[Shapefusion-devel] improved color reduction

[Tito D. C. <ti...@da...>]

Hi!

After a bit of research I finally came out with a new way to quantize
RGB bitmaps against collection palettes. The result is a visible
improvement in image quality when importing RGB bitmaps in collections.
The code is also simpler now, and I think slightly faster too.

You can see some tests on altivec.fisica.indivia.net/sf_color_reduction.
paltest_jugger.png, paltest_water.png and paltest_weapons.png show six
imported RGB bitmaps: the first three bitmaps of each shot are imported
with the new algorithm, the last three are the same bitmaps imported
with the previous lower-quality algorithm (RGB to HSV and comparison in
HSV space). Three shots have been done to test different palettes. See
the gray gradient in paltest_jugger.png! Then look at what happens with
a photo: paltest_photo_bad.png versus paltest_photo_fine.png, the former
begin imported with the old algorithm and the latter with the new one.
You can also see the original (paltest_photo_original.bmp) and the
difference between fine and original
(paltest_photo_fine_minus_original.png, normalized).

In my schedule, this brings ShapeFusion one step closer to 0.4. I just
have to make the color table editor work now, then I'd release.

So please test! :-)

Bye
Tito
-- 
Physics is reverse engineering