lily/tempo-performer.cc

   1 /*
   2   tempo-performer.cc -- implement Tempo_performer
   3
   4   source file of the GNU LilyPond music typesetter
   5
   6   (c)  1997--2000 Jan Nieuwenhuizen <janneke@gnu.org>
   7 */
   8
   9 #include "command-request.hh"
  10 #include "audio-item.hh"
  11 #include "performer.hh"
  12
  13 class Tempo_performer : public Performer
  14 {
  15 public:
  16   VIRTUAL_COPY_CONS(Translator);
  17
  18   Tempo_performer();
  19   ~Tempo_performer();
  20
  21 protected:
  22
  23   virtual bool try_music (Music* req_l);
  24   virtual void stop_translation_timestep ();
  25   virtual void create_audio_elements ();
  26
  27 private:
  28   Tempo_req* tempo_req_l_;
  29   Audio_tempo* audio_p_;
  30 };
  31
  32 ADD_THIS_TRANSLATOR (Tempo_performer);
  33
  34 Tempo_performer::Tempo_performer ()
  35 {
  36   tempo_req_l_ = 0;
  37   audio_p_ = 0;
  38 }
  39
  40 Tempo_performer::~Tempo_performer ()
  41 {
  42 }
  43
  44
  45 void
  46 Tempo_performer::create_audio_elements ()
  47 {
  48   if (tempo_req_l_)
  49     {
  50
  51       SCM met = tempo_req_l_->get_mus_property ("metronome-count");
  52       Duration *d = unsmob_duration (tempo_req_l_->get_mus_property ("tempo"));
  53
  54       audio_p_ = new Audio_tempo (d->length_mom () /
  55                                   Moment (1, 4)
  56                                   * Moment(gh_scm2int (met)));
  57
  58       Audio_element_info info (audio_p_, tempo_req_l_);
  59       announce_element (info);
  60       tempo_req_l_ = 0;
  61     }
  62 }
  63
  64 void
  65 Tempo_performer::stop_translation_timestep ()
  66 {
  67   if (audio_p_)
  68     {
  69       play_element (audio_p_);
  70       audio_p_ = 0;
  71     }
  72 }
  73
  74 bool
  75 Tempo_performer::try_music (Music* req_l)
  76 {
  77   if (tempo_req_l_)
  78     return false;
  79
  80   if (Tempo_req *t =
  81       dynamic_cast <Tempo_req *> (req_l))
  82     {
  83       tempo_req_l_ = t;
  84       return true;
  85     }
  86
  87   return false;
  88 }
  89