copied from deprecated spatstat:::CDF.density() function

cdf_density.R

# copied from spatstat.utils::paren()
paren <- function (x, type = "(") {
  if (length(x) == 0) 
    return(x)
  if (identical(type, "")) 
    type <- "blank"
  switch(type, `(` = {
    out <- paste("(", x, ")", sep = "")
  }, `[` = {
    out <- paste("[", x, "]", sep = "")
  }, `{` = {
    out <- paste("{", x, "}", sep = "")
  }, blank = {
    out <- paste(x)
  }, stop(paste("Unrecognised parenthesis type:", sQuote(type))))
  out
}

# copied from spatstat.utils::prange()
prange <- function (r) {
  stopifnot(length(r) == 2)
  paren(paste(r, collapse = ", "), "[")
}


# copied from deprecated 
CDF.density <- function (f, ..., warn = TRUE){
  stopifnot(inherits(f, "density"))
  if (warn && is.call(cl <- f$call) && any(c("from", "to") %in% 
                                           names(cl))) 
    warning(paste("Density was normalised within the computed range", 
                  "of x values", prange(c(cl$from, cl$to))), call. = FALSE)
  xx <- f$x
  yy <- f$y
  nn <- length(xx)
  Fx <- cumsum(yy * c(0, diff(xx)))
  Fx <- Fx/Fx[nn]
  FF <- approxfun(xx, Fx, method = "linear", rule = 2)
  return(FF)
}