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       typeset_grob (pending_extender_);
  89       pending_extender_ = 0;
  90     }
  91
  92   if (extender_ || pending_extender_)
  93     {
  94       Context *voice = get_voice_to_lyrics (context ());
  95       Grob* h =  (voice) ? get_current_note_head (voice) : 0;
  96
  97       if (h)
  98         {
  99           if (extender_)
 100             Pointer_group_interface::add_grob (extender_,
 101                                                ly_symbol2scm ("heads"), h);
 102           if (pending_extender_)
 103             Pointer_group_interface::add_grob (pending_extender_,
 104                                                ly_symbol2scm ("heads"), h);
 105         }
 106
 107       if (extender_)
 108         {
 109           pending_extender_ = extender_;
 110           extender_ = 0;
 111         }
 112     }
 113
 114   ev_ = 0;
 115 }
 116
 117 void
 118 completize_extender (Spanner* sp)
 119 {
 120   if (!sp->get_bound (RIGHT))
 121     {
 122       SCM heads = sp->get_property ("heads");
 123       if (ly_c_pair_p (heads))
 124         {
 125           Item* it = dynamic_cast<Item*> (unsmob_grob (ly_car (heads)));
 126           if (it)
 127             sp->set_bound (RIGHT, it);
 128         }
 129     }
 130 }
 131
 132
 133
 134 void
 135 Extender_engraver::finalize ()
 136 {
 137   if (extender_)
 138     {
 139       completize_extender (extender_);
 140
 141       if (!extender_->get_bound (RIGHT))
 142         extender_->warning (_ ("unterminated extender"));
 143       typeset_grob (extender_);
 144       extender_ = 0;
 145     }
 146
 147   if (pending_extender_)
 148     {
 149       completize_extender (pending_extender_);
 150
 151       if (!pending_extender_->get_bound (RIGHT))
 152           pending_extender_->warning (_("unterminated extender"));
 153       typeset_grob (pending_extender_);
 154       pending_extender_ =0;
 155     }
 156 }
 157
 158
 159
 160
 161
 162 ENTER_DESCRIPTION (Extender_engraver,
 163 /* descr */       "Create lyric extenders",
 164 /* creats*/       "LyricExtender",
 165 /* accepts */     "extender-event",
 166 /* acks  */       "lyric-syllable-interface",
 167 /* reads */       "",
 168 /* write */       "");