[R] automatically calling dev.off()
Duncan Murdoch
murdoch.duncan at gmail.com
Tue Sep 1 17:00:20 CEST 2015
On 01/09/2015 10:13 AM, axionator wrote:
> Yes, the user could add something. Here, In about 90% of the time, he
> won't. So it would be nice to have a dev.off() as default (and some
> extra handling if more plot commands will follow).
That's a different mental model of how graphics should work, and it's
not compatible with standard R graphics. However, it would be pretty
easy to get this to work with a grid graphics based systems (e.g.
ggplot2, lattice) since they don't draw anything until you print the
object: you'd just need to override the print method.
Duncan Murdoch
>
> On Tue, Sep 1, 2015 at 4:04 PM, Duncan Murdoch <murdoch.duncan at gmail.com
> <mailto:murdoch.duncan at gmail.com>> wrote:
>
> On 01/09/2015 7:34 AM, axionator wrote:
> > Hi,
> > is there a way to automatically call dev.off()?
> > I use options(device="myfunc") to automatically open a device to print to.
> > Afterwards, I would like to close it (so that the file is actually written).
> > I tried to do it via addTaskCallback, but unfortunately, I have to use
> > Rserve and (for any reason), the callback does not work (in the default R
> > console on win7 it works, however).
> >
> > So, the following runs in the R console (but not via Rserve):
> >
> > mypng <- function(filename = "test.png", ...)
> > {
> > times <- function(total = 2, str = "Task") {
> > ctr <- 0
> > function(expr, value, ok, visible) {
> > ctr <<- ctr + 1
> > keep.me <http://keep.me> <- (ctr < total)
> > if (ctr == total) {
> > cat("ENDPRINT")
> > dev.off()
> > }
> > keep.me <http://keep.me>
> > }
> > }
> > png(filename, ...)
> > n <- addTaskCallback(times(1))
> > }
> > options(device="mypng")
> > plot(rnorm(333))
> >
>
> It wouldn't make sense to call dev.off() after the plot() command,
> because the user might be planning to add something to it. You need to
> tell R that you are done, and that's what dev.off() is for.
>
> You can call it automatically in a function by using
>
> on.exit(dev.off())
>
> and it should happen automatically at the end of an R session, but it
> *shouldn't* happen after every plotting call.
>
> Duncan Murdoch
>
>
More information about the R-help
mailing list