dev2: Copy Graphics Between Multiple Devices

Copy Graphics Between Multiple Devices

Description

dev.copy copies the graphics contents of the current device to the device specified by which or to a new device which has been created by the function specified by device (it is an error to specify both which and device). (If recording is off on the current device, there are no contents to copy: this will result in no plot or an empty plot.) The device copied to becomes the current device.

dev.print copies the graphics contents of the current device to a new device which has been created by the function specified by device and then shuts the new device.

dev.copy2eps is similar to dev.print but produces an EPSF output file in portrait orientation (horizontal = FALSE). dev.copy2pdf is the analogue for PDF output.

dev.control allows the user to control the recording of graphics operations in a device. If displaylist is "inhibit" ("enable") then recording is turned off (on). It is only safe to change this at the beginning of a plot (just before or just after a new page). Initially recording is on for screen devices, and off for print devices.

Usage

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

Arguments

Details

Note that these functions copy the device region and not a plot: the background colour of the device surface is part of what is copied. Most screen devices default to a transparent background, which is probably not what is needed when copying to a device such as png.

For dev.copy2eps and dev.copy2pdf, width and height are taken from the current device unless otherwise specified. If just one of width and height is specified, the other is adjusted to preserve the aspect ratio of the device being copied. The default file name is Rplot.eps or Rplot.pdf, and can be overridden by specifying a file argument.

Copying to devices such as postscript and pdf which need font families pre-specified needs extra care – R is unaware of which families were used in a plot and so they will need to manually specified by the fonts argument passed as part of .... Similarly, if the device to be copied from was opened with a family argument, a suitable family argument will need to be included in ....

The default for dev.print is to produce and print a postscript copy. This will not work unless options("printcmd") is set suitably and you have a PostScript printing system: see postscript for how to set this up. Windows users may prefer to use dev.print(win.print).

dev.print is most useful for producing a postscript print (its default) when the following applies. Unless file is specified, the plot will be printed. Unless width, height and pointsize are specified the plot dimensions will be taken from the current device, shrunk if necessary to fit on the paper. (pointsize is rescaled if the plot is shrunk.) If horizontal is not specified and the plot can be printed at full size by switching its value this is done instead of shrinking the plot region.

If dev.print is used with a specified device (even postscript) it sets the width and height in the same way as dev.copy2eps. This will not be appropriate unless the device specifies dimensions in inches, in particular not for png, jpeg, tiff and bmp unless units = "inches" is specified.

Value

dev.copy returns the name and number of the device which has been copied to.

dev.print, dev.copy2eps and dev.copy2pdf return the name and number of the device which has been copied from.

Note

Most devices (including all screen devices) have a display list which records all of the graphics operations that occur in the device. dev.copy copies graphics contents by copying the display list from one device to another device. Also, automatic redrawing of graphics contents following the resizing of a device depends on the contents of the display list.

After the command dev.control("inhibit"), graphics operations are not recorded in the display list so that dev.copy and dev.print will not copy anything and the contents of a device will not be redrawn automatically if the device is resized.

The recording of graphics operations is relatively expensive in terms of memory so the command dev.control("inhibit") can be useful if memory usage is an issue.

See Also

dev.cur and other dev.xxx functions.

Examples

## Not run: 
x11() # on a Unix-alike
plot(rnorm(10), main = "Plot 1")
dev.copy(device = x11)
mtext("Copy 1", 3)
dev.print(width = 6, height = 6, horizontal = FALSE) # prints it
dev.off(dev.prev())
dev.off()

## End(Not run)