lily/glissando-engraver.cc

   1 /*
   2   note-head-line-engraver.cc -- implement Note_head_line_engraver
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 2000--2003 Jan Nieuwenhuizen <janneke@gnu.org>
   7  */
   8
   9 #include "warn.hh"
  10 #include "event.hh"
  11 #include "spanner.hh"
  12 #include "rhythmic-head.hh"
  13 #include "engraver.hh"
  14
  15 /**
  16    Create line-spanner grobs for glissandi lines that connect note
  17    heads.
  18 */
  19 class Glissando_engraver : public Engraver
  20 {
  21 public:
  22   TRANSLATOR_DECLARATIONS(Glissando_engraver);
  23
  24 protected:
  25   virtual void acknowledge_grob (Grob_info);
  26   virtual void finalize ();
  27   virtual void stop_translation_timestep ();
  28   virtual bool try_music (Music *);
  29   virtual void process_music ();
  30 private:
  31   Spanner *line_;
  32   Spanner *last_line_;
  33   Music* event_;
  34 };
  35
  36 Glissando_engraver::Glissando_engraver ()
  37 {
  38   last_line_ = line_ = 0;
  39   event_ = 0;
  40 }
  41
  42 bool
  43 Glissando_engraver::try_music (Music* m)
  44 {
  45   if (!event_)
  46     {
  47       event_ = m;
  48       return true;
  49     }
  50   return false;
  51 }
  52
  53 void
  54 Glissando_engraver::process_music ()
  55 {
  56   if (event_)
  57     {
  58       line_ = new Spanner (get_property ("Glissando"));
  59       announce_grob (line_, event_->self_scm ());
  60     }
  61 }
  62
  63
  64 void
  65 Glissando_engraver::acknowledge_grob (Grob_info info)
  66 {
  67   if (Rhythmic_head::has_interface (info.grob_))
  68     {
  69       Grob * g = info.grob_;
  70       if (line_)
  71         line_->set_bound (LEFT, g);
  72
  73       if (last_line_)
  74         last_line_->set_bound (RIGHT, g);
  75     }
  76 }
  77
  78
  79 void
  80 Glissando_engraver::stop_translation_timestep ()
  81 {
  82   if (last_line_ && last_line_->get_bound (RIGHT))
  83     {
  84       typeset_grob (last_line_);
  85       last_line_ =0;
  86     }
  87   if (line_)
  88     {
  89       if ( last_line_)
  90         programming_error ("Overwriting glissando.");
  91       last_line_ = line_;
  92     }
  93   line_ = 0;
  94   event_ = 0;
  95 }
  96
  97 void
  98 Glissando_engraver::finalize ()
  99 {
 100   if (line_)
 101     {
 102       String msg = _("Unterminated glissando.");
 103
 104       if (event_)
 105         event_->origin ()->warning (msg);
 106       else
 107         warning (msg);
 108
 109       line_->suicide ();
 110       line_ =0;
 111     }
 112 }
 113
 114
 115
 116 ENTER_DESCRIPTION(Glissando_engraver,
 117 /* descr */       "Engrave a glissandi",
 118 /* creats*/       "Glissando",
 119 /* accepts */     "glissando-event",
 120 /* acks  */       "rhythmic-head-interface",
 121 /* reads */       "followVoice",
 122 /* write */       "");