Atkinson dither algorithm & 'for each' loop

[hh]

@Al.
For multiples of 1/8 (Atkinson) you need 8*256=2048 integers,
that is 11 Bit.
For multiples of 1/16 (Floyd-Steinberg) you need 16*256=4096
integers, that is 12 Bit.
In 2 chars = 16 Bit fit even multiples of 1/256.
No dither-algorithm uses such tiny diffusion-errors.