Re: Distance of a grob from its reference point

[David Nalesnik]

On Thu, Jan 16, 2020 at 3:42 PM David Nalesnik <address@hidden> wrote:
>
> Hi Robin,
>
> On Thu, Jan 16, 2020 at 1:02 PM Robin Bannister <address@hidden> wrote:
> >
> > Paolo Prete wrote:
> >
> > > This is *precious* info. Please, can you tell/confirm  if
> > >
> > > 1) you are referring to \offset command ?
> >
> > No.  That would be premature in this case.
> >
> >
> > > 2) is it applicable as a replacement for "\offset Y-offset" for *every*
> > > grob that support Y-offset ?
> >
> > Well, I have trouble following your trains of thought.
> > I won't try to understand that question.
> >
> > And I'm puzzled why you focus directly on the property Y-offset.
> >
> >
> > As regards the \offset command:
> > The section 'Properties which may be offset' at
> > http://lilypond.org/doc/v2.19/Documentation/notation/the-offset-command
> > says the property must have a default setting in define-grobs.scm.
> >
> > OttavaBracket has the property outside-staff-padding because it supports
> > the outside-staff-interface.
> > http://lilypond.org/doc/v2.19/Documentation/internals/outside_002dstaff_002dinterface
> > but define-grobs.scm doesn't set it.
> >
> > So you can't use \offset in this case until that is amended.
>
> This is an argument for adding these hidden default values directly to
> define-grobs.scm.
>

Actually, you can set a default value from which \offset will work.
It relies on the combination \override and \once \offset:
\version "2.19.80"

{
  \override Staff.OttavaBracket.outside-staff-padding = 0.46 % set me
to default first!
  \ottava #1
  c''4 e'' d'' f''
  \ottava #0
  c''1
  \once \offset outside-staff-padding #2 Staff.OttavaBracket
  \ottava #1
  c''4 e'' d'' f''
  \ottava #0
}

Uh oh, now I've opened a can of worms :)

David