Force-directed layout — layout

Positions nodes with a self-contained Fruchterman-Reingold force simulation (attractive edge forces, pairwise repulsion, linear cooling). No external dependency; runs are deterministic when seed is given. Node table gains x/y; edge table gains x, y, xend, yend.

Usage

layout_force(plot, iterations = 500, seed = NULL, ...)

Arguments

plot: A plotit object holding graph data (created via as_graph() + plotit()), or a bare plotit_graph.
iterations: Number of simulation steps.
seed: Random seed; pass one for reproducible output.
...: Optional named argument weights: non-negative numeric vector, one per edge – higher weights pull endpoints closer together. Any other name is ignored with a warning.

Value

A modified plotit object (pipeline form), or a new plotit_graph when called on raw graph data.

Examples

e <- data.frame(source = c("a", "a", "b"), target = c("b", "c", "c"))
g <- as_graph(e) |> layout_force(seed = 1)
g$nodes
#>   id          x            y
#> 1  a  0.4368677  0.008629767
#> 2  b -0.4368677  0.500000000
#> 3  c -0.4288172 -0.500000000

as_graph(e) |>
  plotit() |>
  layout_force(seed = 1) |>
  mark_point(data = ~nodes) |>
  mark_rule(data = ~edges, colour = "grey70")