Module: Feep::Utils

Defined in:
lib/feep/utils.rb

Class Method Summary collapse

Class Method Details

.convert_note_to_freq(freq_or_note) ⇒ Object

makes sure that whatever kind of sound was entered on the CLI it is now a frequency to feed into the sample data generator


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# File 'lib/feep/utils.rb', line 17

def self.convert_note_to_freq(freq_or_note)
  if freq_or_note.match(/[A-Za-z]/)
    if NOTE_FREQ.key?(freq_or_note)
      frequency = NOTE_FREQ[freq_or_note]
    else
      print_error(ERROR_MSG[:invalid_note])
    end
  else
    frequency = freq_or_note
  end
  
  return frequency
end

.freq_to_midi(freq) ⇒ Object

convert frequencies to midi notes


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# File 'lib/feep/utils.rb', line 11

def self.freq_to_midi(freq)
  (69 + 12 * (Math.log2(freq.to_i.abs / 440.0))).round
end

.midi_to_freq(midi_note) ⇒ Object

convert midi notes to frequencies


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# File 'lib/feep/utils.rb', line 6

def self.midi_to_freq(midi_note)
  440.0 * (2.0 ** ((midi_note.to_f-69)/12))
end

.print_error(msg_id) ⇒ Object

displays error, usage, and exits


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# File 'lib/feep/utils.rb', line 32

def self.print_error(msg_id)
  msg = ERROR_MSG[msg_id.to_sym]
  puts "#{File.basename($PROGRAM_NAME).split(".")[0]}: #{msg}"
  puts 'feep -h for usage'
  exit
end