Class: HeadMusic::Notation::LilyPond::PitchWriter

Inherits:
Object
  • Object
show all
Defined in:
lib/head_music/notation/lily_pond/pitch_writer.rb

Overview

Converts a pitch into a LilyPond absolute-mode pitch token using the default (Dutch) note names: letter, is/es alteration suffixes, and octave marks relative to c’ as middle C.

Constant Summary collapse

ALTERATION_SUFFIXES = 
{
  0 => "",
  1 => "is",
  -1 => "es",
  2 => "isis",
  -2 => "eses"
}.freeze

Class Method Summary collapse

Class Method Details

.alteration_suffix(semitones) ⇒ Object

Public so KeyMapper spells its tonic with the same table.



22
23
24
25
26
 
# File 'lib/head_music/notation/lily_pond/pitch_writer.rb', line 22

def self.alteration_suffix(semitones)
  ALTERATION_SUFFIXES.fetch(semitones.to_i) do
    raise RenderError, "no LilyPond spelling is known for an alteration of #{semitones} semitones"
  end
end

.octave_marks(register) ⇒ Object (private)

The gem’s middle C is register 4 and LilyPond’s absolute-mode c’ is middle C (plain c is C3), so the mark count is register - 3.



30
31
32
33
 
# File 'lib/head_music/notation/lily_pond/pitch_writer.rb', line 30

def self.octave_marks(register)
  marks = register - 3
  (marks >= 0) ? "'" * marks : "," * -marks
end

.token(pitch) ⇒ Object 



15
16
17
18
19
 
# File 'lib/head_music/notation/lily_pond/pitch_writer.rb', line 15

def self.token(pitch)
  pitch = HeadMusic::Rudiment::Pitch.get(pitch)
  letter = pitch.letter_name.to_s.downcase
  "#{letter}#{alteration_suffix(pitch.alteration_semitones)}#{octave_marks(pitch.register)}"
end