Re: override stencil question

[Nathan Ho]

On Thu, Jun 4, 2015 at 11:35 AM, priosfilho <address@hidden> wrote:

Hey Nathan

This is just the code developed in the thread plus more adjustable handles
for curveto:

Unfortunately this code isn't compiling for me. There are a few extra )'s in there.

I created this from code earlier in the thread; maybe it'll help you:

%%%%

arc = #(list 0 0) %<< global variable to bezier curve handle 

glissWidth = #0.2 %<< global variable for glissando width 

#(define (set-arc x y) 

        (set! arc (list x y))) 

#(define (get-arc) 

        arc) 

#(define (radians->degrees theta)

   (* theta (/ 180 PI)))

#(define (path-gliss grob) 

                  

        (if (ly:stencil? (ly:line-spanner::print grob)) 

    (let* ((stencil (ly:line-spanner::print grob)) 

                        (X-ext (ly:stencil-extent stencil X)) 

            (Y-ext (ly:stencil-extent stencil Y)) 

            (width (interval-length X-ext)) 

            (height (interval-length Y-ext)) 

            (lefty (cdr (assoc 'Y (ly:grob-property grob 'left-bound-info))))

          (righty (cdr (assoc 'Y (ly:grob-property grob 'right-bound-info)))) 

                        (deltay (- righty lefty)) 

                        (dir (if (> deltay 0) 1 -1)) 

                        (handle (get-arc))) ;<<------------- getting the handle value here

                                

       (ly:stencil-translate

         (ly:stencil-add

           (grob-interpret-markup grob 

             (markup 

             ;(#: tiny (format "~a" (ly:grob-properties grob))) 

           ;(format "~a" (cdr (assoc 'Y (ly:grob-property grob 'left-bound-info)))) 

                           ;(#: tiny (format "~a" handle))

               (#:path glissWidth 

                 (list (list 'moveto 0 0) 

                                           (list 'curveto 0 0 (first handle) (second handle) width (* height dir))))))

           (ly:stencil-translate

             ; the \rotate markup command doesn't let us pick a rotation center, so we resort to the stencil command

             (ly:stencil-rotate

               (grob-interpret-markup grob

                 (markup #:arrow-head X RIGHT #t))

               (radians->degrees

                 ($atan2

                   (- (* height dir) (second handle))

                   (- width (first handle)))) 1 0)

             (cons width (* height dir))))

         (if (> dir 0) 

          (cons (interval-start X-ext) (+ (interval-start Y-ext) 0.1)) 

          (cons (interval-start X-ext) (+ (interval-start Y-ext) height))))) 

      #f))             

\new Staff \with { 

        \override Glissando #'bound-details = #'((right (attach-dir . 0) (end-on-accidental . #f) (padding . 2.)) (left (attach-dir . 0) (padding . 0.))) 

        \override Glissando #'stencil = #path-gliss 

} 

\transpose c c' {

  #(set-arc 2 -4)

  c2\glissando c''2

} 

%%%%

Regards,

Nathan