Re: Behaviour of TextSpanner dashes

[Urs Liska]

Am 06.02.2014 04:49, schrieb Keith OHara:
> At 15:24 on 05 Feb 2014, Urs Liska wrote:
> > > >     - the vertical position of the dashes (i.e. raise
> > > >       it a little bit relatively to the text)
> > >
> > > TextSpanner.bound-details.left.stencil-align-dir-y = #CENTER
> >
> > unfortunately doesn't help. I'd need something like raise the dashes
> > by 0.2 ...
>
> Kieren MacMillan <kieren_macmillan <at> sympatico.ca> writes:
>
> > > Surprisingly it looks different with different texts.
> >
> > Another side-effect of the [irritating] fact that Lilypond doesn’t
> > use the text baseline as the reference point!?!?
>
> Lilypond does use the text baseline as reference point for text.
>
> It seems that override of stencil-align-dir-y = #CENTER
> makes LilyPond *replace* the usual reference point with the vertical
> center of the text, including descenders if there are any.
>
> Other values in place of CENTER move the reference to different fractions
> of the vertical extent.  Looking at the code, leaving stencil-align-dir-y
> unset leaves the reference point at the baseline.

This seems like a plausible explanation of the behaviour.

> The documentation talks next about  stencil-offset
> Try that.


Hm, I finde stencil-offset in the properties of DynamicSpanner, but not 
TextSpanner.
Overriding stencil-offset or left.stencil-offset doesn't seem to have 
any effect.

IR of TextSpanner states left.attach-dir which sounds good, but 
overriding doesn't seem to change anything.

Then there is left.Y - which makes the dashed line diagonal.

What I find interesting too is

left-bound-info (list):
ly:line-spanner::calc-left-bound-info
An alist of properties for determining attachments of spanners to edges.

But unfortunately I don't find any concrete information about this 
"alist of properties".

[That's something I often struggle with: I think the function or 
parameter definition that is generated from the sources is often quite 
sparse]

Any further information or ideas?

TIA
Urs