lily/item.cc

   1 /*
   2   item.cc -- implement Item
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2002 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7 */
   8
   9
  10 #include "paper-score.hh"
  11 #include "warn.hh"
  12 #include "item.hh"
  13 #include "paper-column.hh"
  14 #include "spanner.hh"
  15 #include "lily-guile.hh"
  16 #include "system.hh"
  17 #include "group-interface.hh"
  18
  19 Item::Item (SCM s)
  20   : Grob (s)
  21 {
  22   broken_to_drul_[LEFT] = broken_to_drul_[RIGHT]=0;
  23   Group_interface::add_thing (this, ly_symbol2scm ("interfaces"), ly_symbol2scm ("item-interface"));
  24 }
  25
  26 /**
  27    Item copy ctor.  Copy nothing: everything should be a elt property
  28    or a special purpose pointer (such as broken_to_drul_[]) */
  29 Item::Item (Item const &s)
  30   : Grob (s)
  31 {
  32   broken_to_drul_[LEFT] = broken_to_drul_[RIGHT] =0;
  33 }
  34
  35
  36 bool
  37 Item::breakable_b (Grob*me)
  38 {
  39   if (me->original_)
  40     return false;
  41
  42   if (!dynamic_cast<Item*> (me))
  43     me->programming_error ("only items can be breakable.");
  44
  45   Item * i  =dynamic_cast<Item*> (me->get_parent (X_AXIS));
  46   return (i) ?  Item::breakable_b (i) : to_boolean (me->get_grob_property ("breakable"));
  47 }
  48
  49 Paper_column *
  50 Item::get_column () const
  51 {
  52   Item *parent = dynamic_cast<Item*> (get_parent (X_AXIS));
  53   return parent ? parent->get_column () : 0;
  54 }
  55
  56 System *
  57 Item::get_system () const
  58 {
  59   Grob *g = get_parent (X_AXIS);
  60   return g ?  g->get_system () : 0;
  61 }
  62
  63
  64 void
  65 Item::copy_breakable_items ()
  66 {
  67   Drul_array<Item *> new_copies;
  68   Direction  i=LEFT;
  69   do
  70     {
  71       Grob * dolly = clone ();
  72       Item * item = dynamic_cast<Item*> (dolly);
  73       pscore_->system_->typeset_grob (item);
  74       new_copies[i] =item;
  75     }
  76   while (flip (&i) != LEFT);
  77   broken_to_drul_= new_copies;
  78 }
  79
  80
  81 bool
  82 Item::broken_b () const
  83 {
  84   return broken_to_drul_[LEFT] || broken_to_drul_[RIGHT];
  85 }
  86
  87
  88 /*
  89   Generate items for begin and end-of line.
  90  */
  91 void
  92 Item::discretionary_processing ()
  93 {
  94   if (broken_b ())
  95     return;
  96
  97   if (Item::breakable_b (this))
  98     copy_breakable_items ();
  99 }
 100
 101 Grob*
 102 Item::find_broken_piece (System*l) const
 103 {
 104   if (get_system () == l)
 105     return (Item*) (this);
 106
 107   Direction d = LEFT;
 108   do {
 109     Grob *s = broken_to_drul_[d];
 110     if (s && s->get_system () == l)
 111       return s;
 112   }
 113   while (flip (&d) != LEFT);
 114
 115   return 0;
 116 }
 117
 118
 119 Item*
 120 Item::find_prebroken_piece (Direction d) const
 121 {
 122   Item * me = (Item *) (this);
 123   if (!d)
 124     return me;
 125   return dynamic_cast<Item*> (broken_to_drul_[d]);
 126 }
 127
 128
 129 Direction
 130 Item::break_status_dir () const
 131 {
 132   if (original_)
 133     {
 134       Item * i = dynamic_cast<Item*> (original_);
 135
 136       return (i->broken_to_drul_[LEFT] == this) ? LEFT : RIGHT;
 137     }
 138   else
 139     return CENTER;
 140 }
 141
 142 void
 143 Item::handle_prebroken_dependencies ()
 144 {
 145   Grob::handle_prebroken_dependencies ();
 146
 147   /*
 148     Can't do this earlier, because try_visibility_lambda () might set
 149     the elt property transparent, which would then be copied.
 150
 151     TODO:
 152
 153     give the item to break-visibility itself, so the function can do
 154     more complicated things.
 155   */
 156   SCM vis = get_grob_property ("break-visibility");
 157   if (gh_procedure_p (vis))
 158     {
 159       SCM args = scm_list_n (gh_int2scm (break_status_dir ()), SCM_UNDEFINED);
 160       SCM result = gh_apply (vis, args);
 161       bool trans = gh_scm2bool (ly_car (result));
 162       bool empty = gh_scm2bool (ly_cdr (result));
 163
 164       if (empty && trans)
 165         suicide ();
 166       else if (empty)
 167         {
 168           set_extent (SCM_EOL, X_AXIS);
 169           set_extent (SCM_EOL, Y_AXIS);
 170         }
 171       else if (trans)
 172         set_grob_property ("molecule-callback", SCM_EOL);
 173     }
 174 }
 175
 176 SCM
 177 Item::do_derived_mark ()const
 178 {
 179   if (broken_to_drul_[LEFT])
 180     scm_gc_mark (broken_to_drul_[LEFT]->self_scm ());
 181   if (broken_to_drul_[RIGHT])
 182     scm_gc_mark (broken_to_drul_[RIGHT]->self_scm ());
 183   return SCM_EOL;
 184 }
 185
 186 Item*
 187 unsmob_item (SCM s )
 188 {
 189   return dynamic_cast<Item*> (unsmob_grob (s));
 190 }
 191
 192
 193
 194 ADD_INTERFACE(Item,
 195               "item-interface",
 196               "
 197
 198 Grobs can be distinguished in their role in the horizontal spacing.
 199 Many grobs define constraints on the spacing by their sizes. For
 200 example, note heads, clefs, stems, and all other symbols with a fixed
 201 shape.  These grobs form a subtype called @code{Item}.
 202
 203 ",
 204               "no-spacing-rods break-visibility breakable")