R/theme_graphclass.R

In graphdr/graphclassmate: Companion Materials For A Course In Data Visualization

#' @importFrom ggplot2 theme_minimal theme element_text
#' @importFrom ggplot2 element_rect element_line element_blank unit rel
NULL

#' ggplot theme based on theme_minimal
#'
#' Applies \code{ggplot2::theme_minimal()} with some edits such that all line 
#'        weights and colors and all text associated with the panels and axes 
#'        are identical. 
#'
#' @details    
#' Optional arguments allow specifying a universal font size, line size, and 
#'        line color, facilitating an easy transformation of a figure from a 
#'        print document to a presentation slide. 
#'   
#' The formatting choices are highly personal, but in my opinion, provide a 
#'         good standard not met by themes available in other packages.   
#'
#' @param font_size The size assigned to all text in the figure. 
#'        The default is 10 pt. 
#'   
#' @param font_color The color assigned to all text in the figure. 
#'        The default is black.  
#'   
#' @param line_size The size assigned to all lines in the figure. 
#'        The default is 0.3. 
#'   
#' @param line_color The color assigned to all lines in the figure. 
#'        The default is a light gray (#BDBDBD).   
#'
#' @return Modifies an existing graph.
#'
#' @export
theme_graphclass <- function(font_size = NULL, font_color = NULL, 
                line_size = NULL, line_color = NULL) {
        if (is.null(font_size))  {font_size = 10}
        if (is.null(font_color)) {font_color = "black"}
        if (is.null(line_size))  {line_size  = 0.3}
        if (is.null(line_color)) {line_color = rcb("light_Gray")}
        theme_minimal(base_family = "sans") +
                theme(
                        plot.title    = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        plot.subtitle = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        plot.caption  = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        axis.title    = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        axis.text     = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        legend.title  = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        legend.text   = element_text(size = font_size, 
                                face = "plain", color = font_color),
                        strip.text    = element_text(size = font_size, 
                                face = "plain", color = font_color, hjust = 0),

                        axis.line        = element_line(size = line_size, 
                                colour = line_color),
                        axis.ticks       = element_line(size = line_size, 
                                colour = line_color),
                        panel.grid.major = element_line(size = line_size, 
                                colour = line_color),
                        panel.grid.minor = element_blank(),

                        plot.background = element_blank(),
                        panel.border    = element_rect(
                        size   = line_size ,
                        colour = line_color,
                        fill   = NA
                ),

                legend.key.height = unit(0.8, "line"),
                legend.text.align = 0
        )
}
"theme_graphclass"