GraphicsJS

GraphicsJS is an open-source and free JavaScript library for drawing literally anything easily, including animated and interactive HTML5 graphics. It's lightweight and more robust than the existing SVG/VML based components such as BonsaiJS, Raphael, etc. In particular, it provides the following features out-of-the-box: powerful line drawing (Bezier curves, arcs...), smart layering, virtual DOM, rich text features, cozy API, transformation engine.