+Interval
+Item::pure_height (Grob *g, int start, int end)
+{
+ if (cached_pure_height_valid_)
+ return cached_pure_height_ + pure_relative_y_coordinate (g, start, end);
+
+ cached_pure_height_ = Grob::pure_height (this, start, end);
+ cached_pure_height_valid_ = true;
+ return cached_pure_height_ + pure_relative_y_coordinate (g, start, end);
+}
+
+bool
+Item::less (Grob * const &g1, Grob * const &g2)
+{
+ return dynamic_cast<Item*> (g1)->get_column ()->get_rank () < dynamic_cast<Item*> (g2)->get_column ()->get_rank ();
+}
+