Matplotlib.axis.Axis.add_callback() in Python

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. It is an amazing visualization library in Python for 2D plots of arrays and used for working with the broader SciPy stack.

Matplotlib.axis.Axis.add_callback() Function

The Axis.add_callback() function in axis module of matplotlib library is used to add a callback function that will be called whenever one of the Artist’s properties changes. 

Syntax: Artist.add_callback(self, func) 

Parameters: This method accepts the following parameters. 

• func: This parameter is the callback function.

Return value: This method returns the observer id associated with the callback. 

Below examples illustrate the matplotlib.axis.Axis.add_callback() function in matplotlib.axis:

Example 1:

Python3

# Implementation of matplotlib function
from matplotlib.axis import Axis
import matplotlib.pyplot as plt
import numpy as np
import time

def update():
    plt.get_current_fig_manager()\
    .canvas.figure.patch.\
    set_facecolor(str(np.random.random()))
    plt.draw()
    print("Draw at time :", time.time())

def start_animation():
    timer = fig.canvas.new_timer(interval = 200)
    timer.add_callback(update)
    timer.start()

fig, ax = plt.subplots()
start_animation()

ax.set_title('matplotlib.axis.Axis.add_callback() \
function Example', fontweight ="bold")

plt.show()

Output:

Example 2:

Python3

# Implementation of matplotlib function
from matplotlib.axis import Axis
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)

    ax.draw_artist(arti)
    fig.canvas.blit(ax.bbox)
    print("Draw at time :", time.time())

timer = fig.canvas.new_timer(interval = 1)
timer.add_callback(update)
timer.start()

ax.set_title('matplotlib.axis.Axis.add_callback() \
function Example', fontweight ="bold")

plt.show()

Output:

Draw at time : 1591263025.354224
Draw at time : 1591263025.4612164
Draw at time : 1591263025.6232233
Draw at time : 1591263025.748225
Draw at time : 1591263025.8842134
...... so on...