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--2004 Jan Nieuwenhuizen <janneke@gnu.org>
   7 */
   8
   9 #include "lily-guile.hh"
  10
  11 #include "audio-item.hh"
  12 #include "performer.hh"
  13 #include "warn.hh"
  14
  15
  16 class Key_performer : public Performer
  17 {
  18 public:
  19   TRANSLATOR_DECLARATIONS (Key_performer);
  20   ~Key_performer ();
  21
  22 protected:
  23   virtual bool try_music (Music* req);
  24   virtual void create_audio_elements ();
  25   virtual void stop_translation_timestep ();
  26
  27 private:
  28   Key_change_ev* key_req_;
  29   Audio_key* audio_;
  30 };
  31
  32 Key_performer::Key_performer ()
  33 {
  34   key_req_ = 0;
  35   audio_ = 0;
  36 }
  37
  38 Key_performer::~Key_performer ()
  39 {
  40 }
  41
  42 void
  43 Key_performer::create_audio_elements ()
  44 {
  45   if (key_req_)
  46     {
  47       SCM pitchlist = key_req_->get_property ("pitch-alist");
  48       SCM proc = ly_scheme_function ("alterations-in-key");
  49
  50       SCM acc = scm_call_1 (proc, pitchlist);
  51
  52       Pitch key_do (0,
  53                     ly_scm2int (ly_caar (pitchlist)),
  54                     ly_scm2int (ly_cdar (pitchlist)));
  55
  56       Pitch c_do (0, 0, 0);
  57
  58       SCM c_pitchlist
  59         = ly_transpose_key_alist (pitchlist,
  60                                   interval (key_do, c_do).smobbed_copy ());
  61
  62       /* MIDI keys are too limited for lilypond scales.
  63          We check for minor scale and assume major otherwise.  */
  64       SCM minor = scm_c_eval_string ("minor");
  65       audio_ = new Audio_key (ly_scm2int (acc),
  66                               SCM_BOOL_T != scm_equal_p (minor, c_pitchlist));
  67
  68       Audio_element_info info (audio_, key_req_);
  69       announce_element (info);
  70       key_req_ = 0;
  71     }
  72 }
  73
  74 void
  75 Key_performer::stop_translation_timestep ()
  76 {
  77   if (audio_)
  78     {
  79       play_element (audio_);
  80       audio_ = 0;
  81     }
  82 }
  83
  84 bool
  85 Key_performer::try_music (Music* req)
  86 {
  87   if (Key_change_ev *kc = dynamic_cast <Key_change_ev *> (req))
  88     {
  89       if (key_req_)
  90         warning (_ ("FIXME: key change merge"));
  91
  92       key_req_ = kc;
  93       return true;
  94     }
  95
  96   return false;
  97 }
  98
  99 ENTER_DESCRIPTION (Key_performer,
 100                   "","",
 101                   "key-change-event",
 102                   "","","");