R/BRLThis.R

In BrailleR: Improved Access for Blind Users

# @rdname BRLThis
# @title Convert a graph to a pdf ready for embossing
# @aliases BRLThis
# @description  The first argument to this function must be a call to create a graph, such as a histogram. Instead of opening a new graphics device, the graph will be created in a pdf file, with all text being presented using  a braille font. The function is somewhat experimental as the best braille font is not yet confirmed, and a number of examples need to be tested on a variety of embossers before full confidence in the function is given.
# @details The user's chosen braille font must be installed. This might include the default font shipped as part of the package.
# @return Nothing within the R session, but a pdf file will be created in the user's working directory.
# @author A. Jonathan R. Godfrey.
# @examples
#; data(airquality)
# with(airquality,
# BRLThis(hist(Ozone), "Ozone-hist.pdf"))

# @export BRLThis
# @param x the call to create a graph
# @param file A character string giving the filename where the image is to be saved.
BRLThis =
    function(x, file) {
      extrafont::loadfonts(quiet = TRUE)

      # need to add these arguments to the call
      # family="Braille Normal", cex=1, cex.axis=1, cex.main=1, cex.lab=1, cex.sub=1)
      eval({
             pdf(file, pointsize = 29)
             x
             dev.off()
             extrafont::embed_fonts(file)  # , outfile=file)
           }, parent.frame())
      return(invisible(NULL))
    }