| x11 {grDevices} | R Documentation |
X11 starts a graphics device driver for the X Window System
(version 11). This can only be done on machines/accounts that have
access to an X server.
x11 is recognized as a synonym for X11.
X11(display = "", width, height, pointsize, gamma, bg, canvas,
fonts, xpos, ypos, title, type, antialias)
X11.options(..., reset = FALSE)
display |
the display on which the graphics window will appear. The default is to use the value in the user's environment variable DISPLAY. This is ignored (with a warning) if an X11 device is already open on another display. |
width, height |
the width and height of the plotting window, in
inches. If NA, taken from the resources and if
not specified there defaults to 7 inches. See also
‘Resources’. |
pointsize |
the default pointsize to be used. Defaults to 12. |
gamma |
the gamma correction factor. This value is used
to help ensure that the colours perceived are linearly related to
RGB values (see hsv). By default 1 (default
correction). |
bg |
colour, the initial background colour. Default
"transparent". |
canvas |
colour. The colour of the canvas, which is visible only
when the background colour is transparent. Should be a solid colour
(and any alpha value will be ignored). Default "white". |
fonts |
X11 font description strings into which weight, slant and size will be substituted. There are two, the first for fonts 1 to 4 and the second for font 5, the symbol font. See section ‘Fonts’. |
xpos, ypos |
integer: initial position of the top left corner of the
window, in pixels. Negative values are from the opposite corner,
e.g. xpos=-100 says the top right corner should be 100 pixels
from the right edge of the screen. If NA (the default),
successive devices are cascaded in 20 pixel steps from the top left.
See also ‘Resources’. |
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 (see the
file argument to postscript for further
details). How non-ASCII titles are handled is
implementation-dependent. |
type |
character string, one of "Xlib" (the only type
prior to R 2.7.0) or "cairo" or "nbcairo". The
latter two will only be available if the system was compiled with
support for cairo. Default "cairo" where available, otherwise
"Xlib". |
antialias |
for cairo types, the type of anti-aliasing (if any)
to be used. One of c("default", "none", "gray", "subpixel"). |
reset |
logical: should the defaults be reset to their defaults? |
... |
Any of the arguments to X11, plus colortype
and maxcubesize (see section ‘Colour Rendering’). |
The defaults for all of the arguments of X11 are set by
X11.options: the ‘Arguments’ section gives the
‘factory-fresh’ defaults.
The initial size and position are only hints, and may not be acted on by the window manager. Also, some systems (especially laptops) are set up to appear to have a screen of a different size to the physical screen.
Option type selects between two separate devices: R can be
built with support for neither, type = "Xlib" or both. Where
both are available, types "cairo" and "nbcairo" offer
type = "nbcairo" is the same device as type="cairo"
without buffering: which is faster will depend on the X11
connection. Both will be slower than type = "Xlib", especially
on a slow X11 connection as all the rendering is done on the machine
running R rather than in the X server.
All devices which use an X11 server (including the type =
"Xlib" versions of bitmap devices such as png) share
internal structures, which means that they must use the same
display and visual. If you want to change display, first close
all such devices.
This section applies only to type = "Xlib".
An initial/default font family for the device can be specified via
the fonts argument, but if a device-independent R graphics font
family is specified (e.g., via par(family=) in the graphics
package), the X11 device makes use of the X11 font database (see
X11Fonts) to convert the R graphics font family to an
X11-specific font family description.
X11 chooses fonts by matching to a pattern, and it is quite possible
that it will choose a font in the wrong encoding or which does not
contain glyphs for your language (particularly common in
iso10646-1 fonts).
The fonts argument is a two-element character vector, and the
first element will be crucial in successfully using
non-Western-European fonts. Settings that have proved useful include
"-*-mincho-%s-%s-*-*-%d-*-*-*-*-*-*-*" for CJK languages and
"-cronyx-helvetica-%s-%s-*-*-%d-*-*-*-*-*-*-*" for Russian.
