Matplotlib.artist.Artist.set_alpha() 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.set_alpha() method

The set_alpha() method in artist module of matplotlib library is used to set the alpha value used for blending.

Syntax: Artist.set_alpha(self, alpha)

Parameters: This method accepts the following parameters.

• alpha: This parameter is the contains float value or None.

Returns: This method does not return any value.

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

Example 1:

# Implementation of matplotlib function
from matplotlib.artist import Artist
import matplotlib.pyplot as plt
import numpy as np


# create test data
np.random.seed(10**7)
data = [sorted(np.random.normal(0, std, 100))
       for std in range(1, 5)]

fig, ax1 = plt.subplots()
val = ax1.violinplot(data)
ax1.set_ylabel('Result')
ax1.set_xlabel('Domain Name')

for i in val['bodies']:
    i.set_facecolor('green')
    Artist.set_alpha(i, 0.5)

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

plt.show()

Output:

Example 2:

# Implementation of matplotlib function
from matplotlib.artist import Artist
import matplotlib.pyplot as plt
import numpy as np
from matplotlib.patches import Ellipse


NUM = 200

ells = [Ellipse(xy = np.random.rand(2) * 10,
                width = np.random.rand(),
                height = np.random.rand(),
                angle = np.random.rand() * 360)
        for i in range(NUM)]

fig, ax = plt.subplots(subplot_kw ={'aspect': 'equal'})

for e in ells:
    ax.add_artist(e)
    e.set_clip_box(ax.bbox)
    Artist.set_alpha(e, np.random.rand())
    e.set_facecolor(np.random.rand(4))

ax.set_xlim(3, 7)
ax.set_ylim(3, 7)

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

plt.show()

Output: