Skip to contents

An open, wandering path following a random walk

Source: R/curve_twist.R
curve_twist.Rd

curve_twist is shape_twist()'s path alone, with no ribbon width: an open curve_line()-like polyline between (x, y) and (xend, yend), displaced away from a straight line by a noise_bridge, giving a wandering, twisted appearance.

curve_twists() is a vectorized version of curve_twist(): each argument may be a vector, recycled against the others via purrr::pmap()'s own vctrs-based rules. The result is a sketch containing one curve_twist() per recycled row, rather than a single drawable.

Usage

curve_twist(
  x = 0,
  y = 0,
  xend = 1,
  yend = 1,
  scale = 0.2,
  n = 100L,
  path_distortion = noise_bridge(),
  trans = trans_identity(),
  ...
)

curve_twists(
  x = 0,
  y = 0,
  xend = 1,
  yend = 1,
  scale = 0.2,
  n = 100L,
  path_distortion = noise_bridge(),
  trans = trans_identity(),
  ...
)

Arguments

x, y

Start point. Default 0.

xend, yend

End point. Default 1.

scale

Amplitude of the Brownian-bridge displacement (internally scaled by 0.1, matching shape_twist()'s own scaling of its path). Must be non-negative. Default 0.2.

n

Number of points used along the path. Default 100L.

path_distortion

A noise_bridge controlling the path's Brownian bridge. Default noise_bridge().

trans

A trans object applied to the curve's computed points. Default trans_identity() (no transform).

...

Arguments passed to style().

Value

A drawable.

For curve_twists(), a sketch.

Details

Where shape_twist() also modulates a filled ribbon's width along this same kind of path (via a separate distortion noise_field), curve_twist() has no width or fill at all – just the displaced backbone itself, rendered as an open grid::polylineGrob() (geometry = "path"). Shares its path computation with shape_twist() via the internal twisted_path_points() helper (R/shape_twist.R) rather than duplicating it.

style@fill has no effect for curve_twist() – see drawable's geometry documentation for why "path" geometries have no interior to fill. Passing fill via ... is still accepted (it's simply ignored at draw time), since style() is shared across every geometry.

Any length-1 element is broadcast to the common length; mismatched lengths greater than 1 raise an error. A shared path_distortion noise_bridge is automatically recycled across every path; pass a list() of several different noise_bridges instead to vary it per path.

See also

Other 1D curves: curve_arc(), curve_bezier(), curve_line(), curve_raw(), curve_scribble(), curve_spiral()

Examples

draw(curve_twist(
  x = 0, y = 0, xend = 1, yend = 0,
  path_distortion = noise_bridge(seed = 7734)
))


# a larger scale wanders further from the straight line between the
# endpoints
draw(curve_twist(
  x = 0, y = 0, xend = 1, yend = 0, scale = 0.6,
  path_distortion = noise_bridge(seed = 7734)
))


# curve_twist() is shape_twist()'s backbone alone, with no ribbon width
draw(shape_twist(
  x = 0, y = 0, xend = 1, yend = 0,
  path_distortion = noise_bridge(seed = 7734)
))


draw(curve_twists(x = 1:3, y = 0, xend = 2:4, yend = 1))


# a bundle of independently-wandering strands between the same endpoints
draw(curve_twists(
  x = 0, y = 0, xend = 3, yend = 0,
  path_distortion = list(
    noise_bridge(seed = 1),
    noise_bridge(seed = 2),
    noise_bridge(seed = 3)
  )
))