Tupi: Open 2D Magic is a design and authoring tool for digital artists
interested in 2D Animation. It's source code is based on the KTooN
project.

Some of its main features are: basic illustration tools (shapes, fill,
text), gradient tools, onion skin, brushes editor, pencil with smoothness
support, basic object library (for svg files and raster images) and many
others.

Using its modules of Animation and Reproduction you can export 2D projects
to several formats as OGG, MPEG, AVI, MOV and SWF. Additionally, the
option of exporting Image arrays as output is available.