Re: color notehead according to absolute pitch

[Jay Anderson]

> If anyone can come up with a nice solution, this should definitely be
> added to the LSR...

I'm not sure this is a nice solution yet, but it is at least a little
easier to manipulate the color mapping and it handles enharmonic
spellings easily. Let me know what you think.

-----Jay

\version "2.11.54"

%Association list of semitones from middle c to colors.
#(define color-mapping
  (list
    (cons (ly:pitch-semitones (ly:make-pitch 0 0 0)) (x11-color 'blue))
    (cons 2 (x11-color 'yellow))
    (cons 3 (x11-color 'red))
    (cons -1 (x11-color 'green))
    (cons 5 (x11-color 'purple))
    (cons 7 (x11-color 'cyan))
    (cons 8 (x11-color 'ForestGreen))
    ))

#(define (pitch-to-color pitch)
  (let ((color (assv (ly:pitch-semitones pitch) color-mapping)))
    (if color (cdr color))))

#(define (color-notehead grob)
  (pitch-to-color (ly:event-property (ly:grob-property grob 'cause) 'pitch)))

\score
{
  \new Staff \relative c'
  {
    \override NoteHead #'color = #color-notehead
    c8 b d dis ees f g aes
  }
}