Matplotlib.colors.hsv_to_rgb() in Python

Last Updated : 21 Apr, 2020

Matplotlib is an amazing visualization library in Python for 2D plots of arrays. Matplotlib is a multi-platform data visualization library built on NumPy arrays and designed to work with the broader SciPy stack.

matplotlib.colors.hsv_to_rgb()

The matplotlib.colors.hsv_to_rgb() function is used to convert hsv values to rgb.

Syntax: matplotlib.colors.hsv_to_rgb(hsv) Parameters:

hsv: It is an array-like argument in the form of (..., 3) where all values are assumed to be in the range of 0 to 1.
Returns:

rgb: It returns an ndarray in the form of (..., 3) that comprises of colors converted to RGB values within the range of 0 to 1.

Example 1:

Python3 1==

import matplotlib.pyplot as plt
import matplotlib.colors
import numpy as np
 

# helper function to find 
# mid-points
def helper(z):
    
    k = ()
    for i in range(z.ndim):
        z = (z[k + np.index_exp[:-1]] + z[k + np.index_exp[1:]]) / 2.0
        k += np.index_exp[:]
        
    return z
 
# dummy coordinates with  rgb 
# values attached with each
s, alpha, x = np.mgrid[0:1:11j,
                       0:np.pi*2:25j,
                       -0.5:0.5:11j]
a = s*np.cos(alpha)
b = s*np.sin(alpha)
 
sc, alphac, xc = helper(s), helper(alpha), helper(x)
 
# wobbly torus about [0.7, *, 0]
sphere = (sc - 0.7)**2 + (xc + 0.2*np.cos(alphac*2))**2 < 0.2**2
 
# combining the color components
hsv = np.zeros(sphere.shape + (3,))
hsv[..., 0] = alphac / (np.pi*2)
hsv[..., 1] = sc
hsv[..., 2] = xc + 0.5
 
#the hsv to rgb function
plot_colors = matplotlib.colors.hsv_to_rgb(hsv)
 
# and plot everything
figure = plt.figure()
axes = figure.gca(projection='3d')

axes.voxels(a, b, x, sphere,
          facecolors=plot_colors,
          edgecolors=np.clip(2*plot_colors - 0.5, 0, 1), 
          linewidth=0.5)
 
plt.show()

Output:

Example 2:

Python3 1==

from matplotlib.colors import hsv_to_rgb

# sample squares for example
first_square = np.full((50, 50, 3),
                       fill_value ='698', 
                       dtype = np.uint8) / 255.0

second_square = np.full((50, 50, 3),
                        fill_value ='385',
                        dtype = np.uint8) / 255.0

plt.subplot(1, 2, 1)
plt.imshow(hsv_to_rgb(first_square))

plt.subplot(1, 2, 2)
plt.imshow(hsv_to_rgb(second_square))

plt.show()