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--2005 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 void completize_extender (Spanner *sp);
  20
  21 class Extender_engraver : public Engraver
  22 {
  23   Music *ev_;
  24   Spanner *extender_;
  25   Spanner *pending_extender_;
  26
  27 public:
  28   TRANSLATOR_DECLARATIONS (Extender_engraver);
  29
  30 protected:
  31   virtual void acknowledge_grob (Grob_info);
  32   virtual void finalize ();
  33   virtual bool try_music (Music *);
  34   virtual void stop_translation_timestep ();
  35   virtual void process_music ();
  36 };
  37
  38 Extender_engraver::Extender_engraver ()
  39 {
  40   extender_ = 0;
  41   pending_extender_ = 0;
  42   ev_ = 0;
  43 }
  44
  45 bool
  46 Extender_engraver::try_music (Music *r)
  47 {
  48   if (!ev_)
  49     {
  50       ev_ = r;
  51       return true;
  52     }
  53   return false;
  54 }
  55
  56 void
  57 Extender_engraver::process_music ()
  58 {
  59   if (ev_)
  60     extender_ = make_spanner ("LyricExtender", ev_->self_scm ());
  61 }
  62
  63 void
  64 Extender_engraver::acknowledge_grob (Grob_info i)
  65 {
  66   Item *item = dynamic_cast<Item *> (i.grob_);
  67
  68   if (item
  69       && item->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  70     {
  71       if (extender_)
  72         extender_->set_bound (LEFT, item);
  73
  74       if (pending_extender_)
  75         {
  76           pending_extender_->set_property ("next", item->self_scm ());
  77           completize_extender (pending_extender_);
  78           pending_extender_ = 0;
  79         }
  80     }
  81 }
  82
  83 void
  84 Extender_engraver::stop_translation_timestep ()
  85 {
  86   if (extender_ || pending_extender_)
  87     {
  88       Context *voice = get_voice_to_lyrics (context ());
  89       Grob *h = voice ? get_current_note_head (voice) : 0;
  90
  91       if (h)
  92         {
  93           if (extender_)
  94             {
  95               Pointer_group_interface::add_grob (extender_,
  96                                                  ly_symbol2scm ("heads"), h);
  97             }
  98
  99           if (pending_extender_)
 100             {
 101               Pointer_group_interface::add_grob (pending_extender_,
 102                                                  ly_symbol2scm ("heads"), h);
 103             }
 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 (scm_is_pair (heads))
 123         {
 124           Item *it = dynamic_cast<Item *> (unsmob_grob (scm_car (heads)));
 125           if (it)
 126             sp->set_bound (RIGHT, it);
 127         }
 128     }
 129 }
 130
 131 void
 132 Extender_engraver::finalize ()
 133 {
 134   if (extender_)
 135     {
 136       completize_extender (extender_);
 137
 138       if (!extender_->get_bound (RIGHT))
 139         extender_->warning (_ ("unterminated extender"));
 140       extender_ = 0;
 141     }
 142
 143   if (pending_extender_)
 144     {
 145       completize_extender (pending_extender_);
 146
 147       if (!pending_extender_->get_bound (RIGHT))
 148         pending_extender_->warning (_ ("unterminated extender"));
 149       pending_extender_ = 0;
 150     }
 151 }
 152
 153 ADD_TRANSLATOR (Extender_engraver,
 154                 /* descr */ "Create lyric extenders",
 155                 /* creats*/ "LyricExtender",
 156                 /* accepts */ "extender-event",
 157                 /* acks  */ "lyric-syllable-interface",
 158                 /* reads */ "",
 159                 /* write */ "");