I experimented a bit with New Edge-Directed Interpolation. It isn't fast, but relatively easy to implement, and "good enough" if you just want a 2x or 4x scale. This could be applied both to textures and to field backgrounds, though you may need to tweak the algorithm a bit to avoid occluded pixel messing up the interpolation weights.
The textures included in FF7's battle models are actually fairly detailed (at least that's the way I see it).
I think part of enhancing any such texture one must template (IE make a vectorized outline) the sections that aren't used or are transparent.
Gaussian interpolation works well, but causes edge bleeding. In any case perhaps perform an interpolation pass and then using a vector type outlining type method to make the real edge (and cut anything outside them) would help?
The back ground images are all scanned artwork from what I can tell.
The nice thing about the background, being worked with are the following:
- The backgrounds are already broken into blocks 8x8 ones to be precise. This makes them easier to 'toy' with.
- Transparency information is included in sprites this allows one to excise excess data.
- Each layer of the background can be processed separately this make the need for as much data for scaling the texture.
I'll scan that paper erstwhile to see if there are things that can be used in Q-gears (at a later date).
It's a bit of work here, a bit of work there, playing catchup is slow work.
Cyb