Libart is a library for high-performance 2D graphics. It is currently being used as the antialiased rendering engine for the Gnome Canvas. It is also the rendering engine for Gill, the Gnome Illustration app. Libart supports a very powerful imaging model, basically the same as SVG and the Java 2D API. It includes all PostScript imaging operations, and adds antialiasing and alpha-transparency. Libart is also highly tuned for incremental rendering. It contains data structures and algorithms suited to rapid, precise computation of Region of Interest, as well as a two-phase rendering pipeline optimized for interactive display.