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.

resources

potrace is a library to convert bitmaps to vector. Is this useful somehow?

Calligra Karbon Summer of KDE 2012 Projects list

Project: Variable thickness lines

Student : Sharad Dixit <sharad dot eminence at gmail dot com>
Come from : IIIT Allahabad,India
Lead Mentor : Thorsten Zachmann
Wiki page