R/geom-spct.r

In aphalo/ggspectra: Extensions to 'ggplot2' for Radiation Spectra

#' Spectral data plots.
#'
#' For each continuous x value, \code{geom_spct} displays a y interval.
#' \code{geom_spct} is a special case of \code{geom_area}, where the minimum of
#' the range is fixed to 0, but stacking is not enabled.
#'
#' An spectrum plot is the analog of a line plot (see \code{\link[ggplot2]{geom_path}}),
#' and can be used to show how y varies over the range of x. The difference is that
#' the area under the line is filled.
#'
#' @param mapping The aesthetic mapping, usually constructed with
#'   \code{\link[ggplot2]{aes}} or \code{\link[ggplot2]{aes_}}. Only needs
#'   to be set at the layer level if you are overriding the plot defaults.
#' @param data A data frame. If specified, overrides the default data frame
#'   defined at the top level of the plot.
#' @param stat The statistical transformation to use on the data for this layer,
#'   as a string.
#' @param position Position adjustment, either as a string, or the result of a
#'   call to a position adjustment function.
#' @param na.rm If FALSE (the default), removes missing values with a warning.
#'   If TRUE silently removes missing values.
#' @param show.legend logical. Should this layer be included in the legends?
#'   \code{NA}, the default, includes if any aesthetics are mapped. \code{FALSE}
#'   never includes, and \code{TRUE} always includes.
#' @param inherit.aes If \code{FALSE}, overrides the default aesthetics, rather
#'   than combining with them. This is most useful for helper functions that
#'   define both data and aesthetics and shouldn't inherit behaviour from the
#'   default plot specification, e.g. \code{\link[ggplot2]{borders}}.
#' @param ... other arguments passed on to \code{\link[ggplot2]{layer}}. This
#'   can include aesthetics whose values you want to set, not map. See
#'   \code{\link[ggplot2]{layer}} for more details.
#' @section Aesthetics: See \code{\link[ggplot2]{geom_ribbon}}
#'
#' @seealso \code{\link[ggplot2]{geom_ribbon}} for stacked areas,
#' \code{\link[ggplot2]{geom_path}} for lines (lines),
#' \code{\link[ggplot2]{geom_point}} for scatter plots.
#'
#' @examples
#'
#' # ggplot() methods for spectral objects set a default mapping for x and y.
#' ggplot(sun.spct) + geom_spct()
#'
#' @export
geom_spct <- function(mapping = NULL, data = NULL, stat = "identity",
                      position = "identity", na.rm = FALSE, show.legend = NA,
                      inherit.aes = TRUE, ...) {
  layer(
    data = data,
    mapping = mapping,
    stat = stat,
    geom = GeomSpct,
    position = position,
    show.legend = show.legend,
    inherit.aes = inherit.aes,
    params = list(
      na.rm = na.rm,
      ...
    )
  )
}

#' @rdname gg2spectra-ggproto
#' @format NULL
#' @usage NULL
#' @export
GeomSpct <- ggproto("GeomSpct", GeomRibbon,
  default_aes = aes(color = NA, fill = "grey60", linewidth = 0.5, linetype = 1,
    alpha = NA),

  required_aes = c("x", "y"),

  setup_data = function(data, params) {
    transform(data, ymin = 0, ymax = y)
  }
)