lily/key-performer.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--2010 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 "audio-item.hh"
  21 #include "music-sequence.hh"
  22 #include "performer.hh"
  23 #include "stream-event.hh"
  24 #include "warn.hh"
  25
  26 #include "translator.icc"
  27
  28 class Key_performer : public Performer
  29 {
  30 public:
  31   TRANSLATOR_DECLARATIONS (Key_performer);
  32   ~Key_performer ();
  33
  34 protected:
  35   void process_music ();
  36   void stop_translation_timestep ();
  37
  38   DECLARE_TRANSLATOR_LISTENER (key_change);
  39 private:
  40   Stream_event *key_ev_;
  41   Audio_key *audio_;
  42 };
  43
  44 Key_performer::Key_performer ()
  45 {
  46   key_ev_ = 0;
  47   audio_ = 0;
  48 }
  49
  50 Key_performer::~Key_performer ()
  51 {
  52 }
  53
  54 void
  55 Key_performer::process_music ()
  56 {
  57   if (key_ev_)
  58     {
  59       SCM pitchlist = key_ev_->get_property ("pitch-alist");
  60       SCM proc = ly_lily_module_constant ("alterations-in-key");
  61
  62       SCM acc = scm_call_1 (proc, pitchlist);
  63
  64       Pitch key_do (0,
  65                     scm_to_int (scm_caar (pitchlist)),
  66                     ly_scm2rational (scm_cdar (pitchlist)));
  67
  68       Pitch c_do (0, 0, 0);
  69
  70       SCM c_pitchlist
  71         = ly_transpose_key_alist (pitchlist,
  72                                   pitch_interval (key_do, c_do).smobbed_copy ());
  73
  74       /* MIDI keys are too limited for lilypond scales.
  75          We check for minor scale and assume major otherwise.  */
  76
  77       SCM third = scm_assoc (scm_from_int (2),
  78                              c_pitchlist);
  79       bool minor = (scm_is_pair (third)
  80                     && scm_is_number (scm_cdr (third))
  81                     && ly_scm2rational (scm_cdr (third)) == FLAT_ALTERATION);
  82
  83       audio_ = new Audio_key (scm_to_int (acc),
  84                               !minor);
  85
  86       Audio_element_info info (audio_, key_ev_);
  87       announce_element (info);
  88       key_ev_ = 0;
  89     }
  90 }
  91
  92 void
  93 Key_performer::stop_translation_timestep ()
  94 {
  95   if (audio_)
  96     {
  97       audio_ = 0;
  98     }
  99 }
 100
 101 IMPLEMENT_TRANSLATOR_LISTENER (Key_performer, key_change);
 102 void
 103 Key_performer::listen_key_change (Stream_event *ev)
 104 {
 105   if (!key_ev_)
 106     key_ev_ = ev;
 107 }
 108
 109 ADD_TRANSLATOR (Key_performer,
 110                 /* doc */
 111                 "",
 112
 113                 /* create */
 114                 "",
 115
 116                 /* read */
 117                 "",
 118
 119                 /* write */
 120                 ""
 121                 );