Class: HeadMusic::RhythmicUnit

Inherits:
Object
  • Object
show all
Includes:
Named
Defined in:
lib/head_music/rhythmic_unit.rb

Overview

A rhythmic unit is a rudiment of duration consisting of doublings and divisions of a whole note.

Constant Summary collapse

MULTIPLES = 
["whole", "double whole", "longa", "maxima"].freeze
FRACTIONS = 
[
  "whole", "half", "quarter", "eighth", "sixteenth", "thirty-second",
  "sixty-fourth", "hundred twenty-eighth", "two hundred fifty-sixth"
].freeze
BRITISH_MULTIPLE_NAMES = 
%w[semibreve breve longa maxima].freeze
BRITISH_DIVISION_NAMES = 
%w[
  semibreve minim crotchet quaver semiquaver demisemiquaver
  hemidemisemiquaver semihemidemisemiquaver demisemihemidemisemiquaver
].freeze

Instance Attribute Summary collapse

Attributes included from Named

#alias_name_keys, #name_key

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Named

#ensure_localized_name, included, #localized_name, #localized_names, #name, #name=

Constructor Details

#initialize(canonical_name) ⇒ RhythmicUnit

Returns a new instance of RhythmicUnit.



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# File 'lib/head_music/rhythmic_unit.rb', line 29

def initialize(canonical_name)
  self.name = canonical_name
  @numerator = 2**numerator_exponent
  @denominator = 2**denominator_exponent
end

Instance Attribute Details

#denominator ⇒ Object (readonly)

Returns the value of attribute denominator.



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# File 'lib/head_music/rhythmic_unit.rb', line 23

def denominator
  @denominator
end

#numerator ⇒ Object (readonly)

Returns the value of attribute numerator.



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# File 'lib/head_music/rhythmic_unit.rb', line 23

def numerator
  @numerator
end

Class Method Details

.for_denominator_value(denominator) ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 19

def self.for_denominator_value(denominator)
  get(FRACTIONS[Math.log2(denominator).to_i])
end

.get(name) ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 25

def self.get(name)
  get_by_name(name)
end

Instance Method Details

#british_name ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 60

def british_name
  if multiple?
    BRITISH_MULTIPLE_NAMES[MULTIPLES.index(name)]
  elsif fraction?
    BRITISH_DIVISION_NAMES[FRACTIONS.index(name)]
  elsif BRITISH_MULTIPLE_NAMES.include?(name) || BRITISH_DIVISION_NAMES.include?(name)
    name
  end
end

#flags ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 52

def flags
  FRACTIONS.include?(name) ? [FRACTIONS.index(name) - 2, 0].max : 0
end

#notehead ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 43

def notehead
  return :maxima if relative_value == 8
  return :longa if relative_value == 4
  return :breve if relative_value == 2
  return :open if [0.5, 1].include? relative_value

  :closed
end

#relative_value ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 35

def relative_value
  @numerator.to_f / @denominator
end

#stemmed? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/head_music/rhythmic_unit.rb', line 56

def stemmed?
  relative_value < 1
end

#ticks ⇒ Object 



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# File 'lib/head_music/rhythmic_unit.rb', line 39

def ticks
  HeadMusic::Rhythm::PPQN * 4 * relative_value
end