class RBMusic::Interval

Attributes

coord[RW]

Public Class Methods

from_name(name) click to toggle source

# File lib/rb-music/interval.rb, line 10
def self.from_name(name)
  Interval.new(INTERVALS[name.to_sym])
end

from_semitones(num) click to toggle source

# File lib/rb-music/interval.rb, line 14
def self.from_semitones(num)
  Interval.new(INTERVALS_SEMITONES[num])
end

from_tones_semitones(tone_semitone) click to toggle source

# File lib/rb-music/interval.rb, line 18
def self.from_tones_semitones(tone_semitone)
  # multiply [tones, semitones] vector with [-1 2;3 -5] to get coordinate from tones and semitones
  Interval.new([tone_semitone[0] * -1 + tone_semitone[1] * 3, tone_semitone[0] * 2 + tone_semitone[1] * -5])
end

new(coord) click to toggle source

# File lib/rb-music/interval.rb, line 6
def initialize(coord)
  self.coord = coord
end

Public Instance Methods

add(interval) click to toggle source

# File lib/rb-music/interval.rb, line 34
def add(interval)
  if interval.is_a?(String)
    interval = Interval.from_name(interval)
  end
  Interval.new([coord[0] + interval.coord[0], coord[1] + interval.coord[1]])
end

semitone() click to toggle source

# File lib/rb-music/interval.rb, line 29
def semitone
  # number of semitones of interval = tones * 2 + semitones
  tone_semitone[0] * 2 + tone_semitone[1]
end

subtract(interval) click to toggle source

# File lib/rb-music/interval.rb, line 41
def subtract(interval)
  if interval.is_a?(String)
    interval = Interval.from_name(interval)
  end
  Interval.new([coord[0] - interval.coord[0], coord[1] - interval.coord[1]])
end

tone_semitone() click to toggle source

# File lib/rb-music/interval.rb, line 23
def tone_semitone
  # multiply coord vector with [5 2;3 1] to get coordinate in tones and semitones
  # [5 2;3 1] is the inverse of [-1 2;3 -5], which is the coordinates of [tone; semitone]
  @tone_semitone ||= [coord[0] * 5 + coord[1] * 3, coord[0] * 2 + coord[1] * 1]
end