guitar scales

guitar-scales.py

#!/usr/bin/env python


NOTES = ['A', 'A#', 'B', 'C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#']
note_name = lambda n: NOTES[n % len(NOTES)]

SCALES = {
  'Major (Ionian)': [2, 2, 1, 2, 2, 2, 1],
  'Major Pentatonic': [2, 2, 3, 2, 3],
  'Natural minor (Aeolian)' : [2,1,2,2,1,2,2],
  'Harmonic minor': [2,1,2,2,1,3,1],
  'Melodic minor': [2,1,2,2,2,2,1],
  'Minor Pentatonic': [3,2,2,3,2],
  'Blues': [3,2,1,1,3,2],
  'Arabic': [1,3,1,2,1,3,1],

  'Aeolian':[2, 1, 2, 2, 1, 2, 2],
  'Locryan':[1, 2, 2, 1, 2, 2, 2],
  'Ionian':[2, 2, 1, 2, 2, 2, 1],
  'Dorian':[2, 1, 2, 2, 2, 1, 2],
  'Phrygian': [1, 2, 2, 2, 1, 2, 2],
  'Phrygian Dominant': [1,3,1,2,1,2,2],
  'Lydian':[2, 2, 2, 1, 2, 2, 1],
  'Mixolydian':[2, 2, 1, 2, 2, 1, 2],

  'Balinese': [1, 2, 4, 1, 4],
  'Bartok': [2, 2, 2, 1, 2, 1, 2],
  'Bizantine': [1, 3, 1, 2, 1, 3, 1],
  'Diminished': [2, 1, 2, 1, 2, 1, 2, 1],

  'Iowato': [1, 4, 1, 4, 2],
  'Kumoi': [1, 4, 2, 1, 4],
  'Hirajoshi': [2, 1, 4, 1, 4],
  'Japanese': [1, 4, 2, 1, 4],
  'In Sen': [1, 4, 2, 3, 2],

  'Spanish': [1,3,1,2,1,2,2],
  'Spanish 8 Tone': [1, 2, 1, 1, 1, 2, 2, 2],
}

def scale(intervals):
  for key, key_name in enumerate(NOTES):
    note = key
    scale_notes = []
    for i in intervals:
      note += i
      scale_notes.append(note % len(NOTES))
    yield key, scale_notes

def tuning(first):
  first = NOTES.index(first)
  yield first % len(NOTES)
  for x in [5, 5, 5, 4, 5]:
    first += x
    yield first % len(NOTES)

def guitar(tuning, scale=None):
  frets = [1, 3, 5, 7, 9, 12, 15, 17, 19, 21, 23]
  tuning = list(tuning)
  print '+----' * 24 + '+'
  if scale is None:
    for t in reversed([t + 1 for t in tuning]):
      print '| %s |' % ' | '.join(['%-2s' % note_name(t + i) for i in xrange(24)])
  else:
    def print_note(key, fret):
      note = (key + fret) % len(NOTES)
      if note not in scale:
        return ' ' 
      string_no = tuning.index(key - 1)
      prev_string = tuning[string_no - 1 if string_no > 0 else 4]
      prev_string_notes = [(prev_string + i) % len(NOTES) for i in xrange(24)]
      cur_string_notes = [(key + i) % len(NOTES) for i in xrange(24)]
      fret %= 12
      return '<>' if fret == cur_string_notes.index(scale[-1]) else note_name(note)
    for t in reversed([t + 1 for t in tuning]):
      print '| %s |' % ' | '.join(['%-2s' % print_note(t, i) for i in xrange(24)])
  print '+----' * 24 + '+'
  print '  %s  ' % '   '.join(['%-2s' % (i if i in frets else ' ') for i in xrange(1, 25)])

if __name__ == '__main__':
  for scale_name, scale_intervals in sorted(SCALES.iteritems()):
    for key, intervals in scale(scale_intervals):
      print '%20s: %-2s -> %s' % (scale_name, note_name(key), ' '.join(['%-2s' % note_name(x) for x in intervals]))
    print

  print
  print [note_name(x) for x in tuning('E')]
  guitar(tuning('D#'))

  for scale_name, scale_intervals in sorted(SCALES.iteritems()):
    for key, intervals in scale(scale_intervals):
      print '%20s: %-2s -> %s' % (scale_name, note_name(key), ' '.join(['%-2s' % note_name(x) for x in intervals]))
      guitar(tuning('D#'), intervals)
      print
    print '\n' * 5