Re: Figured Bass Tweaks

[Thomas Morley]

2016-05-08 2:28 GMT+02:00 Sam Bivens <address@hidden>:
> Hi all,
>
> Attached, I show my solutions for two figured bass tweaks: first, a
> parenthesized (not bracketed) figure; and second, a lone integer on the
> "lower line."
>
> The work-arounds are good enough for now, I'm just curious if anyone has any
> better ideas, or if I missed an obvious solution in the manual; I'd
> appreciate any comments anyone would be willing to offer.
>
> Thanks,
>
> Sam


\version "2.19.40"

#(define (brackets->bows grob)
  (let* ((brackets-stil (ly:enclosing-bracket::print grob))
         (edge-height (ly:grob-property grob 'edge-height))
         (y-ext (ly:stencil-extent brackets-stil Y))
         (x-ext (ly:stencil-extent brackets-stil X))
         (up-left (cons (+ (car x-ext) (car edge-height)) (cdr y-ext)))
         (down-left (cons (+ (car x-ext) (car edge-height)) (car y-ext)))
         (up-right (cons (- (cdr x-ext) (cdr edge-height)) (cdr y-ext)))
         (down-right (cons (- (cdr x-ext) (cdr edge-height)) (car y-ext))))
    (ly:stencil-add
      (make-bow-stencil
        down-left
        up-left
        0.1 ;; thick
        0.2   ;; angularity
        0.3 ;; height
        1)
      (make-bow-stencil
        down-right
        up-right
        0.1
        0.2
        0.3
        -1))))

#(define ((make-bass-figures-transparent lst) grob)
  (let* ((array (ly:grob-object (ly:grob-parent grob X) 'elements))
         (bass-figures-list
           (filter
             (lambda (g)
               (grob::has-interface g 'bass-figure-interface))
             (ly:grob-array->list array))))
    (if (> (length lst) (length bass-figures-list))
        (begin
          (ly:warning "Can't apply to items not present, ignoring the rest")
          (set! lst (take lst (length bass-figures-list)))))
    (for-each
      (lambda (bf)
        (ly:grob-set-property!
          (list-ref bass-figures-list (1- bf)) 'transparent #t))
      lst)))

bassFigureTransparent =
#(define-music-function (which-list)(number-list?)
#{
  \once \override BassFigure.after-line-breaking =
    #(make-bass-figures-transparent which-list)
#})


line = {
  \repeat unfold 12 c'4
}

figs = \figuremode {
  <[6]>4
  %\once
  \override BassFigureBracket.stencil = #brackets->bows
  <[6]>4
  <[6 4]>
  <[6 4 2]>

  <9 7 6 4>
  \bassFigureTransparent #'(1)
  <9 7 6 4>
  \bassFigureTransparent #'(2)
  <9 7 6 4>
  \bassFigureTransparent #'(3)
  <9 7 6 4>
  \bassFigureTransparent #'(4)
  <9 7 6 4>
  \bassFigureTransparent #'(1 3)
  <9 7 6 4>
  \bassFigureTransparent #'(2 4)
  <9 7 6 4>
  \bassFigureTransparent #'(1 2 3)
  <9 7 6 4>
}

\score {
  <<
    \new Staff \line
    \new FiguredBass \figs
  >>
}


HTH,
  Harm