Le 2022-06-19 10:58, Stefan Thomas a écrit :
allNotes= { c'8 g' e' g' d' g' f' g' c' g' e' g' }
someNotes = { c' d' c' }
In other words: I would like to filter out every 4th note of allNotes,
so
that I could do in combination with changePitch (see
https://github.com/gilles-th/arranger.ly/blob/master/changePitch.ly)
the
following:
patI = { c8 r r4 }
someNotes = { \cPI { \someNotes s } }
Thanks for Your help,
"arranger.ly" provides a special function to play with the order of
notes in a sequential music : tweak-notes-seq
(see page 25 of
http://gillesth.free.fr/Lilypond/arranger-docs/arrangerDoc-en.pdf )
You just need here a little trick :
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\version "2.22.0"
\include "arranger.ly"
global = { \time 2/4 s2*8 }
#(init '(instru))
%%%%%%%%%%%
allNotes= { c'8 g' e' g'
d' g' f' g'
c' g' e' g' }
#(define (note->skip note) ; the trick function for tweak-notes-seq
"Transforms any music to a single skip"
(make-music 'SkipEvent))
someNotes = #(tweak-notes-seq `(1 ,(cons 4 note->skip))
allNotes)
patI = { c8 r r4 }
#(rm 'instru 1 (cp1 someNotes)) % cp1 = cp patI = \changePitch \patI
\new Staff { << \global \instru >> }
%% => { c' r8 r4
%% d' r8 r4
%% c' r8 r4 }
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
explanation :
(tweak-notes-seq '(1 4) allNotes) would make a sequential music,
taking from allNotes the following notes :
1st 4th 5th 8th 9th 12th...
(tweak-notes-seq `(1 ,(cons 4 note->skip)) allNotes) do the same
but note 4,8,12 etc are transformed into a skip
a skip for changePitch means "skip the current pattern note and go
to the next note (or here return to the beginning of the pattern)"
The number 4 is needed to let tweak-notes-seq knowing the length of
the loop
--
Gilles (trying to make up for lost time)
