Warp wrote:
> Invisible <voi### [at] devnull> wrote:
>> If you generate a PNG image without any fancy filtering, then you don't
>> need any extra memory except for the DEFLATE compressor. But usually PNG
>> files use filtering to increase compression. (I don't know, but I'd
>> *hope* libpng provides a way to control this...) If filtering, you may
>> need the previous row of pixels [only].
> 
>   I think PNG has options to filter with the previous row, the previous
> column, or both. I assume that if you choose to filter with the previous
> column only, you don't need to store the previous row of pixels in memory
> at all. (I don't know if libpng optimizes in this way, but at least in
> theory I think it could be possible to implement png compression like
> that.)

You need to store the previous row in POV-Ray anyway, to know if you need to
antialias the current pixel :)

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