+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; measure counter
+
+(define (measure-counter-stencil grob)
+ "Print a number for a measure count. The number is centered using
+the extents of @code{BreakAlignment} grobs associated with the left and
+right bounds of a @code{MeasureCounter} spanner. Broken measures are
+numbered in parentheses."
+ (let* ((num (markup (number->string (ly:grob-property grob 'count-from))))
+ (orig (ly:grob-original grob))
+ (siblings (ly:spanner-broken-into orig)) ; have we been split?
+ (num
+ (if (or (null? siblings)
+ (eq? grob (car siblings)))
+ num
+ (make-parenthesize-markup num)))
+ (num (grob-interpret-markup grob num))
+ (num (ly:stencil-aligned-to num X (ly:grob-property grob 'self-alignment-X)))
+ (left-bound (ly:spanner-bound grob LEFT))
+ (right-bound (ly:spanner-bound grob RIGHT))
+ (elts-L (ly:grob-array->list (ly:grob-object left-bound 'elements)))
+ (elts-R (ly:grob-array->list (ly:grob-object right-bound 'elements)))
+ (break-alignment-L
+ (filter
+ (lambda (elt) (grob::has-interface elt 'break-alignment-interface))
+ elts-L))
+ (break-alignment-R
+ (filter
+ (lambda (elt) (grob::has-interface elt 'break-alignment-interface))
+ elts-R))
+ (refp (ly:grob-system grob))
+ (break-alignment-L-ext (ly:grob-extent (car break-alignment-L) refp X))
+ (break-alignment-R-ext (ly:grob-extent (car break-alignment-R) refp X))
+ (num
+ (ly:stencil-translate-axis
+ num
+ (+ (interval-length break-alignment-L-ext)
+ (* 0.5
+ (- (car break-alignment-R-ext)
+ (cdr break-alignment-L-ext))))
+ X)))
+ num))
+