More reliable test for line-beginning grobs.

This improves the accuracy of pure-height calculations, particulary
when treble clefs are involved.

diff --git a/lily/axis-group-interface.cc b/lily/axis-group-interface.cc
index d14a56c08440ebdfecfff635ba1c6469272b28fc..87abab3a2f845484a9d9c6c26d2a3c08d92ec804 100644 (file)
--- a/lily/axis-group-interface.cc
+++ b/lily/axis-group-interface.cc
@@ -160,7 +160,7 @@ Axis_group_interface::adjacent_pure_heights (SCM smob)
              && !to_boolean (it->get_property ("cross-staff")))
            {
              Interval dims = items[j]->pure_height (common, start, end);
-             Interval &target_iv = it->pure_is_visible (start-1, end) ? mid_line_iv : begin_line_iv;
+             Interval &target_iv = start == it->get_column ()->get_rank () ? begin_line_iv : mid_line_iv;
 
              if (!dims.is_empty ())
                target_iv.unite (dims);