Re: Double-underline markup

[Thomas Morley]

Am Sa., 19. Okt. 2019 um 14:45 Uhr schrieb David Kastrup <address@hidden>:
>
> Thomas Morley <address@hidden> writes:
>
> > Am Sa., 19. Okt. 2019 um 13:35 Uhr schrieb David Kastrup <address@hidden>:
> >>
> >> Thomas Morley <address@hidden> writes:
> >
> >> > Iiuc, you recommend to fix \underline to make it work with most simple
> >> > input like:
> >> >
> >> > \markup {
> >> >   \override #'(offset . 12) \underline
> >> >   \override #'(offset . 10) \underline
> >> >   \override #'(offset . 8) \underline
> >> >   \override #'(offset . 6) \underline
> >> >   \override #'(offset . 4) \underline
> >> >   "underlined"
> >> > }
> >> >
> >> > I'll have a look.
> >>
> >> No, to have it work with most simple input like
> >>
> >> \markup
> >>   \underline
> >>   \underline
> >>   \underline
> >>   \underline
> >>   \underline
> >>   "underlined"
> >
> > Ok, understood. I'll give it a try...
>
> I mean, I might well be too naive about this.  If the underline is
> occuring in a fixed position with regard to the baseline, there are only
> a few obvious avenues to have multiple underlines work:
>
> a) change the baseline.  That's not really acceptable when mixing
> underlined and non-underlined text

Yep. I think it's not the way to go.

> b) change a property (akin to offset but probably unique to \underline
> to avoid unexpected interactions) for the sake of additional
> underline calls.  That would result in the _innermost_ \underline call
> ending up lowest.

I tried to put a variable into layout's 'text-font-defaults (for now
named foo) to keep track of the used offset.
Ofcourse subsequent calls of \underline with different text will use
the then stored value of foo.
Though, if I clear foo first then it's useless.
Currently I don't see a way out. Maybe putting it in layout is the wrong way?

Any hints?

Anyway, here the insufficient code so far:

#(define-markup-command (underline-tst-II layout props arg)
  (markup?)
  #:category font
  #:properties ((thickness 1) (offset 2))
  (let* ((thick (ly:output-def-lookup layout 'line-thickness))
         (underline-thick (* thickness thick))
         (m (interpret-markup layout props arg))
         (arg-x-ext (ly:stencil-extent m X))
         (x1 (car arg-x-ext))
         (x2 (cdr arg-x-ext))
         (arg-y-ext (ly:stencil-extent m Y))
         (text-font-defaults (ly:output-def-lookup layout 'text-font-defaults))
         (foo (assoc-get 'foo text-font-defaults 0))
         (line (make-line-stencil underline-thick x1 0 x2 0))
         (new-stil
           (ly:stencil-combine-at-edge
             m
             Y
             DOWN
             line
             (- (+ (* thick (+ foo offset)) (car arg-y-ext))
                (/ underline-thick 2))))
         (new-stil-y-ext
           (ly:stencil-extent new-stil Y)))


    (ly:output-def-set-variable! layout 'text-font-defaults
      (acons 'foo (+ offset foo)
             (ly:output-def-lookup layout 'text-font-defaults)))

    (ly:make-stencil
      (ly:stencil-expr new-stil)
      arg-x-ext
      new-stil-y-ext)))

\markup \underline-tst-II \line {
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  "pq-1-tst"

  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  \underline-tst-II
  "pq-2-tst"
}


> c) somehow affect bounding box/outline in a manner that can be
> interpreted for moving the whole next underline to a different position
> while retaining the baseline.  That's sort of the handwavy "do magic"
> option that may or may not be workable at all.

If b) is not doable I'll have think more about the "do magic"
Or "more magic"
http://www.catb.org/~esr/jargon/html/magic-story.html
lol

Thanks,
  Harm