Last evening (European time) main development branch of GIMP gained one of this year's Google Summer of Code projects — a Cage transform tool that allows doing selective deformation of objects right on canvas.

The tool is based on Green Coordinates paper published at SIGGRAPH 2008. The original paper was written with 3D modelling in mind, but the main principle seemed quite applicable to 2D as well. Here is a video demonstration published by gimpusers.com just few days ago:

There are some interesting, albeit a little technical details you might like to know.

First of all, this is the first real interactive tool that makes use of GEGL — the new GIMP's non-destructive image processing core. For that a new GEGL operation was written to do all the mapping. So it's an important step into the bright and shiny GEGL-based future of GIMP.

What's even more interesting is that the underlying GEGL operation provides about one half of functionailty for an interactive version of GIMP's IWarp filter. Which means that a substitution for Photoshop's Liquify filter that would work on canvas is now much closer to reality than it used to be.

The Cage transform tool and the GEGL op were implemented by GSoC student Michael Murй and finished by GIMP developer nicknamed as Alexia Death. The tool currently needs some polishing and much more testing to be officially shipped with upcoming stable v2.8. Nevertheless there is little to be afraid of — developers seems to be resolute in their will to make the tool available to users as soon as possible.