Make arrowheads with any function

Usage

arrow_head_function(
  .fun = stats::dnorm,
  lower_bound = -4,
  upper_bound = 4,
  ...,
  base_width = 0,
  thickness = 1.2,
  closed = TRUE,
  minimum_value = NA,
  rotate = 0,
  rescale = c(1, 1),
  nudge = c(0, 0),
  transformations = c("rotater", "rescaler", "nudger"),
  n = 1001,
  plot = FALSE
)

Arguments

.fun: a function (defaults to dnorm)
lower_bound: lowest value passed to .fun
upper_bound: highest value passed to .fun
...: arguments passed to .fun
base_width: If closed, size of feet
thickness: If closed, thickness of shape (can be negative)
closed: make polygon closed
minimum_value: smallest value in function
rotate: rotation angle in radians
rescale: a single value or 2-length vector for scaling in x and y
nudge: a single value or 2-length vector for nudging in x and y
transformations: a vector of transformation functions
n: number of points in polygon
plot: plot arrowhead if TRUE

Value

a matrix

Examples

# A normal distribution
xy <- arrow_head_function(dnorm, plot = TRUE)

# if closed = FALSE, set thickness and base_width
xy <- arrow_head_function(dnorm, plot = TRUE, closed = FALSE,
                    thickness = 1.5,
                    base_width = .25)


# A cauchy distribution
xy <- arrow_head_function(dt, df = 1, plot = TRUE)

# open with thickness = 1.5
xy <- arrow_head_function(
  dt,
  df = 1,
  plot = TRUE,
  closed = FALSE,
  thickness = 1.5
)

# thickness > 2 creates a bulge
xy <- arrow_head_function(
  dt,
  df = 1,
  lower_bound = -3.25,
  upper_bound = 3.25,
  closed = FALSE,
  thickness = 2.5,
  plot = TRUE,
  rescale = 1 / 3,
  nudge = c(2 / 3, 0)
)


# Make a new function
mytrident <- function(x, s = 160) {
  k <- length(x)
  y1 <- dbeta(x, shape1 = s, shape2 = s) * 2
  y2 <- dbeta(x, shape1 = s * .9, shape2 = s * .1)
  y3 <- dbeta(x, shape1 = s * .1 , shape2 = s * .9)
  y1 + y2 + y3
}

xy <- arrow_head_function(
  mytrident,
  lower_bound = 0,
  upper_bound = 1,
  plot = TRUE,
  minimum_value = -3,
  rescale = .5,
  nudge = c(.5, 0)
)