R/planes.R

In devOpifex/g2r: Interactive Grammar of Graphics

#' Planes
#'
#' Split the chart into planes according to variables.
#'
#' @inheritParams fig_point
#' @param asp Aspects that define split, these must be defined
#' as a formula, e.g.: ~x+y.
#' @param ... Any other option.
#' @param type Type of planes to use.
#' @param sync Whether to sync the aspects used for the planes
#' with others used elsewhere, similar to that of [fig_point()].
#'
#' @examples
#' g2(iris, asp(Sepal.Length, Sepal.Width, color = Species)) %>%
#'   fig_point() %>%
#'   planes(~Species, type = "tree")
#' @importFrom rlang enquos as_label
#' @importFrom purrr map
#' @importFrom stats terms
#'
#' @export
planes <- function(
  g,
  asp,
  ...,
  type = c(
    "rect",
    "list",
    "matrix",
    "circle",
    "tree",
    "mirror"
  ),
  sync = TRUE
) {
  UseMethod("planes")
}

#' @method planes g2r
#' @export
planes.g2r <- function(
  g,
  asp,
  ...,
  type = c(
    "rect",
    "list",
    "matrix",
    "circle",
    "tree",
    "mirror"
  ),
  sync = TRUE
) {
  if (missing(asp)) {
    stop("Missing `asp`", call. = FALSE)
  }

  if (!inherits(asp, "formula")) {
    stop("Must pass `asp` as formula, e.g.: ~x+y")
  }

  if (is.null(g$x$data)) {
    stop("Planes requires data to be passed to `g2`", call. = FALSE)
  }

  type <- match.arg(type)
  asp <- parse_form(asp)

  for (i in 1:length(asp)) {
    g <- sync(g, asp[i], sync, if_true = "mainGroupPlanes")
  }

  g$x$cols <- c(g$x$cols, asp)

  g$x$facet <- list(
    type = type,
    opts = list(
      fields = as.list(asp),
      ...
    )
  )

  g
}

#' Parse Planes Formula
#'
#' @param frm Formula to parse.
#'
#' @return A vector of variables used in the formula.
#'
#' @keywords internal
parse_form <- function(frm) {
  vars <- as.list(attr(terms(frm), "variables"))[-1]

  vars %>%
    map(as_label) %>%
    unlist()
}