geom-function

Polyline of fun(x) sampled uniformly across the x-range.

The trained x-domain is used by default; pass xlim to override it. n samples are taken across that range. Sampled points where fun returns none are dropped silently.

Usage

geom-function(
  fun: none,
  n: 101,
  xlim: none,
  stroke: 0.8pt,
  colour: auto,
  alpha: auto,
  linetype: "solid",
  inherit-aes: false,
)

Parameters

Parameter	Default	Description
`fun`	`none`	Callable taking a numeric x and returning a numeric y, or `none` to skip.
`n`	`101`	Number of samples taken uniformly across the x-range.
`xlim`	`none`	Optional `(lo, hi)` overriding the trained x-domain.
`stroke`	`0.8pt`	Line thickness (a Typst length).
`colour`	`auto`	Fixed line colour. `auto` falls back to the theme `ink`.
`alpha`	`auto`	Line opacity in `[0, 1]`.
`linetype`	`"solid"`	Dash keyword. Defaults to `"solid"`.
`inherit-aes`	`false`	Whether to merge the plot-level mapping into this layer’s mapping. Defaults to `false`.

Returns

Layer dictionary consumed by plot.

Examples

Sine curve sampled across the trained x-domain.

#let frame = ((x: -calc.pi, y: -1), (x: calc.pi, y: 1))
#plot(
  data: frame,
  mapping: aes(x: "x", y: "y"),
  layers: (
    geom-blank(),
    geom-function(fun: x => calc.sin(x)),
  ),
  width: 10cm,
  height: 6cm,
)

Pass xlim to override the domain when the training data does not match the function’s natural range.

#let frame = ((x: 0, y: 0), (x: 1, y: 1))
#plot(
  data: frame,
  mapping: aes(x: "x", y: "y"),
  layers: (
    geom-blank(),
    geom-function(
      fun: x => calc.sin(x) * 0.5 + 0.5,
      xlim: (0, 4 * calc.pi),
      n: 201,
    ),
  ),
  width: 10cm,
  height: 6cm,
)

See also

geom-blank, geom-line, geom-abline.