lily/key-performer.cc

   1 /*
   2   key-performer.cc -- implement Key_performer
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c) 1997--2009 Jan Nieuwenhuizen <janneke@gnu.org>
   7 */
   8
   9 #include "audio-item.hh"
  10 #include "music-sequence.hh"
  11 #include "performer.hh"
  12 #include "stream-event.hh"
  13 #include "warn.hh"
  14
  15 #include "translator.icc"
  16
  17 class Key_performer : public Performer
  18 {
  19 public:
  20   TRANSLATOR_DECLARATIONS (Key_performer);
  21   ~Key_performer ();
  22
  23 protected:
  24   void process_music ();
  25   void stop_translation_timestep ();
  26
  27   DECLARE_TRANSLATOR_LISTENER (key_change);
  28 private:
  29   Stream_event *key_ev_;
  30   Audio_key *audio_;
  31 };
  32
  33 Key_performer::Key_performer ()
  34 {
  35   key_ev_ = 0;
  36   audio_ = 0;
  37 }
  38
  39 Key_performer::~Key_performer ()
  40 {
  41 }
  42
  43 void
  44 Key_performer::process_music ()
  45 {
  46   if (key_ev_)
  47     {
  48       SCM pitchlist = key_ev_->get_property ("pitch-alist");
  49       SCM proc = ly_lily_module_constant ("alterations-in-key");
  50
  51       SCM acc = scm_call_1 (proc, pitchlist);
  52
  53       Pitch key_do (0,
  54                     scm_to_int (scm_caar (pitchlist)),
  55                     ly_scm2rational (scm_cdar (pitchlist)));
  56
  57       Pitch c_do (0, 0, 0);
  58
  59       SCM c_pitchlist
  60         = ly_transpose_key_alist (pitchlist,
  61                                   pitch_interval (key_do, c_do).smobbed_copy ());
  62
  63       /* MIDI keys are too limited for lilypond scales.
  64          We check for minor scale and assume major otherwise.  */
  65
  66       SCM third = scm_assoc (scm_from_int (2),
  67                              c_pitchlist);
  68       bool minor = (scm_is_pair (third)
  69                     && scm_is_number (scm_cdr (third))
  70                     && ly_scm2rational (scm_cdr (third)) == FLAT_ALTERATION);
  71
  72       audio_ = new Audio_key (scm_to_int (acc),
  73                               !minor);
  74
  75       Audio_element_info info (audio_, key_ev_);
  76       announce_element (info);
  77       key_ev_ = 0;
  78     }
  79 }
  80
  81 void
  82 Key_performer::stop_translation_timestep ()
  83 {
  84   if (audio_)
  85     {
  86       audio_ = 0;
  87     }
  88 }
  89
  90 IMPLEMENT_TRANSLATOR_LISTENER (Key_performer, key_change);
  91 void
  92 Key_performer::listen_key_change (Stream_event *ev)
  93 {
  94   if (!key_ev_)
  95     key_ev_ = ev;
  96 }
  97
  98 ADD_TRANSLATOR (Key_performer,
  99                 /* doc */
 100                 "",
 101
 102                 /* create */
 103                 "",
 104
 105                 /* read */
 106                 "",
 107
 108                 /* write */
 109                 ""
 110                 );