Comment 2 for bug 779266

Here are two examples : one where discrete is applied on a semi transparent bitmap image and a second one where it is applied on a blurred object. In the two examples I have built a filter which show what I expect when applying discrete on these semi transparent or blurred objects. It partly works on the bitmap image but it keeps smooth gradients inside the discrete steps.

It's a little bit like if alpha wasn't an opaque greyscale image but already a transparent greyscale image. Like some redundancy ?