View source for Aligning lyrics based on vowels

This snippet shows how, in music with lyrics, you can align lyrics based on where vowels fall within <code>LyricText</code> items.

In each measure of this snippet, '''the first note demonstrates the use of these functions''', and the second note shows LilyPond’s default alignment.

'''Source:''' Solution by Kieren MacMillan posted to the mailing list [https://lists.gnu.org/archive/html/lilypond-user/2026-01/msg00334.html in this thread]. The code for this solution was inspired by [[Center lyric syllables (ignoring punctuation)]].

<lilypond version="2.26">
% View this snippet online:
% https://wiki.lilypond.community/wiki/Aligning_lyrics_based_on_vowels

% Define the set of characters that will be
% classified as vowels for these commands:
#(define vowel-set
   (list->char-set
    (string->list "AÁÀÃÂÆǼEÉÈÊIÍÌÎOÓÒÕÔŒU
        ÚÙÛYaáàãâæǽeéèêiíìîoóòõôœuúùûy")))
% Tweak this set based on your needs.
% For example, if your lyrics are in a language
% in which ⟨y⟩ is *always* pronounced as a vowel,
% you will want to make sure that Y and y are in your list.

% This function returns the width of the
% grob (stencil) for a given piece of text.
#(define (width grob text)
   (let* ((X-extent
           (ly:stencil-extent (grob-interpret-markup grob text) X)))
     (if (interval-empty? X-extent)
         0
         (cdr X-extent))))

% This callback sets the alignment point of a LyricText grob
% to the centre of the first vowel that it contains.
#(define (center-on-first-vowel grob)
   (let* ((text (ly:grob-property-data grob 'text))
          (syllable (markup->string text))
          (vowel-position
           (if (string-index syllable vowel-set)
               (string-index syllable vowel-set)
               0))
          (vowel-end
           (if (string-index syllable vowel-set)
               (+ (string-index syllable vowel-set) 1)
               (string-length syllable)))
          (preword (substring syllable 0 vowel-position))
          (word (substring syllable vowel-position vowel-end))
          (preword-width (width grob preword))
          (word-width (width grob
                             (if (string-null? syllable) text word)))
          (note-column (ly:grob-parent grob X))
          (note-column-extent (ly:grob-extent
                               note-column note-column X))
          (note-column-width (interval-length note-column-extent))
          (self-X (ly:grob-property-data grob 'self-alignment-X)))
     (-
      (*
       (/ (- note-column-width word-width) 2)
       (1+ (if (procedure? self-X) (self-X grob) self-X)))
      preword-width)))

% This callback sets the alignment point of a LyricText grob
% to the point midway between its first and last vowels.
#(define (center-between-vowels grob)
   (let* ((text (ly:grob-property-data grob 'text))
          (syllable (markup->string text))
          (word-position
           (if (string-index syllable vowel-set)
               (string-index syllable vowel-set)
               0))
          (word-end
           (if (string-index-right syllable vowel-set)
               (+ (string-index-right syllable vowel-set) 1)
               (string-length syllable)))
          (preword (substring syllable 0 word-position))
          (word (substring syllable word-position word-end))
          (preword-width (width grob preword))
          (word-width (width grob
                             (if (string-null? syllable) text word)))
          (note-column (ly:grob-parent grob X))
          (note-column-extent (ly:grob-extent
                               note-column note-column X))
          (note-column-width (interval-length note-column-extent))
          (self-X (ly:grob-property-data grob 'self-alignment-X)))

     (-
      (*
       (/ (- note-column-width word-width) 2)
       (1+ (if (procedure? self-X) (self-X grob) self-X)))
      preword-width)))

% Helper functions that use the above code:
cvs = \once \override LyricText.X-offset = #center-between-vowels
cfv = \once \override LyricText.X-offset = #center-on-first-vowel

\fixed c' {
  \*8 { f2 f }
  % The command \* requires
  % version 2.25 or later.
  % For version 2.24, use
  % \repeat unfold 8
}

\addlyrics {
  \cfv piste piste
  \cfv “O—!!!” “O—!!!”
  \cvs “O—!!!” “O—!!!”
  \cfv blessed blessed
  \cfv heaven heaven
  \cvs heav’n heav’n
  \cvs youths youths
  \cvs each each
}
</lilypond>

If you want to apply one of these functions globally, you can place either of the following in your <code>\layout</code> block:
<br>
<code>\override Score.LyricText.X-offset = #center-between-vowels
</code>
<br>
<code>\override Score.LyricText.X-offset = #center-on-first-vowel</code>

If you then need to switch off the function locally, use <code>\once \revert LyricText.X-offset</code>.
[[Category:Vocal music]]
[[Category:Text]]
[[Category:Tweaks and overrides]]
[[Category:Scheme]]
[[Category:Spacing]]
[[Category:Snippet]]