Re: Align text above clef

[Urs Liska]

Am 15.10.2018 um 13:16 schrieb Urs Liska:
> Hi Mats,
>
> thank you for the suggestion.
>
>
> Am 15.10.2018 um 12:54 schrieb Mats Bengtsson:
> > Hi,
> >
> >
> > On 2018-10-15 11:22, Urs Liska wrote:
> > > Hi,
> > >
> > > I have to center-align some texts above and below clefs like in the 
> > > attached image.
> > >
> > > Before I start fiddling around with the Clef stencil and combine the 
> > > markups I'd like to ask if there's a simpler and more 
> > > straightforward way to achieve that.
> > >
> > > Ideally I'd like to have the markups at a fixed vertical position so 
> > > several of those on one system will align properly.
> > How about using the break-alignable-interface, see 
> > http://lilypond.org/doc/v2.19/Documentation/notation/aligning-objects#using-the-break_002dalignable_002dinterface 
> > ?
> > A starting point could be
> >
> > \relative c'{
> >   \clef alto
> >   \override Score.RehearsalMark.break-align-symbols= #'(clef)
> >   \override Score.Clef.break-align-anchor-alignment = #CENTER
> >   \mark "text"
> >   c e f g
> > }
>
> Well, this does solve the horizontal alignment issue, but I can't use 
> it because I need always *two* such texts, one above and one below the 
> clef.

OK, I did get into creating a custom stencil, and (building on what I 
got from the list last week) it was quite possible. The following code 
creates two markup stencils, horizontally aligns them over the clef and 
calculate a padding based on the original clef's vertical extent and the 
staff symbol positions:

\version "2.19.82"

annotateClef =
#(define-music-function (padding text-above text-below) ((number? 1) markup? 
markup?)
   #{
     \once \override Staff.Clef.after-line-breaking =
     #(lambda (grob)
        (let*
         ((stencil (ly:clef::print grob))
          ;; miniml distance between center staff line and markup
          (padding-threshold 5)
          ;; reference point of the original clef
          (vpos (/ (ly:grob-property grob 'staff-position) 2))
          ;; upper and lower edges of the clef
          (vextent (ly:stencil-extent stencil Y))
          (clef-top (+ vpos (cdr vextent)))
          (clef-bottom (+ vpos (car vextent)))
          ;; calculate padding acknowledging distance to clef *and* to staff
          (padding-top (max padding (- padding-threshold clef-top)))
          (padding-bottom (max padding (+ padding-threshold clef-bottom)))
          ;; create stencil for upper text and horizontal shift for centering
          (markup-stencil-above (grob-interpret-markup grob text-above))
          (shift-above (- (interval-center (ly:stencil-extent stencil X))
                   (interval-center (ly:stencil-extent markup-stencil-above 
X))))
          ;; create stencil for lower text
          (markup-stencil-below (grob-interpret-markup grob text-below))
          (shift-below (- (interval-center (ly:stencil-extent stencil X))
                   (interval-center (ly:stencil-extent markup-stencil-below 
X))))
          ;; combine the three stencils
          (new-stencil
           (ly:stencil-combine-at-edge
            (ly:stencil-combine-at-edge
             stencil Y DOWN
             (ly:stencil-translate-axis markup-stencil-below shift-below X)
             padding-bottom)
            Y UP
            (ly:stencil-translate-axis markup-stencil-above shift-above X)
            padding-top)))
         (ly:grob-set-property! grob 'stencil new-stencil)))
   #})

\relative {
  \annotateClef "Treble" "G"
  \clef treble
  c'1
  \annotateClef "Tenor" "C"
  \clef tenor
  c1
  \annotateClef "Soprano" "C"
  \clef soprano
  c1
}

I have one more general question, though (fortunately it doesn't matter 
in my actual example): calculating the padding manually does (I think) 
the same as using the outside-staff-padding property in general: it uses 
the "bounding box" of the markup as its reference. Is there any way to 
have markups be padded above or below the staff so that different text 
elements' *baselines* are aligned?

Urs