R/GGPlot2Tools_GGPlotLims.R

In Ilia-Kosenkov/RLibs: RLibs

#   MIT License
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#   Copyright(c) 2017-2018 Ilia Kosenkov [ilia.kosenkov.at.gm@gmail.com]
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#' @title GGPlotLims
#' @param plt Input \code{ggplot} plot.
#' @return \code{list} with x and y limits.
#' @importFrom dplyr %>%
#' @importFrom rlang %||% eval_tidy is_empty is_null flatten
#' @importFrom purrr map transpose discard
#' @export
GGPlotLims <- function(plt) {
    parentData <- plt$data %||% list()
    parentAes <- plt$mapping %||% list() %>% flatten
    xNms <- c("x", "xend", "xmin", "xmax")
    yNms <- c("y", "yend", "ymin", "ymax")

    plt$layers %>%
        discard(~is_null(.x$mapping)) %>%
        map(function(lyr) {

            aes <- lyr$mapping %||% list() %>% flatten

            if (lyr$inherit.aes)
                aes <- append(parentAes, aes)

            if (is_empty(lyr$data))
                data <- plt$data
            else
                data <- lyr$data

            yAes <- aes[names(aes) %in% yNms]
            xAes <- aes[names(aes) %in% xNms]

            xlim <- xAes %>%
                map(~eval_tidy(.x, data)) %>%
                map(range) %>%
                range(na.rm = TRUE)

            ylim <- yAes %>%
                map(~eval_tidy(.x, data)) %>%
                map(range) %>%
                range(na.rm = TRUE)

            return(list(xlim = xlim, ylim = ylim))
    })  %>%
    transpose %>%
    map(range)
}