Re: guide finger

[David Nalesnik]

Hi pabuhr,

On Mon, Aug 20, 2012 at 11:45 PM, pabuhr <address@hidden> wrote:
> Thank you so much. However, because "rotate" performs its rotation around the
> center of the character I need to make a small adjustment. There is a
> "rotation" routine allowing rotation at an arbitrary point but it appears to 
> be
> solely for music not markups.

I suppose you're thinking of ly:stencil-rotate.  You can use this in
the function, since the result of grob-interpret-markup is a stencil:

#(define (gx rotate-guide fingering)
  (let ((music (make-music 'FingeringEvent))
        (finger (ly:music-property fingering 'digit))
        (guide-char #x2013))
    (set! (ly:music-property music 'tweaks)
      (acons 'stencil
         (lambda (grob)
           (ly:stencil-combine-at-edge
             (ly:stencil-rotate (grob-interpret-markup grob (markup
#:char guide-char)) rotate-guide -1 1)
             X 1
             (grob-interpret-markup grob (number->string finger))
             0))
         (ly:music-property music 'tweaks)))
    music))

>I tried the following change using "translate"
> but there is no "translate-guide" routine, which was a guess on my part after
> looking at the way "rotate" is used. I have attempted to locate a list of 
> these
> Scheme routines but been unsuccessful. I even downloaded the GIT source for
> lilypond and tried to find them there. So I have done due diligence, but I may
> have done the wrong things. Can someone show me how to make translate move the
> character? I can do the fine tuning of the position after that.

I don't find a list of the make-...-markup formulations, and I just
created make-rotate-markup as you made make-translate-markup.

To express markups in Scheme in a way that is closer to ordinary input
you can use the syntax detailed here (I show this below as an
alternative):
http://www.lilypond.org/doc/v2.15/Documentation/extending/markup-construction-in-scheme

This is how to get the translation to work:

#(define (gx rotate-guide fingering)
  (let ((music (make-music 'FingeringEvent))
        (finger (ly:music-property fingering 'digit))
        (guide-char #x2013))
    (set! (ly:music-property music 'tweaks)
          (acons 'stencil
            (lambda (grob)
              (grob-interpret-markup grob
              ; EITHER:
                ;(make-concat-markup
                 ; (list
                    ;(make-translate-markup '(2 . 3)
                      ;(make-rotate-markup rotate-guide (make-char-markup 
guide-char)))
                    ;(number->string finger)))))
              ; OR:
                (markup #:concat
                  (#:translate '(2 . 3) (#:rotate rotate-guide (#:char 
guide-char)))
                  (number->string finger))))
            (ly:music-property music 'tweaks)))
    music))

> ==============================================================================
>
>
>    You might consider upgrading to one of the current development versions if
>    you're interested in writing functions like this.  There is now quite a bit
>    more flexibility and power to music functions (thanks to David Kastrup).
>
> I am using GNU LilyPond 2.15.41 even though my files still have "\version
> "2.14.2"" at the start. Again, I spent some time trying to locate scheme music
> functions but was wholly unsuccessful. But I may just be searching with the
> wrong magic phrases.

Well, here I was meaning that it was a simple matter to keep your
original formulation as a music function and call it from another
music function.  (See attached.  This will cause errors if you try it
with 2.14.2.)

HTH,
David

finger-slide.ly
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