Matplotlib.axes.Axes.draw_artist() in Python

Last Updated : 30 Apr, 2020

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. The Axes Class contains most of the figure elements: Axis, Tick, Line2D, Text, Polygon, etc., and sets the coordinate system. And the instances of Axes supports callbacks through a callbacks attribute.

matplotlib.axes.Axes.draw_artist() Function

The Axes.draw_artist() function in axes module of matplotlib library is used to efficiently update Axes data.

Syntax: Axes.draw_artist(self, a)

Parameters: This method accepts the following parameters.

a: This parameter is the artist to be draw.

Returns: This method does not return any value.

Note: This method can only be used after an initial draw which caches the renderer.

Below examples illustrate the matplotlib.axes.Axes.draw_artist() function in matplotlib.axes:

Example 1:

# Implementation of matplotlib function  
from random import randint, choice 
import time 
import matplotlib.pyplot as plt 
import matplotlib.patches as mpatches 
  
  
back_color = "black"
colors = ['red', 'green', 'blue', 'purple'] 
width, height = 4, 4
  
fig, ax = plt.subplots() 
ax.set(xlim =[0, width], ylim =[0, height]) 
  
fig.canvas.draw() 
  
def update(): 
    x = randint(0, width - 1) 
    y = randint(0, height - 1) 
  
    arti = mpatches.Rectangle( 
        (x, y), 1, 1, 
        facecolor = choice(colors), 
        edgecolor = back_color 
    ) 
    ax.add_artist(arti) 
  
    start = time.time() 
    ax.draw_artist(arti) 
    fig.canvas.blit(ax.bbox) 
    print("Draw at time :", time.time() - start) 
  
timer = fig.canvas.new_timer(interval = 1) 
timer.add_callback(update) 
timer.start() 
  
ax.set_title('matplotlib.axes.Axes.draw_artist()\ 
 function Example')  
  
plt.show()  

Output:

Draw at time : 0.37501978874206543
Draw at time : 0.015624046325683594
Draw at time : 0.03127431869506836
Draw at time : 0.015625953674316406
Draw at time : 0.015601396560668945
Draw at time : 0.015614986419677734
........
so on...

Example 2:

# Implementation of matplotlib function  
import matplotlib.pyplot as plt 
import numpy as np 
import time 
  
  
fig, ax = plt.subplots() 
line, = ax.plot(np.random.randn(100)) 
  
tstart = time.time() 
num_plots = 0
fig.canvas.draw() 
  
while time.time()-tstart < 5: 
    line.set_ydata(np.random.randn(100)) 
    ax.draw_artist(ax.patch) 
    ax.draw_artist(line) 
    num_plots += 1
      
ax.set_title('matplotlib.axes.Axes.draw_artist() \ 
function Example')  
  
plt.show()  