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windows {grDevices}

Windows graphics devices
Package: 
grDevices
Version: 
R 2.12.1

Description

A graphics device is opened. For windows, win.graph, x11 and X11 this is a graphics window on the current Windows display: the multiple names are for compatibility with other systems. win.metafile prints to a file and win.print to the Windows print system.

Usage

windows(width, height, pointsize, record, rescale, xpinch, ypinch,
        bg, canvas, gamma, xpos, ypos, buffered, title,
        restoreConsole, clickToConfirm, fillOddEven)

win.graph(width, height, pointsize)
x11(width, height, pointsize, bg, gamma, xpos, ypos, title)
X11(width, height, pointsize, bg, gamma, xpos, ypos, title)

win.metafile(filename = "", width = 7, height = 7, pointsize = 12,
             restoreConsole = TRUE)

win.print(width = 7, height = 7, pointsize = 12, printer = "",
          restoreConsole = TRUE)

Arguments

width, height
the (nominal) width and height of the canvas of the plotting window in inches. Default 7.
pointsize
the default pointsize of plotted text, interpreted as big points (1/72 inch). Values are rounded to the nearest integer: values less than or equal to zero are reset to 12, the default.
record
logical: sets the initial state of the flag for recording plots. Default FALSE.
rescale
character, one of c("R", "fit", "fixed"). Controls the action for resizing of the device. Default "R". See ‘Details’.
xpinch, ypinch
double. Pixels per inch, horizontally and vertically. Default NA_real_, which means to take the value from Windows.
bg
color. The initial background color. Default "transparent".
canvas
color. The color of the canvas which is visible when the background color is transparent. Should be a solid color (and any alpha value will be ignored). Default "white".
gamma
the gamma correction factor to assume for the display. This value is used to ensure that the colors perceived are linearly related to RGB values (see hsv). Default 1.
xpos, ypos
integer. Position of the top left of the window, in pixels. Negative values are taken from the opposite edge of the monitor. Missing values (the default) mean take the default from the ‘Rconsole’ file, which in turn defaults to xpos=-25, ypos=0: this puts the right edge of the window 25 pixels from the right edge of the monitor.
buffered
logical. Should the screen output be double-buffered? Default TRUE.
title
character string, up to 100 bytes. With the default "", a suitable title is created internally. A C-style format for an integer will be substituted by the device number.
filename
the name of the output file: it will be an enhanced Windows metafile, usually given extension ‘.emf’ or ‘.wmf’. Up to 511 characters are allowed. The page number is substituted if an integer format is included in the character string: see postscript for further details, and tilde-expansion (see path.expand is performed. (The result must be less than 600 characters long.) The default, "", means the clipboard.
printer
The name of a printer as known to Windows. The default causes a dialog box to come for the user to choose a printer.
restoreConsole
logical: see the ‘Details’ below. Defaults to FALSE for screen devices.
clickToConfirm
logical: if true confirmation of a new frame will be by clicking on the device rather than answering a problem in the console. Default TRUE.
fillOddEven
logical controlling the polygon fill mode: see polygon for details. Default TRUE.

Details

All these devices are implemented as variants of the same device.

All arguments of windows have defaults set by windows.options: the defaults given in the arguments section are the defaults for the defaults. These defaults also apply to the internal values of gamma, xpinch, ypinch, buffered and restoreConsole for win.graph, x11 and X11.

The size of a window is computed from information provided about the display: it depends on the system being configured accurately. By default a screen device asks Windows for the number of pixels per inch. This can be overridden (it is often wrong) by specifying xpinch and ypinch, most conveniently via windows.options. For example, a 13.3 inch 1280x800 screen (a typical laptop display) was reported as 96 dpi even though it is physically about 114 dpi.

If the filename is omitted (or specified as "" for a win.metafile device), the output is copied to the clipboard when the device is closed.

