DiaCanvas is in its second incarnation: DiaCanvas2. Aiming towards future
computing needs on GNOME based desktop environments, DiaCanvas2 is providing
you with a full featured diagramming canvas:
   - Model/View/Controller based design: The DiaCanvas class only holds
     abstract data (using DiaShape objects), the data is rendered by one or
     more DiaCanvasView's.
   - Usage of the widely used GnomeCanvas for visualization. This makes it
     easy to let DiaCanvas2 display anti-aliased diagrams with translucency
     (alpha) support.
   - Export facilities for GnomePrint and SVG.
   - Objects can be rotated/sheared/resized/etc. without the need to
     recalculate shapes. DiaCanvas relies heavily on the LibArt library
     (which is a standard GNOME library).
   - Objects can connect to each other with handles. The connection is
     represented as a mathematical equation, which is solved using a real
     linear constraint solver (see the reference documentation for more info).
     Handles do not need predefined connection points, but can connect to each
     other in a more generic way. 
   - Of course DiaCanvas2 has all the features a modern application needs,
     including undo/redo and copy/paste functionality (copying is not
     implemented yet). 

WWW: http://diacanvas.sourceforge.net/