lily/auto-change-iterator.cc

   1 /*
   2   auto-change-iterator.cc -- implement  Auto_change_iterator
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999--2003 Han-Wen Nienhuys <hanwen@cs.uu.nl>
   7
   8  */
   9
  10 #include "music.hh"
  11 #include "auto-change-iterator.hh"
  12 #include "translator-group.hh"
  13 #include "event.hh"
  14
  15
  16
  17 void
  18 Auto_change_iterator::change_to (Music_iterator *it, String to_type,
  19                                  String to_id)
  20 {
  21   Translator_group * current = it->report_to ();
  22   Translator_group * last = 0;
  23
  24   /*
  25     Cut & Paste from Change_iterator (ugh).
  26
  27     TODO: abstract this function
  28    */
  29
  30   /* find the type  of translator that we're changing.
  31
  32      If \translator Staff = bass, then look for Staff = *
  33    */
  34   while (current && current->type_string_ != to_type)
  35     {
  36       last = current;
  37       current = current->daddy_trans_;
  38     }
  39
  40   if (current && current->id_string_ == to_id)
  41     {
  42       String msg;
  43       msg += _ ("Can't switch translators, I'm there already");
  44     }
  45
  46   if (current)
  47     if (last)
  48       {
  49         Translator_group * dest =
  50           it->report_to ()->find_create_translator (to_type, to_id);
  51         current->remove_translator (last);
  52         dest->add_used_group_translator (last);
  53       }
  54     else
  55       {
  56         /*
  57           We could change the current translator's id, but that would make
  58           errors hard to catch
  59
  60            last->translator_id_string_  = get_change ()->change_to_id_string_;
  61         */
  62         //      error (_ ("I'm one myself"));
  63       }
  64   else
  65     ; //    error (_ ("none of these in my family"));
  66
  67 }
  68
  69 /*
  70   Look ahead to find first pitches to determine staff position.
  71   WARNING: this means that
  72
  73   \autochange Staff \notes { .... \context Staff = otherstaff { .. } .. }
  74
  75   will confuse the autochanger, since it will not notice that the
  76   music for OTHERSTAFF is not his.
  77
  78   PRECONDITION: this->ok () holds.
  79 */
  80 Array<Pitch>
  81 Auto_change_iterator::pending_pitch (Moment m) const
  82 {
  83   Music_iterator * iter = child_iter_ ->clone ();
  84   Array<Pitch> ps;
  85   while (1)
  86     {
  87       SCM muses = iter->get_pending_events (m);
  88       for (SCM s = muses; gh_pair_p (s); s=ly_cdr (s))
  89         {
  90           Music * m = unsmob_music (ly_car (s));
  91           if (m && m->is_mus_type ("note-event"))
  92             {
  93               ps.push (*unsmob_pitch (m->get_mus_property ("pitch")));
  94             }
  95         }
  96
  97       if (ps.size ())
  98         break;
  99
 100       iter->skip (m);
 101       if (!iter->ok ())
 102         break;
 103
 104       m = iter->pending_moment ();
 105     }
 106
 107   scm_gc_unprotect_object (iter->self_scm());
 108
 109   return ps;
 110 }
 111
 112 void
 113 Auto_change_iterator::process (Moment m)
 114 {
 115   /*
 116     first we get the pitches, then we do the real work.
 117     Music_wrapper_iterator::process () might process (and throw away)
 118     pitches we need.  */
 119   Array<Pitch> ps = pending_pitch (m);
 120
 121   Music_wrapper_iterator::process (m);
 122   if (ps.size ())
 123     {
 124       Pitch p = ps[0];
 125       Direction s = Direction (sign (p.steps ()));
 126       /*
 127         Don't change for central C.
 128
 129         TODO: make this tunable somehow. Sometimes, you'd want to
 130         switch for C.C. as well.
 131
 132       */
 133       if (s && s != where_dir_)
 134         {
 135           where_dir_ = s;
 136           String to_id = (s >= 0) ?  "up" : "down";
 137           String wh = ly_scm2string (get_music ()->get_mus_property ("what"));
 138           change_to (child_iter_, wh, to_id);
 139         }
 140     }
 141 }
 142
 143 Auto_change_iterator::Auto_change_iterator ()
 144 {
 145   where_dir_ = CENTER;
 146 }
 147
 148 IMPLEMENT_CTOR_CALLBACK (Auto_change_iterator);