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--2009 Jan Nieuwenhuizen <janneke@gnu.org>
   7 */
   8
   9 #include "engraver.hh"
  10 #include "pointer-group-interface.hh"
  11 #include "stem.hh"
  12 #include "rhythmic-head.hh"
  13 #include "side-position-interface.hh"
  14 #include "staff-symbol-referencer.hh"
  15 #include "context.hh"
  16 #include "spanner.hh"
  17 #include "item.hh"
  18
  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 class Note_head_line_engraver : public Engraver
  27 {
  28 public:
  29   TRANSLATOR_DECLARATIONS (Note_head_line_engraver);
  30
  31 protected:
  32   DECLARE_ACKNOWLEDGER (rhythmic_head);
  33   void process_acknowledged ();
  34   void stop_translation_timestep ();
  35
  36 private:
  37   Spanner *line_;
  38   Context *last_staff_;
  39   bool follow_;
  40   Grob *head_;
  41   Grob *last_head_;
  42 };
  43
  44 Note_head_line_engraver::Note_head_line_engraver ()
  45 {
  46   line_ = 0;
  47   follow_ = false;
  48   head_ = 0;
  49   last_head_ = 0;
  50   last_staff_ = 0;
  51 }
  52
  53 void
  54 Note_head_line_engraver::acknowledge_rhythmic_head (Grob_info info)
  55 {
  56   head_ = info.grob ();
  57   Context *tr = context ();
  58
  59   while (tr && !tr->is_alias (ly_symbol2scm ("Staff")))
  60     tr = tr->get_parent_context ();
  61
  62   if (tr
  63       && tr->is_alias (ly_symbol2scm ("Staff")) && tr != last_staff_
  64       && to_boolean (get_property ("followVoice")))
  65     {
  66       if (last_head_)
  67         follow_ = true;
  68     }
  69   last_staff_ = tr;
  70 }
  71
  72 void
  73 Note_head_line_engraver::process_acknowledged ()
  74 {
  75   if (!line_ && follow_ && last_head_ && head_)
  76     {
  77       /* TODO: Don't follow if there's a beam.
  78
  79       We can't do beam-stuff here, since beam doesn't exist yet.
  80       Should probably store follow_ in line_, and suicide at some
  81       later point */
  82       if (follow_)
  83         line_ = make_spanner ("VoiceFollower", head_->self_scm ());
  84
  85       line_->set_bound (LEFT, last_head_);
  86       line_->set_bound (RIGHT, head_);
  87
  88       follow_ = false;
  89     }
  90 }
  91
  92 void
  93 Note_head_line_engraver::stop_translation_timestep ()
  94 {
  95   line_ = 0;
  96   if (head_)
  97     last_head_ = head_;
  98   head_ = 0;
  99 }
 100
 101 #include "translator.icc"
 102
 103 ADD_ACKNOWLEDGER (Note_head_line_engraver, rhythmic_head);
 104 ADD_TRANSLATOR (Note_head_line_engraver,
 105                 /* doc */
 106                 "Engrave a line between two note heads, for example a"
 107                 " glissando.  If @code{followVoice} is set, staff switches"
 108                 " also generate a line.",
 109
 110                 /* create */
 111                 "Glissando "
 112                 "VoiceFollower ",
 113
 114                 /* read */
 115                 "followVoice ",
 116
 117                 /* write */
 118                 ""
 119                 );