在Matplotlib中旋转图像

Question

I'm trying to plot a 2D image in Matplotlib (imported from a png) and rotate it by arbitrary angles. I want to create a simple animation showing the rotation of an object over time, but for now I'm just trying to rotate the image. I've tried several variations on the following code with no success:

import matplotlib.pyplot as plt
import matplotlib.transforms as tr
import matplotlib.cbook as cbook

image_file = cbook.get_sample_data('ada.png')
image = plt.imread(image_file)

imAx = plt.imshow(image)
rot = tr.Affine2D().rotate_deg(30)
imAx.set_transform(imAx.get_transform()+rot)

plt.axis('off') # clear x- and y-axes
plt.show()

I'm sure I'm missing something, but I haven't been able to figure it out from the matplotlib docs and examples.

Thanks!

Answer 1

Take a look at this code:

import scipy
from scipy import ndimage
import matplotlib.pyplot as plt
import numpy as np

lena = scipy.misc.lena()
lx, ly = lena.shape
# Copping
crop_lena = lena[lx/4:-lx/4, ly/4:-ly/4]
# up <-> down flip
flip_ud_lena = np.flipud(lena)
# rotation
rotate_lena = ndimage.rotate(lena, 45)
rotate_lena_noreshape = ndimage.rotate(lena, 45, reshape=False)

plt.figure(figsize=(12.5, 2.5))


plt.subplot(151)
plt.imshow(lena, cmap=plt.cm.gray)
plt.axis('off')
plt.subplot(152)
plt.imshow(crop_lena, cmap=plt.cm.gray)
plt.axis('off')
plt.subplot(153)
plt.imshow(flip_ud_lena, cmap=plt.cm.gray)
plt.axis('off')
plt.subplot(154)
plt.imshow(rotate_lena, cmap=plt.cm.gray)
plt.axis('off')
plt.subplot(155)
plt.imshow(rotate_lena_noreshape, cmap=plt.cm.gray)
plt.axis('off')

plt.subplots_adjust(wspace=0.02, hspace=0.3, top=1, bottom=0.1, left=0,
                    right=1)

plt.show()