prevent formation of new xfades when two regions are precisely co-terminal, and invalidate existing xfades if their participants become co-terminal

git-svn-id: svn://localhost/ardour2/branches/3.0@8605 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 7 insertions, 0 deletions

diff --git a/libs/ardour/crossfade.cc b/libs/ardour/crossfade.cc
index 47b07dc38d..302b19399e 100644
--- a/libs/ardour/crossfade.cc
+++ b/libs/ardour/crossfade.cc
@@ -441,6 +441,13 @@ Crossfade::refresh ()
 		Invalidated (shared_from_this());
 		return false;
 	}
+        
+        /* regions must cannot be identically sized and placed */
+
+        if (_in->position() == _out->position() && _in->length() == _out->length()) {
+		Invalidated (shared_from_this());
+                return false;
+        }
 
 	/* layer ordering cannot change */