Module: MusicUtils::Scales

Included in:
MusicUtils, Interval
Defined in:
lib/music-utils/scales/scales.rb

Overview

Scales module

Constant Summary collapse

DO =

Notes

:do
RE = 
:re
MI = 
:mi
FA = 
:fa
SOL = 
:sol
LA = 
:la
SI = 
:si
DIATONIC_SCALE = 
[DO, RE, MI, FA, SOL, LA, SI]
FLAT =

Alterations:

'f'
DFLAT = 
FLAT + FLAT
SHARP = 
's'
DSHARP = 
SHARP + SHARP
DOF =

Altered notes

(DO.to_s + FLAT).to_sym
DOFF = 
(DO.to_s + DFLAT).to_sym
DOS = 
(DO.to_s + SHARP).to_sym
DOSS = 
(DO.to_s + DSHARP).to_sym
REF = 
(RE.to_s + FLAT).to_sym
REFF = 
(RE.to_s + DFLAT).to_sym
RES = 
(RE.to_s + SHARP).to_sym
RESS = 
(RE.to_s + DSHARP).to_sym
MIF = 
(MI.to_s + FLAT).to_sym
MIFF = 
(MI.to_s + DFLAT).to_sym
MIS = 
(MI.to_s + SHARP).to_sym
MISS = 
(MI.to_s + DSHARP).to_sym
FAF = 
(FA.to_s + FLAT).to_sym
FAFF = 
(FA.to_s + DFLAT).to_sym
FAS = 
(FA.to_s + SHARP).to_sym
FASS = 
(FA.to_s + DSHARP).to_sym
SOLF = 
(SOL.to_s + FLAT).to_sym
SOLFF = 
(SOL.to_s + DFLAT).to_sym
SOLS = 
(SOL.to_s + SHARP).to_sym
SOLSS = 
(SOL.to_s + DSHARP).to_sym
LAF = 
(LA.to_s + FLAT).to_sym
LAFF = 
(LA.to_s + DFLAT).to_sym
LAS = 
(LA.to_s + SHARP).to_sym
LASS = 
(LA.to_s + DSHARP).to_sym
SIF = 
(SI.to_s + FLAT).to_sym
SIFF = 
(SI.to_s + DFLAT).to_sym
SIS = 
(SI.to_s + SHARP).to_sym
SISS = 
(SI.to_s + DSHARP).to_sym
CROMATIC_SCALE = 
[[SIS, DO, REFF], [DOS, REF], [DOSS, RE, MIFF], [RES, MIF, FAFF], [RESS, MI, FAF], [MIS, FA, SOLFF], [MISS, FAS, SOLF], [FASS, SOL, LAFF], [SOLS, LAF], [SOLSS, LA, SIFF], [LAS, SIF], [LASS, SI, DOF]]
MAJ_SCALE = 
[2, 2, 1, 2, 2, 2, 1]
NATURAL_MIN_SCALE = 
[2, 1, 2, 2, 1, 2, 2]
MELODIC_MIN_SCALE = 
[2, 1, 2, 2, 1, 2, 1]
PERF =

Qualities

'P'
MAJ = 
'M'
MIN = 
'm'
AUG = 
'A'
AUGP = 
AUG + AUG
DIM = 
'd'
DIMP = 
DIM + DIM
QUALITIES =

Qualities hash

{
  2 => {0 => DIM, 1 => MIN, 2 => MAJ, 3 => AUG, 4 => AUGP},
  3 => {1 => DIMP, 2 => DIM, 3 => MIN, 4 => MAJ, 5 => AUG, 6 => AUGP},
  4 => {3 => DIMP, 4 => DIM, 5 => PERF, 6 => AUG, 7 => AUGP},
  5 => {5 => DIMP, 6 => DIM, 7 => PERF, 8 => AUG, 9 => AUGP},
  6 => {7 => DIMP, 8 => DIM, 9 => MIN, 10 => MAJ, 11 => AUG, 12 => AUGP},
  7 => {8 => DIMP, 9 => DIM, 10 => MIN, 11 => MAJ, 12 => AUG, 13 => AUGP},
  8 => {10 => DIMP, 11 => DIM, 12 => PERF, 13 => AUG, 14 => AUGP}
}

Class Method Summary collapse

Class Method Details

.diatonic_scale_from(from) ⇒ Object

Create a diatonic scale starting with the “from” note



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# File 'lib/music-utils/scales/scales.rb', line 135

def Scales.diatonic_scale_from(from)
  diatonic_scale = []
  length = DIATONIC_SCALE.length
  i = DIATONIC_SCALE.index(from)
  c = 0
  while c < length
    diatonic_scale << DIATONIC_SCALE[i]
    i += 1
    c += 1
    if i > length - 1
      i = 0
    end 
  end
  diatonic_scale
end

.scale(from, scale_struct) ⇒ Object

Create scale from a note and scale structure



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# File 'lib/music-utils/scales/scales.rb', line 86

def Scales.scale(from, scale_struct)
  from = from.to_sym
  
  i = 0
  find_it = false
  CROMATIC_SCALE.each do |e|
    if e.is_a?(Array)
      e.each do |ee|
        find_it = true if from == ee
      end
    else
      find_it = true if from == e
    end
    break if find_it
    i += 1
  end
  
  scale = []
  scale << from

  from_note, from_alter = MusicUtils::Note.parse(from)
  
  diatonic_scale = diatonic_scale_from(from_note)
  diatonic_scale.delete(from_note)

  length = CROMATIC_SCALE.length

  scale_struct.each do |shift|
    if i + shift > length - 1
      i = (i + shift) - (length)
      shift = 0
    end

    CROMATIC_SCALE[i + shift].each do |e|
      e_note, e_alter = MusicUtils::Note.parse(e)
        
      if diatonic_scale.first == e_note
        scale << e
        diatonic_scale.delete(diatonic_scale.first)
        break
      end 
    end
    i += shift
  end

  scale
end