How does Content-Aware fill work?

Question

In the upcoming version of Photoshop there is a feature called Content-Aware fill.

This feature will fill a selection of an image based on the surrounding image - to the

Answer 1

There is very similar algorithm for GIMP for a quite long time. It is called resynthesizer and probably you should be able to find a source for it (maybe at the project site)

EDIT
There is also source available at the ubuntu repository
And here you can see processing the same images with GIMP: http://www.youtube.com/watch?v=0AoobQQBeVc&feature=related