R/themes.R

In teunbrand/ggh4x: Hacks for 'ggplot2'

#' @title Theme extensions
#' @name theme_extensions
#'
#' @description Some functions in \pkg{ggh4x} are using extensions to the theme
#' system. These extended theme argument are listed below, along with what
#' elements they are expected to be, and in what function(s) they are used.
#'
#' @usage NULL
#'
#' @param ggh4x.facet.nestline An [`element_line()`] used as the parent for the
#'   `nest_line` argument in [`facet_nested()`] and [`facet_nested_wrap()`].
#'   Inherits directly from the '`line`' theme element.
#' @param ggh4x.axis.nestline,ggh4x.axis.nestline.x,ggh4x.axis.nestline.y An
#'   [`element_line()`] used as the line to separate different layers of labels
#'   in [`guide_axis_nested()`]. Inherits from the '`axis.ticks`' theme element.
#' @param ggh4x.axis.nesttext.x,ggh4x.axis.nesttext.y An [`element_text()`] used
#'   to differentiate text higher in the hierarchy from the axis labels directly
#'   next to the axis line in [`guide_axis_nested()`]. Inherits from the
#'   '`axis.text.x`' and '`axis.text.y`' theme elements respectively.
#' @param ggh4x.axis.ticks.length.minor A [`rel()`] object used to set the size
#'   of minor tick marks relative to the regular tick marks. This is used in the
#'   [`guide_axis_minor()`] and [`guide_axis_logticks()`] functions. Defaults
#'   to `rel(2/3)`.
#' @param ggh4x.axis.ticks.length.mini A [`rel()`] object used to set the size
#'   of the smallest tick marks relative to regular tick marks. This is only
#'   used in the [`guide_axis_logticks()`] function. Defaults to `rel(1/3)`.
ggh4x_theme_elements <- function() {
  register_theme_elements(
    ggh4x.facet.nestline  = element_blank(),
    ggh4x.axis.nestline   = element_line(),
    ggh4x.axis.nestline.x = element_line(),
    ggh4x.axis.nestline.y = element_line(),
    ggh4x.axis.nesttext.x = element_text(angle = 0, hjust = 0.5, vjust = 0.5),
    ggh4x.axis.nesttext.y = element_text(),
    ggh4x.axis.ticks.length.minor = rel(2/3),
    ggh4x.axis.ticks.length.mini = rel(1/3),
    element_tree = list(
      ggh4x.facet.nestline  = el_def("element_line", "line"),
      ggh4x.axis.nestline   = el_def("element_line", "axis.ticks"),
      ggh4x.axis.nestline.x = el_def("element_line", "ggh4x.axis.nestline"),
      ggh4x.axis.nestline.y = el_def("element_line", "ggh4x.axis.nestline"),
      ggh4x.axis.nesttext.x = el_def("element_text", "axis.text.x"),
      ggh4x.axis.nesttext.y = el_def("element_text", "axis.text.y"),
      ggh4x.axis.ticks.length.minor = el_def(c("rel")),
      ggh4x.axis.ticks.length.mini = el_def(c("rel"))
    )
  )
}