Re: Calculate BarLine 'kern to fit with a given stencil-x-extent

[Pierre Perol-Schneider]

Hi Harm, Hi David,

Here's what can be done as a first step, just to go a little further even if, for sure, that does not solve our calculation problem.

The idea is to make as many conditions as staff sizes from 1 to 30 (or more if needed).

Each staff size has an acurate parameter tested and controled at a 3000% zoom. 

Here we go :

\version "2.17.21"

%% A markup-command for better viewing and the possibility

%% to read out some values

#(define-markup-command (rectangle layout props x) (number?)

" returns a rectangle "

   (let ((osc (ly:output-def-lookup layout 'output-scale))

         (pt (ly:output-def-lookup layout 'pt)))

    ;; (display "\n\t'output-scale \t")(write osc)

    ;; (display "\n\tpt from layout \t")(write pt)

    ;; (display "\n\t(* osc pt) \t")(write (* osc pt))

    ;; (newline)

   (interpret-markup layout props

     (markup #:stencil (make-filled-box-stencil  `(0 . ,x) '(0 . 3))))))

\paper {

        indent = 30

        %% #(display "\n\tpt from within \\paper \t")

        %% #(write pt)

}

\layout {

        % Better viewing:

        \override Score.RehearsalMark #'color = #red

        \override Score.RehearsalMark #'layer = #10

        \override Score.RehearsalMark #'extra-offset = #'(0 . -2.5)

}

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%% Test here with different values:

#(define staff-size 20)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

#(set-global-staff-size staff-size)

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 

%% Accord. here with param. below :

#(define (adjust-kern x-lngth)

   (* 10.000 x-lngth))

   

   

%{

  St-sz  param

  1 0.742

  2 1.448

  3 2.118

  4 2.755

  5 3.363

  6 3.948

  7 4.505

  8 5.036

  9 5.546

  10 6.035

  11 6.504

  12 6.953

  13 7.385

  14 7.803

  15 8.204

  16 8.590

  17 8.963

  18 9.322

  19 9.667

  20 10.000

  21 10.323

  22 10.635

  23 10.938

  24 11.229

  25 11.515

  26 11.790

  27 12.057

  28 12.314

  29 12.564

  30 12.806

%}

show =

#(define-music-function (parser location x-length)(number?)

"

 returns some test-music, with the rectangle and tweaked BarLine.kern

"

#{

        \set Staff.instrumentName =

        \markup \fontsize #-1 \center-column {

                "stencil/kern-length?"

                #(number->string x-length)

        }

        R1

        \mark \markup

        \rectangle #x-length

        \override Staff.BarLine.kern = #(adjust-kern x-length)

        \bar "||"

        R1

#})

\header {

        title = "Adjust BarLine 'kern to stencil-extent"

        subtitle = #(format #f "Used global-staff-size: ~a" staff-size)

        subsubtitle = \markup \vspace #2

}

\show #1

\show #2

\show #10

\show #20

Of course, I have to let you do the scheme code, it's none of my knowledge.

Cheers, 

Pierre