Xgrab is an editor for directed graphs, derived from
the tool sungrab developed by the GRAB group at UC Berkeley.
The graph is specified in the file named filename.
Xgrab reads the file and automatically
lays out and displays the graph. The user can then
edit the graph interactively (i.e., add, delete, and move nodes and edges),
create a PostScript(tm) version of the graph,
save the graph in a file for future editing, or perform many other functions.
The options are as follows:
-a
Allows the user to specify the initial aspect ratio of
the xgrab window.
That is, the number specified after
the -a flag controls the ratio of the x-axis width to the y-axis
width. For example, invoking xgrab with the option -a2
will produce a window twice as wide as it is
tall. The default aspect ratio is 1.5.
-C
Specify a file of commands, commandFileName,
that are to be executed on the graph on startup.
-t
Print the time required for various steps in the layout routine.
-l1
Stop the layout routine prematurely, before edge crossings have been
minimized.
-l2
Stop the layout routine prematurely, after edge crossings have been
minimized, but before the nodes are placed on the level
according to their barycenters.
-d
Specify the debug level for the code. n should be digit from 0 to 3,
with level 3 supplying the most information, level 0 the least. Included
for backward capability with sungrab, and best if ignored.
-s
Set the showbc option, so that the barycenters of nodes are displayed with
the nodes. Barycenters are used to determine the placing
of nodes on a level. Also included for backward capability;
also best if ignored.
-b
Allows the user to specify the BC-percentage used when laying out the
graphs. The higher the percentage, the closer dummy nodes will be to
their parents/children. Also included for backward capability; also highly
ignorable.
-h
Sets various heuristic flags. Leave it alone.
Before running xgrab, it is necessary to start up X
and to open up a window.
BUGS AND SUCH
Command execution from files doesn't work as well as it ought to.
Disparaging remarks in the documentation are the opinions of the author,
and do not necessarily reflect the views of any of the large entities which
have given him employment over the years.
SEE ALSO
X(1)
Introduction to GRAB (for historical information)
How To Use XgrabPostScript Language Reference Manual
AUTHORS
Greg Barnes at Tera Computer, and the GRAB group at UC Berkeley
NOTES
PostScript is a trademark of Adobe Systems Incorporated