使用Pillow（PIL）在Python中生成图像

Question

I'm trying to generate a 100x100 all-black image with Python (v2.7.2) and Pillow (v2.4.0) and I get a very weird result.

This is my code

from PIL import Image
im = Image.frombytes('L', (100, 100), bytes([0] * 100 * 100))
im.show()

This is my result (zoomed-in and please ignore the grey border - it comes from OS X Preview). The image should be black, but it is not.

What am I doing wrong?

Answer 1

The result of bytes([0] * 10) is the string "[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]" . So, the colors of your pixels are the ASCII codes of '[' , '0' , ',' , ' ' , and ']' symbols.

To get the byte string of zero bytes use bytes("\\x00" * 100 * 100) instead. Here \\x00 is the byte with hexadecimal value 00 .

Actually you don't even need bytes(...) call. bytes is the type only in Python 3.x. In Python 2.7.x bytes is just an alias for str .

So, the final code should be:

from PIL import Image
im = Image.frombytes('L', (100, 100), "\x00" * 100 * 100)
im.show()