Curved link layer — mark

Draws curved segments between (x, y) and (xend, yend) endpoints – the link/diagram edge for arc diagrams, bipartite layouts and network charts, where straight rules overlap node labels. Arrows are available through arrow = grid::arrow() via ....

Usage

mark_curve(
  plot,
  mapping = NULL,
  data = NULL,
  position = NULL,
  ...,
  curvature = 0.5,
  angle = 90,
  arrow = NULL,
  rasterize = FALSE,
  rasterize_dpi = 300,
  rasterize_dev = "cairo"
)

Arguments

plot: A plotit object
mapping: Optional new aesthetics (must include x, y, xend, yend; layout tables bind them automatically)
data: Optional data for this layer; accepts a ~table graph reference
position: Position adjustment.
...: Other arguments passed to geom_curve
curvature: Amount of curvature: 1 is a semicircle, smaller values are flatter, negative values bend the other way (default 0.5).
angle: Angle at which the curve approaches the endpoint, in degrees (default 90).
arrow: Optional grid::arrow() object to draw arrow heads.
rasterize: If TRUE, rasterize via ggrastr::rasterise().
rasterize_dpi: DPI for rasterization (default 300).
rasterize_dev: Graphics device for rasterization (default "cairo").

Value

Modified plotit object

References

AntV G2: Link

D3: d3.linkHorizontal / arc-diagram link generator

Examples

edges <- data.frame(
  x = c(1, 2, 3), y = c(0, 0, 0),
  xend = c(2, 3, 4), yend = c(1, 1, 1)
)
plotit(edges, encode(x = x, y = y, xend = xend, yend = yend)) |>
  mark_point(colour = "#4E79A7", size = 3) |>
  mark_point(
    mapping = encode(x = xend, y = yend),
    colour = "#E15759", size = 3
  ) |>
  mark_curve(curvature = 0.3)


# curved flow with arrows
plotit(edges, encode(x = x, y = y, xend = xend, yend = yend)) |>
  mark_curve(arrow = grid::arrow(length = grid::unit(0.1, "cm")))