Class: MTK::Groups::Melody

Inherits:
Object
  • Object
show all
Includes:
PitchCollection
Defined in:
lib/mtk/groups/melody.rb

Overview

An ordered collection of Pitches.

The “horizontal” (sequential) pitch collection.

Unlike the strict definition of melody, this class is fairly abstract and only models a succession of pitches. To create a true, playable melody one must combine an MTK::Melody and rhythms into a Events::Timeline.

See Also:

Direct Known Subclasses

Chord

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from PitchCollection

#invert, #transpose

Methods included from Collection

#[], #clone, #concat, #each, #empty?, #enumerable_map, #first, #last, #map, #partition, #permute, #repeat, #reverse, #rotate, #size, #to_a

Constructor Details

#initialize(pitches) ⇒ Melody

Returns a new instance of Melody.

Parameters:

  • pitches (#to_a) —

    the collection of pitches

See Also:

  • MTK#Melody


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# File 'lib/mtk/groups/melody.rb', line 21

def initialize(pitches)
  @pitches = pitches.to_a.clone.freeze
end

Instance Attribute Details

#pitches ⇒ Object (readonly)

Returns the value of attribute pitches.



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# File 'lib/mtk/groups/melody.rb', line 16

def pitches
  @pitches
end

Class Method Details

.from_a(enumerable) ⇒ Object 



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# File 'lib/mtk/groups/melody.rb', line 46

def self.from_a enumerable
  new enumerable
end

.from_pitch_classes(pitch_classes, start = MTK::Lang::Pitches::C4, max_distance = 12) ⇒ Object 



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# File 'lib/mtk/groups/melody.rb', line 25

def self.from_pitch_classes(pitch_classes, start=MTK::Lang::Pitches::C4, max_distance=12)
  pitch = start
  pitches = []
  pitch_classes.each do |pitch_class|
    pitch = pitch.nearest(pitch_class)
    pitch -= 12 if pitch > start+max_distance # keep within max_distance of start (default is one octave)
    pitch += 12 if pitch < start-max_distance
    pitches << pitch
  end
  new pitches
end

Instance Method Details

#==(other) ⇒ Object

Parameters:



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# File 'lib/mtk/groups/melody.rb', line 59

def == other
  if other.respond_to? :pitches
    @pitches == other.pitches
  elsif other.is_a? Enumerable
    @pitches == other.to_a
  else
    @pitches == other
  end
end

#=~(other) ⇒ Object

Compare for equality, ignoring order and duplicates

Parameters:



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# File 'lib/mtk/groups/melody.rb', line 71

def =~ other
  @normalized_pitches ||= @pitches.uniq.sort
  @normalized_pitches == case
    when other.respond_to?(:pitches) then other.pitches.uniq.sort
    when (other.is_a? Array and other.frozen?) then other
    when other.respond_to?(:to_a) then other.to_a.uniq.sort
    else other
  end
end

#elements ⇒ Object

See Also:

  • Helper::Collection


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# File 'lib/mtk/groups/melody.rb', line 38

def elements
  @pitches
end

#pitch_classes ⇒ Object 



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# File 'lib/mtk/groups/melody.rb', line 54

def pitch_classes
  @pitch_classes ||= @pitches.map{|p| p.pitch_class }
end

#to_pitch_class_set(remove_duplicates = true) ⇒ Object 



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# File 'lib/mtk/groups/melody.rb', line 50

def to_pitch_class_set(remove_duplicates=true)
  PitchClassSet.new(remove_duplicates ? pitch_classes.uniq : pitch_classes)
end

#to_s ⇒ Object 



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# File 'lib/mtk/groups/melody.rb', line 81

def to_s
  '[' + @pitches.map{|pitch| pitch.to_s}.join(', ') + ']'
end