2.2.3.3 旧的buffer协议

In [9]:

import numpy as np
# import Image 
from PIL import Image
# Let's make a sample image, RGBA format
x = np.zeros((200, 200, 4), dtype=np.int8)
x[:,:,0] = 254 # red
x[:,:,3] = 255 # opaque
data = x.view(np.int32) # Check that you understand why this is OK!
img = Image.frombuffer("RGBA", (200, 200), data)
img.save('test.png')
#
# Modify the original data, and save again.
#
# It turns out that PIL, which knows next to nothing about Numpy,
# happily shares the same data.
#
x[:,:,1] = 254
img.save('test2.png')

/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/IPython/kernel/__main__.py:14: RuntimeWarning: the frombuffer defaults may change in a future release; for portability, change the call to read:
  frombuffer(mode, size, data, 'raw', mode, 0, 1)