screen {graphics} | R Documentation

## Creating and Controlling Multiple Screens on a Single Device

### Description

`split.screen` defines a number of regions within the current device which can, to some extent, be treated as separate graphics devices. It is useful for generating multiple plots on a single device. Screens can themselves be split, allowing for quite complex arrangements of plots.

`screen` is used to select which screen to draw in.

`erase.screen` is used to clear a single screen, which it does by filling with the background colour.

`close.screen` removes the specified screen definition(s).

### Usage

    split.screen(figs, screen, erase = TRUE)
    screen(n = , new = TRUE)
    erase.screen(n = )
    close.screen(n, all.screens = FALSE)

### Arguments

`figs` | A two-element vector describing the number of rows and the number of columns in a screen matrix or a matrix with 4 columns. If a matrix, then each row describes a screen with values for the left, right, bottom, and top of the screen (in that order) in NDC units, that is 0 at the lower left coner of the device surface, and 1 at the upper right corner.
`screen` | A number giving the screen to be split. It defaults to the current screen if there is one, otherwise the whole device region.
`erase` | logical: should be selected screen be cleared?
`n` | A number indicating which screen to prepare for drawing (`screen`), erase (`erase.screen`), or close (`close.screen`). (`close.screen` will accept a vector of screen numbers.)
`new` | A logical value indicating whether the screen should be erased as part of the preparation for drawing in the screen.
`all.screens` | A logical value indicating whether all of the screens should be closed.

### Details

The first call to `split.screen` places R into split-screen mode. The other split-screen functions only work within this mode. While in this mode, certain other commands should be avoided (see the Warnings section below). Split-screen mode is exited by the command `close.screen(all = TRUE)`.

If the current screen is closed, `close.screen` sets the current screen to be the next larger screen number if there is one, otherwise to the first available screen.

### Value

`split.screen` returns a vector of screen numbers for the newly-created screens. With no arguments, `split.screen` returns a vector of valid screen numbers.
`screen` invisibly returns the number of the selected screen. With no arguments, `screen` returns the number of the current screen.
`close.screen` returns a vector of valid screen numbers.
`screen`, `erase.screen`, and `close.screen` all return `FALSE` if R is not in split-screen mode.

### Warnings

The recommended way to use these functions is to completely draw a plot and all additions (ie. points and lines) to the base plot, prior to selecting and plotting on another screen. The behavior associated with returning to a screen to add to an existing plot is unpredictable and may result in problems that are not readily visible.

These functions are totally incompatible with the other mechanisms for arranging plots on a device: `par(mfrow)`, `par(mfcol)` and `layout()`.

The functions are also incompatible with some plotting functions, such as `coplot`, which make use of these other mechanisms.

`erase.screen` will appear not to work if the background colour is transparent (as it is by default on most devices).

### References

Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.

### See Also

`par`, `layout`, `Devices`, `dev.*`

### Examples

    if (interactive()) {
    par(bg = "white")           # default is likely to be transparent
    split.screen(c(2,1))        # split display into two screens
    split.screen(c(1,3), screen = 2) # now split the bottom half into 3
    screen(1) # prepare screen 1 for output
    plot(10:1)
    screen(4) # prepare screen 4 for output
    plot(10:1)
    close.screen(all = TRUE)    # exit split-screen mode

    split.screen(c(2,1))        # split display into two screens
    split.screen(c(1,2),2)      # split bottom half in two
    plot(1:10)                  # screen 3 is active, draw plot
    erase.screen()              # forgot label, erase and redraw
    plot(1:10, ylab= "ylab 3")
    screen(1)                   # prepare screen 1 for output
    plot(1:10)
    screen(4)                   # prepare screen 4 for output
    plot(1:10, ylab="ylab 4")
    screen(1, FALSE)            # return to screen 1, but do not clear
    plot(10:1, axes=FALSE, lty=2, ylab="")  # overlay second plot
    axis(4)                     # add tic marks to right-hand axis
    title("Plot 1")
    close.screen(all = TRUE)    # exit split-screen mode
    }

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