The Reingold-Tilford graph layout algorithm
A tree-like layout, it is perfect for trees, acceptable for graphs with not too many cycles.
layout_as_tree(graph, root = numeric(), circular = FALSE, rootlevel = numeric(), mode = "out", flip.y = TRUE)
- The input graph.
- The index of the root vertex or root vertices. If this is a non-empty vector then the supplied vertex ids are used as the roots of the trees (or a single tree if the graph is connected). If it is an empty vector, then the root vertices are automatically
- Logical scalar, whether to plot the tree in a circular
fashion. Defaults to
FALSE, so the tree branches are going bottom-up (or top-down, see the
- This argument can be useful when drawing forests which are
not trees (i.e. they are unconnected and have tree components). It specifies
the level of the root vertices for every tree in the forest. It is only
considered if the
- Specifies which edges to consider when building the tree. If it
out, then only the outgoing, if it is in, then only the incoming edges of a parent are considered. If it is allthen all edges are used
- Logical scalar, whether to flip the
ycoordinates. The default is flipping because that puts the root vertex on the top.
- Passed to
Arranges the nodes in a tree where the given node is used as the root. The tree is directed downwards and the parents are centered above its children. For the exact algorithm, the refernce below.
If the given graph is not a tree, a breadth-first search is executed first to obtain a possible spanning tree.
- A numeric matrix with two columns, and one row for each vertex.
Reingold, E and Tilford, J (1981). Tidier drawing of trees. IEEE Trans. on Softw. Eng., SE-7(2):223--228.
Other graph layouts:
tree <- make_tree(20, 3) plot(tree, layout=layout_as_tree) plot(tree, layout=layout_as_tree(tree, flip.y=FALSE)) plot(tree, layout=layout_as_tree(tree, circular=TRUE)) tree2 <- make_tree(10, 3) + make_tree(10, 2) plot(tree2, layout=layout_as_tree) plot(tree2, layout=layout_as_tree(tree2, root=c(1,11), rootlevel=c(2,1)))