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 "warn.hh"
  12 #include "lyric-extender.hh"
  13 #include "item.hh"
  14 #include "engraver.hh"
  15
  16 class Extender_engraver : public Engraver
  17 {
  18   Music* ev_;
  19   Spanner* extender_;
  20   Spanner * finished_extender_;
  21 public:
  22   TRANSLATOR_DECLARATIONS(Extender_engraver);
  23
  24 protected:
  25   virtual void acknowledge_grob (Grob_info);
  26   virtual void finalize ();
  27   virtual bool try_music (Music*);
  28   virtual void stop_translation_timestep ();
  29   virtual void start_translation_timestep ();
  30   virtual void process_music ();
  31 private:
  32
  33 };
  34
  35
  36
  37
  38 Extender_engraver::Extender_engraver ()
  39 {
  40   extender_ = 0;
  41   finished_extender_ = 0;
  42   ev_ = 0;
  43 }
  44
  45 void
  46 Extender_engraver::acknowledge_grob (Grob_info i)
  47 {
  48   Item * item =  dynamic_cast<Item*> (i.grob_);
  49   // -> text_item
  50   if (item && item->internal_has_interface (ly_symbol2scm ("lyric-syllable-interface")))
  51     {
  52       if (extender_)
  53         extender_->set_bound (LEFT, item);
  54
  55       if (finished_extender_ && !finished_extender_->get_bound (RIGHT))
  56         finished_extender_->set_bound (RIGHT, item);
  57     }
  58 }
  59
  60
  61 bool
  62 Extender_engraver::try_music (Music* r)
  63 {
  64   if (ev_)
  65     return false;
  66
  67   ev_ = r;
  68   return true;
  69 }
  70
  71 void
  72 Extender_engraver::finalize ()
  73 {
  74   if (extender_)
  75     {
  76       extender_->warning (_ ("unterminated extender"));
  77       typeset_grob (extender_);
  78       extender_ = 0;
  79     }
  80   if (finished_extender_)
  81     {
  82       finished_extender_->warning (_("unterminated extender"));
  83       typeset_grob (finished_extender_);
  84       finished_extender_ =0;
  85     }
  86 }
  87
  88 void
  89 Extender_engraver::process_music ()
  90 {
  91   if (ev_)
  92     {
  93       extender_ = new Spanner (get_property ("LyricExtender"));
  94       announce_grob (extender_, ev_->self_scm());
  95     }
  96 }
  97
  98
  99 void
 100 Extender_engraver::stop_translation_timestep ()
 101 {
 102   if (finished_extender_ && finished_extender_->get_bound (RIGHT))
 103     {
 104       typeset_grob (finished_extender_);
 105       finished_extender_ = 0;
 106     }
 107
 108   if (finished_extender_ && extender_)
 109     {
 110       programming_error ("Haven't finished extender yet.");
 111       typeset_grob (finished_extender_);
 112       finished_extender_ =0;
 113     }
 114
 115   if (extender_)
 116     finished_extender_ = extender_;
 117   extender_ = 0;
 118 }
 119
 120 void
 121 Extender_engraver::start_translation_timestep ()
 122 {
 123   ev_ = 0;
 124 }
 125
 126
 127 ENTER_DESCRIPTION(Extender_engraver,
 128 /* descr */       "Create lyric extenders",
 129 /* creats*/       "LyricExtender",
 130 /* accepts */     "extender-event",
 131 /* acks  */       "lyric-syllable-interface",
 132 /* reads */       "",
 133 /* write */       "");