Re: RE:Decaying squiggle

[Richard Shann]

Could you attach this code as a file - I get it causing a crash in
ghostscript (after using convert-ly and trying on 2.18.0 and 2.19.43), I
suspect this is because of whitespace being inserted by some part of the
food chain.
Thanks!

Richard


On Thu, 2016-06-23 at 16:08 -0400, Stephen MacNeil wrote:
> Hi Andrew
> 
> 
> This is common in guitar. Modern scores. Mark Witmer wrote code for
> this it's old but I still use it. 
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> 
> 
> \version "2.16.0"
> 
> 
> % vibrato.ly
> 
> % Author: Mark Witmer
> 
> 
> % Sets the next trill spanner to draw a waveform with the provided
> wevelength
> 
> % and amplitudes. The waveform will go from one amplitude to the next
> in a
> 
> % linear fashion.
> 
> vibrato = #(define-music-function (parser location amplitudes
> wavelength) (list? number?) #{ 
> 
> \once \override TrillSpanner #'after-line-breaking = $(lambda (grob) 
> 
> (ly:grob-set-property! grob 'stencil (makevib grob amplitudes
> wavelength)))
> 
> #})
> 
> #(define adjustvib #t)
> 
> 
> % Creates the postscript for one system of the vibrato marking
> 
> #(define (make_ps no-sib? lbound xspan span-so-far amplitude-vector
> wavelength) 
> 
> (if (or (= xspan -inf.0) (= xspan +inf.0))
> 
> ""
> 
> (let ((lbound 
> 
> (cond
> 
> ((and (> span-so-far 0) adjustvib) 
> 
> (- lbound 18))
> 
> (no-sib? (+ lbound 1))
> 
> (else lbound)))
> 
> (last 
> 
> (inexact->exact (floor (/ (+ span-so-far xspan) wavelength)))))
> 
> (format 
> 
> #f "gsave currentpoint translate 0.15 setlinewidth newpath /x ~a\
> 
> def\nx 0.0 moveto\n ~a ~a"
> 
> lbound 
> 
> (let make-curve 
> 
> ((current (inexact->exact (floor (/ span-so-far wavelength)))))
> 
> (cond 
> 
> ((= current (vector-length amplitude-vector)) "")
> 
> ((< (vector-ref amplitude-vector current) 0) "")
> 
> (else
> 
> (let ((current-ps 
> 
> (format 
> 
> #f " x ~a add ~a x ~a add ~a x ~a \
> 
> add 0.0 curveto\n/x x ~a add def\n"
> 
> (exact->inexact (/ wavelength 3)) 
> 
> (vector-ref amplitude-vector current)
> 
> (exact->inexact (* 2 (/ wavelength 3))) 
> 
> (- (vector-ref amplitude-vector current))
> 
> wavelength
> 
> wavelength)))
> 
> (if (= (+ current 1) last) 
> 
> current-ps 
> 
> (format #f "~a~a" current-ps 
> 
> (make-curve (+ 1 current))))))))
> 
> "stroke grestore"))))
> 
> 
> % Returns the width of a grob
> 
> #(define (grob-width grob)
> 
> (if (or (= (car (ly:grob-property grob 'X-extent)) -inf.0)
> 
> (= (car (ly:grob-property grob 'X-extent)) +inf.0))
> 
> 0
> 
> (- (cdr (ly:grob-property grob 'X-extent)) 
> 
> (car (ly:grob-property grob 'X-extent)))))
> 
> 
> % Returns the number of ems already traversed by the grob's siblings
> in previous systems
> 
> #(define (width-up-to grob siblings count)
> 
> (if (eq? (car siblings) grob)
> 
> count
> 
> (+ (+ count (width-up-to grob (cdr siblings) count))
> 
> (grob-width (car siblings)))))
> 
> 
> % Returns the total width of the individual grobs for each system that
> make up the original grob
> 
> #(define (calcfull siblings count)
> 
> (if (eqv? (length siblings) 0)
> 
> count
