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Contents
class Scale
ASCENDING_INTERVALS = %w(m M A)
CHROMATIC_SCALE = ['C', 'C#', 'D', 'D#', 'E', 'F', 'F#', 'G', 'G#', 'A', 'A#', 'B']
FLAT_CHROMATIC_SCALE = %w(C Db D Eb E F Gb G Ab A Bb B)
FLAT_KEYS = %w(F Bb Eb Ab Db Gb d g c f bb eb)
def initialize(tonic, scale_name, pattern = nil)
@tonic = tonic.capitalize
@scale_name = scale_name
@pattern = pattern
@chromatic_scale = FLAT_KEYS.include?(tonic) ? FLAT_CHROMATIC_SCALE : CHROMATIC_SCALE
end
def name
"#{tonic} #{scale_name}"
end
def pitches
return reorder_chromatic_scale unless pattern
last_index = 0
scale = pattern.each_char.with_object([]) do |c, collector|
collector << reorder_chromatic_scale[last_index]
last_index += ASCENDING_INTERVALS.index(c) + 1
end
end
private
attr_reader :tonic, :scale_name, :pattern, :chromatic_scale
def reorder_chromatic_scale
return chromatic_scale if tonic == 'C'
index = chromatic_scale.index(tonic)
chromatic_scale[index..-1] + chromatic_scale[0..index - 1]
end
end
module BookKeeping
VERSION = 1
end
Version data entries
396 entries across 396 versions & 1 rubygems