Re: non-markup stencils

[Jonatan Liljedahl]

On Sat, 30 Apr 2005 15:05:27 +0200
Sean Reed <address@hidden> wrote:

> thanks again han-wen, mats, donald axel, jonatan, and fairchild for
> the help with the bartok pizz. it opened my eyes a bit to the
> flexibility of self-programmed extensions, specifically for extended
> performance techniques.
> 
> i am now attempting to put a little cross on the stems of notes for 
> passages or pitches which are to be performed battuto (strings) or
> with "slap" articulations for winds.
> 
> i attempted to modify your examples with the attached patch (see 
> below), but the crosses always remain at a static x-y coordinate. i 
> assume this is because i defined it as a markup command. is there a
> way to define a stencil (forgive me if it's incorrect terminology)
> that would place a cross in the note's corresponding stem while 
> automatically modifying the y-coordinate so as to position it in the 
> middle of that given stem (see attached example)?
> 
> thanks for your help.
> 

There was someone who requested a cross on the stems a while ago, and I
posted something which might be what your want. Try this:

%%% tested with 2.5.18 %%%
#(define (cross-callback callback)
   (define (cross-stencil grob)
     (let* ((cross (ly:font-get-glyph
              (ly:get-default-font grob) "noteheads.s2cross"))
            (s (callback grob))
            (sx (ly:stencil-extent s 0))
            (sy (ly:stencil-extent s 1))
            (cx (ly:stencil-extent cross 0))
            (xadj (/ (interval-length cx) 2))
            (midy (+ (car sy) (/ (interval-length sy) 2))))
        (set! s (ly:stencil-add s 
            (ly:stencil-translate cross (cons (- xadj) midy))))
       (ly:make-stencil (ly:stencil-expr s) sx sy)))
   cross-stencil)

stemCrossStart = \override Stem  #'print-function
    = #(cross-callback Stem::print)
stemCrossStop = \revert Stem #'print-function


/Jonatan    -=( http://kymatica.com )=-