Re: Grouping grobs

[Jean Abou Samra]

Le 17/08/2022 à 10:25, Jean Abou Samra a écrit :
> > Le 16 août 2022 à 21:14, lilypond@lists.johnteskemusic.com a écrit :
> >
> > 
> > Of course, happy to give more context. I primarily write graphic 
> > scores (but with western notation symbols). The score isn't always 
> > static, so I want to be able to manipulate fragments of music after 
> > generation.
> >
> > In the past I have used my own program to place glyphs 
> > programmatically, which requires that I create my own notation<>glyph 
> > mappings and to have the engraving font installed/available to 
> > whoever views it.
> >
> > When I saw that Lilypond produces shapes in SVG output, not glyphs, I 
> > was intrigued--and leveraging Lilypond's input over my own mapping is 
> > appealing as well.
> >
> > I suppose one answer is keep my current system and outline the glyphs 
> > like Lilypond may be doing under the hood. Another is to make and 
> > group selections based on position, not an id attribute, from the 
> > current Lilypond output.
>
>
> Thanks both for your explanations. Is it not possible to use 
> attributes without collapsing different <g> tags into one? John, you 
> have a command that does not work in a comment in your original 
> example, and it does not work because markups are a standalone system 
> for creating any graphics you like, where there are no grobs, but it 
> is possible to implement a markup command that sets attributes as 
> well. Untested (I’m on vacation), but I think this should work:
>
> #(define-markup-command (with-output-attributes attrs arg) (list? markup?)
>    (let ((stil (interpret-markup layout props arg)))
>      (ly:make-stencil (list 'output-attributes attrs (ly:stencil-expr 
> stil))
>                                  (ly:stencil-extent stil X) 
> (ly:stencil-extent stil Y))))
>
>
> \markup \combine a \with-output-attributes #'((mylayer . 4)) { b c }

Now tested, and I was missing "layout props":

\version "2.23.11"

#(define-markup-command (with-output-attributes layout props attrs arg) 
(list? markup?)
   (let ((stil (interpret-markup layout props arg)))
     (ly:make-stencil (list 'output-attributes attrs (ly:stencil-expr 
stil))
                                 (ly:stencil-extent stil X) 
(ly:stencil-extent stil Y))))


\markup { a \with-output-attributes #'((mylayer . 4)) { b c } }