Re: Tight spacing in mensural notation (was: Re: Cadenza Senza Tempo Problem)

[Graham King]

> On 30 Oct 2019, at 00:05, Graham King <address@hidden> wrote:
> 
>> 
>> On 29 Oct 2019, at 22:12, Thomas Morley <address@hidden> wrote:
>> 
>> Am Di., 29. Okt. 2019 um 16:28 Uhr schrieb Graham King
>> <address@hidden>:
>>> 
>>> <snip>
>>> This unanswered part of Reggie's question in [1] lead me to re-scratch an 
>>> old itch.  In manuscripts and old printed editions of mensural notation, 
>>> notes and rests are horizontally densely-spaced without regard for their 
>>> musical duration.  I have struggled to reproduce this in lilypond, and the 
>>> nearest I can get is this:
>>> <snip>
>>> 
>>> It would be good to be able to impose a small amount of horizontal space 
>>> between the noteheads, but I'm at a loss to see how that can be done.  Any 
>>> ideas?
>>> 
>>> -- Graham
>>> 
>>> [1] https://lists.gnu.org/archive/html/lilypond-user/2019-10/msg00420.html
>> 
>> Probably below may be of some help?
>> 
>> \paper { ragged-right = ##t }
>> 
>> \new Score \with {
>> \omit TimeSignature
>> \override SpacingSpanner.spacing-increment = 1
>> \override SpacingSpanner.base-shortest-duration = #(ly:make-moment -3)
>> \override SpacingSpanner.common-shortest-duration = #(ly:make-moment -3)
>> \override NoteHead.style = #'petrucci
>> 
>> %% play around with below, probably useful are settings between 2 and ~10
>> \override SpacingSpanner.shortest-duration-space = #2
>> }
>> 
>> {
>> \cadenzaOn
>> c'\longa \breve 1 \breve 1 2 2 1 4 4 1 2
>> %\bar "" \break % uncomment to observe effect
>> 2 8 8 8 8 c''1 b' a' g'
>> }
> 
> That's lovely. \override SpacingSpanner.shortest-duration-space = #3.5 
> results in something that could almost be from Cantiones Sacrae or any of the 
> movable-type printed editions of the period.
> 
> It will take me a little while to understand fully what you've done, but 
> thanks!
> 
> -- Graham

Harm, I'm afraid I'm struggling with "#(ly:make-moment -3)"

The NR[2] shows four arguments to ly:make-moment, describes two of them, and 
then speaks a little obtusely of the _second_ argument to ly:make-moment being 
possibly negative, and I can't find any examples of a negative first (and only) 
argument online.  Most examples seem to use one argument, a positive rational, 
which I think I do understand.

Where does this syntax come from and what does it mean?
And why did you choose -3 ?

TIA
-- Graham

[2] 
http://lilypond.org/doc/v2.19/Documentation/notation/scheme-functions#index-ly_003amake_002dmoment