Reference line / segment layer — mark

Adds one or more reference lines or segments to a plot. Dispatches to the appropriate ggplot2 geom based on the parameters supplied:

Usage

mark_rule(
  plot,
  mapping = NULL,
  data = NULL,
  xintercept = NULL,
  yintercept = NULL,
  slope = NULL,
  intercept = NULL,
  x = NULL,
  xend = NULL,
  y = NULL,
  yend = NULL,
  color = NULL,
  linetype = NULL,
  linewidth = NULL,
  ...,
  rasterize = FALSE,
  rasterize_dpi = 300,
  rasterize_dev = "cairo"
)

Arguments

plot: A plotit object
mapping: Optional aesthetics for data-driven segments (x/xend/y/yend); layout tables bind them automatically.
data: Optional data for segment mode: one segment per row. Accepts a data.frame or a ~table reference into graph data.
xintercept: x-intercept for vertical line(s)
yintercept: y-intercept for horizontal line(s)
slope: Line slope for abline
intercept: Line intercept for abline
x: Start x coordinate(s) for segment
xend: End x coordinate(s) for segment
y: Start y coordinate(s) for segment
yend: End y coordinate(s) for segment
color: Line colour (default "grey50", the unified soft neutral; ggplot2's black is restored by passing color = "black"). The British spelling colour is still accepted through ....
linetype: Line type
linewidth: Line width in mm (default 0.5).
...: Other arguments passed to the underlying geom
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

Details

xintercept → ggplot2::geom_vline
yintercept → ggplot2::geom_hline
slope + intercept → ggplot2::geom_abline
x/xend/y/yend → ggplot2::geom_segment

Dispatch priority: vline/hline > abline > segment.

References

Vega-Lite: Rule

AntV G2: LineX / LineY / Range

Examples

plotit(iris, encode(x = Sepal.Width, y = Sepal.Length)) |>
  mark_rule(xintercept = 3, color = "red", linetype = "dashed")


# Data-driven segments: network edges from a layout_* transform
e <- data.frame(source = c("a", "a", "b"), target = c("b", "c", "c"))
as_graph(e) |>
  plotit() |>
  layout_force(seed = 1) |>
  mark_point(data = ~nodes) |>
  mark_rule(data = ~edges, color = "grey70")