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