Re: Adjusting OttavaBracket parameters (was "Re: can't seem to apply tweaks on tweaks")

[Thomas Morley]

2016-01-03 0:16 GMT+01:00 David Kastrup <address@hidden>:
> Thomas Morley <address@hidden> writes:
>
>> If you do it 'before-line-breaking it works, yes, but can't be changed
>> 'after-line-breaking anymore ...
>>
>> No idea what's happening and why.
>
> Caching?  I don't see you using unpure-pure containers.  Anything else
> is only evaluated once.
>
> --
> David Kastrup

Well, up to now unpure-pure containers are the most cryptic and
ununderstood topic for me.
Over the years I tried to understand them again and again, with little success.

After your hint above I looked through our docs again.
I found:

NR 5.5.6 unpure-pure containers
http://www.lilypond.org/doc/v2.19/Documentation/notation/unpure_002dpure-containers

unpure-pure-container.ly
in /input/regression

CG 10.13 Understanding pure properties
http://www.lilypond.org/doc/v2.19/Documentation/contributor/understanding-pure-properties


I have to say the documentation became better over the years in the
sense of being more verbose and yes, this is an advantage.
But it lacks of examples. The one in the NR works with _and_ without
unpure-pure-container.
So the only compilable and working example (i.e. where
unpure-pure-container make the difference) is the one from the
reg-tests.
Furthermore, almost always the topic is overriding directly
Y-offset/extent or properties affecting those.

Ok, setting OttavaBracket.text may affect Y-spacing, though I've no
idea idea how to do it with a unpure-pure-container.

May I ask you how to do it with this code-example?

{
  \override Staff.OttavaBracket.after-line-breaking =
    #(lambda (grob) (ly:grob-set-property! grob 'text "foo"))
  \ottava #1 c''4 4 4 4  4 4 \ottava #0 4 4  \break
  \ottava #1 c''4 4 4 4  4 4 \ottava #0 4 4  \break
  \ottava #1 c''4 4 4 4  \break 4 4 \ottava #0 4 4
}

Cheers,
  Harm