R/theme.R

In krisrs1128/ggscaffold: Scaffolding for Verbose ggplot Figures

#! /usr/bin/env Rscript

## File description -------------------------------------------------------------
## Custom theme options not implemented in the usual theme packages.

#' Merge in Theme Defaults
#'
#' For a partially specified list opts, this merges in defaults
#' for those options that are not specified.
#'
#' @param opts [list] A partially specified list used to customize themes in
#'   ggplot theme(). Options that are already specified will not be changed,
#'   those that are not will be filled in with defaults.
#' @return opts [list]  A version of opts with unspecified options filled in
#'   with defaults.
#' @export
merge_theme_opts <- function(opts = list()) {
  default_opts <- list(
    border_size = 0,
    spacing = 0,
    subtitle_size = 7,
    text_size = 5,
    key_width = 0.2,
    key_height = 0.4,
    legend_position = "right"
  )
  modifyList(default_opts, opts)
}

#' Provide a Custom, Minimal Theme
#'
#' @param opts [list] A partially specified list used to customize themes in
#'   ggplot theme(). Options that are already specified will not be changed,
#' @return theme_obj [ggplot theme] A theme object that can be used to modify
#'   the appearance of a ggplot object.
#' @importFrom ggplot2 theme_bw theme element_blank element_text %+replace%
#'   element_rect
#' @importFrom grid unit
#' @export
min_theme <- function(opts = list()) {
  opts <- merge_theme_opts(opts)
  theme_bw() %+replace%
    theme(
      panel.border = element_rect("transparent", size = opts$border_size),
      panel.background = element_blank(),
      panel.grid = element_blank(),
      panel.spacing = unit(opts$spacing, "line"),
      legend.title = element_text(size = opts$subtitle_size),
      legend.text = element_text(size = opts$text_size),
      legend.key = element_blank(),
      legend.key.width = unit(opts$key_width, "line"),
      legend.key.height = unit(opts$key_height, "line"),
      legend.position = opts$legend_position,
      axis.text = element_text(size = opts$text_size),
      axis.title = element_text(size = opts$subtitle_size),
      axis.ticks = element_blank(),
      strip.background = element_blank(),
      strip.text = element_text(size = opts$subtitle_size)
    )
}