Matplotlib.artist.Artist.add_callback() in Python

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. The Artist class contains Abstract base class for objects that render into a FigureCanvas. All visible elements in a figure are subclasses of Artist.

matplotlib.artist.Artist.add_callback() method

The add_callback() method in artist 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.

Returns: This method returns the observer id associated with the callback.

Below examples illustrate the matplotlib.artist.Artist.add_callback() function in matplotlib:

Example 1:

# Implementation of matplotlib function
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 = 50)
    timer.add_callback(update)
    timer.start()

fig = plt.figure()
start_animation()

fig.suptitle('matplotlib.artist.Artist.add_callback() \
function Example', fontweight ="bold")

plt.show()

Output:

Example 2:

# 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 = plt.figure()
plt.xlim([0, width])
plt.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
    )
    fig.add_artist(arti)
    fig.draw_artist(arti)
    fig.canvas.blit(fig.bbox)
    print("Draw at time :", time.time())

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

fig.suptitle('matplotlib.artist.Artist.add_callback() \
function Example', fontweight ="bold")

plt.show()

Output: