quantize.cc

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/*
    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::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 ()
{
}

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();

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

        for (std::vector<Evoral::Sequence<Evoral::Beats>::Notes>::iterator s = seqs.begin(); s != seqs.end(); ++s) {

                even = false;

                /* TODO 'swing' probably requires a 2nd iteration:
                 * first quantize notes to the grid, then apply beat shift
                 */
                for (Evoral::Sequence<MidiModel::TimeType>::Notes::iterator i = (*s).begin(); i != (*s).end(); ++i) {

                        double new_start = round (((*i)->time().to_double() - offset) / _start_grid) * _start_grid + offset;
                        double new_end = round (((*i)->end_time().to_double() - offset) / _end_grid) * _end_grid + offset;

                        if (_swing > 0.0 && !even) {

                                double next_grid = new_start + _start_grid;

                                /* find a spot 2/3 (* swing factor) of the way between the grid point
                                   we would put this note at, and the nominal position of the next note.
                                */

                                new_start = new_start + (2.0/3.0 * _swing * (next_grid - new_start));
                                new_end = new_end + (2.0/3.0 * _swing * (next_grid - new_start));

                        } else if (_swing < 0.0 && !even) {

                                double prev_grid = new_start - _start_grid;

                                /* find a spot 2/3 (* swing factor) of the way between the grid point
                                   we would put this note at, and the nominal position of the previous note.
                                */

                                new_start = new_start - (2.0/3.0 * _swing * (new_start - prev_grid));
                                new_end = new_end - (2.0/3.0 * _swing * (new_start - prev_grid));

                        }

                        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);
                                }
                        }

                        even = !even;
                }
        }

        return cmd;
}