Re: How to detect SpanBar from inside a make-bar-line definition?

[Dan Eble]

On 2024-03-13 17:35, Thomas Morley wrote:

> currently I'm attempting to improve dashed/dotted bar lines wrt to
> changed staff-space and span bars.
> We use both definitions for BarLine _and_ SpanBar, but then SpanBar is
> frequently a little off.
> It would be nice to have a possibility to detect whether a definition
> is used for span bars.

What specifically do you want to know?  Do you expect to code something like

    if the grob is a BarLine:
      adjust ... by ...
    if the grob is a Divisio:
      adjust ... by ...
    if the grob is a SpanBar:
      adjust ... by ...

If so, it seems that you could add a grob property for that adjustment 
and get it from the grob.

> #(define (make-test-bar-line grob extent)
>    (let ((grob::make-span-bar? #f))

Another possibility is for the grob's print procedure to pass more 
information down to this function.  That might be more appropriate if 
the information you require is not associated with the grob only, but is 
derived from a number of sources, like the surrounding staves, and would 
be useful for many different glyph print procedures.  Of course, 
ly:bar-line::print would provide values appropriate for bar lines and 
ly:span-bar::print would provide values appropriate for span bars.

These are the opinions off the top of my head and I reserve the right to 
change them.
--
Dan