If a screen device is re-sized, the default behaviour ("R") is to redraw the plot(s) as if the new size had been specified originally. Using "fit" will rescale the existing plot(s) to fit the new device region, preserving the aspect ratio. Using "fixed" will leave the plot size unchanged, adding scrollbars if part of the plot is obscured.

A graphics window will never be created at more that 85% of the screen width or height, but can be resized to a larger size. For the first two rescale options the width and height are rescaled proportionally if necessary, and if rescale = "fit" the plot(s) are rescaled accordingly. If rescale = "fixed" the initially displayed portion is selected within these constraints, separately for width and height. In MDI mode, the limit is 85% of the MDI client region.

Using strwidth or strheight after a window has been rescaled (when using "fit") gives dimensions in the original units, but only approximately as they are derived from the metrics of the rescaled fonts (which are in integer sizes)

The displayed region may be bigger than the ‘paper’ size, and area(s) outside the ‘paper’ are coloured in the Windows application background colour. Graphics parameters such as "din" refer to the scaled plot if rescaling is in effect.

The different colours need to be distinguished carefully. Area(s) outside the device region is coloured in the Windows application background colour. The device region is coloured in the canvas colour. This is over-painted by the background colour of a plot when a new page is called for, but that background colour can be transparent (and is by default). One difference between setting the canvas colour and the background colour is that when a plot is saved the background colour is copied but the canvas colour is not. The argument bg sets the initial value of par("bg") in base graphics and gpar("fill") in grid graphics

Recorded plot histories are of class "SavedPlots". They have a print method, and a subset method. As the individual plots are of class "recordedplot" they can be replayed by printing them: see recordPlot. The active plot history is stored in variable .SavedPlots in the workspace.

When a screen device is double-buffered (the default) the screen is updated 100ms after last plotting call or every 500ms during continuous plotting. These times can be altered by setting options("windowsTimeout") to a vector of two integers before opening the device.

The fonts used for text drawn in a Windows device may be controlled in two ways. The file RHOME\etc<span class="rdoc-r-proper">R</span>devga can be used to specify mappings for par(font=) (in the graphics package). Alternatively, a device-independent R graphics font family can be specified (e.g., via par(family=) in the graphics package) and this will be mapped via the Windows font database (see windowsFonts).

Line widths as controlled by par(lwd=) are in multiples of 1/96inch. Multiples less than 1 are allowed, down to one pixel width.

pch="." with cex = 1 corresponds to a rectangle of sides the larger of one pixel and 0.01 inch.

For win.metafile only one plot is allowed per file, and Windows seems to disallow reusing the file. So the only way to allow multiple plots is to use a parametrized filename as in the example. The restoreConsole argument is a temporary fix for a problem in the current implementation of several Windows graphics devices, and is likely to be removed in an upcoming release. If set to FALSE, the console will not receive the focus after the new device is opened.

There is support for semi-transparent colours of lines, fills and text on the windows() device. These work for saving (from the ‘File’ menu) to PDF, PNG, BMP, JPEG and TIFF, but will be ignored if saving to Metafile and PostScript.

Values

A plot device is opened: nothing is returned to the R interpreter.

Conventions

This section describes the implementation of the conventions for graphics devices set out in the “R Internals Manual”.

  • The default device size is 7 inches square, although this is often incorrectly implemented by Windows.
  • Font sizes are in big points.
  • The default font family is Arial.
  • Line widths are as a multiple of 1/96 inch, with a minimum of one pixel.
  • The minimum radius of a circle is 1 pixel.
  • Colours are interpreted via the unprofiled colour mapping of the graphics card -- this is likely to be close to sRGB.

Gamma

PC displays map RGB numbers non-linearly to luminosities (and the eye/brain system also perceives non-linearly). For a typical PC display, a value of gamma of around 2.2 will result in the unit steps in the RGB values are being perceived as roughly equal.

Examples

## Not run:## A series of plots written to a sequence of metafiles
win.metafile("Rplot%02d.wmf", pointsize = 10)
## End(Not run)

Documentation reproduced from R 2.12.1. License: GPL-2.