OK I see, the solution is to place a space char in the empty string.
On Fri, Oct 9, 2020 at 12:30 AM Aaron Hill <[email protected]> wrote:
> On 2020-10-08 3:03 am, K.L. wrote:
> > Yes, if a global \markup, it can be reserved, but not for the \markup
> > in *\header
> > title*.
>
> My testing shows no change in behavior regardless of where the \markup
> occurs: at the top-level, in \header, or attached to a note.
>
> Here is a more complete test:
>
> %%%%
> \version "2.18.2"
> #(format #t "\nversion=~s" (ly:version))
> #(define (stencil-empty? sten)
> (let ((xex (ly:stencil-extent sten X))
> (yex (ly:stencil-extent sten Y)))
> (and (> (car xex) (cdr xex))
> (> (car yex) (cdr yex)))))
> #(define-markup-command
> (assert layout props id pred? arg)
> (string? procedure? markup?)
> (let ((sten (interpret-markup layout props arg)))
> (or (pred? sten)
> (ly:warning "assertion failed: expected ~a ~a"
> id (procedure-name pred?)))
> sten))
> buildTestMarkup =
> #(define-scheme-function (parser location scope) (string?)
> #{
> \markup {
> \assert #(string-append scope " \\column {...}")
> #stencil-empty?
> \column {
> \assert #(string-append scope " \\line { \"\" }")
> #stencil-empty?
> \line { "" }
> \line { "" }
> }
> }
> #})
> \header { title = \buildTestMarkup "\\header" }
> \buildTestMarkup "top-level"
> { b'4 -\buildTestMarkup "TextScript" }
> %%%%
>
>
> > I checked this in a svg backend result.
>
> That is the critical piece of information. The behavior only reproduces
> using the SVG backend.
>
> This is a bug in 2.20.0 and earlier, where \line { "" } does not resolve
> to an empty-stencil but rather a point-stencil, so it ends up taking up
> space when it should not.
>
> This appears to have been resolved in 2.21.x.
>
>
> -- Aaron Hill
>
