25 lines
1.3 KiB
Text
25 lines
1.3 KiB
Text
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In contrast to Graphviz and other graph optimizers, graphopt does
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not use a heuristic approach to layout optimization. Instead, it
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uses basic principles of physics to iteratively determine optimal
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layout. Each node is given mass and an electric charge, and each
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edge is represented as a spring. Node mass, electric charge,
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optimal spring length, and the spring constant are tweakable in
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the gui in realtime.
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For most graphs, this is all that is needed - hit 'go' and the
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graph organizes itself much as the analagous real-life system would
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if constrained to two dimensions. For more complex graphs, some
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fiddling with the physical parameters at different stages of
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optimization usually does the trick.
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To accomodate very large graphs, an additional mechanism called
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layering was added. When a graph is loaded, nodes are assigned to
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layers based on their relative positions. During optimization,
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you can choose to hide any number of layers. Any nodes assigned
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to a layer lower than the selected layer are not only hidden, but
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neither their electric charges nor the forces of the springs attached
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to them are figured into the forces acting on the visible nodes.
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In effect, those nodes cease to exist, and a smaller graph is
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allowed to lay itself out without being constrained by an excessive
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number of nodes.
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