annotate base/Pitch.cpp @ 1752:6d09d68165a4 by-id

Further review of ById: make IDs only available when adding a model to the ById store, not by querying the item directly. This means any id encountered in the wild must have been added to the store at some point (even if later released), which simplifies reasoning about lifecycles

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#include "Pitch.h"
#include "Preferences.h"
#include "system/System.h"

#include <cmath>

double
Pitch::getFrequencyForPitch(int midiPitch,
                            double centsOffset,
                            double concertA)
{
    if (concertA <= 0.0) {
        concertA = Preferences::getInstance()->getTuningFrequency();
    }
    double p = double(midiPitch) + (centsOffset / 100);
    return concertA * pow(2.0, (p - 69.0) / 12.0);
}

int
Pitch::getPitchForFrequency(double frequency,
                            double *centsOffsetReturn,
                            double concertA)
{
    if (concertA <= 0.0) {
        concertA = Preferences::getInstance()->getTuningFrequency();
    }
    double p = 12.0 * (log(frequency / (concertA / 2.0)) / log(2.0)) + 57.0;

    int midiPitch = int(round(p));
    double centsOffset = (p - midiPitch) * 100.0;

    if (centsOffset >= 50.0) {
        midiPitch = midiPitch + 1;
        centsOffset = -(100.0 - centsOffset);
    }
    if (centsOffset < -50.0) {
        midiPitch = midiPitch - 1;
        centsOffset = (100.0 + centsOffset);
    }
    
    if (centsOffsetReturn) *centsOffsetReturn = centsOffset;
    return midiPitch;
}

int
Pitch::getPitchForFrequencyDifference(double frequencyA,
                                      double frequencyB,
                                      double *centsOffsetReturn,
                                      double concertA)
{
    if (concertA <= 0.0) {
        concertA = Preferences::getInstance()->getTuningFrequency();
    }

    if (frequencyA > frequencyB) {
        std::swap(frequencyA, frequencyB);
    }

    double pA = 12.0 * (log(frequencyA / (concertA / 2.0)) / log(2.0)) + 57.0;
    double pB = 12.0 * (log(frequencyB / (concertA / 2.0)) / log(2.0)) + 57.0;

    double p = pB - pA;

    int midiPitch = int(p + 0.00001);
    double centsOffset = (p - midiPitch) * 100.0;

    if (centsOffset >= 50.0) {
        midiPitch = midiPitch + 1;
        centsOffset = -(100.0 - centsOffset);
    }
    
    if (centsOffsetReturn) *centsOffsetReturn = centsOffset;
    return midiPitch;
}

static QString notes[] = {
    "C%1",  "C#%1", "D%1",  "D#%1",
    "E%1",  "F%1",  "F#%1", "G%1",
    "G#%1", "A%1",  "A#%1", "B%1"
};

static QString flatNotes[] = {
    "C%1",  "Db%1", "D%1",  "Eb%1",
    "E%1",  "F%1",  "Gb%1", "G%1",
    "Ab%1", "A%1",  "Bb%1", "B%1"
};

int
Pitch::getPitchForNoteAndOctave(int note, int octave)
{
    int baseOctave = Preferences::getInstance()->getOctaveOfLowestMIDINote();
    return (octave - baseOctave) * 12 + note;
}

void
Pitch::getNoteAndOctaveForPitch(int midiPitch, int &note, int &octave)
{
    int baseOctave = Preferences::getInstance()->getOctaveOfLowestMIDINote();

    octave = baseOctave;

    // Note, this only gets the right octave number at octave
    // boundaries because Cb is enharmonic with B (not B#) and B# is
    // enharmonic with C (not Cb). So neither B# nor Cb will be
    // spelled from a MIDI pitch + flats flag in isolation.

    if (midiPitch < 0) {
        while (midiPitch < 0) {
            midiPitch += 12;
            --octave;
        }
    } else {
        octave = midiPitch / 12 + baseOctave;
    }

    note = midiPitch % 12;
}

QString
Pitch::getPitchLabel(int midiPitch,
                     double centsOffset,
                     bool useFlats)
{
    int note, octave;
    getNoteAndOctaveForPitch(midiPitch, note, octave);

    QString plain = (useFlats ? flatNotes : notes)[note].arg(octave);

    long ic = lrint(centsOffset);
    if (ic == 0) return plain;
    else if (ic > 0) return QString("%1+%2c").arg(plain).arg(ic);
    else return QString("%1%2c").arg(plain).arg(ic);
}

QString
Pitch::getPitchLabelForFrequency(double frequency,
                                 double concertA,
                                 bool useFlats)
{
    if (concertA <= 0.0) {
        concertA = Preferences::getInstance()->getTuningFrequency();
    }
    double centsOffset = 0.0;
    int midiPitch = getPitchForFrequency(frequency, &centsOffset, concertA);
    return getPitchLabel(midiPitch, centsOffset, useFlats);
}

QString
Pitch::getLabelForPitchRange(int semis, double cents)
{
    if (semis > 0) {
        while (cents < 0.0) {
            --semis;
            cents += 100.0;
        }
    }
    if (semis < 0) {
        while (cents > 0.0) {
            ++semis;
            cents -= 100.0;
        }
    }

    long ic = lrint(cents);

    if (ic == 0) {
        if (semis >= 12) {
            return QString("%1'%2").arg(semis/12).arg(semis - 12*(semis/12));
        } else {
            return QString("%1").arg(semis);
        }
    } else {
        if (ic > 0) {
            if (semis >= 12) {
                return QString("%1'%2+%3c").arg(semis/12).arg(semis - 12*(semis/12)).arg(ic);
            } else {
                return QString("%1+%3c").arg(semis).arg(ic);
            }
        } else {
            if (semis >= 12) {
                return QString("%1'%2%3c").arg(semis/12).arg(semis - 12*(semis/12)).arg(ic);
            } else {
                return QString("%1%3c").arg(semis).arg(ic);
            }
        }
    }
}

bool
Pitch::isFrequencyInMidiRange(double frequency,
                              double concertA)
{
    double centsOffset = 0.0;
    int midiPitch = getPitchForFrequency(frequency, &centsOffset, concertA);
    return (midiPitch >= 0 && midiPitch < 128);
}