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--2003 Glen Prideaux <glenprideaux@iname.com>,
   7                   Han-Wen Nienhuys <hanwen@cs.uu.nl>,
   8                   Jan Nieuwenhuizen <janneke@gnu.org>
   9 */
  10
  11 #include "flower-proto.hh"
  12 #include "event.hh"
  13 #include "lyric-extender.hh"
  14 #include "paper-column.hh"
  15 #include "item.hh"
  16 #include "engraver.hh"
  17 #include "drul-array.hh"
  18 #include "lyric-extender.hh"
  19 #include "pqueue.hh"
  20
  21
  22 /**
  23   Generate an centred extender.  Should make a Extender_spanner that
  24   typesets a nice centred extender of varying length depending on the
  25   gap between syllables.
  26
  27   We remember the last Item that come across. When we get a
  28   event, we create the spanner, and attach the left point to the
  29   last lyrics, and the right point to any lyrics we receive by
  30   then.  */
  31 class Extender_engraver : public Engraver
  32 {
  33   Grob *last_lyric_;
  34   Grob *current_lyric_;
  35   Music* req_;
  36   Spanner* extender_;
  37 public:
  38   TRANSLATOR_DECLARATIONS(Extender_engraver);
  39
  40 protected:
  41   virtual void acknowledge_grob (Grob_info);
  42   virtual void finalize ();
  43   virtual bool try_music (Music*);
  44   virtual void stop_translation_timestep ();
  45   virtual void start_translation_timestep ();
  46   virtual void process_music ();
  47 private:
  48
  49 };
  50
  51
  52
  53
  54 Extender_engraver::Extender_engraver ()
  55 {
  56   current_lyric_ = 0;
  57   last_lyric_ = 0;
  58   extender_ = 0;
  59   req_ = 0;
  60 }
  61
  62 void
  63 Extender_engraver::acknowledge_grob (Grob_info i)
  64 {
  65   // -> text_item
  66   if (i.grob_->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  67     {
  68       current_lyric_ = i.grob_;
  69       if (extender_
  70           && !extender_->get_bound (RIGHT)
  71             )
  72           {
  73             Lyric_extender::set_textitem (extender_, RIGHT, dynamic_cast<Item*> (i.grob_));
  74           }
  75     }
  76 }
  77
  78
  79 bool
  80 Extender_engraver::try_music (Music* r)
  81 {
  82   if (req_)
  83     return false;
  84
  85   req_ = r;
  86       return true;
  87 }
  88
  89 void
  90 Extender_engraver::finalize ()
  91 {
  92   if (extender_)
  93     {
  94       req_->origin ()->warning (_ ("unterminated extender"));
  95       extender_->set_bound (RIGHT, unsmob_grob (get_property ("currentCommandColumn")));
  96     }
  97 }
  98
  99 void
 100 Extender_engraver::process_music ()
 101 {
 102   if (req_ && ! extender_)
 103     {
 104       if (!last_lyric_)
 105         {
 106           req_->origin ()->warning (_ ("Nothing to connect extender to on the left.  Ignoring extender event."));
 107           return;
 108         }
 109
 110       extender_ = new Spanner (get_property ("LyricExtender"));
 111
 112
 113       Lyric_extender::set_textitem (extender_, LEFT, last_lyric_);
 114       announce_grob(extender_, req_->self_scm());
 115     }
 116 }
 117
 118
 119 void
 120 Extender_engraver::stop_translation_timestep ()
 121 {
 122   if (extender_)
 123     {
 124       typeset_grob (extender_);
 125       extender_ = 0;
 126     }
 127
 128   if (current_lyric_)
 129     {
 130       last_lyric_ = current_lyric_;
 131       current_lyric_ =0;
 132     }
 133 }
 134
 135 void
 136 Extender_engraver::start_translation_timestep ()
 137 {
 138   req_ = 0;
 139 }
 140
 141
 142 ENTER_DESCRIPTION(Extender_engraver,
 143 /* descr */       "Create lyric extenders",
 144 /* creats*/       "LyricExtender",
 145 /* accepts */     "extender-event",
 146 /* acks  */      "lyric-syllable-interface",
 147 /* reads */       "",
 148 /* write */       "");