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Re: Adam7 and narrow PNG

From: Vladimir 'φ-coder/phcoder' Serbinenko
Subject: Re: Adam7 and narrow PNG
Date: Wed, 02 Oct 2013 14:05:29 +0200
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On 02.10.2013 11:28, Vladimir 'φ-coder/phcoder' Serbinenko wrote:
> On 02.10.2013 08:57, Melki Christian (consultant) wrote:
>> Limited usefullness. I've used a lot of PNG's in GRUB lately and can't think 
>> of a reason why I would use either.
>> Maybe paletted 8-bit (if-that’s what you meant?) to save space..
> 8-bit palette is an easy one. The tricky one is 4-/2-/1-bit palettes
> (16-/4-/2-color) since then PNG packs several pixels in a single byte.
> Usefulness of it to compress image is debatable since although it saves
> space by itself, it messes with filter and huffman.
Narrow PNG part is easy, small, doesn't affect performance of other
supported types and surely useful, so I committed this part.
>> but adam7? It's still going to be loaded as a bitmap.
>> If I had some web png's and was to lazy to pass them through a converter...
> The compatibility is the idea. Or if editor used by artist defaults to
> adam7 and doesn't have an option (at least not easily accessible one) to
> change this behaviour
Remaining (adam7) attached. However this increases pnd.mod by 27% (from
8776 to 11192). I don't know of performance of adam7 compared to normal
png. Complexity involved is not easy either. Any more opinions?

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