For UTF-8 locales, the XLC_LOCALE databases provide mappings
between character encodings, and you may need to add an entry for your
locale (e.g. Fedora Core 3 lacked one for ru_RU.utf8).
The cairo-based device works directly with font family names such as
"Helvetica" which should be selected by par or
gpar. There are mappings for the three
device-independent font families, "sans" for a sans-serif font
(to "Helvetica"), "serif" for a serif font (to
"Times") and "mono" for a monospaced font (to
"Courier").
The font selection is handled by Pango (usually) or
cairo (on Mac OS X and perhaps elsewhere). Both make use of
fontconfig (http://wwww.fontconfig.org) to select fonts
and so the results depend on the fonts installed on the system running
R – setting the environmnent variable FC_DEBUG to 1 allows
some tracing of the selection process.
This works best when high-quality scalable fonts are installed, usually in Type 1 or TrueType formats: see the “R Installation and Administration Manual” for advice on how to obtain and install such fonts.
The standard X11 resource geometry can be used to specify the
window position and/or size, but will be overridden by values
specified as arguments or non-NA defaults set in
X11.options. The class looked for is R_x11. Note that
the resource specifies the width and height in pixels and not in
inches. See for example
http://web.mit.edu/answers/xwindows/xwindows_resources.html and
perhaps man X (or http://www.xfree86.org/current/X.7.html).
An example line in ‘~/.Xresources’ might be
R_x11*geometry: 900x900-0+0which specifies a 900 x 900 pixel window at the top right of the screen.
X11 supports several ‘visual’ types, and nowadays almost all
systems support ‘truecolor’ which X11 will use by
default. This uses a direct specification of any RGB colour up to the
depth supported (usually 8 bits per colour). Other visuals make use
of a palette to support fewer colours, only grays or even only
black/white. The palette is shared between all X11 clients, so it can
be necessary to limit the number of colours used by R.
Cairo-based devices currently support only ‘truecolor’ visuals. (Cairo 1.6 will support other visuals.)
The default for type="Xlib" is to use the best possible colour
model for the visual of the X11 server. This can be overridden by the
colortype argument of X11.options. Note: All
X11 and type = "Xlib" bmp, jpeg,
png and tiff devices share a colortype which is
set when the first device to be opened. To change the
colortype you need to close all open such devices, and
then use X11.options(colortype=).
The colortype types are tried in the order "true",
"pseudo", "gray" and "mono" (black or white
only). The values "pseudo" and "pseudo.cube" provide
colour strategies for a pseudocolor visual. The first strategy
provides on-demand colour allocation which produces exact colours until
the colour resources of the display are exhausted (when plotting will
fail). The second allocates (if possible) a standard colour cube, and
requested colours are approximated by the closest value in the cube.
With colortype equal to "pseudo.cube" or "gray"
successively smaller palettes are tried until one is completely
allocated. If allocation of the smallest attempt fails the device will
revert to "mono". For "gray" the search starts at 256
grays for a display with depth greater than 8, otherwise with half
the available colours. For "pseudo.cube" the maximum cube size
is set by X11.options(maxcolorsize=) and defaults to
256. With that setting the largest cube tried is 4 levels each for
RGB, using 64 colours in the palette.
Anti-aliasing is only supported for cairo-based devices, and applies to
graphics and to fonts. It is generally preferable for lines and text,
but can lead to undesirable effects for fills, e.g. for
image plots, and so is never used for fills.
antialias = "default" is in principle platform-dependent, but
seems most often equivalent to antialias = "gray".
This section describes the implementation of the conventions for graphics devices set out in the “R Internals Manual”.
type =
"Xlib", 0.01 otherwise.
type = "Xlib" circle radii are in pixels with
minimum one.
## Not run:
## put something this is your .Rprofile to customize the defaults
setHook(packageEvent("grDevices", "onLoad"),
function(...) grDevices::X11.options(width=8, height=6, xpos=0,
pointsize=10))
## End(Not run)