R/roboto-slab.R

In mmusori/ochathemes: 'ggplot2' themes and and theme components inspired by OCHA graphics stylebook.

#' A precise & pristine [ggplot2] theme with opinionated defaults and an emphasis on typoghraphy
#'
#' You should [import_roboto_slab]() first and also install the fonts on your
#' system before trying to use this theme.
#'
#' There is an option `ochathemes.loadfonts` which -- if set to `TRUE` -- will
#' call `extrafont::loadfonts()` to register non-core fonts with R PDF & PostScript
#' devices. If you are running under Windows, the package calls the same function
#' to register non-core fonts with the Windows graphics device.
#'
#' @md
#' @section Why Roboto Slab?:
#' It's free, has tolerable kerning pairs and multiple weights.
#' 
#' @md
#' @param base_family,base_size base font family and size
#' @param plot_title_family,plot_title_face,plot_title_size,plot_title_margin plot tilte family, face, size and margin
#' @param subtitle_family,subtitle_face,subtitle_size plot subtitle family, face and size
#' @param subtitle_margin plot subtitle margin bottom (single numeric value)
#' @param strip_text_family,strip_text_face,strip_text_size facet label font family, face and size
#' @param caption_family,caption_face,caption_size,caption_margin plot caption family, face, size and margin
#' @param axis_title_family,axis_title_face,axis_title_size axis title font family, face and size
#' @param axis_title_just axis title font justificationk one of `[blmcrt]`
#' @param axis_text_size font size of axis text
#' @param plot_margin plot margin (specify with [ggplot2::margin])
#' @param grid_col grid color
#' @param grid panel grid (`TRUE`, `FALSE`, or a combination of `X`, `x`, `Y`, `y`)
#' @param axis_col axis color
#' @param axis add x or y axes? `TRUE`, `FALSE`, "`xy`"
#' @param ticks ticks if `TRUE` add ticks
#' @export
#' @examples \dontrun{
#' library(ggplot2)
#' library(dplyr)
#'
#' # seminal scatterplot
#' ggplot(mtcars, aes(mpg, wt)) +
#'   geom_point() +
#'   labs(x="Fuel effiiency (mpg)", y="Weight (tons)",
#'        title="Seminal ggplot2 scatterplot example",
#'        subtitle="A plot that is only useful for demonstration purposes",
#'        caption="Brought to you by the letter 'g'") +
#'   theme_ocha_rsl()
#'
#' # seminal bar chart
#'
#' # note: make this font_rsl on Windows
#' update_geom_font_defaults(family = font_rsl_light)
#'
#' count(mpg, class) %>%
#'   ggplot(aes(class, n)) +
#'   geom_col() +
#'   geom_text(aes(label=n), nudge_y=3) +
#'   labs(x="Fuel effiiency (mpg)", y="Weight (tons)",
#'        title="Seminal ggplot2 bar chart example",
#'        subtitle="A plot that is only useful for demonstration purposes",
#'        caption="Brought to you by the letter 'g'") +
#'   theme_ocha_rsl(grid="Y") +
#'   theme(axis.text.y=element_blank())
#' }
theme_ocha_rsl <- function(
  base_family = "Roboto Slab", base_size = 11.5,
  plot_title_family = base_family, plot_title_size = 18,
  plot_title_face = "bold", plot_title_margin = 10,
  subtitle_family = if (.Platform$OS.type == "windows") "Roboto Slab" else "Roboto Slab Light",
  subtitle_size = 13,
  subtitle_face = "plain", subtitle_margin = 15,
  strip_text_family = base_family, strip_text_size = 12,
  strip_text_face = "plain",
  caption_family = if (.Platform$OS.type == "windows") "Roboto Slab" else "Roboto Slab Light",
  caption_size = 9,
  caption_face = "plain", caption_margin = 10,
  axis_text_size = base_size,
  axis_title_family = base_family,
  axis_title_size = 9,
  axis_title_face = "plain",
  axis_title_just = "rt",
  plot_margin = margin(30, 30, 30, 30),
  grid_col = "#cccccc", grid = TRUE,
  axis_col = "#cccccc", axis = FALSE, ticks = FALSE) {

  ret <- ggplot2::theme_minimal(base_family = base_family, base_size = base_size)

  ret <- ret + theme(legend.background = element_blank())
  ret <- ret + theme(legend.key = element_blank())

  if (inherits(grid, "character") | grid == TRUE) {

    ret <- ret + theme(panel.grid = element_line(color = grid_col, size = 0.2))
    ret <- ret + theme(panel.grid.major = element_line(color = grid_col, size = 0.2))
    ret <- ret + theme(panel.grid.minor = element_line(color = grid_col, size = 0.15))

    if (inherits(grid, "character")) {
      
      if (regexpr("X", grid)[1] < 0) ret <- ret + theme(panel.grid.major.x = element_blank())
      if (regexpr("Y", grid)[1] < 0) ret <- ret + theme(panel.grid.major.y = element_blank())
      if (regexpr("x", grid)[1] < 0) ret <- ret + theme(panel.grid.minor.x = element_blank())
      if (regexpr("y", grid)[1] < 0) ret <- ret + theme(panel.grid.minor.y = element_blank())
    }

