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"
11 #include "separation-item.hh"
12 #include "paper-column.hh"
13 #include "output-def.hh"
14 #include "dimensions.hh"
15 #include "group-interface.hh"
18 Separating_group_spanner::find_rods (Item * r, SCM next, Real padding)
22 This is an inner loop: look for the first normal (unbroken) Left
23 grob. This looks like an inner loop (ie. quadratic total), but in
24 most cases, the interesting L will just be the first entry of
25 NEXT, making it linear in most of the cases.
27 if (Separation_item::width (r).is_empty ())
31 for (; ly_c_pair_p (next); next = ly_cdr (next))
33 Item *l = dynamic_cast<Item*> (unsmob_grob (ly_car ( next)));
34 Item *lb = l->find_prebroken_piece (RIGHT);
38 Interval li (Separation_item::width (lb));
39 Interval ri (Separation_item::conditional_width (r, lb));
40 if (!li.is_empty () && !ri.is_empty ())
44 rod.item_l_drul_[LEFT] = lb;
45 rod.item_l_drul_[RIGHT] = r;
47 rod.distance_ = li[RIGHT] - ri[LEFT] + padding;
52 Interval li (Separation_item::width (l));
53 Interval ri (Separation_item::conditional_width (r, l));
54 if (!li.is_empty () && !ri.is_empty ())
58 rod.item_l_drul_[LEFT] =l;
59 rod.item_l_drul_[RIGHT]=r;
61 rod.distance_ = li[RIGHT] - ri[LEFT] + padding;
68 this grob doesn't cause a constraint. We look further until we
75 MAKE_SCHEME_CALLBACK (Separating_group_spanner,set_spacing_rods,1);
77 Separating_group_spanner::set_spacing_rods (SCM smob)
79 Grob*me = unsmob_grob (smob);
82 Ugh: padding is added doubly, also for SeparationItem
84 Real padding = robust_scm2double (me->get_property ("padding"), 0.1);
86 for (SCM s = me->get_property ("elements"); ly_c_pair_p (s) && ly_c_pair_p (ly_cdr (s)); s = ly_cdr (s))
89 Order of elements is reversed!
92 Item *r = unsmob_item (elt);
98 = dynamic_cast<Item*> (r->find_prebroken_piece (LEFT));
100 find_rods (r, ly_cdr (s), padding);
102 find_rods (rb, ly_cdr (s), padding);
105 return SCM_UNSPECIFIED ;
109 Separating_group_spanner::add_spacing_unit (Grob* me ,Item*i)
111 Pointer_group_interface::add_grob (me, ly_symbol2scm ("elements"), i);
112 me->add_dependency (i);
119 ADD_INTERFACE (Separating_group_spanner,"separation-spanner-interface",
120 "A spanner that calculates spacing constraints (\"rods\") "
121 "using the @code{separation-item-interface} grobs in @code{elements}.",