Re: markup-command boxing the real printed ink?

[Jean Abou Samra]

Le 20/04/2021 à 16:59, Valentin Petzel a écrit :
> Hello David,
>
> That is a very different thing. with-outline simply tells the outputter to use
> a different stencil for calculating the skylines of a stencil. The problem
> here is that Lilypond relies on the stencil basically telling it’s extent. The
> problem Harm has is that this extent might be smaller than the actual size of
> the printed symbol.
>
> So Harm is looking for a way to determine the acutal printed size of a symbol.
>
> And no, Lilypond does not draw this stuff internally. I mean, Lilypond relies
> on Ghostscript to draw it’s output. If Lilypond wanted to do this, it would
> need it’s own PostScript interpreter.


Hello Valentin,

Compile the file

#(ly:set-option 'debug-skylines)
{ c'^\f }

and I think you will realize you are wrong. Skylines are
a concept of LilyPond,not PostScript. The skylines are
determined algorithmically and used foraccurate spacing
of the music. LilyPond doesn't need to understand PostScript
for that: it has its own internal representation of stencils,
and the fonts are not PostScript.

The problem is that there are no Scheme-accessible interfaces
for dealing with skylines. The smobification is superficial,
and I think it's for performance, because skyline construction
takes up a non-negligible part of the compilation time.

Regards,
Jean