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# frozen_string_literal: true
module Coltrane
module Theory
# Interval describe the logarithmic distance between 2 frequencies.
# It's measured in cents.
class FrequencyInterval
include Comparable
attr_reader :cents
class << self
alias [] new
end
def initialize(cents)
@cents = cents.round
end
def semitones
(cents.to_f / 100).round
end
def ascending
self.class[cents.abs]
end
def descending
self.class[-cents.abs]
end
def ascending?
cents > 0
end
def descending?
cents < 0
end
def inversion
self.class[(-cents.abs % 1200) * (ascending? ? +1 : -1)]
end
def opposite
self.class.new(-cents)
end
def interval_class
IntervalClass.new(semitones)
end
def ==(other)
return false unless other.is_a? FrequencyInterval
cents == other.cents
end
alias eql? ==
alias hash cents
def +(other)
case other
when Numeric then FrequencyInterval[cents + other]
when Interval then FrequencyInterval[cents + other.cents]
end
end
def -(other)
case other
when Numeric then FrequencyInterval[cents - other]
when Interval then FrequencyInterval[cents - other.cents]
end
end
def -@
FrequencyInterval[-cents]
end
def <=>(other)
cents <=> other.cents
end
end
end
end
Version data entries
22 entries across 22 versions & 1 rubygems