Le mer. 31 juil. 2024 à 18:18, Gilles Sadowski <gillese...@gmail.com> a écrit :
>
> Hello.
>
> A common accompaniment motive is "oom pah":
> https://en.wikipedia.org/wiki/Oom-pah
>
> An excerpt of a LilyPond-generated score is attached.
> I get this PDF output by encoding separately the "oom" ("bassoon" line)
> and the "pah" (the chord line), for the purpose of getting the MIDI output
> right: Bass note on the downbeat; chord on the upbeat.
> However, this entails that in the PDF the chord name is also displayed
> on the upbeat (as expected) despite it should also appear above the
> downbeat in order to convey the correct semantics of the harmonic
> structure.
>
> The excerpt below shows how the "upbeat" part is encoded (in its own file).
> ---CUT---
> aMajorBar = \chordmode {
> s8 a s a |
> }
> aMajorGMinorBar = \chordmode {
> s8 g:m s g:m |
> }
> harmonyChords = \chordmode {
> \time 2/4
> % Intro
> \repeat percent 2 {
> \aMajorBar
> }
> % A
> \repeat volta 2 {
> \aMajorGMinorBar
> \aMajorBar
> \aMajorGMinorBar
> \aMajorBar
> }
> % etc.
> }
> harmony = \context ChordNames = "Harmony" {
> \set chordChanges = ##t
> \set ChordNames.midiInstrument = "accordion"
> %
> \harmonyChords
> }
> ---CUT---
>
> Is there a recommended way to encode "oom pah" style accompaniment
> that would produce both outputs (PDF and MIDI) right?
Partially answering my initial question, the correct outputs are achieved
with encoding the upbeat accompaniment (and chord line) as
---CUT---
aMajorBar = \chordmode {
\tag #'no-layout {
s8 a s a |
}
\tag #'no-midi {
a2 |
}
}
---CUT---
> If not, it looks like what I'm looking for is a function with two arguments
> (a duration and a chord name) that would shift the graphics (to the left)
> while not changing its timing position:
> ---CUT---
> aMajorBar = \chordmode {
> s8 \shiftChordSymbol { 8 a } s \shiftChordSymbol { 8 a } |
> }
> ---CUT---
Hence the new question: How to define an "oompah" function
---CUT---
aMajorBar = \oompah { a2 }
---CUT---
that would expand to
---CUT---
aMajorBar = \chordmode {
\tag #'no-layout {
a,,8:1 a e,,:1 a |
}
\tag #'no-midi {
a2 |
}
}
---CUT---
i.e. from the chord name (and duration) argument, the function
would create
* the two "tag" blocks and
* the "oom pah" motif that consists of the bass notes (I, V) and
upbeat chords.
Best regards,
Gilles
