Creating Image from Pixels stored in an array in Python

Question

import os, sys
from PIL import Image


im = Image.open("result_bw.png")
l = []
print im.size
pix = im.load()
for x in range(im.size[0]):
    for y in range(im.size[1]):
        l.append(pix[x,y])

img = Image.new('L', (im.size[1],im.size[0] ))
img.putdata(l)
img.save('image.png')

The above code reads a black and white image and stores the pixel value in a list.

When I am creating a new image from the pixels stored in the list, I get the original image which is rotated anti-clockwise.

Why am I getting a rotated image?

How can I correct it?

Dagrooms · Accepted Answer · 2016-03-30 04:48:33Z

1

Flip the x and y values you read. Computers write images with an origin in the top-left of a screen, y positive axis pointing down, and x positive axis pointing right. Your implementation assumes an origin at the bottom-left corner.

answered Mar 30, 2016 at 4:48

Dagrooms

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Comments

fuenfundachtzig · Accepted Answer · 2016-03-30 06:50:08Z

0

Where there is putdata, there is likely also getdata. Indeed, you could use

l = list(im.getdata())

instead of your for loops. This would also fix the rotation problem.

edited Mar 30, 2016 at 6:50

answered Mar 30, 2016 at 6:26

fuenfundachtzig

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