Re: polyphonic shorthand; line-spanner-interface in Hairpin

[Mats Bengtsson]

Kieren MacMillan wrote:
> > > 2. Can Hairpin inherit line-spanner-interface? If so, can this be 
> > > done in Scheme, or does it require C++?
> > It already has the line-interface and the spanner-interface as well 
> > as 3 other interfaces. Exactly what are you missing in the Hairpin?
>
> I'd like to be able to set #'bound-details, in particular the padding:
>
> \version "2.12.2"
> \paper { ragged-right = ##f }
> hairpinBoundTest = \relative { c'4\< c\! \override Hairpin 
> #'(bound-details right padding) = #5.0 c\< c\! }
> \score { \hairpinBoundTest }
>
> Eventually, I'd like to have a callback function that gives me the 
> padding in terms of beats in the current measure (as opposed to staff 
> spaces), so that I could "trim" a Hairpin by (e.g.) a half note. This 
> ability would completely eliminate the need for spacer skips, extra 
> voices, etc.
>
> Does that make sense?
Implementing such a feature by first trying to translate the duration 
into a numerical value and then set the padding doesn't seem like the 
best solution to me. For example, how do you handle the situation where 
there's a line break inbetween? I'd rather go for a solution that 
internally is equivalent to spacer notes in a parallel line of music 
(within the same Voice context, though), but where the user doesn't have 
to see this internal representation.

   /Mats