For maximum flexibility, Sugar was designed around two seperate subsystems: the Document Services subsystem and the Rendering Services subsystem.
Sugar subsystems
The document services subsystem provides functionality for reading in the SVG document and provides access to this information once it has been read in.
The rendering services subsystem utilizes the document services to do the actual rendering of the SVG document.
This provides a very flexible system, in that you can have mulitple rendering service subsystems for a single document service subsystem. For example, you could have an OpenGL render that could be used to draw SVG icons in your favorite GUI toolkit and a PNG renderer to output bitmaps suitable for inclusion on a webpage.
Please see the architecture sections in the Sugar Docuemnt Services and Suger Rendering Services chapters for the specific architectures of these subsystems.