Re: Double-underline markup

[David Kastrup]

Thomas Morley <address@hidden> writes:

> Am Sa., 19. Okt. 2019 um 14:45 Uhr schrieb David Kastrup <address@hidden>:
>
> 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?

Oh very most definitely.  I was thinking of props here.

> 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)))

Basically, the idea was to just call something like

  (interpret-markup layout (prepend-alist-chain 'offset (1+ offset) props) arg)

for the call of interpret-markup (of course using the proper arithmetic
on the proper property).

-- 
David Kastrup