Re: Detecting polyphony from stencil-override

[David Kastrup]

Urs Liska <address@hidden> writes:

> Hi all,
>
> (how) is it possible to determine (from within a stencil override
> callback) if at any given point there is more than one active voice?
> I've asked a similar question before but probably from the wrong
> perspective.
>
> I'm overriding a stencil have to make a decision depending on the
> situation of being in a single voice or a << { } \\ { } >> polyphony
> construct.
>
> Any pointers? I assume this has something to do with contexts but I'm
> not really there yet.

Bad idea.  At the time a stencil callback is being called, contexts are
long gone.  What context information you want should be left in the
grob.  You can still look at the 'direction of the event-cause of the
grob and that's a reliable measure for figuring out explicit directions
(like ^( or _) ) in the source.  You may try looking at the
grob-property-data of 'direction which will be a direction when there is
a direction override in progress (pointing to a multi-voice situation)
and usually some sort of callback for the decision-making when it isn't.
Except that the callback might already have been called and replaced
with a direction.  So it's a bit shaky.

-- 
David Kastrup