Re: guide finger

[pabuhr]

   I suppose you're thinking of ly:stencil-rotate.

Brilliant!

Now let me see if I can reward your patience by showing you I have learned
something.

The rotation needs to be along the right centre (center) so the character
appears to rotate in the middle of the finger number, which I figured out.
Also, I put in some documentation. And I generalize one step further by
allowing the ornamentation character to be passed as an argument.  However, I
don't know how to write "gsc" (see below) to pass in a character or unicode to
"gx". So I still need help.

Also, does scheme have optional positional parameters and/or named parameters
to possibly allow more generalization, such as the padding size or putting the
ornamentation before or after the finger symbol? (Yea, I'm probably getting
carried away here. ;-)

==============================================================================

\version "2.14.2"

#(define (gx slope character fingering)
  ;; Purpose
  ;;   add ornamentation character before fingering symbol
  ;; Parameters
  ;;   slope : angle of rotation around right centre
  ;;   character : ornamentation character before fingering
  ;;   fingering : fingering designation for note
  ;; Examples
  ;;   (gx 0 #x2013 fingering)
  ;;        unicode #x2011 <-> #x2015 are different length "-" punctuation
  (let ((music (make-music 'FingeringEvent))
        (finger (ly:music-property fingering 'digit))
        (guide-char character))
    (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))
              slope 1 0)            ;; rotate "slope" around right centre
             X 1                    ;; combine stencils along X-axis on right
             (grob-interpret-markup grob (number->string finger))
             0.2))                  ;; add padding to move guide slightly left 
from finger number
         (ly:music-property music 'tweaks)))
    music))

% guide-neutral
gn = #(define-music-function (parser location fingering) (ly:music?)
       (gx 0 #x2013 fingering))
% guide-down
gd = #(define-music-function (parser location fingering) (ly:music?)
       (gx 30 #x2013 fingering))
% guide-up
gu = #(define-music-function (parser location fingering) (ly:music?)
       (gx -30 #x2013 fingering))
% guide slope
gs = #(define-music-function (parser location slope fingering) (number? 
ly:music?)
       (gx slope #x2013 fingering))
% guide slope character
gsc = #(define-music-function (parser location slope character fingering) 
(number? char? ly:music?)
       (gx slope character fingering))

\relative c' {
  \override Fingering #'font-size = #-2
  \override Fingering #'color = #red
  \set fingeringOrientations = #'(left)
  <c-\gn-1>4
  c4^\gn^2
  c4-\gn-3
  c4_\gn_4
  \set fingeringOrientations = #'(right)
  <c-\gn-3>4

  r4
  <c-\gu-1>4
  r4
  c4^\gu^2
  c4-\gd-3
  c4_\gd_4

  r4
  <c-\gs #-15 -1>4
  r4
  c4^\gs #15 ^2
  c4-\gs #45 -3
  c4_\gs #-45 _4

% these don't work

%  r4
%  <c-\gsc #-15 ##x2011 -1>4
%  r4
%  c4^\gsc #15 ##x2012 ^2
%  c4-\gsc #45 ##x2013 -3
%  c4_\gsc #-4 ##x2014 _4

%  r4
%  <c-\gsc #-15 '+' -1>4
%  r4
%  c4^\gsc #15 '+' ^2
%  c4-\gsc #45 '+' -3
%  c4_\gsc #-4 '+' _4
}