R/ggsave2.r

In wch/vtest: Tools for visual testing of R packages

# This code is copied verbatim from ggplot2::ggsave.
# This copy is needed here because loading it from ggplot2 can cause problems
# with the namespace when loading and testing ggplot2. Perhaps there is a better
# solution?
ggsave2 <- function(filename=default_name(plot), plot = last_plot(), device=default_device(filename), path = NULL, scale=1, width=par("din")[1], height=par("din")[2], units=c("in", "cm", "mm"), dpi=300, ...) {
  if (!inherits(plot, "ggplot")) stop("plot should be a ggplot2 plot")

  eps <- ps <- function(..., width, height)  
    grDevices::postscript(..., width=width, height=height, onefile=FALSE,
      horizontal = FALSE, paper = "special")
  tex <- function(..., width, height) 
    grDevices::pictex(..., width=width, height=height)
  pdf <- function(..., version="1.4") 
    grDevices::pdf(..., version=version)
  svg <- function(...) 
    grDevices::svg(...)
  wmf <- function(..., width, height) 
    grDevices::win.metafile(..., width=width, height=height)

  png <- function(..., width, height) 
    grDevices::png(...,  width=width, height=height, res = dpi, units = "in")
  jpg <- jpeg <- function(..., width, height) 
    grDevices::jpeg(..., width=width, height=height, res = dpi, units = "in")
  bmp <- function(..., width, height) 
    grDevices::bmp(...,  width=width, height=height, res = dpi, units = "in")
  tiff <- function(..., width, height) 
    grDevices::tiff(..., width=width, height=height, res = dpi, units = "in")
  
  default_name <- function(plot) { 
    paste(digest.ggplot(plot), ".pdf", sep="")
  }
  
  default_device <- function(filename) {
    pieces <- strsplit(filename, "\\.")[[1]]
    ext <- tolower(pieces[length(pieces)])
    match.fun(ext)
  }

  units <- match.arg(units)
  convert_to_inches <- function(x, units) {
    x <- switch(units,
      `in` = x,
      cm = x / 2.54,
      mm = x / 2.54 /10
    )
  }

  convert_from_inches <- function(x, units) {
    x <- switch(units,
      `in` = x,
      cm = x * 2.54,
      mm = x * 2.54 * 10
    )
  }

  # dimensions need to be in inches for all graphic devices
  # convert width and height into inches when they are specified
  if (!missing(width)) {
    width <- convert_to_inches(width, units)
  }
  if (!missing(height)) {
    height <- convert_to_inches(height, units)
  }
  # if either width or height is not specified, display an information message
  # units are those specified by the user
  if (missing(width) || missing(height)) {
    message("Saving ", prettyNum(convert_from_inches(width * scale, units), digits=3), " x ", prettyNum(convert_from_inches(height * scale, units), digits=3), " ", units, " image")
  }

  width <- width * scale
  height <- height * scale
  
  if (!is.null(path)) {
    filename <- file.path(path, filename)
  }
  device(file=filename, width=width, height=height, ...)
  on.exit(capture.output(dev.off()))
  print(plot)
  
  invisible()
}