I'm Michael Muré, a French student in computer science. I'd like to propose
a GSOC about a new cage-based deformation tool. This tool wil be based on
this paper:

The basic behavior of this tool would be:
- you "put" a closed polygon on the image (not limited to 4 handles)
- you deform the cage, the image is deformed accordingly
- user can choice if the pixels can go outside of the cage or not. In the
normal behavior of the Green Coordinates, the pixels can overflow the cage,
due to the shape preservation.

Unlike the other classical method (mean value coordinates, harmonic
coordinates, ..), the Green Coordinates allow high quality deformation by
preserving the shape. That mean that you don't have side effect like
shear. Example can be found in the paper. However, a restriction, the figure
14 show a deformation of the outside of the cage, that require a cutting of
the outside. I think that's not relevant for a software like the Gimp.

That was for the presentation.

I would really like some advise or opinion of the community, to improve my
proposal. For instance, I've some question:

- Since the GC is affine-invariant, it can do rotation and translation as
well. However, it is less efficient than this simple tools. Should this
tools be merged in the same tool ?

- Generally speaking, I'm not sure about the best UI solution

- Concerning the code, I'm a bit rookie with the code base of the Gimp. I
usually follow more the Blender's development. Any hint or advise or thing
to know would be appreciated.


Michael Muré
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