Re: TextScript implements self-alignment interface

[Trevor Bača]

On 9/6/06, Markus Schneider <address@hidden> wrote:
> Hi Trevor,
>
> I derived this from the hint given regarding the OctavateEight in
> define-grobs.scm:
>
> \override TextScript #'X-offset =
>       #(ly:make-simple-closure
>         `(,+ ,(ly:make-simple-closure (list
> ly:self-alignment-interface::x-aligned-on-self))
>       ,(ly:make-simple-closure (list
> ly:self-alignment-interface::centered-on-x-parent))))
>
> Tested in 2.9.17 (W2K).

Hi Markus,

This is exactly what I was looking for. Wow, thanks.

The Scheme code passed in as the last argument to \override is a
mouthful and so it's possible to save the whole thing to a named
variable. And, with that, here's an example of centering TextScripts
on their (NoteHead) X-parents, combined with moving around the
self-alignment-X of three different TextScripts.


%%% BEGIN X-PARENT CENTERING SNIPPET %%%

\version "2.9.16"

textScriptCenterOnParent = \override TextScript #'X-offset =
       #(ly:make-simple-closure
         `(,+ ,(ly:make-simple-closure (list
  ly:self-alignment-interface::x-aligned-on-self))
       ,(ly:make-simple-closure (list
  ly:self-alignment-interface::centered-on-x-parent))))

\new Staff {
  \textScriptCenterOnParent
  \override TextScript #'self-alignment-X = #left
  c'4_\markup { MMM }
  \override TextScript #'self-alignment-X = #center
  c'4_\markup { MMM }
  \override TextScript #'self-alignment-X = #right
  c'4_\markup { MMM }
}


%%% END X-PARENT SNIPPET %%%


Also, since I've been lazy about actually learning Scheme, your
solution is educational because it taught me how transcribe the
craziest bits of the grob definition code in scr/define-grobs.scm into
Scheme code I can stick inside a normal .ly file.

I'll add this to the archive so I can find it easily next time I'm
wanting to copy over the behavior of any existing grob:

In the OctavateEight definition in scm/define-grobs.scm we find ...

  <snip>
  (X-offset . ,(ly:make-simple-closure
           `(,+ ,(ly:make-simple-closure (list
ly:self-alignment-interface::x-aligned-on-self))
           ,(ly:make-simple-closure (list
ly:self-alignment-interface::centered-on-x-parent)))))
  <snip>

... which then, in an ly input file, becomes ...

  \override MyGrob #'X-offset =
       #(ly:make-simple-closure
         `(,+ ,(ly:make-simple-closure (list
  ly:self-alignment-interface::x-aligned-on-self))
       ,(ly:make-simple-closure (list
  ly:self-alignment-interface::centered-on-x-parent))))


... which looks like a pretty direct mapping: the last argument to
\override begins, like always, with a hash sign, whereas the second
element of the pair in scm/define-grobs.scm starts with a comma
instead.

Thanks again.

--
Trevor Bača
address@hidden

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