  } else {
    ret <- ret + theme(panel.grid = element_blank())
  }

  if (inherits(axis, "character") | axis == TRUE) {
    ret <- ret + theme(axis.line = element_line(color = axis_col, size = 0.15))
    if (inherits(axis, "character")) {
      axis <- tolower(axis)
      if (regexpr("x", axis)[1] < 0) {
        ret <- ret + theme(axis.line.x = element_blank())
      } else {
        ret <- ret + theme(axis.line.x = element_line(color = axis_col, size = 0.15))
      }
      if (regexpr("y", axis)[1] < 0) {
        ret <- ret + theme(axis.line.y = element_blank())
      } else {
        ret <- ret + theme(axis.line.y = element_line(color = axis_col, size = 0.15))
      }
    } else {
      ret <- ret + theme(axis.line.x=element_line(color = axis_col, size = 0.15))
      ret <- ret + theme(axis.line.y=element_line(color = axis_col, size = 0.15))
    }
  } else {
    ret <- ret + theme(axis.line=element_blank())
  }

  if (!ticks) {
    ret <- ret + theme(axis.ticks = element_blank())
    ret <- ret + theme(axis.ticks.x = element_blank())
    ret <- ret + theme(axis.ticks.y = element_blank())
  } else {
    ret <- ret + theme(axis.ticks = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.x = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.y = element_line(size = 0.15))
    ret <- ret + theme(axis.ticks.length = grid::unit(5, "pt"))
  }

  xj <- switch(tolower(substr(axis_title_just, 1, 1)), b = 0, l = 0, m = 0.5, c = 0.5, r = 1, t = 1)
  yj <- switch(tolower(substr(axis_title_just, 2, 2)), b = 0, l = 0, m = 0.5, c = 0.5, r = 1, t = 1)

  ret <- ret + theme(axis.text.x = element_text(size = axis_text_size, margin = margin(t = 0)))
  ret <- ret + theme(axis.text.y = element_text(size = axis_text_size, margin = margin(r = 0)))
  ret <- ret + theme(axis.title = element_text(size = axis_title_size, family = axis_title_family))
  ret <- ret + theme(axis.title.x = element_text(hjust = xj, size = axis_title_size,
                                               family = axis_title_family, face = axis_title_face))
  ret <- ret + theme(axis.title.y = element_text(hjust = yj, size = axis_title_size,
                                               family = axis_title_family, face = axis_title_face))
  ret <- ret + theme(axis.title.y.right = element_text(hjust = yj, size = axis_title_size, angle = 90,
                                                     family = axis_title_family, face = axis_title_face))
  ret <- ret + theme(strip.text = element_text(hjust = 0, size = strip_text_size,
                                             face = strip_text_face, family = strip_text_family))
  ret <- ret + theme(panel.spacing = grid::unit(2, "lines"))
  ret <- ret + theme(plot.title = element_text(hjust = 0, size = plot_title_size,
                                             margin = margin(b = plot_title_margin),
                                             family = plot_title_family, face = plot_title_face))
  ret <- ret + theme(plot.subtitle = element_text(hjust = 0, size = subtitle_size,
                                                margin = margin(b = subtitle_margin),
                                                family = subtitle_family, face = subtitle_face))
  ret <- ret + theme(plot.caption = element_text(hjust = 1, size = caption_size,
                                               margin = margin(t = caption_margin),
                                               family = caption_family, face = caption_face))
  ret <- ret + theme(plot.margin = plot_margin)

  ret

}

#' Import Roboto Slab font for use in charts
#'
#' Roboto Slab is a trademark of Google.
#'
#' There is an option `ochathemes.loadfonts` which -- if set to `TRUE` -- will
#' call `extrafont::loadfonts()` to register non-core fonts with R PDF & PostScript
#' devices. If you are running under Windows, the package calls the same function
#' to register non-core fonts with the Windows graphics device.
#'
#' @md
#' @note This will take care of ensuring PDF/PostScript usage. The location of the
#'   font directory is displayed after the base import is complete. It is highly
#'   recommended that you install them on your system the same way you would any
#'   other font you wish to use in other programs.
#' @export
import_roboto_slab <- function() {

  rsl_font_dir <- system.file("fonts", "roboto-slab", package = "ochathemes")

  suppressWarnings(suppressMessages(extrafont::font_import(rsl_font_dir, prompt = FALSE)))

  message(
    sprintf(
      "You will likely need to install these fonts on your system as well.\n\nYou can find them in [%s]",
      rsl_font_dir)
  )

}

#' @rdname RobotoSlab
#' @md
#' @title Roboto Slab font name R variable aliases
#' @description `font_rsl` == "`Roboto Slab`"
#' @format length 1 character vector
#' @export
font_rsl <- "Roboto Slab"

#' @rdname RobotoSlab
#' @md
#' @note `font_rsl_light` (a.k.a. "`Roboto Slab Light`") is not available on
#'     Windows and will throw a warning if used in plots.
#' @description `font_fc_light` == "`Roboto Slab Light`"
#' @export
font_rsl_light <- "Roboto Slab Light"