[Qt-interest] QImage scaling with filters other than bilinear?

[Nikos Chantziaras]

Has anyone done scaling of QImages with anything else than the only 
filter supported by Qt (bilinear)?  I'm more interested in scaling down 
rather than scaling up.  Currently, scaling from, say, 2000x2000 to 
300x300 results in an extreme blur when using Qt::SmoothTransformation 
and extreme pixelation when using Qt::FastTransformation.

I'm hoping for available source code somewhere that can do smarter 
filtering (or maybe interpolation, not sure if it applies to scaling 
down) on QImages.