Fix (sort of) the ending position of a line-spanner over a line break.

diff --git a/lily/line-spanner.cc b/lily/line-spanner.cc
index d764a3b717041b909c7f3564660d16913e64e018..4e75d0382a1d19e487923cac5e4466326f89a398 100644 (file)
--- a/lily/line-spanner.cc
+++ b/lily/line-spanner.cc
@@ -92,7 +92,8 @@ Line_spanner::calc_bound_info (SCM smob, Direction dir)
 
       Real extra_dy = robust_scm2double (me->get_property ("extra-dy"),
                                         0.0);
-         
+
+      Grob *common_y = me->common_refpoint (me->get_bound (dir), Y_AXIS);
       if (me->get_bound (dir)->break_status_dir ())
        {
          Spanner *next_sp = me->broken_neighbor (dir);
@@ -109,13 +110,21 @@ Line_spanner::calc_bound_info (SCM smob, Direction dir)
          Grob *next_common_y = next_sp->common_refpoint (next_bound, X_AXIS);
          Interval next_ext = next_bound->extent (next_common_y, Y_AXIS);
 
-         y = next_ext.center ();
+         /* FIXME: this is not a real solution. We want to know would be the
+            y-position of the right bound (relative to the line-spanner)
+            if it belonged to the same system
+            as the left bound. What we do instead is to calculate the
+            y-position of the right bound relative to the VerticalAlignment
+            (of the next System!) and subtract the y-position of the
+            line-spanner relative to the VerticalAlignment (of this System!).
+            This works as long as the distance between staves is approximately
+            the same before and after breaking. */
+         y = next_ext.center () - me->relative_coordinate (common_y, Y_AXIS);
        }
       else
        {
-         Grob *commony = me->common_refpoint (me->get_bound (dir), Y_AXIS);
-         y = me->get_bound (dir)->extent (commony, Y_AXIS).center ();
-         details = scm_acons (ly_symbol2scm ("common-Y"), commony->self_scm (), details);
+         y = me->get_bound (dir)->extent (common_y, Y_AXIS).center ();
+         details = scm_acons (ly_symbol2scm ("common-Y"), common_y->self_scm (), details);
        }
 
       y += dir * extra_dy / 2;