The Ggram System : an interactive graphics system for Graph Manipulation

The design and implementation of an interactive graphics system for graph manipulation are discussed. The activation fcr such a system is examined, and the relevant literature is described and evaluated. A number of ways to improve and extend the system are presented. The system provides the basic graph drawing operations cf adding, deleting, labeling, and changing both vertices and edges. Also included are a number of graph manipulation operations which, among ether things, allow a user to subdivide edges, associate vertices, reverse the direction cf arcs, move vertices about the screen, cr even move whole graphs about the sc teen. A facility is provided whereby the screen can te divided into as many as four regions, thus allowing users tc display more than one graph at a time. Graphs can be saved on disk and later restored. The image on the graphics screen can te easily plotted tc obtain a hard copy of graphs. A few routines which perform graph-theoretic operations have teen implemented. Among these are a routine for finding the minimum and maximum degrees of a graph, and a routine fcr finding the blocks, cutnodes, and bridges cf a graph. Moreover, the system is designed to allow users to add their own routines.Science, Faculty ofComputer Science, Department ofGraduat