Re: Displaying typesetting information at compile time

[Jean Abou Samra]

Le 20/03/2022 à 19:09, Richard Shann a écrit :
> On Sun, 2022-03-20 at 18:43 +0100, Jean Abou Samra wrote:
> > \version "2.22.2"
> >
> > markWithPageInfo =
> >     %% Must not get called before line breaking
> >     \tweak X-extent #'(0 . 0)
> >     \tweak Y-extent #'(0 . 0)
> >     \tweak horizontal-skylines
> >       #(ly:make-unpure-pure-container ly:grob::simple-horizontal-
> > skylines-from-extents)
> >     \tweak vertical-skylines
> >       #(ly:make-unpure-pure-container ly:grob::simple-vertical-
> > skylines-from-extents)
> >     \tweak stencil
> >       #(lambda (grob)
> >          (let* ((sys (ly:grob-system grob))
> >                 ;; No broken pieces for systems ...
> >                 (alignment (ly:grob-object sys 'vertical-alignment))
> >                 (all-alignments (ly:spanner-broken-into (ly:grob-
> > original alignment)))
> >                 (all-systems (map ly:grob-system all-alignments))
> >                 (n-systems (length all-systems))
> >                 (all-pages (map (lambda (s) (ly:grob-property s 'page-
> > number))
> >                                 all-systems))
> >                 (n-pages (1+ (- (apply max all-pages)
> >                                 (apply min all-pages))))
> >                 (layout (ly:grob-layout grob))
> >                 (defs (append `((n-systems . ,(number->string n-
> > systems))
> >                                 (n-pages . ,(number->string n-pages)))
> >                               (ly:output-def-lookup layout 'text-font-
> > defaults)))
> >                 (props (ly:grob-alist-chain grob defs))
> >                 (text (ly:grob-property grob 'text)))
> >            (interpret-markup layout props text)))
> >     \mark \etc
> >
> > {
> >     \markWithPageInfo \markup { Have \fromproperty #'n-systems systems
> > on \fromproperty #'n-pages pages }
> >     \repeat unfold 20 { 1 1 \break }
> > }
> Wow! That goes beyond what I had in mind - it actually outputs the
> information within the typeset (I guess the stuff with skylining might
> be to avoid the typesetting of this information affecting the number of
> pages/systems??).



Sort of, yes. Normally, the RehearsalMark is drawn before line breaking 
is done, and its width and height are accounted for during page breaking 
and page spacing. At that time, there is obviously no number of pages or 
systems available. So I'm giving it predetermined extents and skylines, 
which are used for page breaking and page spacing purposes, only after 
which the RehearsalMark's stencil is computed. The drawback is that it 
could collide with something on top of it.

However, there was a flaw in that code. When you have several scores in 
a bookpart, page-count and system-count override the total numbers for 
the whole bookpart, but I was counting them per score. Here is a fixed 
version:

\version "2.22.2"

\paper {
  page-post-process =
    #(lambda (paper pages)
       (let ((n-systems 0)
             (page-min #f)
             (page-max #f))
         (for-each
          (lambda (page)
            (for-each
             (lambda (line)
               (let ((sys (ly:prob-property line 'system-grob)))
                 (if (ly:grob? sys)
                     (let ((sys-page (ly:grob-property sys 'page-number)))
                      (set! n-systems (1+ n-systems))
                      (set! page-min (if page-min
                                         (min page-min sys-page)
                                         sys-page))
                      (set! page-max (if page-max
                                         (max page-max sys-page)
                                         sys-page))))))
             (ly:prob-property page 'lines)))
          pages)
         (ly:output-def-set-variable! paper 'n-systems n-systems)
         (ly:output-def-set-variable! paper 'n-pages (1+ (- page-max 
page-min)))))
}

#(define-markup-command (page-info layout props arg) (markup?)
   (ly:make-stencil
    `(delay-stencil-evaluation
      ,(delay
        (let* ((n-systems (ly:output-def-lookup layout 'n-systems))
               (n-pages (ly:output-def-lookup layout 'n-pages)))
                (ly:stencil-expr
                 (interpret-markup
                  layout
                  (cons `((n-systems . ,(number->string n-systems))
                          (n-pages . ,(number->string n-pages)))
                        props)
                  arg)))))
    '(0 . 0)
    '(0 . 0)))

\header {
  subsubtitle = \markup \page-info \line {
    Have \fromproperty #'n-systems systems
    on \fromproperty #'n-pages pages
  }
}

\book {
  \bookpart {
    \repeat unfold 10 { 1 1 \break }
    \repeat unfold 10 { 1 1 \break }
  }
  \bookpart {
    \repeat unfold 20 { 1 1 \break }
    \repeat unfold 20 { 1 1 \break }
  }
}


Jean