R/optimal.tickmarks.R

In lozalojo/mem: The Moving Epidemic Method

#' Find tickmarks for a given range of the y-axis that best fit an optimal number of tickmarks
#' you decide. f.i: what if i want to have a graph with 8 tickmarks in a range of 34 to 345
#'
#' @keywords internal
optimal.tickmarks <- function(i.min, i.max, i.number.ticks = 10,
                              i.valid.ticks = apply(expand.grid(c(1, 2, 2.5, 5), 10^(-10:10)), 1, FUN = function(x) {
                                x[1] * x[2]
                              }),
                              i.include.min = F, i.include.max = F) {
  if (i.include.min) dif0 <- i.min else dif0 <- 0
  e.min <- i.min - dif0
  e.max <- i.max - dif0
  ticks.min <- floor(e.min / i.valid.ticks)
  ticks.max <- ceiling(e.max / i.valid.ticks)
  ticks.maxmin <- ticks.max - ticks.min + 1
  n.valid.ticks <- length(i.valid.ticks)
  posicion.ticks <- (1:n.valid.ticks)[min(abs(ticks.maxmin - i.number.ticks)) == abs(ticks.maxmin - i.number.ticks)][1]
  ini <- (ticks.min * i.valid.ticks)[posicion.ticks] + dif0
  fin <- (ticks.max * i.valid.ticks)[posicion.ticks] + dif0
  salto <- i.valid.ticks[posicion.ticks]
  # Tickmarks
  tickmarks <- seq(ini, fin, salto)
  # Number of ticks
  numero.ticks <- length(tickmarks)
  if (i.include.max) {
    fin <- i.max
    tickmarks[numero.ticks] <- i.max
  }
  # Rank
  range.y <- c(ini, fin)
  # Returning
  return(list(by = salto, number = numero.ticks, range = range.y, tickmarks = tickmarks))
}