Class: Fretboard

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

Overview

Fretboard class for learning the guitar fretboard.

Constant Summary collapse

FRETS = 
12
STRINGS = 
6
VERSION = 
'0.0.10'

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(args) ⇒ Fretboard

Returns a new instance of Fretboard.



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# File 'lib/fretboard.rb', line 123

def initialize(args)
  @timeout = args[:timeout] || 0

  if args.has_key?(:fret)
    a = args[:fret]
    @first_fret = a[0].to_i
    @last_fret = a.size == 2 ? a[1].to_i : @first_fret
  else
    @first_fret = 0
    @last_fret = FRETS
  end

  if @first_fret < 0 || @first_fret > FRETS ||
    @last_fret < 0 || @last_fret > FRETS ||
    @first_fret > @last_fret
    raise ArgumentError, "Invalid FRET value/range specified"
  end

  if args.has_key?(:string)
    a = args[:string]
    @first_string = a[0].to_i
    @last_string = a.size == 2 ? a[1].to_i : @first_string
  else
    @first_string = 1
    @last_string = STRINGS
  end

  if @first_string < 1 || @first_string > STRINGS ||
    @last_string < 1 || @last_string > STRINGS ||
    @first_string > @last_string
    raise ArgumentError, "Invalid STRING value/range specified"
  end

  @logfile = nil
  if args.has_key?(:logfile)
    @logfile = File.open(args[:logfile], "a")
  end

  @frets=(0..FRETS)
  @strings=(0..STRINGS-1)

  scale_sharps = %w(A A# B C C# D D# E F F# G G#)
  scale_flats  = %w(A Bb B C Db D Eb E F Gb G Ab)
  accidentals  = [1, 4, 6, 9, 11]

  # This is for the standard EADGBE tuning
  scale_index = [7, 2, 10, 5, 0, 7]

  @fretboard = []

  #
  # Fretboard is an array of strings indexed by fret number
  #
  row = []
  @frets.each do |i|
    @strings.each do |j|
      s = (scale_index[j] + i) % 12

      # For positions which contain accidentals, represent both
      # sharps and flats for the given string and fret with a
      # subarray.
      if accidentals.include?(s)
        row[j] = [scale_sharps[s], scale_flats[s]]
      else
        row[j] = scale_sharps[s]
      end
      s = (s == scale_sharps.size - 1) ? 0 : s + 1
    end
    @fretboard << row
    row = []
  end

  if args.has_key?(:show_fretboard)
    self.display(args[:show_fretboard] == "sharp" ? true : false)
  end

  # Select random fret and string numbers from within the specified
  # ranges
  @fret_max = @last_fret - @first_fret + 1
  @string_max = @last_string - @first_string + 1

rescue => e
  puts "Error: " + e
  exit 1
end

Class Method Details

.display_version ⇒ Object 



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# File 'lib/fretboard.rb', line 72

def self.display_version
  puts "#{File.basename(__FILE__)} version #{VERSION}"
end

.parse_args(args) ⇒ Object 



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# File 'lib/fretboard.rb', line 76

def self.parse_args(args)
  options = Hash.new

  op = OptionParser.new do |opts|
    opts.on("-t SECONDS", "--timeout SECONDS",
      "Set timeout on prompt") do |opt|
      options[:timeout] = opt.to_i
    end
  
    opts.on("-f MIN[:MAX]", "--fret MIN[:MAX]",
      "Set fret number(s) to drill (default 0-12)") do |opt|
      o = opt.split(":")
      o.each { |s| s.strip! }
      options[:fret] = o
    end
  
    opts.on("-s MIN[:MAX]", "--string MIN[:MAX]",
      "Set string number(s) on which to drill",
      "(default 1-6)") do |opt|
      o = opt.split(":")
      o.each { |s| s.strip! }
      options[:string] = o
    end

    opts.on("-d [0|1]", "--display [FLAT|SHARP]", "Show fretboard") do |opt|
      options[:show_fretboard] = opt
    end

    opts.on("-l LOGFILE", "--log LOGFILE", "Log score to LOGFILE") do |opt|
      options[:logfile] = opt
    end

    opts.on("-v", "--version", "Show version") do
      display_version
      exit 0
    end
  end

  begin
    op.parse!(args)
  rescue OptionParser::ParseError => e
      puts e
      exit 1
  end
  options
end

Instance Method Details

#display(sharps = true) ⇒ Object

Display an ASCII chart of the guitar fretboard



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# File 'lib/fretboard.rb', line 210

def display(sharps = true)
  nut =  "    ===============================\n"
  pos =  " %2d | %-2s | %-2s | %-2s | %-2s | %-2s | %-2s |\n"
  fret = "    +-----------------------------+\n"

  @fretboard.each_with_index do |row, i|
    r = *row.reverse
    r.each_with_index do |e, j|
      if r[j].is_a?(Array)
        slot = sharps ? 0 : 1
        r[j, 1] = r[j][slot]
      end
    end
    if i == 0
      printf(pos, i, *r)
      puts nut
      next
    end
    printf(pos, i, *r)
    puts fret
  end
end

#run ⇒ Object

Run the main query loop for the fretboard trainer.



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# File 'lib/fretboard.rb', line 260

def run
  i = 1
  errors = 0

  at_exit do
    puts "\n\nYou missed #{errors} out of #{i}.\n\n"
    if @logfile
      t = Time.now
      @logfile.puts "[#{t}] String #{@first_string}:#{@last_string}, "  +
        "Fret #{@first_fret}:#{@last_fret} -- Missed #{errors} out of #{i}"
    end
  end

  # Skip stack traceback on ctrl-c
  trap("SIGINT") { exit }

  loop do
    s = @first_string + rand(@string_max)
    f = @first_fret + rand(@fret_max)
    printf("\n[#{i}] String #{s}, fret #{f}\n")
    printf("? ")
    $stdout.flush
    ans, timed_out = gets
    ans = ans.chomp.downcase
    note = @fretboard[f][s-1]
    correct = false

    if note.is_a?(Array)
      puts "  #{note[0]} / #{note[1]}"
      if ans == note[0].downcase || ans.downcase == note[1].downcase
        correct = true
      end
    else
      puts "  #{@fretboard[f][s-1]}"
      if ans.upcase == @fretboard[f][s-1].to_s
        correct = true
      end
    end

    if correct
      puts green(bold("Correct."))
    else
      errors += 1
      puts red(bold("Incorrect.")) + (timed_out ? " [Timeout]" : "")
      if timed_out
        printf("\nContinue? ")
        $stdin.gets
      end
    end

    i += 1
  end
end

#to_s ⇒ Object Also known as: inspect

Return string representation of Fretboard instance.



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# File 'lib/fretboard.rb', line 234

def to_s
  str = ""
  @frets.each_with_index do |f, i|
    str << "#{i}: " + @fretboard[f].reverse.inspect + "\n"
  end
  str
end