Class: StringyFi::Converter

Inherits:
Object
  • Object
show all
Defined in:
lib/stringyfi/converter.rb

Overview

Main controller for the conversion process

Constant Summary collapse

INITIAL_OCTAVE =

setup by the stringy firmware

1
OCTAVE_OFFSET =

how many octaves to offset the source

3

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename) ⇒ Converter

Returns a new instance of Converter.



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# File 'lib/stringyfi/converter.rb', line 13

def initialize(filename)
  self.filename = filename
end

Instance Attribute Details

#filename ⇒ Object

Returns the value of attribute filename.



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# File 'lib/stringyfi/converter.rb', line 10

def filename
  @filename
end

#xml_doc ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 159

def xml_doc
  @xml_doc ||= Nokogiri::XML(io_stream)
end

Instance Method Details

#convert! ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 17

def convert!
  $stderr.puts "converting #{filename}.."
  shortest_fractional_duration = measures.shortest_fractional_duration
  $stderr.puts "  shortest_fractional_duration: #{shortest_fractional_duration}"
  $stderr.puts "  octave_range: #{measures.octave_range.inspect}"

  puts score_preamble
  puts score_body(shortest_fractional_duration)
  puts score_coda

  $stderr.puts '.. done.'
end

#encoding_date ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 93

def encoding_date
  xml_doc.xpath('//identification/encoding/encoding-date').text
end

#encoding_software ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 97

def encoding_software
  xml_doc.xpath('//identification/encoding/software').text
end

#identification ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 101

def identification
  {
    title: title,
    encoding: {
      date: encoding_date,
      software: encoding_software
    }
  }
end

#io_stream ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 163

def io_stream
  File.open(filename).read
end

#measure(measure_id) ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 155

def measure(measure_id)
  measures[measure_id]
end

#measures ⇒ Object

Returns measures for the piece. only converts one part (for now) only includes staff 1



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# File 'lib/stringyfi/converter.rb', line 126

def measures
  @measures ||= begin
    measures = StringyFi::Measures.new
    part = parts.first
    part.xpath('measure').each_with_index do |part_measure, m|
      measures[m] ||= []
      part_measure.xpath('note').each_with_object(measures[m]) do |note, memo|
        next unless note.xpath('staff').text == '1'
        next unless note.xpath('voice').text == '1'

        pitch = note.xpath('pitch')
        duration = note.xpath('duration').text.to_i
        actual_notes = note.xpath('actual-notes').text.to_i
        normal_notes = note.xpath('normal-notes').text.to_i
        duration = duration * 1.0 * normal_notes / actual_notes if actual_notes.positive? && normal_notes.positive?
        duration_type = note.xpath('type').text
        memo << StringyFi::Note.new(
          pitch.xpath('step').text,
          pitch.xpath('octave').text,
          pitch.xpath('alter').text,
          duration,
          duration_type
        )
      end
    end
    measures
  end
end

#part_list ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 111

def part_list
  xml_doc.xpath('//part-list/score-part').each_with_object([]) do |part, memo|
    h = {}
    h[:id] = part.attr('id')
    memo << h
  end
end

#parts ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 119

def parts
  xml_doc.xpath('//part')
end

#score_body(shortest_fractional_duration) ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 50

def score_body(shortest_fractional_duration)
  lines = []
  current_octave = INITIAL_OCTAVE + OCTAVE_OFFSET
  measures.each_with_index do |measure, measure_index|
    lines << "\t; measure #{measure_index + 1}"
    measure.each do |note|
      unless note.rest?
        if note.octave != current_octave
          delta = note.octave - current_octave
          sign = delta.positive? ? '+' : '-'
          delta.abs.times do
            lines << "\ttoctave #{sign}1"
          end
          current_octave = note.octave
        end
      end
      short_repeats, medium_repeats, long_repeats, very_long_repeats = note.stringy_durations(shortest_fractional_duration)
      if note.rest?
        short_repeats.times     { lines << "\ttrest 1" }
        medium_repeats.times    { lines << "\ttrest 2" }
        long_repeats.times      { lines << "\ttrest 3" }
        very_long_repeats.times { lines << "\ttrest 4" }
      else
        short_repeats.times     { lines << "\ttnote #{note.to_stringy(current_octave)},1,0  ; #{note.to_note_id}" }
        medium_repeats.times    { lines << "\ttnote #{note.to_stringy(current_octave)},2,0  ; #{note.to_note_id}" }
        long_repeats.times      { lines << "\ttnote #{note.to_stringy(current_octave)},3,0  ; #{note.to_note_id}" }
        very_long_repeats.times { lines << "\ttnote #{note.to_stringy(current_octave)},4,0  ; #{note.to_note_id}" }
      end
    end
  end
  lines
end

#score_coda ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 43

def score_coda
  <<~CODA
    \ttrest 8
    \ttstop
  CODA
end

#score_preamble ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 30

def score_preamble
  <<~PREAMBLE
    ;**************************************************************************
    ;** Title: #{title}
    ;** Tempo: #{tempo}
    ;** Encoded: #{encoding_date} with #{encoding_software}
    ;** Stringyfied: #{Time.now}
    ;**************************************************************************

    \ttstart DemoTune
  PREAMBLE
end

#tempo ⇒ Object

Simplified - only supports one tempo for the piece assumed for quarter note



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# File 'lib/stringyfi/converter.rb', line 89

def tempo
  @tempo ||= xml_doc.xpath('//measure/direction/sound/@tempo').to_s.to_i
end

#title ⇒ Object 



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# File 'lib/stringyfi/converter.rb', line 83

def title
  xml_doc.xpath('//work/work-title').text
end