Re: Completion_heads_engraver for line-ends only?

[Graham King]

> On 17 Jan 2023, at 17:56, Jean Abou Samra <jean@abou-samra.fr> wrote:
> 
> Le 17/01/2023 à 18:31, Graham King a écrit :
>> I'm preparing an edition of de Wert's motet "Ascendente Jesu in naviculam" 
>> which has an extended stretto section with dotted rhythms across barlines.  
>> For this, Harm's Mensurstriche example in the Learning Manual produces a 
>> mostly beautiful result.
>> 
>> However, for the sake of those singers who, faced with this passage, find 
>> themselves <ahem> all at sea, I would like to avoid notes extending across 
>> line-breaks.  The idea is to use something like the 
>> Completion_heads_engraver that would take effect only at those barlines that 
>> coincide with a line break.  Does such a thing exist?
> 
> 
> 
> I am afraid this would be exceedingly difficult technically.
> Engravers run way earlier than line breaking, so the only
> option would be to let the engraver create both notations
> (with notes straddling over bar lines and with tied notes),
> and remove one of them later, but there is a lot of code in
> between that is not prepared for ignoring the collisions
> that will unavoidably ensue, it would have consequences on
> horizontal spacing, etc.

OK, that makes sense.  It's certainly not worth a lot of software development 
effort.
> 
> Also, I have to say I would find it confusing as a performer.
> In your shoes, I'd go either for modern notation with ties, or
> for ancient notation, but not a mixture of both.
> 
> 
>> As a secondary question: Is there a straightforward way to avoid collisions 
>> of mensurstriche with beams?
> 
> 
> Do you have an example?

Here's an extract from the de Wert, that illustrates the "problem" (lilypond 
2.25.0):

I'm not really sure what best practice is here; it might be that these 
collisions are just to be expected?  (I can certainly live with them).  If you 
would like an MWE with code, that'll take me a little while to prepare.  
(Probably not tonight).  Or I could just send you the .ly file (25kB).

-- Graham

> 
> Regards,
> Jean
>