I wanted to get bar lines after each sub-meter of a compound meter, and
to have Completion_heads_engraver recognize these bar lines and split
and tie notes as needed.
Thanks to David and Jan-Peter, I was able to change their
doubleBarlinesAfterTimeSig engraver to achieve this effect. I still have
a little more work to do since some of the moment variables currently
have fixed values.
The engraver works well as seen in the code below. Again, I do not
really understand the significance of why, for example time-signature is
set to '() although it does not change in the engraver. Also, when I
tried to change the variable last-fraction to last-bnum, it resulted in
a syntax error, even after changing the #f to #0. Perhaps someone may
know the answer to this.
Here is the modified engraver. Currently, it sets up timings of 3/4, 5/4
and 2/4 and puts a double bar at the end of the three measures. Also
notice how the double notes are split and tied across the bar lines.
Pretty cool, I would say.
\version "2.18.0"
%{
Based on a Scheme engraver that places
double bar lines before time signature changes
Provided by Jan-Peter Voigt
Presumably written by David Nalesnik
%}
last-bnum = #0
fs = #(ly:make-moment 3 4)
rs = #(ly:make-moment 2 4)
ts = #(ly:make-moment 5 4)
alternateTiming =
#(lambda (context)
(let ((time-signature '()) ;not sure why this time-signature is set
to '()
(last-fraction #f)) ;not sure why I can not change last-
fraction to last-bnum
`((process-music
. ,(lambda (trans)
(let ((bnum (ly:context-property context
'currentBarNumber)))
(format #t "bnum = ~a measurelength ~a ~%" bnum
(ly:context-property context 'measureLength))
(case (modulo bnum 3)
((1) (ly:context-set-property! context 'measureLength
fs)
(if (> bnum last-bnum) (ly:context-set-property!
context 'whichBar "||") )
(set! last-bnum bnum))
((0) (ly:context-set-property! context 'measureLength
rs))
((2) (ly:context-set-property! context 'measureLength
ts)))
)
))
(stop-translation-timestep
. ,(lambda (trans)
(set! time-signature '()))))
))
music = {
\compoundMeter #'((3 4) (5 4) (2 4) )
\relative c' {c d e2 f g4 a2 b c4 b2 a g4 f2 e d c d e f g a b c}
}
\score {
\new Staff \music
\layout {
\context {
\Score
\consists #alternateTiming
}
\context {
\Voice
\remove Note_heads_engraver
\remove Rest_engraver
\consists Completion_heads_engraver
\consists Completion_rest_engraver
}
}
}
\paper {
indent = 0\cm
}
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