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livetrax/libs/ardour/beats_frames_converter.cc
David Robillard 3963d2b0b2 Move all beats <-> frames time conversion into a single object that can be passed around.
This has 3 main benefits:
 - All conversion code is in one place (less duplication, potential bugs)
 - The conversion method can be passed to things that are ignorant
   of the actual time units involved, information required, etc.
   (In the future it would be nice to have user selectable tempo/frame time)
 - It should be relatively simple now to support tempo changes part-way
   through a MIDI region (at least architecturally speaking)


git-svn-id: svn://localhost/ardour2/branches/3.0@4594 d708f5d6-7413-0410-9779-e7cbd77b26cf
2009-02-16 02:51:16 +00:00

55 lines
1.7 KiB
C++

/*
Copyright (C) 2009 Paul Davis
Author: Dave Robillard
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
$Id: midiregion.h 733 2006-08-01 17:19:38Z drobilla $
*/
#include <ardour/audioengine.h>
#include <ardour/beats_frames_converter.h>
#include <ardour/session.h>
#include <ardour/tempo.h>
namespace ARDOUR {
nframes_t
BeatsFramesConverter::to(double beats) const
{
// FIXME: assumes tempo never changes after origin
const Tempo& tempo = _session.tempo_map().tempo_at(_origin);
const double frames_per_beat = tempo.frames_per_beat(
_session.engine().frame_rate(),
_session.tempo_map().meter_at(_origin));
return lrint(beats * frames_per_beat);
}
double
BeatsFramesConverter::from(nframes_t frames) const
{
// FIXME: assumes tempo never changes after origin
const Tempo& tempo = _session.tempo_map().tempo_at(_origin);
const double frames_per_beat = tempo.frames_per_beat(
_session.engine().frame_rate(),
_session.tempo_map().meter_at(_origin));
return frames / frames_per_beat;
}
} /* namespace ARDOUR */