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livetrax/libs/ardour/quantize.cc

184 lines
5.1 KiB
C++

/*
Copyright (C) 2004 Paul Davis
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.
*/
#include <cmath>
#include "pbd/basename.h"
#include "ardour/quantize.h"
#include "ardour/midi_model.h"
#include "i18n.h"
using namespace std;
using namespace PBD;
using namespace ARDOUR;
/** Quantize notes
*
* grid parameters are the quantize value in beats, ie 1.0 = quantize to beats,
* 0.25 = quantize to beats/4, etc.
*/
Quantize::Quantize (bool snap_start, bool snap_end,
double start_grid, double end_grid,
float strength, float swing, float threshold)
: _snap_start (snap_start)
, _snap_end (snap_end)
, _start_grid(start_grid)
, _end_grid(end_grid)
, _strength (strength/100.0)
, _swing (swing/100.0)
, _threshold (threshold)
{
}
Quantize::~Quantize ()
{
}
static double
swing_position (double pos, double grid, double swing, double offset)
{
/* beats start out numbered at zero.
*
* every other position on the start-quantize-grid is
* optionally swung, meaning that its position is moved
* somewhere between its natural position and 2/3 of
* the way to the next start-quantize-grid position.
*
* so, if the _start grid is 0.5, the beat at 0 isn't
* swung, but something at 0.5 is, the beat at 1 isn't
* swung, but something at 1.5 is.
*
* if the start grid is 1.0, the beat at 0 isn't swung,
* but the beat at 1.0 is. the beat at 2.0 isn't swung,
* but the beat at 3.0 is. and so on.
*
* so the criterion for a position being swung is
* whether or not ((possible_grid_position / grid) % 2) != 0
*/
const bool swing_quantize_grid_position = pos > 0.0 && fmod ((pos/grid), 2.0) != 0;
const bool swing_previous_grid_position = pos > grid && fmod ((pos-grid)/grid, 2.0) != 0;
/* one of these will not be subject to swing */
double swung_pos = pos;
double swung_previous_grid_position;
if (pos > grid) {
swung_previous_grid_position = pos - grid;
} else {
swung_previous_grid_position = 0.0;
}
if (swing_previous_grid_position) {
swung_previous_grid_position = swung_previous_grid_position + (2.0/3.0 * swing * grid);
}
if (swing_quantize_grid_position) {
swung_pos = swung_pos + (2.0/3.0 * swing * grid);
}
/* now correct for start-of-model offset */
pos += offset;
if (fabs (pos - swung_pos) > fabs (pos - swung_previous_grid_position)) {
pos = swung_previous_grid_position;
} else {
pos = swung_pos;
}
return pos;
}
Command*
Quantize::operator () (boost::shared_ptr<MidiModel> model,
Evoral::Beats position,
std::vector<Evoral::Sequence<Evoral::Beats>::Notes>& seqs)
{
/* TODO: Rewrite this to be precise with fixed point? */
/* Calculate offset from start of model to next closest quantize step,
to quantize relative to actual session beats (etc.) rather than from the
start of the model.
*/
const double round_pos = round(position.to_double() / _start_grid) * _start_grid;
const double offset = round_pos - position.to_double();
MidiModel::NoteDiffCommand* cmd = new MidiModel::NoteDiffCommand (model, "quantize");
for (std::vector<Evoral::Sequence<Evoral::Beats>::Notes>::iterator s = seqs.begin(); s != seqs.end(); ++s) {
for (Evoral::Sequence<MidiModel::TimeType>::Notes::iterator i = (*s).begin(); i != (*s).end(); ++i) {
/* compute new start + end points WITHOUT the offset
* caused by the start of the model (see above).
*
* these versions of new_start and new_end are
* guaranteed to precisely align with the quantize grid(s).
*/
double new_start = round (((*i)->time().to_double() - offset) / _start_grid) * _start_grid;
double new_end = round (((*i)->end_time().to_double() - offset) / _end_grid) * _end_grid;
if (_swing) {
new_start = swing_position (new_start, _start_grid, _swing, offset);
new_end = swing_position (new_end, _end_grid, _swing, offset);
} else {
/* now correct for start-of-model offset */
new_start += offset;
new_end += offset;
}
double delta = new_start - (*i)->time().to_double();
if (fabs (delta) >= _threshold) {
if (_snap_start) {
delta *= _strength;
cmd->change ((*i), MidiModel::NoteDiffCommand::StartTime,
(*i)->time() + delta);
}
}
if (_snap_end) {
delta = new_end - (*i)->end_time().to_double();
if (fabs (delta) >= _threshold) {
Evoral::Beats new_dur(new_end - new_start);
if (!new_dur) {
new_dur = Evoral::Beats(_end_grid);
}
cmd->change ((*i), MidiModel::NoteDiffCommand::Length, new_dur);
}
}
}
}
return cmd;
}