How can I plot to multiple devices at the same time?

Question

When I am plotting, I often plot to an eps file and a png file like this:

postscript(file=paste(dir, output, "_ggplot.eps", sep=""), onefile=FALSE, horizontal=FALSE, width=4.8, height=4.0)
# Plotting code
dev.off()

png(paste(dir, output, "_ggplot.png", sep=""), width=450, height=300)
# Plotting code
dev.off()

The problem is that the plotting code is repeated twice. Is it possible to specify multiple devices for plotting?

Answer 1

You can combine them using dev.copy(). For example,

  X11 ()
  plot (x,y)
  dev.copy (jpeg,filename="test.jpg");
  dev.off ();

Lookup help(dev.copy) for more details.

Usage:

     dev.copy(device, ..., which = dev.next())
     dev.print(device = postscript, ...)
     dev.copy2eps(...)
     dev.copy2pdf(..., out.type = "pdf")
     dev.control(displaylist = c("inhibit", "enable"))

Answer 2

No it's not possible. At least not according to the manual for ?grDevices:

"Details: Only one device is the ‘active’ device: this is the device in which all graphics operations occur. There is a "null device" which is always open but is really a placeholder: any attempt to use it will open a new device specified by getOption("device"))."