Karbon is a vector-based drawing application for Calligra. It allows artists to create complex drawings without losing image quality when zooming in on, or resizing the drawing. Additionally you can use Karbon to add finishing touches to diagrams created using Calligra/Flow or charts created using Calligra/KChart. Graphic design ideas can be quickly and easily transformed into high quality illustrations with Karbon.
potrace is a library to convert bitmaps to vector. Is this useful somehow?