Editing Using any arbitrary markup as LyricHyphen

Lyric hyphens have several user-modifiable properties such as length and thickness; this doesn’t allow, however, for further tweaking, for example, rendering hyphens as rounded boxes to better match the font possibly used for <code>LyricText</code>, or even printing hyphens as actual glyphs rather than drawing basic boxes.

This snippet rewrites the <code>LyricHyphen</code> stencil procedure to use a proper glyph… or indeed any arbitrary markup.

<lilypond version="2.24.0" full>
%% Originally contributed by Aaron Hill:
%% https://lists.gnu.org/archive/html/lilypond-user/2019-03/msg00257.html

#(define (lyric-hyphen-text-stencil grob)
   "Draws a LyricHyphen using an arbitrary text markup."
   
   (define (span-point side common dir)
     (let ((iv
            (ly:generic-bound-extent side common)))
       (if (interval-empty? iv)
           (ly:grob-relative-coordinate side common X)
           (interval-bound iv dir))))
           
   (define (get-text-stencil grob)
     (let* ((orig (ly:grob-original grob))
            (into (ly:spanner-broken-into orig)))
       (grob-interpret-markup
        (ly:spanner-bound (if (null? into) orig (first into)) LEFT)
        (ly:grob-property grob 'text "-"))))
        
   (let* ((left-bound (ly:spanner-bound grob LEFT))
          (right-bound (ly:spanner-bound grob RIGHT))
          (common (ly:grob-common-refpoint left-bound right-bound X))
          (left-span (span-point left-bound common RIGHT))
          (right-span (span-point right-bound common LEFT))
          (span-length (- right-span left-span))
          (padding (ly:grob-property grob 'padding 0.1))
          (minimum-length (ly:grob-property grob 'minimum-length 0.3))
          (usable-length 
            (- span-length
               (if (zero? (ly:item-break-dir left-bound)) padding 0)
               (if (zero? (ly:item-break-dir right-bound)) padding 0))))
     (if (< usable-length minimum-length) '()
         (let* ((dash-sten (get-text-stencil grob))
                (dash-extent (ly:stencil-extent dash-sten X))
                (dash-length (min (interval-length dash-extent) usable-length))
                (scaled-sten (ly:stencil-scale
                              (ly:stencil-translate-axis
                               dash-sten (- (interval-start dash-extent)) X)
                              (/ dash-length (interval-length dash-extent)) 1))
                (dash-period 
                  (max (ly:grob-property grob 'dash-period 1.0) dash-length))
                (dash-count 
                  (1+ (floor (/ (- usable-length dash-length) dash-period))))
                (extra 
                  (- usable-length 
                     dash-length 
                     (* (- dash-count 1) dash-period)))
                (offset 
                  (+ (- left-span (ly:grob-relative-coordinate grob common X))
                     (if (zero? (ly:item-break-dir left-bound)) padding 0)
                     (/ extra 2))))
           (apply 
             ly:stencil-add 
             (map 
               (lambda (n)
                 (ly:stencil-translate-axis 
                   scaled-sten 
                   (+ offset (* n dash-period)) 
                   X))
               (iota dash-count)))))))

\paper {
  indent = 0
  ragged-right = ##f
  tagline = ##f
}

\relative c' {
  \omit Staff.TimeSignature
  \repeat unfold 3 {
    b4. b8 b4 b4 |
    b8 b8 b8 b8 b2 \break
  }
  r2 b'2~ \break b1~ \break b2 b2
}
\addlyrics {
  \override Score.RehearsalMark.self-alignment-X = #LEFT
  
  \mark "LyricHyphen.text is \"-\""
  \override LyricHyphen.dash-period = #5
  \override LyricHyphen.padding = #0.2
  \override LyricHyphen.stencil = #lyric-hyphen-text-stencil
  
  Lo -- rem ip -- sum do -- lor sit a -- met.
  
  \mark "LyricHyphen.text is \"–\""
  \override LyricHyphen.text = #"–" %#"\xe2\x80\x93" % U+2013
  \override LyricText.font-series = #'bold
  Lo -- rem ip -- sum do -- lor sit a -- met.
  
  \mark \markup { "LyricHyphen.text is " \circle  \with-color #red "&" }
  \override LyricHyphen.text = 
    \markup
      \circle \with-color #red 
      %% For unknown reason "\xe2\x99\xa5", which is "♥", U+2665, does not work in LSR, 
      %% replacing it with "&" 
      %% Outside of LSR it works -- Harm
      %%
      %% Outside LSR it's possible to use "♥" directly for guile-v1 and guile-v2  --Harm (May 2022)
      #"&"
  \override LyricText.font-size = #3
  Lo -- rem ip -- sum do -- lor sit a -- met.

      %% Same here for "\xe2\x89\x8b", which is "≋", U+224B, does not work in LSR, 
      %% replacing it with "~" 
      %% Outside of LSR it works -- Harm
      %%
      %% Outside LSR it's possible to use "≋" directly for guile-v1 and guile-v2  --Harm (May 2022)

  \mark \markup { "LyricHyphen.text is blue" \with-color #blue #"~" }
  \override LyricHyphen.text = 
    \markup
      \scale #'(3 . 1) \with-color #blue #"~"
  \override LyricText.font-size = #6
  Break -- ing
}
</lilypond>

[[Category:Vocal music]]
[[Category:Tweaks and overrides]]