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_)
  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
  81   if (finished_extender_)
  82     {
  83       finished_extender_->warning (_("unterminated extender"));
  84       typeset_grob (finished_extender_);
  85       finished_extender_ =0;
  86     }
  87 }
  88
  89 void
  90 Extender_engraver::process_music ()
  91 {
  92   if (ev_)
  93     {
  94       extender_ = new Spanner (get_property ("LyricExtender"));
  95       announce_grob (extender_, ev_->self_scm());
  96     }
  97 }
  98
  99
 100 void
 101 Extender_engraver::stop_translation_timestep ()
 102 {
 103   if (finished_extender_ && finished_extender_->get_bound (RIGHT))
 104     {
 105       typeset_grob (finished_extender_);
 106       finished_extender_ = 0;
 107     }
 108
 109   if (finished_extender_ && extender_)
 110     {
 111       programming_error ("Haven't finished extender yet.");
 112       typeset_grob (finished_extender_);
 113       finished_extender_ =0;
 114     }
 115
 116   if (extender_)
 117     finished_extender_ = extender_;
 118   extender_ = 0;
 119 }
 120
 121 void
 122 Extender_engraver::start_translation_timestep ()
 123 {
 124   ev_ = 0;
 125 }
 126
 127
 128 ENTER_DESCRIPTION(Extender_engraver,
 129 /* descr */       "Create lyric extenders",
 130 /* creats*/       "LyricExtender",
 131 /* accepts */     "extender-event",
 132 /* acks  */       "lyric-syllable-interface",
 133 /* reads */       "",
 134 /* write */       "");