R/xkcdaxis.R

In xkcd: Plotting 'ggplot2' Graphics in an 'XKCD' Style

## Emilio Torres Manzanera
## University of Oviedo
## Time-stamp: <2018-05-23 17:37 emilio on emilio-despacho>
## ============================================================

## NOTE: The utility functions 'pointssegment', 'pointscircunference',
## and 'doforeachrow' have been removed from this file, as per the
## modernization plan, and moved to another file (e.g., xkcdline.R).

#' Plot the axis
#'
#' This function plots the axis in an XKCD style.
#'
#' @param xrange The range of the X axe.
#' @param yrange The range of the Y axe.
#' @param ... Other arguments passed to geom_xkcdpath.
#' @return A list of layers containing the axes, coordinate system, and theme.
#' @import ggplot2
#' @import extrafont
#' @importFrom Hmisc bezier
#' @importFrom stats runif
#' @export
#' @examples
#' \dontrun{
#' xrange <- range(mtcars$mpg)
#' yrange <- range(mtcars$wt)
#' p <- ggplot() +
#'      geom_point(aes(mpg, wt), data=mtcars) +
#'      xkcdaxis(xrange,yrange)
#' p
#' }
xkcdaxis <- function(xrange, yrange, ...) {
  if( is.null(xrange) | is.null(yrange) )
    stop("Arguments are: xrange, yrange")
  
  # Calculate jitter amounts based on ranges
  xjitteramount <- diff(xrange)/50
  yjitteramount <- diff(yrange)/50
  
  # Data for the X-axis line
  dataaxex <- data.frame(x=xrange[1]-xjitteramount,
                         y=yrange[1]-yjitteramount,
                         xend=xrange[2]+xjitteramount,
                         yend=yrange[1]-yjitteramount)
  
  # Use direct aes() call (modernized: removed 'with(dataaxex, ...)')
  mappingsegment <- aes(x=x,y=y,xend=xend,yend=yend)
  
  # Draw X-axis using the new geom_xkcdpath
  axex <- geom_xkcdpath(mappingsegment,
                        dataaxex,
                        yjitteramount = yjitteramount,
                        mask = FALSE,
                        ... )
  
  # Data for the Y-axis line
  dataaxey <- data.frame(x=xrange[1]-xjitteramount,
                         y=yrange[1]-yjitteramount,
                         xend=xrange[1]-xjitteramount,
                         yend=yrange[2]+yjitteramount)
  
  # Draw Y-axis using the new geom_xkcdpath
  axey <- geom_xkcdpath(mappingsegment,
                        dataaxey,
                        xjitteramount = xjitteramount,
                        mask = FALSE,
                        ... )
  
  # Set up the coordinate system and theme
  coordcarte <- coord_cartesian(xlim = xrange + 1.5*c(-xjitteramount,xjitteramount),
                                ylim = yrange + 1.5*c(-yjitteramount,yjitteramount))
  
  # Return the layers
  list(c(axex,axey), coordcarte, theme_xkcd())
}

# --------------------------------------------------------------------------
# The following functions are DELETED as they are part of the old NSE system.
# The new geom_xkcdpath handles these tasks internally.
# --------------------------------------------------------------------------

# DELETED: createdefaultmappinganddata
# DELETED: doforeachrow
# DELETED: mappingjoin
# DELETED: mappingjoin2
# DELETED: pointscircunference (MOVED)
# DELETED: pointssegment (MOVED)