Class: Musa::Scales::Scale

Inherits:
Object
  • Object
show all
Extended by:
Forwardable
Defined in:
lib/musa-dsl/music/scales.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(kind, root_pitch:) ⇒ Scale

Returns a new instance of Scale.



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# File 'lib/musa-dsl/music/scales.rb', line 270

def initialize(kind, root_pitch:)
  @notes_by_grade = {}
  @notes_by_pitch = {}

  @kind = kind

  @root_pitch = root_pitch

  @kind.class.grades_functions.each do |name|
    define_singleton_method name do
      self[name]
    end
  end

  freeze
end

Instance Attribute Details

#kind ⇒ Object (readonly)

Returns the value of attribute kind.



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# File 'lib/musa-dsl/music/scales.rb', line 289

def kind
  @kind
end

#root_pitch ⇒ Object (readonly)

Returns the value of attribute root_pitch.



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# File 'lib/musa-dsl/music/scales.rb', line 289

def root_pitch
  @root_pitch
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 414

def ==(other)
  self.class == other.class &&
      @kind == other.kind &&
      @root_pitch == other.root_pitch
end

#[](grade_or_symbol) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/musa-dsl/music/scales.rb', line 309

def [](grade_or_symbol)

  raise ArgumentError, "grade_or_symbol '#{grade_or_symbol}' should be a Integer, String or Symbol" unless grade_or_symbol.is_a?(Symbol) || grade_or_symbol.is_a?(String) || grade_or_symbol.is_a?(Integer)

  wide_grade, sharps = grade_of(grade_or_symbol)

  unless @notes_by_grade.key?(wide_grade)

    octave = wide_grade / @kind.class.grades
    grade = wide_grade % @kind.class.grades

    pitch = @root_pitch +
        octave * @kind.tuning.notes_in_octave +
        @kind.class.pitches[grade][:pitch]

    note = NoteInScale.new self, grade, octave, pitch

    @notes_by_grade[wide_grade] = @notes_by_pitch[pitch] = note
  end


  @notes_by_grade[wide_grade].sharp(sharps)
end

#absolut ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 299

def absolut
  @kind[0]
end

#chromatic ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 295

def chromatic
  @kind.tuning.chromatic[@root_pitch]
end

#grade_of(grade_or_string_or_symbol) ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 333

def grade_of(grade_or_string_or_symbol)
  name, wide_grade, accidentals = parse_grade(grade_or_string_or_symbol)

  grade = @kind.class.grade_of_function name if name

  octave = wide_grade / @kind.class.grades if wide_grade
  grade = wide_grade % @kind.class.grades if wide_grade

  octave ||= 0

  return octave * @kind.class.grades + grade, accidentals
end

#inspect ⇒ Object Also known as: to_s 



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# File 'lib/musa-dsl/music/scales.rb', line 420

def inspect
  "<Scale: kind = #{@kind} root_pitch = #{@root_pitch}>"
end

#note_of_pitch(pitch, allow_chromatic: nil, allow_nearest: nil) ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 374

def note_of_pitch(pitch, allow_chromatic: nil, allow_nearest: nil)
  allow_chromatic ||= false
  allow_nearest ||= false

  note = @notes_by_pitch[pitch]

  unless note
    pitch_offset = pitch - @root_pitch

    pitch_offset_in_octave = pitch_offset % @kind.tuning.scale_system.notes_in_octave
    pitch_offset_octave = pitch_offset / @kind.tuning.scale_system.notes_in_octave

    grade = @kind.class.pitches.find_index { |pitch_definition| pitch_definition[:pitch] == pitch_offset_in_octave }

    if grade
      wide_grade = pitch_offset_octave * @kind.class.grades + grade
      note = self[wide_grade]

    elsif allow_nearest
      sharps = 0

      until note
        note = note_of_pitch(pitch - (sharps += 1) * @kind.tuning.scale_system.part_of_tone_size)
        note ||= note_of_pitch(pitch + sharps * @kind.tuning.scale_system.part_of_tone_size)
      end

    elsif allow_chromatic
      nearest = note_of_pitch(pitch, allow_nearest: true)

      note = chromatic.note_of_pitch(pitch).with_background(scale: self, grade: nearest.grade, octave: nearest.octave, sharps: (pitch - nearest.pitch) / @kind.tuning.scale_system.part_of_tone_size)
    end
  end

  note
end

#octave(octave) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/musa-dsl/music/scales.rb', line 303

def octave(octave)
  raise ArgumentError, "#{octave} is not integer" unless octave == octave.to_i

  @kind[@root_pitch + octave * @kind.class.grades]
end

#offset_of_interval(interval_name) ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 410

def offset_of_interval(interval_name)
  @kind.tuning.offset_of_interval(interval_name)
end

#parse_grade(neuma_grade) ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 346

def parse_grade(neuma_grade)
  name = wide_grade = nil
  accidentals = 0

  case neuma_grade
  when Symbol, String
    match = /\A(?<name>[^[#|_]]*)(?<accidental_sharps>#*)(?<accidental_flats>_*)\Z/.match neuma_grade.to_s

    if match
      if match[:name] == match[:name].to_i.to_s
        wide_grade = match[:name].to_i
      else
        name = match[:name].to_sym unless match[:name].empty?
      end
      accidentals = match[:accidental_sharps].length - match[:accidental_flats].length
    else
      name = neuma_grade.to_sym unless (neuma_grade.nil? || neuma_grade.empty?)
    end
  when Numeric
    wide_grade = neuma_grade.to_i

  else
    raise ArgumentError, "Cannot eval #{neuma_grade} as name or grade position."
  end

  return name, wide_grade, accidentals
end

#root ⇒ Object 



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# File 'lib/musa-dsl/music/scales.rb', line 291

def root
  self[0]
end