[Image-SIG] ImageOps.equalize division by zero

[Douglas Bagnall]

hello,

For images with fewer than 255 pixels, ImageOps.equalize raises a 
ZeroDivisionError.

     h = image.histogram()
     #...
     for b in range(0, len(h), 256):
         step = reduce(operator.add, h[b:b+256]) / 255
         n = 0
         for i in range(256):
             lut.append(n / step)  # error shows up here
             n = n + h[i+b]


AFAICT, using a float for step works best, but a trusty old "or 1" is 
tolerable for all but the tiniest images.

As a matter of curiousity, is  reduce(operator.add, h[b:b+256]) (for b,h 
above) ever different from image.size[0] * image.size[1] ?



douglas bagnall


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