PIL : How to write array to image ???

[Martin]

Dear group

I'm trying to use PIL to write an array (a NumPy array to be exact) to
an image.
Peace of cake, but it comes out looking strange.

I use the below mini code, that I wrote for the purpose. The print of
a looks like expected:

[[ 200.  200.  200. ...,    0.    0.    0.]
 [ 200.  200.  200. ...,    0.    0.    0.]
 [ 200.  200.  200. ...,    0.    0.    0.]
 ...,
 [   0.    0.    0. ...,  200.  200.  200.]
 [   0.    0.    0. ...,  200.  200.  200.]
 [   0.    0.    0. ...,  200.  200.  200.]]

But the image looks nothing like that.

Please see the images on:
http://hvidberg.net/Martin/temp/quat_col.png
http://hvidberg.net/Martin/temp/quat_bw.png

or run the code to see them locally.

Please – what do I do wrong in the PIL part ???

:-? Martin



import numpy as np
from PIL import Image
from PIL import ImageOps

maxcol = 100
maxrow = 100

a = np.zeros((maxcol,maxrow),float)

for i in range(maxcol):
    for j in range(maxrow):
        if (i<(maxcol/2) and j<(maxrow/2)) or (i>=(maxcol/2) and j>=
(maxrow/2)):
            a[i,j] = 200
        else:
            a[i,j] = 0

print a

pilImage = Image.fromarray(a,'RGB')
pilImage.save('quat_col.png')
pilImage = ImageOps.grayscale(pilImage)
pilImage.save('quat_bw.png')