dev.interactive: Is the Current Graphics Device Interactive?
Test if the current graphics device (or that which would be opened) is
dev.interactive(orNone = FALSE)
deviceIsInteractive(name = NULL)
logical; if TRUE, the function also returns
TRUE when .Device == "null device" and
getOption("device") is among the known
one or more device names as a character vector,
or NULL to give the existing list.
dev.interactive() returns a logical, TRUE if and only if an
interactive (screen) device is in use.
deviceIsInteractive returns the updated list of known
interactive devices, invisibly unless name = NULL.
The X11 (Unix), windows (Windows) and quartz
(macOS, on-screen types only) are regarded as interactive, together
with JavaGD (from the package of the same name) and
CairoWin and CairoX11 (from package Cairo).
Packages can add their devices to the list by calling
Devices for the available devices on your platform.