +1665,21 @@ Playlist::regions_at (framepos_t frame)
 	return find_regions_at (frame);
 }
 
+uint32_t
+Playlist::count_regions_at (framepos_t frame)
+{
+	RegionLock rlock (this);
+	uint32_t cnt = 0;
+
+	for (RegionList::iterator i = regions.begin(); i != regions.end(); ++i) {
+		if ((*i)->covers (frame)) {
+			cnt++;
+		}
+	}
+
+	return cnt;
+}
+
 boost::shared_ptr<Region>
 Playlist::top_region_at (framepos_t frame)
 
@@ -2463,10 +2478,10 @@ Playlist::relayer ()
 void
 Playlist::raise_region (boost::shared_ptr<Region> region)
 {
-	uint32_t rsz = regions.size();
+	uint32_t top = regions.size() - 1;
 	layer_t target = region->layer() + 1U;
 
-	if (target >= rsz) {
+	if (target >= top) {
 		/* its already at the effective top */
 		return;
 	}