The task of the modeler is that of allowing the user to create the model of a form class. The user interface is based on the X-window system and contains interactive functions to define the form layout and fields, operating on a prototype form image. Each form class is described by means of two graphs. The first one represents the entire form, while the second one is a subgraph that represents the entities (nodes and arcs) to be used in the form registration. When constructing the form graph the operator points to the items (lines, instruction and information fields, logos) that are relevant for representing the structure of the forms. These items correspond to the nodes of the form graph; their location and characteristics are input into the system according to the node attributes. In the same way mutual positions of pairs of items are described by means of graph arcs.
