annotate base/Pitch.cpp @ 220:e08cb0158e81

...
author Chris Cannam
date Thu, 25 Jan 2007 15:26:15 +0000 (2007-01-25)
parents 4f26f623a8bc
children e412f65884ee
rev   line source
Chris@49 1 /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
Chris@19 2
Chris@19 3 /*
Chris@52 4 Sonic Visualiser
Chris@52 5 An audio file viewer and annotation editor.
Chris@52 6 Centre for Digital Music, Queen Mary, University of London.
Chris@52 7 This file copyright 2006 Chris Cannam.
Chris@19 8
Chris@52 9 This program is free software; you can redistribute it and/or
Chris@52 10 modify it under the terms of the GNU General Public License as
Chris@52 11 published by the Free Software Foundation; either version 2 of the
Chris@52 12 License, or (at your option) any later version. See the file
Chris@52 13 COPYING included with this distribution for more information.
Chris@19 14 */
Chris@19 15
Chris@19 16 #include "Pitch.h"
Chris@141 17 #include "Preferences.h"
Chris@19 18
Chris@19 19 #include <cmath>
Chris@19 20
Chris@19 21 float
Chris@19 22 Pitch::getFrequencyForPitch(int midiPitch,
Chris@19 23 float centsOffset,
Chris@19 24 float concertA)
Chris@19 25 {
Chris@141 26 if (concertA <= 0.0) {
Chris@141 27 concertA = Preferences::getInstance()->getTuningFrequency();
Chris@141 28 }
Chris@19 29 float p = float(midiPitch) + (centsOffset / 100);
Chris@19 30 return concertA * powf(2.0, (p - 69.0) / 12.0);
Chris@19 31 }
Chris@19 32
Chris@19 33 int
Chris@19 34 Pitch::getPitchForFrequency(float frequency,
Chris@19 35 float *centsOffsetReturn,
Chris@19 36 float concertA)
Chris@19 37 {
Chris@141 38 if (concertA <= 0.0) {
Chris@141 39 concertA = Preferences::getInstance()->getTuningFrequency();
Chris@141 40 }
Chris@19 41 float p = 12.0 * (log(frequency / (concertA / 2.0)) / log(2.0)) + 57.0;
Chris@19 42
Chris@19 43 int midiPitch = int(p + 0.00001);
Chris@19 44 float centsOffset = (p - midiPitch) * 100.0;
Chris@19 45
Chris@19 46 if (centsOffset >= 50.0) {
Chris@19 47 midiPitch = midiPitch + 1;
Chris@19 48 centsOffset = -(100.0 - centsOffset);
Chris@19 49 }
Chris@19 50
Chris@19 51 if (centsOffsetReturn) *centsOffsetReturn = centsOffset;
Chris@19 52 return midiPitch;
Chris@19 53 }
Chris@19 54
Chris@19 55 static QString notes[] = {
Chris@19 56 "C%1", "C#%1", "D%1", "D#%1",
Chris@19 57 "E%1", "F%1", "F#%1", "G%1",
Chris@19 58 "G#%1", "A%1", "A#%1", "B%1"
Chris@19 59 };
Chris@19 60
Chris@26 61 static QString flatNotes[] = {
Chris@26 62 "C%1", "Db%1", "D%1", "Eb%1",
Chris@26 63 "E%1", "F%1", "Gb%1", "G%1",
Chris@26 64 "Ab%1", "A%1", "Bb%1", "B%1"
Chris@26 65 };
Chris@26 66
Chris@19 67 QString
Chris@19 68 Pitch::getPitchLabel(int midiPitch,
Chris@26 69 float centsOffset,
Chris@26 70 bool useFlats)
Chris@19 71 {
Chris@19 72 int octave = -2;
Chris@19 73
Chris@19 74 if (midiPitch < 0) {
Chris@19 75 while (midiPitch < 0) {
Chris@19 76 midiPitch += 12;
Chris@19 77 --octave;
Chris@19 78 }
Chris@19 79 } else {
Chris@19 80 octave = midiPitch / 12 - 2;
Chris@19 81 }
Chris@19 82
Chris@26 83 QString plain = (useFlats ? flatNotes : notes)[midiPitch % 12].arg(octave);
Chris@19 84
Chris@19 85 int ic = lrintf(centsOffset);
Chris@19 86 if (ic == 0) return plain;
Chris@19 87 else if (ic > 0) return QString("%1+%2c").arg(plain).arg(ic);
Chris@19 88 else return QString("%1%2c").arg(plain).arg(ic);
Chris@19 89 }
Chris@19 90
Chris@19 91 QString
Chris@19 92 Pitch::getPitchLabelForFrequency(float frequency,
Chris@26 93 float concertA,
Chris@26 94 bool useFlats)
Chris@19 95 {
Chris@141 96 if (concertA <= 0.0) {
Chris@141 97 concertA = Preferences::getInstance()->getTuningFrequency();
Chris@141 98 }
Chris@19 99 float centsOffset = 0.0;
Chris@19 100 int midiPitch = getPitchForFrequency(frequency, &centsOffset, concertA);
Chris@26 101 return getPitchLabel(midiPitch, centsOffset, useFlats);
Chris@19 102 }
Chris@19 103