Class: Musa::Transcriptors::FromGDV::ToMIDI::Turn

Inherits:
Musa::Transcription::FeatureTranscriptor show all
Defined in:
lib/musa-dsl/transcription/from-gdv-to-midi.rb

Overview

Process: .turn

Instance Method Summary collapse

Methods inherited from Musa::Transcription::FeatureTranscriptor

#check

Instance Method Details

#transcript(gdv, base_duration:, tick_duration:) ⇒ Object 



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# File 'lib/musa-dsl/transcription/from-gdv-to-midi.rb', line 79

def transcript(gdv, base_duration:, tick_duration:)
  turn = gdv.delete :turn

  if turn
    start = :up

    check(turn) do |turn|
      case turn
      when :true, :up
        start = :up
      when :down, :low
        start = :down
      end
    end

    duration = gdv[:duration] / 4r

    gdvs = []

    case start
    when :up
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 1; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 0; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += -1; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 0; gdv[:duration] = duration }
    when :down
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += -1; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 0; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 1; gdv[:duration] = duration }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += 0; gdv[:duration] = duration }
    end

    super gdvs, base_duration: base_duration, tick_duration: tick_duration
  else
    super
  end
end