Proposed horizontal spacing adjustment [was Re: film score example]

[Jim Long]

On Sat, Sep 14, 2013 at 12:14:55PM +0200, Janek Warcho?? wrote:
> 
> I think that we should add to LilyPond a simple, user-friendly
> interface that would allow choosing the "density" of music, so that
> one could write
> \layout { \horizontalSpacingLoose }
> and it would result in common-shortest-duration being increased by
> some factor.

I like this idea, also.  I would suggest that the factor be
specified by the user, to make this a fully (or at least, widely)
adjustable parameter.  A factor of 1.0 could mean no change.  A
factor of 1.1 would increase (loosen) the spacing by 10%, while a
factor or 0.9 would tighten the spacing by 10%, etc.

\layout { \horizontalSpacingFactor #1.04 }

I suppose that, by extension, this means that a factor of #0.0
means the layout would have no spacing at all, and all glyphs
would be engraved over the top of each other in one big blob, and
a factor of #-1.0 would mean that the glyphs are engraved
normally, but spaced right-to-left.  For the sake of
reasonableness/sanity, perhaps Lily might just disallow factors <
or perhaps even <= 0, unless someone can make a compelling use
case for non-positive spacing factors.