spanner::bounds-width

diff --git a/lily/spanner.cc b/lily/spanner.cc
index c0ac823b02b5329f8c7991b1f019aca551e1512f..f4909f53b2cd69216b5743d481adb8ea6f657626 100644 (file)
--- a/lily/spanner.cc
+++ b/lily/spanner.cc
@@ -384,11 +384,30 @@ unsmob_spanner (SCM s)
   return dynamic_cast<Spanner *> (unsmob_grob (s));
 }
 
+MAKE_SCHEME_CALLBACK(Spanner, bounds_width, 1);
+SCM
+Spanner::bounds_width (SCM grob)
+{
+  Spanner *me = unsmob_spanner (grob);
+
+
+  Grob *common = me->get_bound (LEFT)->common_refpoint (me->get_bound (RIGHT), X_AXIS);
+
+  Interval w (me->get_bound (LEFT)->relative_coordinate (common, X_AXIS),
+             me->get_bound (RIGHT)->relative_coordinate (common, X_AXIS));
+             
+  w -= me->relative_coordinate (common, X_AXIS);
+
+  return ly_interval2scm (w);
+}
+
 ADD_INTERFACE (Spanner,
               "Some objects are horizontally spanned between objects. For\n"
               "example, slur, beam, tie, etc. These grobs form a subtype called\n"
               "@code{Spanner}. All spanners have two span-points (these must be\n"
               "@code{Item} objects), one on the left and one on the right. The left bound is\n"
               "also the X-reference point of the spanner.\n",
-              "minimum-length");
+
+              "minimum-length "
+              );