Re: programming error for thickness/control-points of Slur

[Jean Abou Samra]

Le 27/05/2022 à 11:54, Thomas Morley a écrit :
> Thanks Jean!
> After further thinking and testing I'll not reset the 'control-points:
> It would trash a user-tweak for \shape and ua ser-override for \shape
> returns a more serious ERROR:
>
> #(define (variable-bow-thickness-harm min-l max-l min-t max-t)
>    (lambda (grob)
>        (let* ((cpt (ly:grob-property grob 'control-points))
>               (cp0 (car cpt))
>               (cp3 (cadddr cpt))
>               (dx (- (car cp3) (car cp0)))
>               (dy (- (cdr cp3) (cdr cp0)))
>               (len (magnitude (make-rectangular dx dy)))
>               (thickness
>                 (cond ((< len min-l) min-t)
>                       ((> len max-l) max-t)
>                       (else
>                         (+ min-t
>                           (* (- len min-l)
>                              (/ (- max-t min-t)
>                                 (- max-l min-l))))))))
>          (ly:grob-set-property! grob 'thickness thickness)
>          ;; DELETE-ME:
>          (ly:grob-set-property! grob 'control-points
>            ((assoc-get 'control-points (ly:grob-basic-properties grob)) grob))
>            )))
>
> {
>    \override Slur.after-line-breaking = #(variable-bow-thickness-harm 1 2 1 33)
>
>    %% \shape as override errors, if overruled by the 'thickness-override
>    \shape #'((10 . 0) (0 . 0) (0 . 0) (0 . 0) ) Slur
>    b1( b')
>
>    %% \shape as tweak works, if not overruled by the 'thickness-override
>    %b1-\shape #'((10 . 0) (0 . 0) (0 . 0) (0 . 0)) ( b')
> }
>
> =>
> ERROR: Wrong type to apply: #<unpure-pure-container #<procedure
> 560c1a58a580 at ice-9/eval.scm:333:13 (a)> #<procedure 560c1a58a560 at
> ice-9/eval.scm:386:13 (a . rest)> >


\shape puts an unpure-pure container in the result of
ly:grob-basic-properties, you can't call that as if it
were a function. Rather:


\version "2.23.9"

#(define (variable-bow-thickness-harm min-l max-l min-t max-t)
  (lambda (grob)
    (let* ((cpt-computer
            (ly:grob-property-data grob 'control-points))
           (cpt (ly:grob-property grob 'control-points))
           (cp0 (car cpt))
           (cp3 (cadddr cpt))
           (dx (- (car cp3) (car cp0)))
           (dy (- (cdr cp3) (cdr cp0)))
           (len (magnitude (make-rectangular dx dy)))
           (thickness
             (cond ((< len min-l) min-t)
                   ((> len max-l) max-t)
                   (else
                     (+ min-t
                       (* (- len min-l)
                          (/ (- max-t min-t)
                             (- max-l min-l))))))))
      (ly:grob-set-property! grob 'thickness thickness)
      (ly:grob-set-property! grob 'control-points (ly:unpure-call 
cpt-computer grob)))))

{
  \override Slur.after-line-breaking = #(variable-bow-thickness-harm 1 
2 1 33)

  b1( b')

  \shape #'((10 . 0) (0 . 0) (0 . 0) (0 . 0) ) Slur
  b1( b')

  b1-\shape #'((10 . 0) (0 . 0) (0 . 0) (0 . 0)) ( b')
}


Best,
Jean