Class: Beats::Pattern

Inherits:
Object
  • Object
show all
Defined in:
lib/beats/pattern.rb

Overview

Domain object which models one or more Tracks playing a part of the song at the same time. For example, a bass drum, snare drum, and hi-hat track playing the song’s chorus.

This object is like sheet music; the AudioEngine is responsible creating actual audio data for a Pattern (with the help of a Kit).

Constant Summary collapse

FLOW_TRACK_NAME = 
"flow"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ Pattern

Returns a new instance of Pattern.



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# File 'lib/beats/pattern.rb', line 10

def initialize(name)
  @name = name
  @tracks = {}
end

Instance Attribute Details

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/beats/pattern.rb', line 70

def name
  @name
end

#tracks ⇒ Object

Returns the value of attribute tracks.



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# File 'lib/beats/pattern.rb', line 70

def tracks
  @tracks
end

Instance Method Details

#same_tracks_as?(other_pattern) ⇒ Boolean

Returns whether or not this pattern has the same number of tracks as other_pattern, and that each of the tracks has the same name and rhythm. Ordering of tracks does not matter; will return true if the two patterns have the same tracks but in a different ordering.

Returns:

  • (Boolean) 


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# File 'lib/beats/pattern.rb', line 41

def same_tracks_as?(other_pattern)
  @tracks.keys.each do |track_name|
    other_pattern_track = other_pattern.tracks[track_name]
    if other_pattern_track.nil? || @tracks[track_name].rhythm != other_pattern_track.rhythm
      return false
    end
  end

  @tracks.length == other_pattern.tracks.length
end

#step_count ⇒ Object 



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# File 'lib/beats/pattern.rb', line 34

def step_count
  @tracks.values.collect {|track| track.rhythm.length }.max || 0
end

#to_yaml ⇒ Object

Returns a YAML representation of the Pattern. Produces nicer looking output than the default version of to_yaml().



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# File 'lib/beats/pattern.rb', line 54

def to_yaml
  longest_track_name_length =
    @tracks.keys.inject(0) do |max_length, name|
      (name.to_s.length > max_length) ? name.to_s.length : max_length
    end
  ljust_amount = longest_track_name_length + 7

  yaml = "#{@name.to_s.capitalize}:\n"
  @tracks.keys.sort.each do |track_name|
    yaml += "  - #{track_name}:".ljust(ljust_amount)
    yaml += "#{@tracks[track_name].rhythm}\n"
  end

  yaml
end

#track(name, rhythm) ⇒ Object

Adds a new track to the pattern.



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# File 'lib/beats/pattern.rb', line 16

def track(name, rhythm)
  track_key = unique_track_name(name)
  new_track = Track.new(name, rhythm)
  @tracks[track_key] = new_track

  # If the new track is longer than any of the previously added tracks,
  # pad the other tracks with trailing . to make them all the same length.
  # Necessary to prevent incorrect overflow calculations for tracks.
  longest_track_length = step_count()
  @tracks.values.each do |track|
    if track.rhythm.length < longest_track_length
      track.rhythm += "." * (longest_track_length - track.rhythm.length)
    end
  end

  new_track
end