-MAKE_SCHEME_CALLBACK (Self_alignment_interface, avoid_x_colliding_grobs, 2);
-SCM
-Self_alignment_interface::avoid_x_colliding_grobs (SCM smob, SCM o)
-{
- SCM avoided = avoid_colliding_grobs (unsmob_grob (smob), X_AXIS, robust_scm2double (o, 0.0));
- return scm_is_null (avoided) ? o : avoided;
-}
-
-MAKE_SCHEME_CALLBACK (Self_alignment_interface, x_colliding_grobs, 1);
-SCM
-Self_alignment_interface::x_colliding_grobs (SCM smob)
-{
- Grob *me = unsmob_grob (smob);
- extract_grob_set (me, "potential-X-colliding-grobs", pot);
- vector<Grob *> act;
- Direction d = get_grob_direction (me->get_parent (Y_AXIS));
- for (vsize i = 0; i < pot.size (); i++)
- if (d == get_grob_direction (pot[i])
- && to_boolean (pot[i]->get_property ("cross-staff")))
- act.push_back (pot[i]);
-
- SCM grobs_scm = Grob_array::make_array ();
- unsmob_grob_array (grobs_scm)->set_array (act);
-
- return grobs_scm;
-}
-
-SCM
-Self_alignment_interface::avoid_colliding_grobs (Grob *me, Axis a, Real offset)
-{
- extract_grob_set (me, a == X_AXIS ? "X-colliding-grobs" : "Y-colliding-grobs", colls);
- if (!colls.size ())
- return SCM_EOL;
- vector<Interval> ivs;
-
- Item *refp = dynamic_cast<Item *> (common_refpoint_of_array (colls, me, a));
- if (!refp)
- return SCM_EOL;
-
- Interval iv = me->extent (me, a) + offset;
- for (vsize i = 0; i < colls.size (); i++)
- ivs.push_back (colls[i]->extent (refp, a));
-
- Interval_minefield minefield (Interval (iv.center (), iv.center ()), iv.length ());
- for (vsize i = 0; i < ivs.size (); i++)
- minefield.add_forbidden_interval (ivs[i]);
- minefield.solve ();
- Interval pos = minefield.feasible_placements ();
-
- if (pos[LEFT] == pos[RIGHT])
- return SCM_EOL;
-
- Direction col_dir = ((abs (pos[LEFT] - iv.center ())
- + robust_scm2double (me->get_property ("collision-bias"), 0.0))
- > abs (pos[RIGHT] - iv.center ()))
- ? RIGHT
- : LEFT;
-
- return scm_from_double ((pos[col_dir] - (iv.length () / 2)
- + col_dir
- * robust_scm2double (me->get_property ("collision-padding"), 0.0)));
-}
+ if (scm_is_number (self_align))
+ {
+ // Empty extent doesn't mean an error - we simply don't align such grobs.
+ // However, empty extent and non-empty stencil would be suspicious.
+ if (!ext.is_empty ())
+ x -= ext.linear_combination (scm_to_double (self_align));
+ else if (me->get_stencil ())
+ warning (me->name () + " has empty extent and non-empty stencil.");
+ }