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 "warn.hh"
  12 #include "lyric-extender.hh"
  13 #include "item.hh"
  14 #include "engraver.hh"
  15 #include "context.hh"
  16 #include "group-interface.hh"
  17
  18 class Extender_engraver : public Engraver
  19 {
  20   Music* ev_;
  21   Spanner* extender_;
  22   Spanner * pending_extender_;
  23 public:
  24   TRANSLATOR_DECLARATIONS (Extender_engraver);
  25
  26 protected:
  27   virtual void acknowledge_grob (Grob_info);
  28   virtual void finalize ();
  29   virtual bool try_music (Music*);
  30   virtual void stop_translation_timestep ();
  31   virtual void process_music ();
  32 private:
  33
  34 };
  35
  36
  37
  38
  39 Extender_engraver::Extender_engraver ()
  40 {
  41   extender_ = 0;
  42   pending_extender_ = 0;
  43   ev_ = 0;
  44 }
  45
  46 bool
  47 Extender_engraver::try_music (Music* r)
  48 {
  49   if (ev_)
  50     return false;
  51
  52   ev_ = r;
  53   return true;
  54 }
  55
  56
  57 void
  58 Extender_engraver::process_music ()
  59 {
  60   if (ev_)
  61     {
  62       extender_ = make_spanner ("LyricExtender", ev_->self_scm ());
  63     }
  64 }
  65
  66
  67 void
  68 Extender_engraver::acknowledge_grob (Grob_info i)
  69 {
  70   Item * item =  dynamic_cast<Item*> (i.grob_);
  71
  72   if (item
  73       && item->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  74     {
  75       if (extender_)
  76         extender_->set_bound (LEFT, item);
  77
  78       if (pending_extender_)
  79         pending_extender_->set_bound (RIGHT, item);
  80     }
  81 }
  82
  83 void
  84 Extender_engraver::stop_translation_timestep ()
  85 {
  86   if (pending_extender_ && pending_extender_->get_bound (RIGHT))
  87     {
  88       pending_extender_ = 0;
  89     }
  90
  91   if (extender_ || pending_extender_)
  92     {
  93       Context *voice = get_voice_to_lyrics (context ());
  94       Grob* h =  (voice) ? get_current_note_head (voice) : 0;
  95
  96       if (h)
  97         {
  98           if (extender_)
  99             Pointer_group_interface::add_grob (extender_,
 100                                                ly_symbol2scm ("heads"), h);
 101           if (pending_extender_)
 102             Pointer_group_interface::add_grob (pending_extender_,
 103                                                ly_symbol2scm ("heads"), h);
 104         }
 105
 106       if (extender_)
 107         {
 108           pending_extender_ = extender_;
 109           extender_ = 0;
 110         }
 111     }
 112
 113   ev_ = 0;
 114 }
 115
 116 void
 117 completize_extender (Spanner* sp)
 118 {
 119   if (!sp->get_bound (RIGHT))
 120     {
 121       SCM heads = sp->get_property ("heads");
 122       if (ly_c_pair_p (heads))
 123         {
 124           Item* it = dynamic_cast<Item*> (unsmob_grob (ly_car (heads)));
 125           if (it)
 126             sp->set_bound (RIGHT, it);
 127         }
 128     }
 129 }
 130
 131
 132
 133 void
 134 Extender_engraver::finalize ()
 135 {
 136   if (extender_)
 137     {
 138       completize_extender (extender_);
 139
 140       if (!extender_->get_bound (RIGHT))
 141         extender_->warning (_ ("unterminated extender"));
 142       extender_ = 0;
 143     }
 144
 145   if (pending_extender_)
 146     {
 147       completize_extender (pending_extender_);
 148
 149       if (!pending_extender_->get_bound (RIGHT))
 150           pending_extender_->warning (_("unterminated extender"));
 151       pending_extender_ =0;
 152     }
 153 }
 154
 155
 156
 157
 158
 159 ENTER_DESCRIPTION (Extender_engraver,
 160 /* descr */       "Create lyric extenders",
 161 /* creats*/       "LyricExtender",
 162 /* accepts */     "extender-event",
 163 /* acks  */       "lyric-syllable-interface",
 164 /* reads */       "",
 165 /* write */       "");