Area, ribbon, and step marks — mark

mark_area() fills the region between a y line and the zero baseline; mark_ribbon() fills between ymin and ymax; mark_step() draws a staircase line. All connect points in x order.

Usage

mark_area(
  plot,
  ...,
  position = "stack",
  blend = NULL,
  sketch = NULL,
  data = NULL
)

mark_ribbon(plot, ..., blend = NULL, sketch = NULL, data = NULL)

mark_step(
  plot,
  ...,
  direction = "hv",
  auto = FALSE,
  blend = NULL,
  effects = list(),
  sketch = NULL,
  data = NULL
)

Arguments

plot: A PlotSpec (from vplot()).
...: Encodings (tidy-eval): x and y for area/step; x, ymin, ymax for ribbon; plus color/fill/alpha.
position: For mark_area(), how areas sharing an x combine when fill/color is mapped: "stack" (default) stacks them into a band, "fill" normalises each x to 1, "identity" overlays them from the zero baseline. With no fill mapping all three are equivalent (a single area).
blend: Optional blend mode for compositing this layer against what is already drawn beneath it (the panel and earlier layers), one of the CSS mix-blend-mode names, e.g. "multiply", "screen", "darken". The whole layer composites as one isolated group (not per element).
sketch: A sketch() spec giving this layer a hand-drawn look (wobbly outlines, hachure fills), NA/FALSE to force it crisp (overriding a plot-wide theme_sketch()), or NULL (default) to inherit. Geometry marks accept it; text, raster, hex and datashade marks do not.
data: Optional layer data frame; overrides the plot data for this layer.
direction: For mark_step(), "hv" (horizontal then vertical, default) or "vh".
auto: For mark_point(), mark_line(), mark_step(), mark_segment(), and mark_edges(), when TRUE and the layer has very many rows, automatically render it as a datashaded density raster (see mark_datashade()) instead of individual vector marks: points bin into a density grid (vellum::datashade()), dense lines/steps rasterise as connected polylines (vellum::datashade_lines()), and segments/edges as independent segments (vellum::datashade_segments()). The datashaded line/segment output is dynspread-ed so thin marks stay visible (see the spread argument of mark_datashade()). The fallback is skipped under a warped coordinate system (coord_polar() / coord_trans()), which draws the vector marks instead.
effects: A list of layer render effects applied to the mark at draw time — glow(), outline(), and shadow(). Available on stroked and point marks.

Value

The modified PlotSpec.

Examples

vplot(pressure) |> mark_area(x = temperature, y = pressure)