Re: [frogs] Changing subproperties with grob-set-property (working on bug #40)

[Neil Puttock <n.puttock@xxxxxxxxx>]

2009/11/19 Marc Hohl <marc@xxxxxxxxxx>:

> How can I get access to the fingering grob? I need its x-extent and the
> orientation, but strangely, I cannot use the same mechanism as for
> accidentals;
> here (ly:grob-object right-bound 'accidental-grob) works, but it seems that
> there
> is no (ly:grob-object right-bound 'fingering).

Why is that strange?  Accidentals are a completely different kettle of
fish to fingerings: they influence all sorts of typesetting decisions,
so it's important for a NoteHead to cache them.

Fingerings are just boring scripts placed near a notehead.  :)

> In scm/translation-functions.scm are some routines concerning fingerings, so
> I found out how to check whether there is a fingering or not, but I still
> cannot
> access its grob (I fear this is just an easy function call someplace, but I
> just don't see
> it now, and this will show my lack of deeper scheme knowledge as well :-( )

There's no easy way, I'm afraid.

Since you can't access children from a grob unless they're explicitly
added as a grob-array, I think the only method would be to use
'all-elements from the System grob, filtering out all the
undesirables.  This would be very expensive computationally.

>              (let* ((accidental-width (cdr (ly:grob-extent accidental
> accidental X)))

Careful here: the car isn't always zero (see for example the extent of
a flat), though in practice, the spacing difference probably isn't
that noticeable.

Regards,
Neil

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