lily/tempo-performer.cc

   1 /*
   2   This file is part of LilyPond, the GNU music typesetter.
   3
   4   Copyright (C) 1997--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 "performer.hh"
  21
  22 #include "audio-item.hh"
  23 #include "duration.hh"
  24 #include "stream-event.hh"
  25
  26 #include "translator.icc"
  27
  28 class Tempo_performer : public Performer
  29 {
  30 public:
  31   TRANSLATOR_DECLARATIONS (Tempo_performer);
  32   ~Tempo_performer ();
  33
  34 protected:
  35
  36   virtual void derived_mark () const;
  37   void stop_translation_timestep ();
  38   void process_music ();
  39 private:
  40   Audio_tempo *audio_;
  41   SCM last_tempo_;
  42 };
  43
  44 void
  45 Tempo_performer::derived_mark () const
  46 {
  47   scm_gc_mark (last_tempo_);
  48 }
  49
  50 Tempo_performer::Tempo_performer ()
  51 {
  52   last_tempo_ = SCM_EOL;
  53   audio_ = 0;
  54 }
  55
  56 Tempo_performer::~Tempo_performer ()
  57 {
  58 }
  59
  60 void
  61 Tempo_performer::process_music ()
  62 {
  63   SCM w = get_property ("tempoWholesPerMinute");
  64   if (unsmob_moment (w)
  65       && !ly_is_equal (w, last_tempo_))
  66     {
  67       Rational r = unsmob_moment (w)->main_part_;
  68       r *= Rational (4, 1);
  69
  70       audio_ = new Audio_tempo (r.to_int ());
  71
  72       Audio_element_info info (audio_, 0);
  73       announce_element (info);
  74
  75       last_tempo_ = w;
  76     }
  77 }
  78
  79 void
  80 Tempo_performer::stop_translation_timestep ()
  81 {
  82   if (audio_)
  83     {
  84       audio_ = 0;
  85     }
  86 }
  87
  88 ADD_TRANSLATOR (Tempo_performer,
  89                 /* doc */
  90                 "",
  91
  92                 /* create */
  93                 "",
  94
  95                 /* read */
  96                 "tempoWholesPerMinute ",
  97
  98                 /* write */
  99                 ""
 100                 );