lily/note-head-line-engraver.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 2000--2011 Jan Nieuwenhuizen <janneke@gnu.org>
   5
   6   LilyPond is free software: you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation, either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   LilyPond is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with LilyPond.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "engraver.hh"
  21 #include "pointer-group-interface.hh"
  22 #include "stem.hh"
  23 #include "rhythmic-head.hh"
  24 #include "side-position-interface.hh"
  25 #include "staff-symbol-referencer.hh"
  26 #include "context.hh"
  27 #include "spanner.hh"
  28 #include "item.hh"
  29
  30
  31 /**
  32    Create line-spanner grobs for lines that connect note heads.
  33
  34    TODO: have the line commit suicide if the notes are connected with
  35    either slur or beam.
  36 */
  37 class Note_head_line_engraver : public Engraver
  38 {
  39 public:
  40   TRANSLATOR_DECLARATIONS (Note_head_line_engraver);
  41
  42 protected:
  43   DECLARE_ACKNOWLEDGER (rhythmic_head);
  44   void process_acknowledged ();
  45   void stop_translation_timestep ();
  46
  47 private:
  48   Spanner *line_;
  49   Context *last_staff_;
  50   bool follow_;
  51   Grob *head_;
  52   Grob *last_head_;
  53 };
  54
  55 Note_head_line_engraver::Note_head_line_engraver ()
  56 {
  57   line_ = 0;
  58   follow_ = false;
  59   head_ = 0;
  60   last_head_ = 0;
  61   last_staff_ = 0;
  62 }
  63
  64 void
  65 Note_head_line_engraver::acknowledge_rhythmic_head (Grob_info info)
  66 {
  67   head_ = info.grob ();
  68   Context *tr = context ();
  69
  70   while (tr && !tr->is_alias (ly_symbol2scm ("Staff")))
  71     tr = tr->get_parent_context ();
  72
  73   if (tr
  74       && tr->is_alias (ly_symbol2scm ("Staff")) && tr != last_staff_
  75       && to_boolean (get_property ("followVoice")))
  76     {
  77       if (last_head_)
  78         follow_ = true;
  79     }
  80   last_staff_ = tr;
  81 }
  82
  83 void
  84 Note_head_line_engraver::process_acknowledged ()
  85 {
  86   if (!line_ && follow_ && last_head_ && head_)
  87     {
  88       /* TODO: Don't follow if there's a beam.
  89
  90       We can't do beam-stuff here, since beam doesn't exist yet.
  91       Should probably store follow_ in line_, and suicide at some
  92       later point */
  93       if (follow_)
  94         line_ = make_spanner ("VoiceFollower", head_->self_scm ());
  95
  96       line_->set_bound (LEFT, last_head_);
  97       line_->set_bound (RIGHT, head_);
  98
  99       follow_ = false;
 100     }
 101 }
 102
 103 void
 104 Note_head_line_engraver::stop_translation_timestep ()
 105 {
 106   line_ = 0;
 107   if (head_)
 108     last_head_ = head_;
 109   head_ = 0;
 110 }
 111
 112 #include "translator.icc"
 113
 114 ADD_ACKNOWLEDGER (Note_head_line_engraver, rhythmic_head);
 115 ADD_TRANSLATOR (Note_head_line_engraver,
 116                 /* doc */
 117                 "Engrave a line between two note heads, for example a"
 118                 " glissando.  If @code{followVoice} is set, staff switches"
 119                 " also generate a line.",
 120
 121                 /* create */
 122                 "Glissando "
 123                 "VoiceFollower ",
 124
 125                 /* read */
 126                 "followVoice ",
 127
 128                 /* write */
 129                 ""
 130                 );