DCpic is a package of TeX macros for graph modeling (e.g. 
commutative diagrams) in a (La)TeX or ConTeXt document. 
Its distinguishing features are: the use of PiCTeX a 
powerful graphical engine, and a simple specification 
syntax. A graph is described in terms of its objects and 
its edges. The objects are textual elements and the edges 
can have various straight or curved forms.

It is under the LaTeX Project Public License