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");
  63       announce_grob (extender_, ev_->self_scm ());
  64     }
  65 }
  66
  67
  68 void
  69 Extender_engraver::acknowledge_grob (Grob_info i)
  70 {
  71   Item * item =  dynamic_cast<Item*> (i.grob_);
  72
  73   if (item
  74       && item->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  75     {
  76       if (extender_)
  77         extender_->set_bound (LEFT, item);
  78
  79       if (pending_extender_)
  80         pending_extender_->set_bound (RIGHT, item);
  81     }
  82 }
  83
  84 void
  85 Extender_engraver::stop_translation_timestep ()
  86 {
  87   if (pending_extender_ && pending_extender_->get_bound (RIGHT))
  88     {
  89       typeset_grob (pending_extender_);
  90       pending_extender_ = 0;
  91     }
  92
  93   if (extender_ || pending_extender_)
  94     {
  95       Context *voice = get_voice_to_lyrics (daddy_context_);
  96       Grob* h =  (voice) ? get_current_note_head (voice) : 0;
  97
  98       if (h)
  99         {
 100           if (extender_)
 101             Pointer_group_interface::add_grob (extender_,
 102                                                ly_symbol2scm ("heads"), h);
 103           if (pending_extender_)
 104             Pointer_group_interface::add_grob (pending_extender_,
 105                                                ly_symbol2scm ("heads"), h);
 106         }
 107
 108       if (extender_)
 109         {
 110           pending_extender_ = extender_;
 111           extender_ = 0;
 112         }
 113     }
 114
 115   ev_ = 0;
 116 }
 117
 118 void
 119 completize_extender (Spanner* sp)
 120 {
 121   if (!sp->get_bound (RIGHT))
 122     {
 123       SCM heads = sp->get_property ("heads");
 124       if (is_pair (heads))
 125         {
 126           Item* it = dynamic_cast<Item*> (unsmob_grob (ly_car (heads)));
 127           if (it)
 128             sp->set_bound (RIGHT, it);
 129         }
 130     }
 131 }
 132
 133
 134
 135 void
 136 Extender_engraver::finalize ()
 137 {
 138   if (extender_)
 139     {
 140       completize_extender (extender_);
 141
 142       if (!extender_->get_bound (RIGHT))
 143         extender_->warning (_ ("unterminated extender"));
 144       typeset_grob (extender_);
 145       extender_ = 0;
 146     }
 147
 148   if (pending_extender_)
 149     {
 150       completize_extender (pending_extender_);
 151
 152       if (!pending_extender_->get_bound (RIGHT))
 153           pending_extender_->warning (_("unterminated extender"));
 154       typeset_grob (pending_extender_);
 155       pending_extender_ =0;
 156     }
 157 }
 158
 159
 160
 161
 162
 163 ENTER_DESCRIPTION (Extender_engraver,
 164 /* descr */       "Create lyric extenders",
 165 /* creats*/       "LyricExtender",
 166 /* accepts */     "extender-event",
 167 /* acks  */       "lyric-syllable-interface",
 168 /* reads */       "",
 169 /* write */       "");