Re: drawing a range reguardless of transposition

[Michael Käppler]

While I would strongly suggest that you update to the latest development
version, which can regarded
as very stable, this would work with 2.18.2:

% LilyBin
\version "2.18.2"

highlightOutOfRange = #(define-scheme-function
  (parser location color lower upper)
  ((color? red) ly:pitch? ly:pitch?)
  (lambda (grob)
    (let* ((cause (ly:grob-property grob 'cause))
            (pitch (ly:event-property cause 'pitch)))
      (if (or (ly:pitch<? pitch lower) (ly:pitch<? upper pitch))
        color black))))

\layout {
  \context { \Voice
    \override NoteHead.color = \highlightOutOfRange c' c''
}
}

{
  \transpose c g, \relative c' { c d e f g a b c }
  \transpose c f \relative c' { c d e f g a b c }
}

The three adjustments I made are:
1. (define-scheme-function) does need the (parser location) arguments in
2.18.2.
2.(grob-transformer) does not exist in 2.18.2. This function allows to
obtain the property value the grob already had.
In this particular snippet you could color your note heads blue through
a global override and the
callback would leave it as it is.
As a simple solution for 2.18.2 I set the default note head color (for
notes within the allowed pitch range) to black.
3. \fixed does not exist in 2.18.2.

Regards,
Michael

Am 15.11.2019 um 10:18 schrieb Sandro Santilli:
> On Thu, Nov 14, 2019 at 09:09:16AM -0800, Aaron Hill wrote:
>
> > \layout {
> >    \context { \Voice
> >      \override NoteHead.color = \highlightOutOfRange c' c''
> >    }
> > }
> I like the highlighting idea! Is it compatible at all with 2.18.2 ?
>
> It seems not to be: http://lilybin.com/166vv7/1
>
>    Parsing.../usr/share/lilypond/2.18.2/scm/ly-syntax-constructors.scm:56:23: 
> In expression (apply (ly:music-function-extract fun) parser ...):
>    /usr/share/lilypond/2.18.2/scm/ly-syntax-constructors.scm:56:23: Wrong number of 
> arguments to #<procedure #f (color lower upper)>
>
> --strk;