lily/note-head-line-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--2004 Jan Nieuwenhuizen <janneke@gnu.org>
   7  */
   8
   9 #include "engraver.hh"
  10 #include "group-interface.hh"
  11 #include "item.hh"
  12 #include "event.hh"
  13 #include "spanner.hh"
  14 #include "stem.hh"
  15 #include "rhythmic-head.hh"
  16 #include "side-position-interface.hh"
  17 #include "staff-symbol-referencer.hh"
  18 #include "translator-group.hh"
  19
  20 /**
  21    Create line-spanner grobs for lines that connect note heads.
  22
  23    TODO: have the line commit suicide if the notes are connected with
  24    either slur or beam.
  25
  26 */
  27 class Note_head_line_engraver : public Engraver
  28 {
  29 public:
  30   TRANSLATOR_DECLARATIONS(Note_head_line_engraver);
  31
  32 protected:
  33   virtual void acknowledge_grob (Grob_info);
  34   virtual void process_acknowledged_grobs ();
  35   virtual void stop_translation_timestep ();
  36
  37 private:
  38   Spanner* line_;
  39   Translator* last_staff_;
  40   bool follow_;
  41   Grob* head_;
  42   Grob* last_head_;
  43 };
  44
  45 Note_head_line_engraver::Note_head_line_engraver ()
  46 {
  47   line_ = 0;
  48   follow_ = false;
  49   head_ = 0;
  50   last_head_ = 0;
  51   last_staff_ = 0;
  52 }
  53
  54 void
  55 Note_head_line_engraver::acknowledge_grob (Grob_info info)
  56 {
  57   if (Rhythmic_head::has_interface (info.grob_))
  58     {
  59       head_ = info.grob_;
  60       if (to_boolean (get_property ("followVoice")))
  61         {
  62           Translator_group  * tr = daddy_trans_;
  63           while (tr && !tr->is_alias (ly_symbol2scm ( "Staff")))
  64             tr = tr->daddy_trans_ ;
  65
  66           if (tr && tr->is_alias (ly_symbol2scm ("Staff")) && tr != last_staff_)
  67             {
  68               if (last_head_)
  69                 follow_ = true;
  70               last_staff_ = tr;
  71             }
  72         }
  73     }
  74 }
  75
  76
  77 void
  78 Note_head_line_engraver::process_acknowledged_grobs ()
  79 {
  80   if (!line_ && follow_ && last_head_ && head_)
  81     {
  82       /* TODO: Don't follow if there's a beam.
  83
  84          We can't do beam-stuff here, since beam doesn't exist yet.
  85          Should probably store follow_ in line_, and suicide at some
  86          later point */
  87       if (follow_)
  88         line_ = make_spanner ("VoiceFollower");
  89
  90       line_->set_bound (LEFT, last_head_);
  91       line_->set_bound (RIGHT, head_);
  92
  93       announce_grob(line_, head_->self_scm ());
  94
  95       follow_ = false;
  96     }
  97 }
  98
  99 void
 100 Note_head_line_engraver::stop_translation_timestep ()
 101 {
 102   if (line_)
 103     {
 104       typeset_grob (line_);
 105       line_ = 0;
 106     }
 107   if (head_)
 108     last_head_ = head_;
 109   head_ = 0;
 110 }
 111
 112
 113
 114
 115 ENTER_DESCRIPTION(Note_head_line_engraver,
 116 /* descr */       "Engrave a line between two note heads, for example a glissando.  If "
 117 " followVoice is set, staff switches also generate a line.",
 118 /* creats*/       "Glissando VoiceFollower",
 119 /* accepts */     "glissando-event",
 120 /* acks  */       "rhythmic-head-interface",
 121 /* reads */       "followVoice",
 122 /* write */       "");