A tribute to Paul Haeberli, who wrote an image processing demo for SGI using a variant of this UX. I added the visual undo stack.
This demo requires Flash.

This is an experimental UI prototype. There are eight filters. In the first screen, you choose the filter by selecting it from the grid. Once you choose the filter, you choose the amount of the filter, by clicking on the box. Just click on the thing that you like best. Click in the center to choose a new filter.

The column on the right is a visual undo stack. An idea I was playing with.

All of the filters are written in Pixel Bender.

The photo is from the Pixel Bender Toolkit samples and was taken by Brian Ronan.