A pie-slice wedge or annulus segment

shape_wedge is a drawable defined by a centroid, a radius, and a start/end angle (in radians): its outline is the centroid, followed by n points along the circular arc from start to end.

shape_wedges() is a vectorized version of shape_wedge(): each argument may be a vector, recycled against the others. The result is a sketch containing one shape_wedge() per recycled row, rather than a single drawable.

Usage

shape_wedge(
  x = 0,
  y = 0,
  radius = 1,
  inner_radius = 0,
  start = 0,
  end = pi/2,
  n = 100L,
  trans = trans_identity(),
  ...
)

shape_wedges(
  x = 0,
  y = 0,
  radius = 1,
  inner_radius = 0,
  start = 0,
  end = pi/2,
  n = 100L,
  trans = trans_identity(),
  ...
)

Arguments

x, y

Centroid coordinates. Default 0.

radius

Radius. Must be non-negative. Default 1.

inner_radius

Inner radius. Must be non-negative and no greater than radius. Default 0 (a pie-slice wedge, i.e. no inner arc; see Details for the ring-slice/annulus-segment shape a positive value gives instead).

start, end

Start/end angle of the arc, in radians. Default 0/ pi / 2.

n

Number of points used to approximate the arc. Must be at least 2. 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_wedges(), a sketch.

Details

grid's own polygon closing then draws the final straight edge back from the arc's last point to the centroid, giving the familiar pie-slice/wedge shape. curve_arc() is the arc alone, with no centroid vertex or fill.

inner_radius (default 0) turns the pie slice into a ring slice (an annulus segment): when greater than 0, the centroid vertex is dropped entirely, and the outline instead traces the outer arc from start to end followed by a second, inner arc of radius inner_radius swept back from end to start – grid's own polygon closing then draws the final straight edge back to the outer arc's first point, giving a four-sided (two arcs, two straight radial edges) ring-slice outline rather than a pie slice's three-sided one (two straight edges meeting at the centroid, one arc). inner_radius = 0 (the default) recovers the original pie-slice outline exactly, since a zero-radius "inner arc" would otherwise degenerate to the centroid repeated n times.

Recycling uses 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.

See also

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

Examples

draw(shape_wedge(start = 0, end = pi / 2))

draw(shape_wedge(
  x = 1,
  y = 1,
  radius = 0.5,
  start = pi,
  end = 2 * pi,
  color = "darkred"
))


# a nearly-full sweep gives a pac-man-like shape; the arc always closes
# straight back to the centroid
draw(shape_wedge(start = 0, end = 1.9 * pi, fill = "goldenrod"))


# inner_radius > 0 gives a ring slice (annulus segment) instead of a
# pie slice -- no centroid vertex, a hole in the middle
draw(shape_wedge(
  radius = 1, inner_radius = 0.6, start = 0, end = 1.5 * pi,
  fill = "steelblue"
))


# a full sweep (start = 0, end = 2 * pi) with inner_radius > 0 gives a
# complete ring/annulus
draw(shape_wedge(radius = 1, inner_radius = 0.7, start = 0, end = 2 * pi))


draw(shape_wedges(start = 0, end = seq(pi / 2, 2 * pi, length.out = 3)))


# a pie chart: adjacent wedges sharing a centroid, one slice per value
value <- c(30, 20, 50)
cum <- c(0, cumsum(value)) / sum(value) * 2 * pi
draw(shape_wedges(
  start = cum[-length(cum)], end = cum[-1],
  fill = c("steelblue", "tomato", "goldenrod")
))


# a donut chart: the same idea, with inner_radius > 0
draw(shape_wedges(
  inner_radius = 0.5,
  start = cum[-length(cum)], end = cum[-1],
  fill = c("steelblue", "tomato", "goldenrod")
))