Create a caugi Graph Plot Object

Creates a grid graphics object (gTree) representing a caugi graph. If the graph has not been built yet, it will be built automatically before plotting. This implementation uses idiomatic grid graphics with viewports for proper coordinate handling.

Arguments

x

A caugi object. Must contain only directed edges for Sugiyama layout.

layout

Specifies the graph layout method. Can be:

• A character string: "auto" (default), "sugiyama", "fruchterman-reingold", "kamada-kawai", "bipartite". See caugi_layout() for details.

• A layout function: e.g., caugi_layout_sugiyama, caugi_layout_bipartite, etc. The function will be called with x and any additional arguments passed via ....

• A pre-computed layout data.frame with columns name, x, and y.

...

Additional arguments passed to caugi_layout(). For bipartite layouts, include partition (logical vector) and orientation ("rows" or "columns").

node_style

List of node styling parameters. Supports:

• Appearance (passed to gpar()): fill, col, lwd, lty, alpha

• Geometry: padding (text padding inside nodes in mm, default 2), size (node size multiplier, default 1)

• Local overrides via by_node: a named list of nodes with their own style lists, e.g. by_node = list(A = list(fill = "red"), B = list(col = "blue"))

edge_style

List of edge styling parameters. Can specify global options or per-type options via directed, undirected, bidirected, partial. Supports:

• Appearance (passed to gpar()): col, lwd, lty, alpha, fill.

• Geometry: arrow_size (arrow length in mm, default 3), circle_size (radius of endpoint circles for partial edges in mm, default 1.5)

• Local overrides via by_edge: a named list with:

  • Node-wide styles: applied to all edges touching a node, e.g. A = list(col = "red", lwd = 2)

  • Specific edges: nested named lists for particular edges, e.g. A = list(B = list(col = "blue", lwd = 4))

  Multiple levels can be combined: Style precedence (highest to lowest): specific edge settings > node-wide settings > edge type settings > global settings.

label_style

List of label styling parameters. Supports:

• Appearance (passed to gpar()): col, fontsize, fontface, fontfamily, cex

tier_style

List of tier box styling parameters. Tier boxes are shown when boxes = TRUE is set within this list. Supports:

• Appearance (passed to gpar()): fill, col (border color), lwd, lty, alpha

• Geometry: padding (padding around tier nodes as proportion of plot range, default 0.05)

• Labels: labels (logical or character vector). If TRUE, uses tier names from tiers argument. If a character vector, uses custom labels (one per tier). If FALSE or NULL (default), no labels are shown.

• Label styling: label_style (list with col, fontsize, fontface, etc.)

• Values can be scalars (applied to all tiers) or vectors (auto-expanded to each tier in order)

• Local overrides via by_tier: a named list (using tier names from tiers argument) or indexed list for per-tier customization, e.g. by_tier = list(exposures = list(fill = "lightblue"), outcome = list(fill = "yellow")) or by_tier = list(1 = list(fill = "lightblue"))

main

Optional character string for plot title. If NULL (default), no title is displayed.

title_style

List of title styling parameters. Supports:

• Appearance (passed to gpar()): col, fontsize, fontface, fontfamily, cex

outer_margin

Grid unit specifying outer margin around the plot. Default is grid::unit(2, "mm").

title_gap

Grid unit specifying gap between title and graph. Default is grid::unit(1, "lines").

Value

A caugi_plot object that wraps a gTree for grid graphics display. The plot is automatically drawn when printed or explicitly plotted.

See also

Other plotting: add-caugi_plot-caugi_plot, caugi_layout(), caugi_layout_bipartite(), caugi_layout_fruchterman_reingold(), caugi_layout_kamada_kawai(), caugi_layout_sugiyama(), caugi_layout_tiered(), caugi_plot(), divide-caugi_plot-caugi_plot

Examples

cg <- caugi(
  A %-->% B + C,
  B %-->% D,
  C %-->% D,
  class = "DAG"
)

plot(cg)


# Use a specific layout method (as string)
plot(cg, layout = "kamada-kawai")


# Use a layout function
plot(cg, layout = caugi_layout_sugiyama)


# Pre-compute layout and use it
coords <- caugi_layout_fruchterman_reingold(cg)
plot(cg, layout = coords)


# Bipartite layout with a function
cg_bp <- caugi(A %-->% X, B %-->% X, C %-->% Y)
partition <- c(TRUE, TRUE, TRUE, FALSE, FALSE)
plot(cg_bp, layout = caugi_layout_bipartite, partition = partition)


# Customize nodes
plot(cg, node_style = list(fill = "lightgreen", padding = 0.8))


# Customize edges by type
plot(
  cg,
  edge_style = list(
    directed = list(col = "blue", arrow_size = 4),
    undirected = list(col = "red")
  )
)


# Add a title
plot(cg, main = "Causal Graph")


# Customize title
plot(
  cg,
  main = "My Graph",
  title_style = list(fontsize = 18, col = "blue", fontface = "italic")
)