lily/extender-engraver.cc

   1 /*
   2   extender-engraver.cc -- implement Extender_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1999--2004 Glen Prideaux <glenprideaux@iname.com>,
   7                   Han-Wen Nienhuys <hanwen@cs.uu.nl>,
   8                   Jan Nieuwenhuizen <janneke@gnu.org>
   9 */
  10
  11 #include "context.hh"
  12 #include "engraver.hh"
  13 #include "group-interface.hh"
  14 #include "item.hh"
  15 #include "lyric-extender.hh"
  16 #include "note-head.hh"
  17 #include "warn.hh"
  18
  19 class Extender_engraver : public Engraver
  20 {
  21   Music *ev_;
  22   Spanner *extender_;
  23   Spanner *pending_extender_;
  24
  25 public:
  26   TRANSLATOR_DECLARATIONS (Extender_engraver);
  27
  28 protected:
  29   virtual void acknowledge_grob (Grob_info);
  30   virtual void finalize ();
  31   virtual bool try_music (Music*);
  32   virtual void stop_translation_timestep ();
  33   virtual void process_music ();
  34 };
  35
  36
  37 Extender_engraver::Extender_engraver ()
  38 {
  39   extender_ = 0;
  40   pending_extender_ = 0;
  41   ev_ = 0;
  42 }
  43
  44 bool
  45 Extender_engraver::try_music (Music *r)
  46 {
  47   if (!ev_)
  48     {
  49       ev_ = r;
  50       return true;
  51     }
  52   return false;
  53 }
  54
  55 void
  56 Extender_engraver::process_music ()
  57 {
  58   if (ev_)
  59     extender_ = make_spanner ("LyricExtender", ev_->self_scm ());
  60 }
  61
  62 void
  63 Extender_engraver::acknowledge_grob (Grob_info i)
  64 {
  65   Item *item = dynamic_cast<Item*> (i.grob_);
  66
  67   if (item
  68       && item->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  69     {
  70       if (extender_)
  71         extender_->set_bound (LEFT, item);
  72
  73       if (pending_extender_)
  74         pending_extender_->set_bound (RIGHT, item);
  75     }
  76 }
  77
  78 void
  79 Extender_engraver::stop_translation_timestep ()
  80 {
  81   if (pending_extender_ && pending_extender_->get_bound (RIGHT))
  82     pending_extender_ = 0;
  83
  84   if (extender_ || pending_extender_)
  85     {
  86       Context *voice = get_voice_to_lyrics (context ());
  87       Grob *h = voice ? get_current_note_head (voice) : 0;
  88       Grob *r = voice ? get_current_rest (voice) : 0;
  89
  90       if (h)
  91         {
  92           if (extender_)
  93             Pointer_group_interface::add_grob (extender_,
  94                                                ly_symbol2scm ("heads"), h);
  95           if (pending_extender_)
  96             Pointer_group_interface::add_grob (pending_extender_,
  97                                                ly_symbol2scm ("heads"), h);
  98         }
  99       else if (r && pending_extender_)
 100         /* Rest: stop right here. */
 101         pending_extender_->set_bound (RIGHT, r);
 102
 103       if (extender_ && !r)
 104         {
 105           pending_extender_ = extender_;
 106           extender_ = 0;
 107         }
 108     }
 109
 110   ev_ = 0;
 111 }
 112
 113 void
 114 completize_extender (Spanner *sp)
 115 {
 116   if (!sp->get_bound (RIGHT))
 117     {
 118       SCM heads = sp->get_property ("heads");
 119       if (ly_c_pair_p (heads))
 120         {
 121           Item *it = dynamic_cast<Item*> (unsmob_grob (ly_car (heads)));
 122           if (it)
 123             sp->set_bound (RIGHT, it);
 124         }
 125     }
 126 }
 127
 128 void
 129 Extender_engraver::finalize ()
 130 {
 131   if (extender_)
 132     {
 133       completize_extender (extender_);
 134
 135       if (!extender_->get_bound (RIGHT))
 136         extender_->warning (_ ("unterminated extender"));
 137       extender_ = 0;
 138     }
 139
 140   if (pending_extender_)
 141     {
 142       completize_extender (pending_extender_);
 143
 144       if (!pending_extender_->get_bound (RIGHT))
 145         pending_extender_->warning (_ ("unterminated extender"));
 146       pending_extender_ =0;
 147     }
 148 }
 149
 150
 151 ENTER_DESCRIPTION (Extender_engraver,
 152 /* descr */       "Create lyric extenders",
 153 /* creats*/       "LyricExtender",
 154 /* accepts */     "extender-event",
 155 /* acks  */       "lyric-syllable-interface",
 156 /* reads */       "",
 157 /* write */       "");