+Stencil
+Line_interface::make_trill_line (Grob *me,
+ Offset from,
+ Offset to)
+{
+ Offset dz = (to - from);
+
+ Font_metric *fm = Font_interface::get_default_font (me);
+
+ Stencil elt = fm->find_by_name ("scripts.trill_element");
+ elt.align_to (Y_AXIS, CENTER);
+ Real elt_len = elt.extent (X_AXIS).length ();
+ if (elt_len <= 0.0)
+ {
+ programming_error ("can't find scripts.trill_element");
+ return Stencil ();
+ }
+
+ Stencil line;
+ Real len = 0.0;
+ do
+ {
+ line.add_at_edge (X_AXIS, RIGHT, elt, 0);
+ len = line.extent (X_AXIS).length ();
+ }
+ while (len + elt_len < dz.length ());
+
+ line.rotate (dz.arg (), Offset (LEFT, CENTER));
+ line.translate (from);
+
+ return line;
+}
+
+Stencil
+Line_interface::make_zigzag_line (Grob *me,
+ Offset from,
+ Offset to)
+{
+ Offset dz = to - from;
+
+ Real thick = Staff_symbol_referencer::line_thickness (me);
+ thick *= robust_scm2double (me->get_property ("thickness"), 1.0); // todo: staff sym referencer?
+
+ Real staff_space = Staff_symbol_referencer::staff_space (me);
+
+ Real w = robust_scm2double (me->get_property ("zigzag-width"), 1) * staff_space;
+ int count = (int) ceil (dz.length () / w);
+ w = dz.length () / count;
+
+ Real l = robust_scm2double (me->get_property ("zigzag-length"), 1) * w;
+ Real h = l > w / 2 ? sqrt (l * l - w * w / 4) : 0;
+
+ Offset rotation_factor = complex_exp (Offset (0, dz.arg ()));
+
+ Offset points[3];
+ points[0] = Offset (0, -h / 2);
+ points[1] = Offset (w / 2, h / 2);
+ points[2] = Offset (w, -h / 2);
+ for (int i = 0; i < 3; i++)
+ points[i] = complex_multiply (points[i], rotation_factor);
+
+ Stencil squiggle (Line_interface::make_line (thick, points[0], points[1]));
+ squiggle.add_stencil (Line_interface::make_line (thick, points[1], points[2]));
+
+ Stencil total;
+ for (int i = 0; i < count; i++)
+ {
+ Stencil moved_squiggle (squiggle);
+ moved_squiggle.translate (from + Offset (i * w, 0) * rotation_factor);
+ total.add_stencil (moved_squiggle);
+ }
+
+ return total;
+}
+