Re: Tweaking in scheme

[Thomas Morley]

2015-06-29 12:54 GMT+02:00 Peter Gentry <address@hidden>:
>
> Tweaking in scheme
>
> The heart of the scheme procedure  I'm trying is
>
> #(define (instrumentrange music instrument )
>    (  ly:music? string? )
> ; extract the various portions of the music object
> (let ((es (ly:music-property music 'elements))
>            (e   (ly:music-property music 'element))
>            (p   (ly:music-property music 'pitch)));rebuild the pitch and if a 
> changed pitch add the color tweak
> ...
> ...
>
> (if (ly:pitch? p)
>           (let ((new-pitch (naturalize-instrument-range p instrument)))
>           (ly:music-set-property! music 'pitch new-pitch)
>           (if (and (not (equal? p new-pitch)) (color? my-color))
>               (ly:music-set-property! music 'tweaks
>               (acons
>                 'color my-color
>                (ly:music-property music 'tweaks))))))
>
>      music))
>
> This works fine and I have used \displayMusic to show the music stream to 
> investigate other possible properties that can be
> specified in this way.
>
> I would like to specify note head style but this does not seem to appear as a 
> property that can be applied in the acons list.
> In display music there is a complex list

This is an \override

> (make-music
> 'ContextSpeccedMusic
> 'contextt-type
> 'Bottom
> 'element
> (make-music
>  'OverrideProperty
> 'pop-first
> #t
> 'grob-property-path
> (list (quote style))
> 'grob-value
> 'harmonic
> 'symbol
> 'NoteHead))
>
> Can this in any way be implimented by  the 'tweaks method.



How about:

\version "2.19.21"

%% regard output of:
\displayMusic
{ \tweak style #'harmonic a'1 }

tweakI =
#(define-music-function (parser location music)(ly:music?)
  (ly:music-set-property! music 'tweaks
    (acons 'style 'harmonic
      (acons 'color red
        (ly:music-property music 'tweaks))))
  music)

{ \tweakI a'1 }

%% or:

tweakII =
#(define-music-function (parser location music)(ly:music?)
  #{
    \tweak color #red
    \tweak style #'harmonic
    $music
  #})

{ \tweakII a'1 }


HTH,
  Harm