Lukas-Fabian Moser <l...@gmx.de> writes:
>> is there a way of automagically adding some volume increase
>> ("accent") in MIDI output to any note that happens to start on the
>> first beat in a bar?
>>
>> It seems a well-defined enough request to me so that it should be
>> perfectly possible to do this in scheme, but I'm afraid this exceeds
>> my very limited LilyPond-scheme abilites...
>>
>> Slight complication (maybe): In my scores, the metre changes all the
>> time, so one really would have to use the actual timing of a note.
>
> Ok, so I tried to boldly dive into the hitherto unknown realm of
> engraver construction and came up with the following:
>
> \version "2.19.82"
>
> #(define (measure-position-from-context context)
> (ly:moment-main (ly:context-property context 'measurePosition)))
>
> accent_downbeat_engraver =
> #(lambda (ctx) (make-engraver
> (listeners
> ((note-event engraver event)
> (if (eq? 0 (measure-position-from-context ctx))
> (ly:broadcast (ly:context-event-source ctx)
> (ly:make-stream-event
> (ly:make-event-class 'articulation-event)
> (list
> (cons 'midi-extra-velocity 20)
> (cons 'articulation-type "accent")))))))))
> This works fine in that it adds accents to any notes happening to
> start a new measure. But - and this would be crucial for my
> application - the accents do not survive in the MIDI output. (At first
> I thought that \consist'ing the engraver to the Voice context in the
> \midi might help, but alas...)
Well, it creates the engraver. But in \midi, only performers are
called. There are no scheme-defined MIDI performers.
> My guess is that I'm broadcasting an articulation event that suffices
> for the articulation being printed, but is either not "connected" to
> the actual note or is for some other reason missed by the MIDI
> performers.
>
> How could I proceed?
Your idea is good. The infrastructure is not there. We probably should
have something like make-translator for stuff that just translates
events and/or meddles with context properties.
So you probably need to work on the music expressions for now similar to
how articulate.ly does things.
--
David Kastrup
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