I would think that anything that did that would just about be Visio itself!
Most of the mathematics in Visio cells is fairly standard, maybe with a
slight change in spelling (like CHAR( ) instead of CHR() ) But it's the
inter-cell and inter-shape references that really make the ShapeSheet
special. A shape can reference cell's in other shapes, on other pages, etc.
You get the idea.
If you just need graphics, then Visio exports to SVG, there is a free
Visio-viewer plug-in for web browsers, and I have seen XSLT tranformations
of the VDX file format to SVG. Once you're in SVG, you could write custom
code to make special use of Visio information as much as you want, or have
time for.
--
Hope this helps,
Chris Roth
Visio MVP