def get_plotting_vtx(vertex_lst):
leftmost, rightmost, top, bottom = Point_2(), Point_2(), Point_2(
), Point_2()
CGAL_Convex_hull_2.ch_n_point(vertex_lst, top) # maximal y coordinate.
CGAL_Convex_hull_2.ch_e_point(vertex_lst,
rightmost) # maximal x coordinate.
CGAL_Convex_hull_2.ch_s_point(vertex_lst, bottom) # minimal y coordinates
CGAL_Convex_hull_2.ch_w_point(vertex_lst, leftmost) # minimal x coordinate
lt, rt = leftmost.x(), rightmost.x()
tp, btm = top.y(), bottom.y()
draw_pt_list = []
for pair in product([lt, rt], [tp, btm]):
draw_pt_list.append(pair)
# left_btm_x, left_btm_y= draw_pt_list[1]
delta_x = (lt + rt) / 2 - 0
delta_y = (tp + btm) / 2 - 0
ch_height = tp - btm
ch_width = rt - lt
return ch_height, ch_width, delta_x, delta_y
