[Rd] issues with dev.new avoiding RStudio plot device on unix?

[Stefan Evert]

> The problem is that the device chosen by dev.new() depends on the GUI.
> You can see the code that does this in grDevices:::.onLoad.  So in fact
> with noRstudioGD=TRUE, the decision is identical to what it is in R:
> you only get X11 if your GUI is X11 or Tk, you get pdf otherwise.
> It's pretty common to use R on a machine where X11 won't work, so this
> makes sense.

But not if running from RStudio always causes the X11 check to fail.  If the function is used outside RStudio, there's little point in specifying noRStudioGD=TRUE in the first place.

If you consider the code used to determine whether quartz() or X11() is available

	dsp <- Sys.getenv("DISPLAY")
	if (.Platform$OS.type == "windows")
		windows
	else if (.Platform$GUI == "AQUA" || ((!nzchar(dsp) || grepl("^/tmp/launch-", dsp)) && .Call(C_makeQuartzDefault)))
		quartz
	else if (nzchar(dsp) && .Platform$GUI %in% c("X11", "Tk"))
		X11
	else defdev 

you can see that it checks for a DISPLAY variable and assumes that X11 can be used if it is set.  Wouldn't it be just as safe to add RStudio to the list of accepted .Platform$GUIs?

In my case (Mac OS X 10.10.5), I'd like to get a quartz device.  The problem here is that I have XQuartz installed, so DISPLAY is always set and looks like this

	/private/tmp/com.apple.launchd.2wKas4wzPe/org.macosforge.xquartz:0 

while dev.new() checks for ^/tmp/launch-; I suppose the DISPLAY variable has changed between different versions of Mac OS X or XQuartz.  Perhaps the additional patterns could just be added to the grepl() call?

Best,
Stefan