Customizing the position and number of dots in repeat sign bar lines

If you want to customize the position and/or number of dots in repeat sign bar lines, you can define new custom bar lines or redefine the way default repeat signs are drawn. This may be particularly helpful when using a staff with custom line positions, also demonstrated below.

\version "2.24"

#(define ((make-custom-dot-bar-line dot-positions) grob extent)
   "Draw dots (repeat sign dots) at DOT-POSITIONS.

The coordinates of DOT-POSITIONS are equivalent to the coordinates of
`StaffSymbol.line-positions`; a dot position of X and a line position
of X indicate the same vertical position."
   (let* ((staff-space (ly:staff-symbol-staff-space grob))
          (dot (ly:font-get-glyph (ly:grob-default-font grob)
                                  "dots.dot"))
          (stencil empty-stencil))
     (for-each
      (lambda (dp)
        (set! stencil (ly:stencil-add stencil
                                      (ly:stencil-translate-axis
                                       dot (* dp (/ staff-space 2)) Y))))
      dot-positions)
     stencil))

% With the procedure above we can define custom bar lines, for example,
% that resemble standard repeat sign bar lines except that there are
% three dots at staff positions -3, 0, and 3.

#(add-bar-glyph-print-procedure "*" (make-custom-dot-bar-line '(-3 0 3)))
\defineBarLine ".|*" #'("" "*" "")
\defineBarLine "*|." #'("" "*" "")

% We can also customize the dot positions used in all default repeat
% signs by redefining the print procedure of the colon bar glyph (":").
% On a staff with line positions of `(-4 -2 2 4)`, the default repeat
% sign dots appear at `(-3 3)`, but we can put them at `(-1 1)` instead.
#(add-bar-glyph-print-procedure ":" (make-custom-dot-bar-line '(-1 1)))


\new Staff \with {
  \override StaffSymbol.line-positions = #'(-4 -2 2 4)
  \override StaffSymbol.staff-space = #1.3
} \relative f' {
  g1 \bar ".|*"
  g \bar "*|."
  g \bar ".|:-|"
  g \bar ":|."
  g |
  \repeat volta 2 { g }
}