A closed Bezier curve

shape_bezier is a drawable whose outline follows a Bezier curve defined by an arbitrary number of control points (x, y). With two control points this is a straight line; with four, a cubic Bezier of the kind used to build ribbons and other flowing shapes.

shape_beziers() is a vectorized version of shape_bezier(). Since x/y are themselves numeric vectors of control points for a single curve, shape_beziers() takes them as a list() of numeric vectors instead – one vector of control points per shape – rather than a bare vector (which shape_circles()-style constructors use for a plain per-shape scalar).

Usage

shape_bezier(x, y, n = 100L, trans = trans_identity(), ...)

shape_beziers(x, y, n = 100L, trans = trans_identity(), ...)

Arguments

x, y

For shape_bezier(), numeric vectors of control point coordinates, the same length, with at least two control points. For shape_beziers(), a list() of such vectors instead – one vector of control points per shape.

n

Number of points used to sample the curve. Default 100L.

trans

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

...

Arguments passed to style().

Value

A drawable.

For shape_beziers(), a sketch.

Details

Since draw() renders every "polygon"-geometry drawable's points as a closed polygon, the curve is implicitly closed from its last control point back to its first – for an open Bezier curve/path instead, see curve_bezier().

Every other argument may be a plain vector, recycled against x/y via purrr::pmap()'s own vctrs-based rules (any length-1 element is broadcast to the common length; mismatched lengths greater than 1 raise an error). The result is a sketch containing one shape_bezier() per list element/recycled row, rather than a single drawable.

See also

Other 2D shapes: shape_blob(), shape_circle(), shape_combine(), shape_ellipse(), shape_polygon(), shape_raw(), shape_rectangle(), shape_ribbon(), shape_star(), shape_stroke(), shape_strokepath(), shape_twist(), shape_wedge()

Examples

draw(shape_bezier(x = c(0, 0.5, 1, 0.5), y = c(0, 1, 0, -1)))


# two control points collapse the curve to a straight-edged polygon
draw(shape_bezier(x = c(0, 1), y = c(0, 1), fill = "steelblue"))


# more control points give the curve more inflections
draw(shape_bezier(
  x = c(0, 0.3, 0.6, 1, 0.6, 0.3), y = c(0, 1, -1, 0, 1, -1),
  fill = fill_hatch(angle = 60, spacing = 0.08)
))


draw(shape_beziers(
  x = list(c(0, 0.5, 1, 0.5), c(2, 2.5, 3, 2.5)),
  y = list(c(0, 1, 0, -1), c(0, 1, 0, -1))
))