问题
I was using imshow to plot an array with a custom colormap and boundarynorm. However, this is going to be an automated script and I want to save the image produced by imshow without the axes. So I wasn't sure imshow was the best way to do this since its going to be running in the background. Is there an alternative where I can just set the colormap and boundarynorm and produce a rgba array that I can give to imsave? Or am I just left with hacking the image that imshow produce and saving that?
回答1:
You can use as_rgba_str to get the image data from the image. Here's an example:
import numpy as np
import matplotlib.pyplot as plt
x = np.linspace(0, 2, 1000)
X, Y = np.meshgrid(x, x)
data = np.sin((X-2)**3 + Y**4)
im = plt.imshow(data)
x = im.make_image()
h, w, d = x.as_rgba_str()
n = np.fromstring(d, dtype=np.uint8).reshape(h, w, 4)
plt.figure()
plt.imshow(n[:,:,0], cmap="gray", origin='lower')
plt.show()
The original image:
The R channel from the RGBA data (note all the blue sections are black since these have no red in them):
来源：https://stackoverflow.com/questions/31393769/getting-an-rgba-array-from-a-matplotlib-image