lily/extender-engraver.cc

   1 /*
   2   extender-engraver.cc -- implement Extender_engraver
   3
   4   (c) 1999 Glen Prideaux <glenprideaux@iname.com>,
   5   Han-Wen Nienhuys, Jan Nieuwenhuizen.
   6
   7 */
   8
   9 #include "flower-proto.hh"
  10 #include "request.hh"
  11 #include "lyric-extender.hh"
  12 #include "paper-column.hh"
  13 #include "item.hh"
  14 #include "engraver.hh"
  15 #include "drul-array.hh"
  16 #include "lyric-extender.hh"
  17 #include "pqueue.hh"
  18
  19
  20 /**
  21   Generate an centred extender.  Should make a Extender_spanner that
  22   typesets a nice centred extender of varying length depending on the
  23   gap between syllables.
  24
  25   We remember the last Item that come across. When we get a
  26   request, we create the spanner, and attach the left point to the
  27   last lyrics, and the right point to any lyrics we receive by
  28   then.  */
  29 class Extender_engraver : public Engraver
  30 {
  31   Grob *last_lyric_;
  32   Grob *current_lyric_;
  33   Music* req_;
  34   Spanner* extender_;
  35 public:
  36   TRANSLATOR_DECLARATIONS(Extender_engraver);
  37
  38 protected:
  39   virtual void acknowledge_grob (Grob_info);
  40   virtual void finalize ();
  41   virtual bool try_music (Music*);
  42   virtual void stop_translation_timestep ();
  43   virtual void start_translation_timestep ();
  44   virtual void process_music ();
  45 private:
  46
  47 };
  48
  49
  50
  51
  52 Extender_engraver::Extender_engraver ()
  53 {
  54   current_lyric_ = 0;
  55   last_lyric_ = 0;
  56   extender_ = 0;
  57   req_ = 0;
  58 }
  59
  60 void
  61 Extender_engraver::acknowledge_grob (Grob_info i)
  62 {
  63   // -> text_item
  64   if (i.grob_->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  65     {
  66       current_lyric_ = i.grob_;
  67       if (extender_
  68           && !extender_->get_bound (RIGHT)
  69             )
  70           {
  71             Lyric_extender::set_textitem (extender_, RIGHT, dynamic_cast<Item*> (i.grob_));
  72           }
  73     }
  74 }
  75
  76
  77 bool
  78 Extender_engraver::try_music (Music* r)
  79 {
  80   if (req_)
  81     return false;
  82
  83   req_ = r;
  84       return true;
  85 }
  86
  87 void
  88 Extender_engraver::finalize ()
  89 {
  90   if (extender_)
  91     {
  92       req_->origin ()->warning (_ ("unterminated extender"));
  93       extender_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  94     }
  95 }
  96
  97 void
  98 Extender_engraver::process_music ()
  99 {
 100   if (req_ && ! extender_)
 101     {
 102       if (!last_lyric_)
 103         {
 104           req_->origin ()->warning (_ ("Nothing to connect extender to on the left.  Ignoring extender request."));
 105           return;
 106         }
 107
 108       extender_ = new Spanner (get_property ("LyricExtender"));
 109
 110
 111       Lyric_extender::set_textitem (extender_, LEFT, last_lyric_);
 112       announce_grob(extender_, req_->self_scm());
 113     }
 114 }
 115
 116
 117 void
 118 Extender_engraver::stop_translation_timestep ()
 119 {
 120   if (extender_)
 121     {
 122       typeset_grob (extender_);
 123       extender_ = 0;
 124     }
 125
 126   if (current_lyric_)
 127     {
 128       last_lyric_ = current_lyric_;
 129       current_lyric_ =0;
 130     }
 131 }
 132
 133 void
 134 Extender_engraver::start_translation_timestep ()
 135 {
 136   req_ = 0;
 137 }
 138
 139
 140 ENTER_DESCRIPTION(Extender_engraver,
 141 /* descr */       "Create lyric extenders",
 142 /* creats*/       "LyricExtender",
 143 /* accepts */     "extender-event",
 144 /* acks  */      "lyric-syllable-interface",
 145 /* reads */       "",
 146 /* write */       "");