[Scummvm-devel] png support

[Max Horn]

Hi Filippos, all,


Am 29.04.2011 um 13:20 schrieb Filippos Karapetis:

> Hello
> 
> I'm the one who wrote the PNG decoder. The situation is as follows:
> Broken Sword 2.5 requires both a PNG decoder (for its images) and a PNG encoder (for the thumbnails in its saved games).
> Right now, the thumbnails in the saved games are broken (they always were broken), it's something I haven't looked into yet.
> 
> The PNG decoder works almost flawlessly.
> I haven't written a PNG encoder, which is where libpng is still needed.

Thanks, that explains that :). Could you please add this explanation in a comment in png.h or png.cpp ? (Or a variation thereof, whatever) ? The idea being that people know (a) what the code does, and (b) what exactly is missing. Maybe add an entry on the TODO wiki page, too?

> 
> The original plan was to remove compatibility with the saved games that the original engine creates (as they are version
> specific anyway), starting with the thumbnail support. If you don't mind dropping savegame compatibility with the original
> engine, we can remove the libpng dependency.
> 
> So... the available options are:
> - Keep savegame compatibility with game version 1.0, keep libpng, remove our own PNG decoder (which works, as I said) and
> attempt to find the problem with the savegame thumbnails
> - Drop savegame compatibility, use our own thumbnail code, remove libpng and use our own PNG decoder

Can we otherwise load savegames made using the original engine? What about the converse? If so, then we should try to preserve compatibility.

But if we break compatibility anyway, I don't see why we should keep the burden of a PNG encoder, so then I'd just use a plain thumbnail.

The sword25 devs should decide what they want, in the end.

Bye,
Max