geom-curve

Curved segment layer: one quadratic bezier from (x, y) to (xend, yend) per row.

curvature chooses the magnitude and side of the bow:

• 0 collapses to a straight geom-segment.
• Positive values curve to the right of the chord (looking from start to end).
• Negative values curve to the left.

angle shifts the control point along the chord (in addition to the perpendicular offset), producing asymmetric arcs. 90deg gives a symmetric bow; smaller or larger angles bias the apex toward one end.

Usage

geom-curve(
  mapping: none,
  data: none,
  curvature: 0.5,
  angle: 90deg,
  n: 32,
  stroke: 0.8pt,
  colour: auto,
  alpha: auto,
  linetype: "solid",
  stat: "identity",
  position: "identity",
  inherit-aes: true,
)

Parameters

Parameter	Default	Description
mapping	none	Layer-specific aesthetic mapping built with aes. Must map x, y, xend, yend.
data	none	Layer-specific dataset. Falls back to the plot data when none.
curvature	0.5	Bezier-control offset as a fraction of the chord length. 0 draws a straight segment; sign flips the side of the bow.
angle	90deg	Apex angle in (0deg, 180deg). 90deg is symmetric.
n	32	Number of polyline samples along the curve.
stroke	0.8pt	Line thickness (a Typst length).
colour	auto	Fixed line colour. auto resolves via the colour scale.
alpha	auto	Line opacity in [0, 1].
linetype	"solid"	Dash keyword. Defaults to "solid".
stat	"identity"	Statistical transform name. Usually "identity".
position	"identity"	Position adjustment name. Usually "identity".
inherit-aes	true	Whether to merge the plot-level mapping into this layer’s mapping.

Returns

Layer dictionary consumed by plot.

Examples

Three curved connectors with the default symmetric bow.

#let d = (
  (x: 0, y: 0, xend: 4, yend: 3, k: "a"),
  (x: 0, y: 3, xend: 4, yend: 0, k: "b"),
  (x: 2, y: 0, xend: 2, yend: 3, k: "a"),
)
#plot(
  data: d,
  mapping: aes(x: "x", y: "y", xend: "xend", yend: "yend", colour: "k"),
  layers: (geom-curve(curvature: 0.5, stroke: 1pt),),
  width: 10cm,
  height: 6cm,
)

Negative curvature flips the arc to the other side.

#let d = ((x: 0, y: 0, xend: 4, yend: 3),)
#plot(
  data: d,
  mapping: aes(x: "x", y: "y", xend: "xend", yend: "yend"),
  layers: (geom-curve(curvature: -0.5, stroke: 1pt),),
  width: 10cm,
  height: 6cm,
)

See also

geom-segment, geom-line.