+ /* TODO: grace notes look bad when things are stretched. Should we increase
+ their stretch strength? */
+ Spring ret (max (0.0, ideal), min_dist);
+ ret.set_inverse_compress_strength (max (0.0, ideal - min_desired_space));
+ ret.set_inverse_stretch_strength (max (0.1, base_space - increment));
+ return ret;
+}
+
+static Real
+knee_correction (Grob *note_spacing, Grob *right_stem, Real increment)
+{
+ Real note_head_width = increment;
+ Grob *head = right_stem ? Stem::support_head (right_stem) : 0;
+ Grob *rcolumn = dynamic_cast<Item *> (head)->get_column ();
+
+ Interval head_extent;
+ if (head)
+ {
+ head_extent = head->extent (rcolumn, X_AXIS);
+
+ if (!head_extent.is_empty ())
+ note_head_width = head_extent[RIGHT];
+
+ note_head_width -= Stem::thickness (right_stem);
+ }
+
+ return -note_head_width * get_grob_direction (right_stem)
+ * robust_scm2double (note_spacing->get_property ("knee-spacing-correction"), 0);
+}
+
+static Real
+different_directions_correction (Grob *note_spacing,
+ Drul_array<Interval> stem_posns,
+ Direction left_stem_dir)
+{
+ Real ret = 0.0;
+ Interval intersect = stem_posns[LEFT];
+ intersect.intersect (stem_posns[RIGHT]);
+
+ if (!intersect.is_empty ())
+ {
+ ret = abs (intersect.length ());
+
+ /*
+ Ugh. 7 is hardcoded.
+ */
+ ret = min (ret / 7, 1.0)
+ * left_stem_dir
+ * robust_scm2double (note_spacing->get_property ("stem-spacing-correction"), 0);
+ }
+ return ret;
+}
+
+static Real
+same_direction_correction (Grob *note_spacing, Drul_array<Interval> head_posns)
+{