Re: [Adonthell-artwork] map gfx design

[Alexandre Courbot]

> Question: what image format are we using for Adonthell? Are we using a
> custom format, or an already-established format?
> 
> If the latter, the choice seems clear: PNG. But I dunno, maybe there's
> something prohibiting us from using it. . .?

The raw data (16 bits per pixel, that is 2 * length * height bytes for
an image) is simply compressed using zlib. This is roughly what PNG does
(PNG uses the same algorithm as Gzip, which has been developped to
replace the compress and gif formats, unusuable because of patent
issues) - but it is much simplier to do that than using libpng, for
instance. So it's rather a custom format, but which compression
algorithm is the same then PNG. Ultimately we should even get better
results, since we use 16 bits per pixel (against 24 for PNG). I'll run
some comparison tests, and see if changing the data organisation gives
us better results.

Alex.
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