Re: Lyrics break estimation of vertical spacing

[Joe Neeman]

On Mon, 2010-03-29 at 15:53 -0400, Boris Shingarov wrote:
> On Mon, 29 Mar 2010 08:48:35 -0700, Joe Neeman  wrote:
>  
> > Keep in mind that a lyric line is the same as a staff to the
>   > page-breaker. Don't your one-staffers have lyrics? If so, they are
>   > really two-staffers and so the problem could still be in the
>   > within-system estimation. 
>  
> My one-staffers do have lyrics, but I have overwhelmingly convincing
> proof the problem is the between-system estimation.  (Also, the
> bug exhibits itself even when there are no lyrics, just music on
> low ledgers -- the estimator does not know that they go below
> the top point of the treble clef on the next line; and because these
> are one-liners, the error is  very significant (30% of the page is
> blank)). 
>  
> I've already spent some time writing a patch, and it's almost ready. 
> The difficult problem is not in the estimator itself -- it's just simple
> arithmetic -- but in intervalues crossing the libGuile FFI boundary,
> there is a lot of places where the API we are traversing is generic,
> and we don't know whether in this instance we are dealing with
> a single Interval or with a (begin, rest) pair. 
> What I did was I generalized "Interval" to be augmentable with
> a "rest-of-line" interval, but only if need be.

Do we really need this to be included in every Interval? I'd have
thought that the only data structure that needs to change is
Line_details.

Cheers,
Joe