libs/ardour/beats_frames_converter.cc

   1 /*
   2     Copyright (C) 2009 Paul Davis
   3     Author: Dave Robillard
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18
  19     $Id: midiregion.h 733 2006-08-01 17:19:38Z drobilla $
  20 */
  21
  22 #include "ardour/beats_frames_converter.h"
  23 #include "ardour/tempo.h"
  24
  25 namespace ARDOUR {
  26
  27 sframes_t
  28 BeatsFramesConverter::to(double beats) const
  29 {
  30         // FIXME: assumes tempo never changes after origin
  31         const Tempo& tempo = _tempo_map.tempo_at(_origin);
  32         const double frames_per_beat = tempo.frames_per_beat(
  33                         _tempo_map.frame_rate(),
  34                         _tempo_map.meter_at(_origin));
  35
  36         return lrint(beats * frames_per_beat);
  37 }
  38
  39 double
  40 BeatsFramesConverter::from(sframes_t frames) const
  41 {
  42         // FIXME: assumes tempo never changes after origin
  43         const Tempo& tempo = _tempo_map.tempo_at(_origin);
  44         const double frames_per_beat = tempo.frames_per_beat(
  45                         _tempo_map.frame_rate(),
  46                         _tempo_map.meter_at(_origin));
  47
  48         return frames / frames_per_beat;
  49 }
  50
  51 } /* namespace ARDOUR */
  52