[cairo] pixman box filtering code prototype

[Jeff Muizelaar]

On Mon, Nov 17, 2008 at 06:00:03PM -0500, Jeff Muizelaar wrote:
> On Wed, Nov 05, 2008 at 04:52:03PM -0500, Jeff Muizelaar wrote:
> > On Tue, Nov 04, 2008 at 05:37:51PM -0500, Jeff Muizelaar wrote:
> > > Here's an update. It should be basically correct at this time (although
> > > it doesn't filter masks yet...). It still needs cleanup and
> > > optimization.
> > 
> > And another update. This version is pretty much feature complete and I
> > gave it a basic run through with firefox. (there's still a rounding
> > problem...).
> > 
> > I've also done some quick performance tests compared to the current
> > bilinear downscaling:
> > scale:.8 speed: 2x faster
> > scale:.4 speed: a little faster
> > scale:.2 speed: slower
> > 
> > The speed gains currently come at a cost. The image quality when scaling
> > between 1. and .5 is lower than the current filtering because we use a
> > combination of two integer box sizes which causes some blockiness. It's
> > possible to fix this by using a non-integer box-filter but that will
> > probably have a performance impact.
> 
> I've attached a rough cut of what this could look like.

Note: The new code is in pixman-rescale-mult.c

-Jeff