+Real
+Paper_column::minimum_distance (Grob *left, Grob *right)
+{
+ Drul_array<Grob*> cols (left, right);
+ Drul_array<Skyline> skys = Drul_array<Skyline> (Skyline (RIGHT), Skyline (LEFT));
+
+ Direction d = LEFT;
+ do
+ {
+ Skyline_pair *sp = Skyline_pair::unsmob (cols[d]->get_property ("horizontal-skylines"));
+ if (sp)
+ skys[d] = (*sp)[-d];
+ }
+ while (flip (&d) != LEFT);
+
+ skys[RIGHT].merge (Separation_item::conditional_skyline (right, left));
+
+ return max (0.0, skys[LEFT].distance (skys[RIGHT]));
+}
+
+Interval
+Paper_column::break_align_width (Grob *me)
+{
+ Grob *p = me->get_parent (X_AXIS);
+
+ if (is_musical (me))
+ {
+ me->programming_error ("tried to get break-align-width of a non-musical column");
+ return Interval (0, 0) + me->relative_coordinate (p, X_AXIS);
+ }
+
+ Grob *align = Pointer_group_interface::find_grob (me, ly_symbol2scm ("elements"),
+ Break_alignment_interface::has_interface);
+ if (!align)
+ return Interval (0, 0) + me->relative_coordinate (p, X_AXIS);
+
+ return align->extent (p, X_AXIS);
+}
+