Class: Musa::Transcriptors::FromGDV::ToMIDI::Trill

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

Overview

Process: .tr

Instance Method Summary collapse

Methods inherited from Musa::Transcription::FeatureTranscriptor

#check

Constructor Details

#initialize(duration_factor: nil) ⇒ Trill

Returns a new instance of Trill.



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# File 'lib/musa-dsl/transcription/from-gdv-to-midi.rb', line 120

def initialize(duration_factor: nil)
  @duration_factor = duration_factor || 1/4r
end

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 124

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

  if tr
    note_duration = base_duration * @duration_factor

    check(tr) do |tr|
      case tr
      when Numeric # duration factor
        note_duration *= base_duration * tr.to_r
      end
    end

    used_duration = 0r
    last = nil

    gdvs = []

    check(tr) do |tr|
      case tr
      when :low # start with lower note
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = -1); gdv[:duration] = note_duration }
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration }
        used_duration += 2 * note_duration

      when :low2 # start with upper note but go to lower note once
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 1); gdv[:duration] = note_duration }
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration }
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = -1); gdv[:duration] = note_duration }
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration }
        used_duration += 4 * note_duration

      when :same # start with the same note
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration }
        used_duration += note_duration
      end
    end

    2.times do
      if used_duration + 2 * note_duration <= gdv[:duration]
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 1); gdv[:duration] = note_duration }
        gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration }

        used_duration += 2 * note_duration
      end
    end

    while used_duration + 2 * note_duration * 2/3r <= gdv[:duration]
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 1); gdv[:duration] = note_duration * 2/3r }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = note_duration * 2/3r }

      used_duration += 2 * note_duration * 2/3r
    end

    duration_diff = gdv[:duration] - used_duration
    if duration_diff >= note_duration
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 1); gdv[:duration] = duration_diff / 2 }
      gdvs << gdv.clone.tap { |gdv| gdv[:grade] += (last = 0); gdv[:duration] = duration_diff / 2 }

    elsif duration_diff > 0
      gdvs[-1][:duration] += duration_diff / 2
      gdvs[-2][:duration] += duration_diff / 2
    end

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