> 
> (calcfull (cdr siblings) (+ count (grob-width (car siblings))))))
> 
> 
> % Fills a vector of length len with linear interpolations between the
> values found in amplitudes
> 
> #(define (fill-amplitude-vector! amplitude-vector len current-index
> amplitudes)
> 
> (if (> (length amplitudes) 1)
> 
> (let ((start-amplitude (car amplitudes))
> 
> (end-amplitude (cadr amplitudes))
> 
> (start-index current-index)
> 
> (end-index (+ current-index 
> 
> (inexact->exact 
> 
> (floor (/ (vector-length amplitude-vector) 
> 
> (- len 1)))))))
> 
> (do ((n current-index (+ 1 n)))
> 
> ((or (> n (+ start-index end-index)) 
> 
> (>= n (vector-length amplitude-vector))))
> 
> (vector-set! amplitude-vector n 
> 
> (exact->inexact 
> 
> (+ start-amplitude 
> 
> (* (/ (- n start-index) (- end-index start-index))
> 
> (- end-amplitude start-amplitude))))))
> 
> (fill-amplitude-vector!
> 
> amplitude-vector len end-index (cdr amplitudes)))))
> 
> 
> % Makes the vector of amplitudes for the vibrato marking
> 
> #(define (make-amplitude-vector amplitudes total-span wavelength)
> 
> (let* ((current-start 0)
> 
> (len (inexact->exact (floor (/ total-span wavelength))))
> 
> (amplitude-vector (make-vector len)))
> 
> (if (> (length amplitudes) 1) 
> 
> (fill-amplitude-vector! 
> 
> amplitude-vector (length amplitudes) 0 amplitudes)
> 
> (vector-fill! amplitude-vector (car amplitudes)))
> 
> amplitude-vector))
> 
> 
> % Creates a stencil that draws a sine wave for vibrato based on the
> provided amplitudes and wavelength
> 
> #(define (makevib grob amplitudes wavelength)
> 
> (let* ((orig (ly:grob-original grob))
> 
> (siblings (if (ly:grob? orig) (ly:spanner-broken-into orig) '()))
> 
> (span (ly:grob-property grob 'X-extent))
> 
> (xbeg (car span))
> 
> (xend (cdr span))
> 
> (xspan (- xend xbeg))
> 
> (total-span (if (eqv? (length siblings) 0) (- xspan 3) (- (calcfull
> siblings 0) 3)))
> 
> (lbound (if (or (null? siblings) (eq? (car siblings) grob)) 
> 
> 0 (+ 14 (cdr (assq 'X (ly:grob-property grob 'left-bound-info))))))
> 
> (span-so-far (if (null? siblings) 0 
> 
> (width-up-to grob siblings 0))))
> 
> (ly:make-stencil 
> 
> (list 'embedded-ps 
> 
> (make_ps (null? siblings) lbound xspan span-so-far 
> 
> (make-amplitude-vector amplitudes total-span wavelength)
> 
> wavelength))
> 
> '(0 . 0) '(-0.7 . 0.5))))
> 
> 
> vib = #(define-music-function (parser location sizes) (list?)
> #{ \vibrato $sizes #0.7 #})
> 
> sVib = \startTrillSpan
> 
> eVib = \stopTrillSpan
> 
> 
> % Example:
> 
> \relative c' {\time 4/4 \key d \major \vibrato #'(4 0 4) #1.5 c
> \startTrillSpan d e d c d e d c\stopTrillSpan 
> 
> \vibrato #'(1 6 2 1 3 7 4) #1 c\startTrillSpan d e d c d e d c d e d c
> d e d c d e d c d e d c d e d c d e d 
> 
> c d e d c d e d c d e d c d e d c d e d c d e d c d e d c d e
> \stopTrillSpan}
> 
> %%%%%%%%%%%
> 
> \paper {
> 
> ragged-right = ##f
> 
> }
> 
> 
> \relative c' {
> 
> \vibrato #'(4 .2 0) #1.2 c1\startTrillSpan c\stopTrillSpan
> 
> }
> 
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%
> 
> 
> 
> 
> HTH
> 
> Stephen
> 
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