+ Spacing_spanner::stretch_to_regularity (me, &springs, cols);
+ for (int i=springs.size (); i --;)
+ springs[i].add_to_cols ();
+}
+
+/*
+ Look at COLS, searching for columns that have 'regular-distance-to
+ set. A sequence of columns that have this property set should have
+ an equal distance (an equispaced run). Extract the projected
+ distance from SPRINGS, and scale SPRINGS for the equispaced run, to the
+ widest space necessary.
+
+
+ TODO:
+
+ -- inefficient code; maybe it is easier to twiddle with the springs
+ after they've become grob properties (ie. have their
+ minimum-distances set)
+
+ -- does not adjust strength field of the springs very well: result
+ awkward spacing at the start of a line. (?)
+
+ -- will be confused when there are multiple equispaced runs in a measure.
+
+ -- dealing with springs for line breaks is a little tricky; in any
+ case, we will only space per measure.
+
+ -- we scale to actual distances, not to optical effects. Eg. if the
+ equispaced run contains optical corrections, then the scaling will
+ cancel those.
+
+ -- Regular_spacing_engraver doesn't mark the first column of the
+ next bar, making the space before a barline too short, in this case
+
+
+ x<- 16ths--> x(8th)
+ x(8th) x(8th) <- equispaced run.
+
+*/
+
+void
+Spacing_spanner::stretch_to_regularity (Grob *me,
+ Array<Spring> * springs,
+ Link_array<Grob> const & cols)
+{
+ /*
+ Find the starting column of the run. REGULAR-DISTANCE-TO points
+ back to a previous column, so we look ahead to find a column
+ pointing back to the first one.
+
+ */
+ Grob * first_regular_spaced_col = 0;
+ for (int i = 0 ; i < cols.size () && !first_regular_spaced_col; i++)
+ {
+ SCM rdt = cols[i]->get_grob_property ("regular-distance-to");
+ if (cols.find_l (unsmob_grob (rdt)))
+ first_regular_spaced_col = unsmob_grob (rdt);
+ }
+ for (int i = springs->size (); i-- ;)
+ springs->elem (i).set_to_cols ();
+
+ int i;
+ for (i = 0; i < springs->size ()
+ && springs->elem (i).item_l_drul_[RIGHT] != first_regular_spaced_col;
+ i++)
+ ;
+
+
+ if (i==springs->size ())
+ return ;
+
+ Real maxdist = 0.0;
+ Real dist =0.0;
+ Grob *last_col = first_regular_spaced_col;
+ Grob *last_regular_spaced_col = first_regular_spaced_col;
+
+
+ /*
+ find the max distance for this run.
+ */
+ for (int j = i; j < springs->size (); j++)
+ {
+ Spring *s = &(springs->elem_ref (j));
+ if (s->item_l_drul_[LEFT] != last_col)
+ continue;
+
+ dist += s->distance_f_;
+
+ last_col = s->item_l_drul_[RIGHT];
+ SCM rdt = last_col->get_grob_property ("regular-distance-to");
+ if (unsmob_grob (rdt) == last_regular_spaced_col)
+ {
+ maxdist = maxdist >? dist;
+ dist = 0.0;
+ last_regular_spaced_col = last_col;
+ }
+
+ }
+
+ /*
+ Scale the springs
+ */
+ dist =0.0;
+ last_col = first_regular_spaced_col;
+ last_regular_spaced_col = first_regular_spaced_col;
+ for (int j = i; j < springs->size (); j++)
+ {
+ Spring *s = &springs->elem_ref (j);
+ if (s->item_l_drul_[LEFT] != last_col)
+ continue;
+ dist += s->distance_f_;
+
+ last_col = s->item_l_drul_[RIGHT];
+ SCM rdt = last_col->get_grob_property ("regular-distance-to");
+ if (unsmob_grob (rdt) == last_regular_spaced_col)
+ {
+ do {
+ springs->elem_ref (i).distance_f_ *= maxdist / dist;
+ springs->elem_ref (i).strength_f_ *= dist / maxdist;
+ } while (i++ < j);
+ last_regular_spaced_col = last_col;
+ dist =0.0;
+ }
+ }