ardour/libs/ardour/quantize.cc

/*
 * Copyright (C) 2007-2015 David Robillard <d@drobilla.net>
 * Copyright (C) 2008-2017 Paul Davis <paul@linuxaudiosystems.com>
 * Copyright (C) 2010-2012 Carl Hetherington <carl@carlh.net>
 * Copyright (C) 2013-2015 Robin Gareus <robin@gareus.org>
 *
 * 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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include <cassert>
#include <cmath>

#include "pbd/basename.h"

#include "ardour/quantize.h"
#include "ardour/midi_model.h"

#include "pbd/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,
                    Temporal::Beats start_grid, Temporal::Beats end_grid,
                    float strength, float swing, Temporal::Beats const & threshold)
	: _snap_start (snap_start)
	, _snap_end (snap_end)
	, _start_grid(start_grid)
	, _end_grid(end_grid)
	, _strength (strength/100.0)
	, _swing (swing)
	, _threshold (threshold)
{
}

Quantize::~Quantize ()
{
}

static Temporal::Beats
swing_position (Temporal::Beats pos, Temporal::Beats grid, double swing_strength, Temporal::Beats 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
	 */

	using namespace Temporal;

	const bool swing_quantize_grid_position = pos > Beats() && ((pos/grid) % Beats (0, 2)) != Beats();
	const bool swing_previous_grid_position = pos > grid && (((pos-grid)/grid) % Beats (0, 2)) != Beats();

	/* one of these will not be subject to swing */

	Beats swung_pos = pos;
	Beats swung_previous_grid_position;

	if (pos > grid) {
		swung_previous_grid_position = pos - grid;
	} else {
		swung_previous_grid_position = Beats();
	}

	const ratio_t r (swing_strength, 300);

	if (swing_previous_grid_position) {
		swung_previous_grid_position = swung_previous_grid_position + (grid * r);
	}

	if (swing_quantize_grid_position) {
		swung_pos = swung_pos + (grid * r);
	}

	if ((pos - swung_pos).abs() > (pos - swung_previous_grid_position).abs()) {
		pos = swung_previous_grid_position;
	} else {
		pos = swung_pos;
	}

	/* now correct for start-of-model offset */

	pos += offset;

	return pos;
}

PBD::Command*
Quantize::operator () (std::shared_ptr<MidiModel> model,
                       Temporal::Beats position,
                       std::vector<Evoral::Sequence<Temporal::Beats>::Notes>& seqs)
{
	/* 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 Temporal::Beats round_pos = (position / _start_grid) * _start_grid;
	const Temporal::Beats offset    = round_pos - position;

	MidiModel::NoteDiffCommand* cmd = new MidiModel::NoteDiffCommand (model, "quantize");

	for (std::vector<Evoral::Sequence<Temporal::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).
			 */

			Temporal::Beats new_start = (((*i)->time()  - offset) / _start_grid) * _start_grid;
			Temporal::Beats new_end = (((*i)->end_time() - 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;
			}

			Temporal::Beats delta = new_start - (*i)->time();

			if (delta.abs() >= _threshold) {
				if (_snap_start) {
					/* this is here because Beats intentionally does not have operator* (double) */
					delta = Temporal::Beats::ticks (llrintf (delta.to_ticks()) * _strength);
					std::cerr << "new start " << (*i)->time() + delta << " shift was " << delta << std::endl;
					cmd->change ((*i), MidiModel::NoteDiffCommand::StartTime, (*i)->time() + delta);
				}
			}

			if (_snap_end) {
				delta = new_end - (*i)->end_time();

				if (delta.abs() >= _threshold) {

					Temporal::Beats new_dur (new_end - new_start);

					if (!new_dur) {
						new_dur = Temporal::Beats (_end_grid);
					}

					cmd->change ((*i), MidiModel::NoteDiffCommand::Length, new_dur);
				}
			}
		}
	}

	return cmd;
}

void
Quantize::set_start_grid (Temporal::Beats const & sg)
{
	_start_grid = sg;
}

void
Quantize::set_end_grid (Temporal::Beats const & eg)
{
	_end_grid = eg;
}