R/openGraphCairo.R

In visStatistics: Automated Selection and Visualisation of Statistical Hypothesis Tests

#' Cairo wrapper function
#'
#' Cairo wrapper function returning NULL if not \code{type} is specified
#'
#' \code{openGraphCairo()} \code{Cairo()} wrapper function. Differences to
#' \code{Cairo:} a) prematurely ends the function call to \code{Cairo()}
#' returning NULL, if no output \code{type}  of types 'png', 'jpeg', 'pdf',
#' 'svg', 'ps' or 'tiff' is provided. b) The \code{file} argument of the
#' underlying Cairo function is generated by
#' \code{file.path(fileDirectory,paste(fileName,'.', type, sep = ''))}.

#' @param width see \code{Cairo()}
#' @param height see \code{Cairo()}
#' @param fileName name of file to be created. Does not include both file
#'   extension '.\code{type}' and file \code{filedirectory}. Default file name
#'   'visstat_plot'.
#' @param type Supported output types are 'png', 'jpeg', 'pdf', 'svg', 'ps' and
#'   'tiff'. See \code{Cairo()}
#' @param fileDirectory path of directory, where plot is stored. Default current
#'   working directory.
#' @param pointsize see \code{Cairo()}
#' @param bg see \code{Cairo()}
#' @param canvas see \code{Cairo()}
#' @param units see \code{Cairo()}
#' @param dpi DPI used for the conversion of units to pixels. Default value 150.
#' @name openGraphCairo
#' @return NULL, if no \code{type} is specified. Otherwise see \code{Cairo()}
#' @examples
#'
#' ##  adapted from example in \code{Cairo()}
#' openGraphCairo(fileName = "normal_dist", type = "pdf", fileDirectory = tempdir())
#' plot(rnorm(4000), rnorm(4000), col = "#ff000018", pch = 19, cex = 2)
#' dev.off() # creates a file 'normal_dist.pdf' in the directory specified in fileDirectory
#' # ## remove the plot from fileDirectory
#' file.remove(file.path(tempdir(), "normal_dist.pdf"))
#' @import Cairo
#' @export

openGraphCairo <- function(width = 640,
                           height = 480,
                           fileName = NULL,
                           type = NULL,
                           fileDirectory = getwd(),
                           pointsize = 12,
                           bg = "transparent",
                           canvas = "white",
                           units = "px",
                           dpi = 150) {
  oldparCairo <- par(no.readonly = TRUE)
  oldparCairo$new <- FALSE
  on.exit(par(oldparCairo))

  if (is.null(type)) {
    return()
  } else {
    # set default fileName to 'visstat_plot'
    if (is.null(fileName)) {
      fileName <- "visstat_plot"
    }

    fullfilename <- paste(fileName, ".", type, sep = "")
    Cairofilename <- file.path(fileDirectory, fullfilename)

    if (type == "png") {
      CairoPNG(filename = Cairofilename)
    } else if (type == "pdf") {
      CairoPDF(file = Cairofilename)
    } else if (type == "jpeg") {
      CairoJPEG(filename = Cairofilename)
    } else if (type == "tiff") {
      CairoTIFF(filename = Cairofilename)
    } else if (type == "svg") {
      CairoSVG(file = Cairofilename)
    } else if (type == "ps") {
      CairoPS(file = Cairofilename, family = "Helvetica")
    } else {
      warning("Chosen output type not supported. No graphics saved.")
      return()
    }
  }
}