On Sun, May 24, 2009 at 8:36 PM, Michael Lauer <[email protected]> wrote:
> Wilbert Berendsen <lilykde <at> xs4all.nl> writes:
>
> >
> > Op zondag 24 mei 2009, schreef madMuze:
> > > perhaps a Schemer could pull the X-extent info from the attachment
> point
> > > notehead, divide it by 2 and send that to the offset. Meanwhile, it may
> to
> > > helpful to know that:
> > > quarter-note head width = about 1.31
> > > half-note head width = about 1.39
> > > whole-note head width = about 1.96
> > > (in staff space units)
> >
> > Thanks! But I think lyrics and dynamics are also able to center
> themselves
> > nicely. So there must be way to get the center.
> >
>
> I think the difference is that LyricTexts have NoteHeads as grob-parents,
> while TextScripts have PaperColumns.
>
> Here's something that's pretty hacky, but seems to work, at least
> in this simple case:
>
> #(define lastNoteHeadWidth 0)
>
> #(define (centerTextFn grob grob-origin context)
> (cond ((grob::has-interface grob 'note-head-interface)
> (set! lastNoteHeadWidth (cdr (ly:grob-property grob 'X-
> extent))))
> ((grob::has-interface grob 'text-script-interface)
> (let* ((xext (ly:grob-property grob 'X-extent))
> (offset (* (- lastNoteHeadWidth (car xext) (cdr
> xext))
> 0.5)))
> (ly:grob-set-property! grob 'X-offset offset)))))
>
> centerText = \applyOutput #'Voice #centerTextFn
>
> {
> \centerText c'1-"Text"
> \centerText c'4-"Text"
> }
>
>
Hi Michael, hi Wilbert,
Mark Polesky just pointed out to me that a thread I started yesterday ...
http://lists.gnu.org/archive/html/lilypond-user/2009-06/msg00735.html
... asks essentially the same question that you guys were tackling here. So
I thought I'd respond back to your posts here.
First: Michael, that \centerText Scheme function you cooked up is very cool.
If I'm reading correctly you're doing two things in the function. If the
grob passed in is a notehead then you're saving the width (X-extent) of the
notehead for use in the second condition. If the grob passed in is a
TextScript then you're setting the X-offset of the TextScript to half the
value of d, where d equals the width of the TextScript minus the width of
the last known notehead. Yes? (So, basically exactly as David had sketched
earlier in the thread?)
Second: there used to be a (somewhat more) direct way of specifying the
point-on-notehead to which TextScripts would make reference during
positioning. Here're some settings from 2006:
%%% 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 %%%
These are settings that I put together in September 2006 ...
http://lists.gnu.org/archive/html/lilypond-user/2006-09/msg00088.html
... and, at that time, they worked great. See notehead-centering.png,
reattached here for convenience.
(And I should also mention that I cobbled together the settings given above
by looking at the settings for OctavateEight in define-grobs.scm rather
blindly. But they worked great.)
But running that same code now (2.13.2) produces bizarre results. See
weird-notehead-centering.png.
So, thinking about Michael's statement here ...
ML> I think the difference is that LyricTexts have NoteHeads as
grob-parents,
while TextScripts have PaperColumns.
... is it possible that TextScripts *used to* have NoteHeads as grob-parents
(at least in 2.9.16) and have since changed to have PaperColumns as grob
parents, thus rendering the settings from 2.9.16 no longer functional?
Or is something else now going that would prevent calls to
Self_alignment_interface::aligned_on_x_parent and centered_on_x_parent from
working as they did previously?
Trevor.
--
Trevor Bača
[email protected]
<<attachment: notehead-centering.png>>
<<attachment: weird-notehead-centering.png>>
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