Re: Parenthesized second key signature

[Thomas Morley]

Am Do., 29. Nov. 2018 um 11:57 Uhr schrieb Tyler Mitchell <address@hidden>:
>
> I'm trying to figure out how to add a "parenthesized" second key
> signature to my music, something like this:
>
>         https://www.ldx.ca/tmp/paren-key-1.png
>
> I experimented with adding two \key commands one after the other,
> but I get the error:
>
>         foo.ly:5:9: warning: Two simultaneous key-change events, junking this 
> one
>
> The following comes somewhat close, though there's a bit of an
> undesirable gap between the two key signatures; and I can't figure
> out how to increase the size of the parentheses; and I have to use
> the 'second' key signature throughout to avoid a lot of unneeded
> accidentals; and I wouldn't be able to use a time signature, as it
> would be stuck between these two key signatures.
>
> \version "2.18.2"
>
> \relative c'' {
>   \key a \major
>   \once\override NoteHead.stencil = ##f
>   \once\override Stem.stencil = ##f
>   a4
>   % Doesn't seem to have any effect:
>   \override ParenthesesItem.font-size = #5
>   \parenthesize
>   \key aes \major
>   aes4
> }
>
> \layout { \context { \Staff printKeyCancellation = ##f \remove 
> Time_signature_engraver } }
>
> Any suggestions for how I should approach this?
>
> A "stretch goal" would be to have accidentals handled automatically
> in the same way, eg:
>
>         https://www.ldx.ca/tmp/paren-key-2.png
>
> But this seems a bit more involved (and unneeded, at least
> initially).
>
> Many thanks,
> Tyler

Hi,

I once made below (here a little lifted up):

\version "2.19.82"

alternativeKey =
#(define-music-function (p-1 p-2 scale-def)
     (ly:pitch? ly:pitch? number-pair-list?)
#{
  \override Staff.KeySignature.stencil =
   #(lambda (grob)
      (let* ((staff-space (ly:staff-symbol-staff-space grob))
             (line-thickness (ly:staff-symbol-line-thickness grob))
             (th line-thickness)
             (default-stil (ly:key-signature-interface::print grob))
             ;; To avoid programming error @code{(markup #:null)} is returned if
             ;; the scale would not result in a printed KeySignature.
             ;; TODO: add the other scales: ionian, locrian etc
             (stil-to-add
               (grob-interpret-markup grob
                 (if (or (and (= (ly:pitch-notename p-2) 5)
                              (= (ly:pitch-alteration p-2) 0)
                              (eq? scale-def minor))
                         (and (= (ly:pitch-notename p-2) 0)
                              (= (ly:pitch-alteration p-2) 0)
                              (eq? scale-def major)))
                 (markup #:null)
                 #{
                   \markup
                     \score {
                       { \key $p-2 $scale-def }
                       \layout {
                         \override Staff.TimeSignature #'stencil = ##f
                         \override Staff.Clef #'stencil = ##f
                         \override Staff.StaffSymbol #'line-count = #0
                         indent = 0
                       }
                   }
                 #})
                 ))
             (stil-to-add-x-ext (ly:stencil-extent stil-to-add X))
             (stil-to-add-y-ext (ly:stencil-extent stil-to-add Y)))
    (if (< 0 (interval-length stil-to-add-x-ext))
        (if (or (and (= (ly:pitch-notename p-1) 5)
                     (= (ly:pitch-alteration p-1) 0)
                     (eq? scale-def minor))
                (and (= (ly:pitch-notename p-1) 0)
                     (= (ly:pitch-alteration p-1) 0)
                     (eq? scale-def major)))
            (bracketify-stencil
              (ly:make-stencil
                (ly:stencil-expr stil-to-add)
                ;; left bracket is to far away
                ;; trimmed a little
                (cons
                   (+ (car stil-to-add-x-ext) (* 0.7 staff-space) )
                   (cdr stil-to-add-x-ext))
                ;; adjusting the top and bottom ending of the bracket
                (cons
                   (+ (car stil-to-add-y-ext) (* 0.2 staff-space))
                   (- (cdr stil-to-add-y-ext) (* 0.5 staff-space))))
              Y th (* 2.5 th) th)
            (ly:stencil-combine-at-edge
              default-stil
              X
              RIGHT
              (bracketify-stencil
                (ly:make-stencil
                  (ly:stencil-expr stil-to-add)
                  ;; left bracket is to far away
                  ;; trimmed a little
                  (cons
                     (+ (car stil-to-add-x-ext) (* 0.7 staff-space) )
                     (cdr stil-to-add-x-ext))
                  ;; adjusting the top and bottom ending of the bracket
                  (cons
                     (+ (car stil-to-add-y-ext) (* 0.2 staff-space))
                     (- (cdr stil-to-add-y-ext) (* 0.5 staff-space))))
                Y th (* 2.5 th) th)
                1))
      default-stil)))

  \key $p-1 $scale-def
#})

%%%%%%%%%%%%%%
% EXAMPLES
%%%%%%%%%%%%%%
%%{
\relative c' {
    \alternativeKey c f \major
    c1
    \alternativeKey b c \major
    c
    \alternativeKey e ees \major
    c
    \alternativeKey a aes \major
    c
    \alternativeKey d des \major
    c
    \alternativeKey g ges \major
    c
    \alternativeKey c ces \major
    c
    \alternativeKey ges g \major
    c1
    \alternativeKey des d \major
    c
    \alternativeKey aes a \major
    c
    \alternativeKey ees e \major
    c
    \alternativeKey bes b \major
    c
    \alternativeKey f fis \major
    c
    \alternativeKey ces cis \major
    c
}

Current limitation: both keys need to use the same scale, i.e.
supported is neither something like a \minor a \major or other scales
like \dorian etc


HTH,
  Harm