+
+ extract_grob_set (beam_grob, "normal-stems", stems);
+ Interval_t<int> vertical_span;
+ for (vsize j = 0; j < stems.size (); j++)
+ {
+ int vag = Grob::get_vertical_axis_group_index (stems[j]);
+ if (vag >= 0)
+ vertical_span.add_point (vag);
+ }