- horz_line (xr, x0, x1, x2, x3, y1, left, right, shorten_y1_lines);
- horz_line (xr, x0, x1, x2, x3, y2, left, right, shorten_y2_lines);
+ horz_line (xr, x0, x1, x2, x3, y1, start_of_line, end_of_line, shorten_y1_lines);
+ horz_line (xr, x0, x1, x2, x3, y2, start_of_line, end_of_line, shorten_y2_lines);