Hi,
I have just checked in to my private Coons Patch Mesh Gradient branch, code that allows the ability to create and edit mesh gradients. Warning: This code is a real Hack. It is known to segfault and eat kittens for lunch. It will need lots of reworking by real experts before one can hope to see it in Inkscape trunk (as well as dealing with the issue that meshes are not part of the SVG 1.2 standard... they have been accepted as part of SVG 2.0 but that standard is along way from being appearing even in a draft form).
What you can do with the code:
1. Create a simple one patch square mesh the size of an objects bounding box. (Select the third button on the Gradient Tool-Tool Bar and the double click the object.)
2. Drag corner nodes (diamonds).
3. Change color of corner nodes.
4. Drag handles (circles). There is no indication of what handle belongs with which corner node or path so it can be confusing.
5. Divide a row or column of patches into two rows or columns. (Double click on the lines connecting corner nodes. Double clicking elsewhere may lead to a crash.) At the moment, the row or column is split down the middle.
6. Save the mesh. The mesh is saved in the proposed SVG standard format (highly likely to change).
7. Read in saved meshes.
Some of what is missing:
1. Ability to undo node moves/color changes.
2. Ability to merge two rows or columns into one or delete edge rows or columns.
3. Ability to change paths between straight lines and Bezier curves. Handles are shown even for straight lines.
4. Display of Bezier curves (they are shown as straight lines).
5. Stability (I did tell you it will segfault, didn't I?).
6. Sane coding.
7. Properly handling of gradient copying.
8. Auto-creation of conical gradients or other non-square gradient types.
9. Output to PS/PDF/PNG(?)
10. Update to current trunk.
You can check out the code at:
https://code.launchpad.net/~tavmjong-free/inkscape/mesh
Tav