It is not only possible to fold regions dynamically, i.e. interactively with the mouse, but also statically, i.e. in the specification of the graph.
The format of a region specification is:
region: {
state:
< state of the region (folded, boxed, etc.) >
sourcename:
< list of strings specifying start nodes >
targetname:
< list of strings specifying end nodes >
class:
< list of integers specifying edge classes >
range:
< integer specifying the neighbor region range >
}
The delimiter between items of a list is one or more whitespace characters. The range is optional, it is used to specify a neighbor region, in which case it gives the maximum number of edges to be followed in order to reach all the nodes of the neighbor region.