Re: Stencil questions (adding text and defining line style)

[Thomas Morley]

Hi Urs,

2016-09-21 23:47 GMT+02:00 David Nalesnik <address@hidden>:

>> The other thing I didn't find is: how can I create a dashed (or
>> otherwise styled) line stencil with make-line-stencil?

I was going to write:
If you regard the basics you'll see something like the following example:

\markup
  \box {
  \stencil
    #(ly:make-stencil
       (list
         'dashed-line
         0.2 ; width
         0.5 ;; on
         0.5 ; off
         10 ;; x-end
         10 ;; y-end
         0 ;; phase
         )
       ;; x-ext
       (cons 0 10)
       ;; y-ext
       (cons 0 10))
  \stencil
    #(ly:make-stencil
       (list
         'draw-line
         0.2 ; width
         0  ; startx
         0 ; starty
         10 ; endx
         10 ;endy
         )
       '(0 . 10)
      '(0 . 10))
}

So there's no direct method to switch between both, because of the
kind and amount of arguments differ.
But you can use some "meta"-functions like:

(and now follow David' reply)


>
> You should use ly:line-interface::line (which is available from
> 2.19.27, off the top of my head).
>
> Here's an example with both text and different line styles.
>
> (Even though TextScript doesn't support line-interface, you can still
> tweak line-related properties!)
>
> \version "2.19.46"
>
> #(define (my-stencil grob)
>    (let* ((line (ly:line-interface::line grob 1.5 0 6 0))
>           (text (grob-interpret-markup grob "A"))
>           (stil (apply ly:stencil-add (list line text))))
>      stil))
>
> {
>   \override TextScript.stencil = #my-stencil
>   c''1 -\tweak style #'dashed-line ^""
>   c''1 -\tweak style #'zigzag ^""
> }
>
>>
>> More generally: how can I learn more about these things? Searching
>> lilypond.org seems to only point to snippets and no real explanations.
>
> There's not much to go on.
>
> grob-interpret-markup is mentioned here:
> http://lilypond.org/doc/v2.19/Documentation/extending/callback-functions
>
> The function doesn't have a docstring:
>
> #(display (procedure-documentation grob-interpret-markup))
>
> returns #f ...
>
> ly:line-interface::line is listed in the IR (Scheme functions)
>
> Sorry I can't be more helpful.
>
> David

Cheers,
  Harm