Dumbbell comparison chart layer

Creates a dumbbell chart with two connected points showing before/after or paired comparisons. This is a syntax-sugar composite mark combining two mark_point calls and a geom_segment.

Usage

mark_dumbbell(
  plot,
  mapping = NULL,
  data = NULL,
  color_start = NULL,
  color_end = NULL,
  line_color = NULL,
  point_size = ._MARK_STYLE$point_head,
  line_width = ._MARK_STYLE$lw_thin,
  ...
)

Arguments

plot

A plotit object

mapping

Optional new aesthetics

data

Optional data for this layer

color_start

Colour for the start point. NULL (default) uses primary #0072B2 when no colour channel is mapped; a live colour aesthetic colours both endpoints instead.

color_end

Colour for the end point. NULL (default) uses secondary #E15759 when no colour channel is mapped; a live colour aesthetic colours both endpoints instead.

line_color

Colour for the connecting line. NULL (default) follows a mapped colour, else soft grey.

point_size

Size for both dumbbell points (default 3).

line_width

Width for the connecting line (default 0.5, connector rung).

...

Other arguments passed to mark_point() calls

Value

Modified plotit object

Details

Equivalent expansion:

  p |> mark_rule(x = x, xend = x, y = y_start, yend = y_end) |>
       mark_point(x = x, y = y_start, colour = color_start) |>
       mark_point(x = x, y = y_end, colour = color_end)

References

AntV G2: Link (corelib)

Examples

df <- data.frame(
  cat = LETTERS[1:5], before = c(3, 5, 2, 8, 4),
  after = c(7, 6, 5, 10, 6)
)
plotit(df, encode(x = cat, y = before, yend = after)) |>
  mark_dumbbell()