[cairo] High Quality ImagePattern Scaling

[Antoine Azar]

> It only wins if you expect to draw the same image at many 
> scales, such as when it is a texture map for a 3D object that moves in Z.
Since Cairo 
> does not do perspective transforms it cannot do this use case.

You don't need perspective transforms to want to interactively scale up and
down an image.

> This is really fast as each pixel is just the average of a non-overlapping
rectangle of 
> source pixels.

A summed area table could actually be the best solution there?

Antoine