2 separating-group-spanner.cc -- implement Separating_group_spanner
4 source file of the GNU LilyPond music typesetter
6 (c) 1998--2004 Han-Wen Nienhuys <hanwen@cs.uu.nl>
10 #include "separating-group-spanner.hh"
12 #include "separation-item.hh"
13 #include "paper-column.hh"
14 #include "output-def.hh"
15 #include "dimensions.hh"
16 #include "group-interface.hh"
19 Separating_group_spanner::find_rods (Item * r, SCM next, Real padding)
23 This is an inner loop: look for the first normal (unbroken) Left
24 grob. This looks like an inner loop (ie. quadratic total), but in
25 most cases, the interesting L will just be the first entry of
26 NEXT, making it linear in most of the cases.
28 if (Separation_item::width (r).is_empty ())
32 for (; scm_is_pair (next); next = scm_cdr (next))
34 Item *l = dynamic_cast<Item*> (unsmob_grob (scm_car ( next)));
35 Item *lb = l->find_prebroken_piece (RIGHT);
39 Interval li (Separation_item::width (lb));
40 Interval ri (Separation_item::conditional_width (r, lb));
41 if (!li.is_empty () && !ri.is_empty ())
45 rod.item_l_drul_[LEFT] = lb;
46 rod.item_l_drul_[RIGHT] = r;
48 rod.distance_ = li[RIGHT] - ri[LEFT] + padding;
53 Interval li (Separation_item::width (l));
54 Interval ri (Separation_item::conditional_width (r, l));
55 if (!li.is_empty () && !ri.is_empty ())
59 rod.item_l_drul_[LEFT] =l;
60 rod.item_l_drul_[RIGHT]=r;
62 rod.distance_ = li[RIGHT] - ri[LEFT] + padding;
69 this grob doesn't cause a constraint. We look further until we
76 MAKE_SCHEME_CALLBACK (Separating_group_spanner,set_spacing_rods,1);
78 Separating_group_spanner::set_spacing_rods (SCM smob)
80 Grob*me = unsmob_grob (smob);
83 Ugh: padding is added doubly, also for SeparationItem
85 Real padding = robust_scm2double (me->get_property ("padding"), 0.1);
87 for (SCM s = me->get_property ("elements"); scm_is_pair (s) && scm_is_pair (scm_cdr (s)); s = scm_cdr (s))
90 Order of elements is reversed!
92 SCM elt = scm_car (s);
93 Item *r = unsmob_item (elt);
99 = dynamic_cast<Item*> (r->find_prebroken_piece (LEFT));
101 find_rods (r, scm_cdr (s), padding);
103 find_rods (rb, scm_cdr (s), padding);
106 return SCM_UNSPECIFIED ;
110 Separating_group_spanner::add_spacing_unit (Grob* me ,Item*i)
112 Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), i);
113 me->add_dependency (i);
120 ADD_INTERFACE (Separating_group_spanner,"separation-spanner-interface",
121 "A spanner that calculates spacing constraints (\"rods\") "
122 "using the @code{separation-item-interface} grobs in @code{elements}.",