matplotlib.pyplot.gray()函数

Matplotlib是Python中的一个库，它是NumPy库的数值-数学扩展。Pyplot是一个基于状态的Matplotlib模块接口，该模块提供了一个类似matlab的接口。

Matplotlib.pyplot.gray()函数

使用matplotlib库pyplot模块中的gray()函数将colormap设置为“gray”。

语法:

matplotlib.pyplot.gray()

下面的例子演示了matplotlib.pyplot.gray()函数在matplotlib.pyplot中的作用:

示例1

# Implementation of matplotlib function
import matplotlib.pyplot as plt
import matplotlib.tri as tri
import numpy as np 
      
ang = 40
rad = 10
radm = 0.35
radii = np.linspace(radm, 0.95, rad)
      
angles = np.linspace(0, 3 * np.pi, ang)
angles = np.repeat(angles[..., np.newaxis], 
                   rad, axis = 1)
angles[:, 1::2] += np.pi / ang
      
x = (radii * np.cos(angles)).flatten()
y = (radii * np.sin(angles)).flatten()
z = (np.sin(4 * radii) * np.cos(4 * angles)).flatten()
      
triang = tri.Triangulation(x, y)
triang.set_mask(np.hypot(x[triang.triangles].mean(axis = 1),
                         y[triang.triangles].mean(axis = 1))
                < radm)
      
tpc = plt.tripcolor(triang, z, shading ='flat')
  
plt.colorbar(tpc)
plt.gray()
plt.title('matplotlib.pyplot.gray() function\
Example\n\n', fontweight ="bold")
  
plt.show()

输出:

matplotlib.pyplot.gray()函数

示例2

# Implementation of matplotlib function
import matplotlib.pyplot as plt
import numpy as np
from matplotlib.colors import LogNorm
         
      
dx, dy = 0.015, 0.05
x = np.arange(-4.0, 4.0, dx)
y = np.arange(-4.0, 4.0, dy)
X, Y = np.meshgrid(x, y)
      
extent = np.min(x), np.max(x), np.min(y), np.max(y)
     
Z1 = np.add.outer(range(8), range(8)) % 2
  
plt.imshow(Z1, cmap ="binary_r", 
           interpolation ='nearest',
           extent = extent, alpha = 1)
      
def geeks(x, y):
      
    return (1 - x / 2 + x**5 + y**6) * np.exp(-(x**2 + y**2))
      
Z2 = geeks(X, Y)
      
plt.imshow(Z2, alpha = 0.7, 
           interpolation ='bilinear',
           extent = extent)
plt.gray()
plt.title('matplotlib.pyplot.gray() function Example\n\n',
          fontweight ="bold")
  
plt.show()