Re: Error in resolving number of staff lines

[Marc Hohl]

Am 22.06.2012 10:49, schrieb David Kastrup:
> Marc Hohl <address@hidden> writes:
>
> > > You are only overriding line-positions.  While the bar line printer will
> > > see that this now contains a value and heeds it, this does not magically
> > > affect the (now ignored) line-count property.
> > Ah, I see, thanks for the explanation.
> > But why are the dots placed as if there were only four lines?
> > If the line number is still 5 and the routine in lily/bar-line.cc
> > works as expected, why are the dots placed correctly?
> Huh?  Because there is a lot of code for doing that?
>
>          {
>            std::vector<Real> linepos = Staff_symbol::line_positions (staff);
>            if (!linepos.empty ())
>              {
>                centre = Staff_symbol::line_span (staff).center ();
>
>                /*
>                  fold the staff into two at centre and find the first gap
>                  big enough to hold a dot and some space below and above
>                */
>
>                [lots and lots]
>
> And you'll see that Staff_symbol::line_positions consults both in order:
>
> vector<Real>
> Staff_symbol::line_positions (Grob *me)
> {
>    SCM line_positions = me->get_property ("line-positions");
>    if (scm_is_pair (line_positions))
>      {
>        int line_count = scm_ilength (line_positions);
>        vector<Real> values (line_count);
>        int i = 0;
>        for (SCM s = line_positions; scm_is_pair (s);
>             s = scm_cdr (s))
>          {
>            values[i++] = scm_to_double (scm_car (s));
>          }
>        return values;
>      }
>    else
>      {
>        int line_count = Staff_symbol::line_count (me);
>        Real height = line_count - 1;
>        vector<Real> values (line_count);
>        for (int i = 0; i < line_count; i++)
>          {
>            values[i] = height - i * 2;
>          }
>        return values;
>      }
> }
Ok, but in lily/bar-line.cc, Bar_line::compound_barline, the number
of lines is computed by

int lines = Staff_symbol_referencer::line_count (me)

which is defined as

int
Staff_symbol_referencer::line_count (Grob *me)
{
  Grob *st = get_staff_symbol (me);
  return st ? Staff_symbol::line_count (st) : 0;
}

so the line positions are *not* taken into account, as far as I see.
The computation of the colon stencil follows on the next 8 lines or so,
with the two dots being moved accordingly.

Obviously, I am missing something?

Regards

Marc