Python: plot (3) table graphing

Abstract: draw a table using matplotlib

The script:
# -*- coding: utf-8 -*-
"""
Created on Wed Jul 22 11:16:07 2015

@author: yuan
"""

import matplotlib.pylab as plt
import numpy as np

def get_coord(table, irow, icol):
    # get coordinates of a cell. This seems to work, don't ask why.
    cell = table.get_celld()[irow+1,icol] # row 0 is column headers
    box = cell.get_bbox().get_points() # [[x0, y0],[x1, y1]]
    xc, yc = box.mean(axis=0) # get center
    return xc, yc

col_labels=['0','1','2','3','4']
row_labels= ['0','1','2','3','4','5']
table_vals= [    ['Null','Null','Null','Null','Null'],    ['Null','Start','','x',''],
             ['Null','','','',''],    ['Null','','','x',''],
            ['Null','','x','End',''], ['Null','','','','x']]
#column row
line = np.array([    [1, 2, 2, 3, 4, 4, 4, 3],   
                     [1, 1, 2, 2, 2, 3, 4, 4]] )   
ncol = len(col_labels)
nrow = len(row_labels)

# draw grid lines
plt.plot(np.tile([0, ncol+1], (nrow+2,1)).T, np.tile(np.arange(nrow+2), (2,1)),
    'k', linewidth=3)
plt.plot(np.tile(np.arange(ncol+2), (2,1)), np.tile([0, nrow+1], (ncol+2,1)).T,
    'k', linewidth=3)

# plot labels
for icol, col in enumerate(col_labels):
    plt.text(icol + 1.5, nrow + 0.5, col, ha='center', va='center')
for irow, row in enumerate(row_labels):
    plt.text(0.5, nrow - irow - 0.5, row, ha='center', va='center')

# plot table content
for irow, row in enumerate(table_vals):
    for icol, cell in enumerate(row):
        plt.text(icol + 1.5, nrow - irow - 0.5, cell, ha='center', va='center')

# plot line
plt.plot(line[0] + 1.5, nrow - line[1] - 0.5, 'r', linewidth = 5, alpha = 0.5)

plt.axis([-0.5, ncol + 1.5, -0.5, nrow+1.5])

plt.show()