I wrote:
In other words, the index is
not of RGB values, but of RGBA values.
Ray Pasco wrote:
I asked this because I just learned that indexed PNG
images *can* have a separate "alpha" index table in parallel with the
color index table.
Yes, and these two sentences amount to the same thing -- "in parallel" is an implementation detail of the index. You don't get more information out of it.
If you have such an image (I can't seem to make one with either the Gimp or PIL), have you tried:
>>> im = Image.open('indexed.png').convert('RGBA')
>>> r, g, b, a = im.split()
>>> a.save('alpha.png')alpha.png should be greyscale image containing only the alpha information from the original image.
cheers,
Douglas _______________________________________________ Image-SIG maillist - [email protected] http://mail.python.org/mailman/listinfo/image-sig
