Re: color notehead according to absolute pitch

[Jay Anderson]

Kenny Stephens <kfstephensii <at> yahoo.com> writes:
> Our church has a handbell group whose members are not all musically literate. 
> To
> keep themselves from having to learn to read music, they mark their notes 
> using
> differently colored highlighters.
>
> Is there a means by which I can color the notes based on its absolute pitch 
> ---
> not its pitch class? Some of the music spans three octaves. The requirements 
> are:
>   1) b4 and b5 are different colors.
>   2) b\flat4 and b4 are different colors.
>   3) different pitches can be assigned to the same color (some "ringers" play
> two or more handbells).
>
> I've only been playing around with Lilypond for about a week (though I've 
> logged
> numerous hours) for typesetting organ music; but this is different. I did find
> an example using Scheme and 'staff-position,' but this fails condition 1.
>
> Ideas, suggestions or solutions would be appreciated.

Using the same idea as the example you mentioned
(http://lilypond.org/doc/v2.11/Documentation/user/lilypond-learning/Advanced-tweaks-with-Scheme)
you can base the color on the pitch:

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

Now you'd just have to figure out how to implement the pitch-to-color
function. For example this colors all the flat notes blue:

#(define (pitch-to-color pitch)
  (if (eqv? (ly:pitch-alteration pitch) -1/2) (x11-color 'blue)))

You might want to get a little fancy to make sure enharmonic spellings
of the same pitch are the same color, but for most cases that
shouldn't be a problem.

-----Jay