annotate base/Pitch.h @ 1394:9ef1cc26024c

Add Range01 normalisation method to ColumnOp. This is the normalisation that is actually used in the Colour 3D Plot layer historically when column normalisation is enabled (not Max1 after all).

/* -*- 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.
*/

#ifndef _PITCH_H_
#define _PITCH_H_

#include <QString>

class Pitch
{
public:
    /**
     * Return the frequency at the given MIDI pitch plus centsOffset
     * cents (1/100ths of a semitone).  centsOffset does not have to
     * be in any particular range or sign.
     *
     * If concertA is non-zero, use that as the reference frequency
     * for the A at MIDI pitch 69; otherwise use the tuning frequency
     * specified in the application preferences (default 440Hz).
     */
    static double getFrequencyForPitch(int midiPitch,
				      double centsOffset = 0,
				      double concertA = 0.0);

    /**
     * Return the nearest MIDI pitch to the given frequency.
     *
     * If centsOffsetReturn is non-NULL, return in *centsOffsetReturn
     * the number of cents (1/100ths of a semitone) difference between
     * the given frequency and that of the returned MIDI pitch.  The
     * cents offset will be in the range [-50,50).
     * 
     * If concertA is non-zero, use that as the reference frequency
     * for the A at MIDI pitch 69; otherwise use the tuning frequency
     * specified in the application preferences (default 440Hz).
     */
    static int getPitchForFrequency(double frequency,
				    double *centsOffsetReturn = 0,
				    double concertA = 0.0);

    /**
     * Compatibility version of getPitchForFrequency accepting float
     * pointer argument.
     */
    static int getPitchForFrequency(double frequency,
				    float *centsOffsetReturn,
				    double concertA = 0.0) {
        double c;
        int p = getPitchForFrequency(frequency, &c, concertA);
        if (centsOffsetReturn) *centsOffsetReturn = float(c);
        return p;
    }

    /**
     * Return the nearest MIDI pitch range to the given frequency
     * range, that is, the difference in MIDI pitch values between the
     * higher and lower frequencies.
     *
     * If centsOffsetReturn is non-NULL, return in *centsOffsetReturn
     * the number of cents (1/100ths of a semitone) difference between
     * the given frequency difference and the returned MIDI pitch
     * range.  The cents offset will be in the range [-50,50).
     * 
     * If concertA is non-zero, use that as the reference frequency
     * for the A at MIDI pitch 69; otherwise use the tuning frequency
     * specified in the application preferences (default 440Hz).
     */
    static int getPitchForFrequencyDifference(double frequencyA,
                                              double frequencyB,
                                              double *centsOffsetReturn = 0,
                                              double concertA = 0.0);

    /**
     * Compatibility version of getPitchForFrequencyDifference
     * accepting float pointer argument.
     */
    static int getPitchForFrequencyDifference(double frequencyA,
                                              double frequencyB,
                                              float *centsOffsetReturn,
                                              double concertA = 0.0) {
        double c;
        int p = getPitchForFrequencyDifference(frequencyA, frequencyB,
                                               &c, concertA);
        if (centsOffsetReturn) *centsOffsetReturn = float(c);
        return p;
    }
    
    /**
     * Return the MIDI pitch for the given note number (0-12 where 0
     * is C) and octave number. The octave numbering system is based
     * on the application preferences (default is C4 = middle C,
     * though in previous SV releases that was C3).
     */
    static int getPitchForNoteAndOctave(int note, int octave);
    
    /**
     * Return the note number (0-12 where 0 is C) and octave number
     * for the given MIDI pitch. The octave numbering system is based
     * on the application preferences (default is C4 = middle C,
     * though in previous SV releases that was C3).
     */
    static void getNoteAndOctaveForPitch(int midiPitch, int &note, int &octave);

    /**
     * Return a string describing the given MIDI pitch, with optional
     * cents offset.  This consists of the note name, octave number,
     * and optional cents. The octave numbering system is based on the
     * application preferences (default is C4 = middle C, though in
     * previous SV releases that was C3).
     *
     * For example, "A#3" (A# in octave 3) or "C2-12c" (C in octave 2,
     * minus 12 cents).
     *
     * If useFlats is true, spell notes with flats instead of sharps,
     * e.g. Bb3 instead of A#3.
     */
    static QString getPitchLabel(int midiPitch,
				 double centsOffset = 0,
				 bool useFlats = false);
    
    /**
     * Return a string describing the nearest MIDI pitch to the given
     * frequency, with cents offset.
     *
     * If concertA is non-zero, use that as the reference frequency
     * for the A at MIDI pitch 69; otherwise use the tuning frequency
     * specified in the application preferences (default 440Hz).
     *
     * If useFlats is true, spell notes with flats instead of sharps,
     * e.g. Bb3 instead of A#3.
     */
    static QString getPitchLabelForFrequency(double frequency,
					     double concertA = 0.0,
					     bool useFlats = false);

    /**
     * Return a string describing the given pitch range in octaves,
     * semitones and cents.  This is in the form e.g. "1'2+4c".
     */
    static QString getLabelForPitchRange(int semis, double cents = 0);

    /**
     * Return true if the given frequency falls within the range of
     * MIDI note pitches, plus or minus half a semitone.  This is
     * equivalent to testing whether getPitchForFrequency returns a
     * pitch in the MIDI range (0 to 127 inclusive) with any cents
     * offset.
     *
     * If concertA is non-zero, use that as the reference frequency
     * for the A at MIDI pitch 69; otherwise use the tuning frequency
     * specified in the application preferences (default 440Hz).
     */
    static bool isFrequencyInMidiRange(double frequency,
                                       double concertA = 0.0);
};


#endif