> I wouldn't bother with Window's native interfaces, just because they're
> needlessly convoluted. All you need it a bitmap that you can manipulate without
> worrying too much about the rest. You can use either Allegro or SDL for that. I
> personally use Allegro just because I've been using it since the early DOS days
> (so it feels familiar), but SDL is very popular too.
I've worked this out now, and it's dozens of times faster (using StretchDIBitmap()). I didn't end up needing to use Allegro or SDL or DirectX for this, but thanks for the advice anyway.
I agree totally that Windows is convoluted :-)