Hi Abraham,
On Sat, Mar 21, 2015 at 9:13 PM, tisimst <tisimst.lilyp...@gmail.com> wrote:
> David,
>
> You are a genius! I've almost got it, but I'm not sure how to handle
> rests. Here's my current function:
>
> #(define (flipnotes grob)
> (let ((notes (ly:grob-array->list (ly:grob-object grob 'note-heads))))
> (for-each
> (lambda (note)
> (let* ((pitch (ly:event-property (event-cause note) 'pitch))
> (stem (ly:grob-object note 'stem))
> (dir (ly:grob-property stem 'direction))
> (offset (ly:grob-relative-coordinate note grob X)))
> (if (eq? dir DOWN)
> (if (and (< offset 0.1) (> offset -0.1))
> (ly:grob-set-property! note 'rotation '(180 0 0))
> (ly:grob-set-property! note 'rotation '(0 0 0)))
> (if (and (< offset 0.1) (> offset -0.1))
> (ly:grob-set-property! note 'rotation '(0 0 0))
> (ly:grob-set-property! note 'rotation '(180 0 0)))
> )
> ))
> notes)))
>
>
> This works perfectly when there are NO rests, but I get this error when
> there is a rest in the NoteColumn:
>
> In procedure ly:grob-array->list in expression (ly:grob-array->list
> (ly:grob-object grob #)): Wrong type argument in position 1 (expecting
> Grob_array): ()
>
>
>
Glad I could help!
If there's a rest, then the note-heads array will be empty. To make this
work, just add a check that the note-heads list isn't the empty list '().
%%%%
#(define (flipnotes grob)
(let ((notes (ly:grob-array->list (ly:grob-object grob 'note-heads))))
(if (pair? notes)
(for-each
(lambda (note)
(let* (;(pitch (ly:event-property (event-cause note) 'pitch))
;; don't need this
(stem (ly:grob-object note 'stem))
(dir (ly:grob-property stem 'direction))
(offset (ly:grob-relative-coordinate note grob X)))
(if (eq? dir DOWN)
(if (and (< offset 0.1) (> offset -0.1))
(ly:grob-set-property! note 'rotation '(180 0 0))
(ly:grob-set-property! note 'rotation '(0 0 0)))
(if (and (< offset 0.1) (> offset -0.1))
(ly:grob-set-property! note 'rotation '(0 0 0))
(ly:grob-set-property! note 'rotation '(180 0 0)))
)
))
notes)
; alternate return?
)))
%%%%
If you get a rest, this function will return an unspecified value, so you
might want to add another clause to the if-block if you need meaningful
output.
Hope this helps!
David
_______________________________________________
lilypond-user mailing list
lilypond-user@gnu.org
https://lists.gnu.org/mailman/listinfo/lilypond-user
