UML_class_diagrams_with_graphviz

UML Class Diagrams can be made with graphviz.  

(1) download graphviz
    http://www.graphviz.org/Download.php
    
(2) write your dot file.
    Note that in your dot file, you may want to exclude most dependencies
    because the dot layout algorithm will weigh them equally with 
    the inheritance edges and you probably want a preference for better
    display of the inheritance and composition relationships.
   
    Here's the contents of example_graphviz.dat showing how to draw
    inheritance, composition, aggregation, and dependencies.
   
    digraph G {
        rankdir = "TB"
        fontname = "Bitstream Vera Sans"
        fontsize = 8
    
        node [
            fontname = "Bitstream Vera Sans"
            fontsize = 8
            shape = "box"
        ]
    
        edge [
            fontname = "Bitstream Vera Sans"
            fontsize = 8
        ]
    
        edge [
            arrowhead = "empty"
        ]
        //inheritance: superclass -> subclass
        Animal -> Dog [dir = "back" arrowtail = "empty"]
        Animal -> Cat [dir = "back" arrowtail = "empty"]
    
        //composition:  class -> member variable
        Dog -> DogBark [dir = "back" arrowtail = "diamond"]
    
        // aggregation:  class -> member variable w/ root reference created elsewhere,
        edge [
            arrowhead = "none"
            headlabel = "0..*"
            taillabel = "0..*"
        ]
        Cat -> Dog
        
         // "uses", i.e. dependency
        edge [
            arrowhead = "vee"
            style = "dotted"
            taillabel = "uses"
            headlabel = ""
        ]
        Bird -> BirdFood
    }

   
(3) dot -T png -o classes.png example_graphviz.dat