| par {graphics} | R Documentation |
par can be used to set or query graphical parameters.
Parameters can be set by specifying them as arguments to par in
tag = value form, or by passing them as a list of tagged
values.
par(..., no.readonly = FALSE) <highlevel plot> (..., <tag> = <value>)
... |
arguments in tag = value form, or a list of tagged
values. The tags must come from the graphical parameters described
below. |
no.readonly |
logical; if TRUE and there are no other
arguments, only parameters are returned which can be set by a
subsequent par() call. |
Parameters are queried by giving one or more character vectors to
par.
par() (no arguments) or par(no.readonly=TRUE) is used to
get all the graphical parameters (as a named list). Their
names are currently taken from the unexported variable .Pars.
R.O. indicates read-only arguments: These
may only be used in queries and cannot be set. ("cin",
"cra", "csi", "cxy" and "din" are always
read-only, and "gamma" is on most devices.)
There are several parameters can only be set by a call to par():
"ask",
"fig", "fin",
"lheight",
"mai", "mar", "mex",
"mfcol", "mfrow", "mfg",
"new",
"oma", "omd", "omi",
"pin", "plt", "ps", "pty",
"usr",
"xlog", "ylog"
The remaining parameters can also be set as arguments (often via
...) to high-level plot functions such as
plot.default, plot.window,
points, lines, abline,
axis, title, text,
mtext, segments, symbols,
arrows, polygon, rect,
box, contour, filled.contour
and image. Such settings will be active during the
execution of the function, only. However, see the comments on
bg and cex, which may be taken as arguments to certain
plot functions rather than as graphical parameters.
The meaning of ‘character size’ is not well-defined: this is
set up for the device taking pointsize into account but often
not the actual font family in use. It can be considered to be an
estimate of the size of character M in a proportionally-spaced
font.
When parameters are set, their former values are returned in an
invisible named list. Such a list can be passed as an argument to
par to restore the parameter values.
Use par(no.readonly = TRUE) for the full list of parameters
that can be restored.
When just one parameter is queried, the value of that parameter
is returned as (atomic) vector. When two or more parameters are
queried, their values are returned in a list, with the list names
giving the parameters.
Note the inconsistency: setting one parameter returns a list, but
querying one parameter returns a vector.
adjadj determines the way in
which text strings are justified. A value of 0 produces
left-justified text, 0.5 centered text and 1
right-justified text. (Any value in [0, 1] is allowed, and
on most devices values outside that interval will also work.)
Note that the adj argument of text also
allows adj = c(x, y) for different adjustment in x- and y-
direction.annFALSE, high-level plotting
functions calling plot.default do not annotate the
plots they produce with axis titles and overall titles. The
default is to do annotation.askTRUE (and the R session is
interactive) the user is asked for input, before a new figure is
drawn. As this applies to the device, it also affects output by
packages grid and lattice. It can be set even on
non-screen devices.bgpar() it also sets new=FALSE.
A description of how colors are specified is given below.
Note that some graphics functions such as
plot.default and points have an
argument of this name with a different meaning.btybox which is drawn about plots. If bty is one of
"o", "l", "7", "c", "u", or
"]" the resulting box resembles the corresponding upper
case letter. A value of "n" suppresses the box.cexplot.default have an argument of this name
which multiplies this graphical parameter.cex.axiscex.
(Some functions such as points accept a vector of values
which are recycled. Other uses will take just the first value if
a vector of length greater than one is supplied.)
cex.labcex.cex.maincex.cex.subcex.cin(width, height) in inches.collines accept a vector of values
which are recycled. Other uses will take just the first value if
a vector of length greater than one is supplied.)
col.axiscol.labcol.maincol.subcra(width, height) in “rasters” (pixels).crtsrt which does string rotation.csicxy(width, height) in user coordinate units.
par("cxy") is par("cin")/par("pin") scaled to user
coordinates.
Note that c(strwidth(ch), strheight(ch)) for
a given string ch is usually much more precise.din(width,height), in inches.errfamily"" which means that the
default device fonts will be used.
Standard values are "serif", "sans",
"mono", and "symbol" and the Hershey
font families are also available. (Different devices
may define others, and some devices will ignore this setting
completely.) This can be specified inline for
text.fgpar() this also sets
parameter col to the same value.
A description of how colors are specified is given below.
figc(x1, x2, y1,
y2) which gives the (NDC) coordinates of the figure region in
the display region of the device. If you set this, unlike S, you
start a new plot, so to add to an existing plot use
new=TRUE as well.fin(width,height), in inches. If you set this, unlike S, you
start a new plot.fontfamily to choose different sets of 5 fonts.font.axisfont.labfont.mainfont.subgammagamma
to hsv. This is only accepted if the current device
has support for changing the gamma correction: currently only
windows and quartz do. (X11 has support for
setting the gamma correction when opening the device, but not for
changing it.)labc(x, y, len)
which modifies the default way that axes are annotated. The values of
x and y give the (approximate) number of tickmarks
on the x and y axes and len specifies the label length. The
default is c(5, 5, 7). Note that this only affects the way
the parameters xaxp and yaxp are set when the user
coordinate system is set up, and is not consulted when axes are drawn.
len is unimplemented in R.las
Note that other string/character rotation (via argument srt
to par) does not affect the axis labels.
lend0"round" mean rounded line caps
[default];1"butt" mean butt line caps;2"square" mean square line caps.lheightljoin0"round" mean rounded line joins
[default];1"mitre" mean mitred line joins;2"bevel" mean bevelled line joins.lmitrelty"blank", "solid",
"dashed", "dotted", "dotdash",
"longdash", or "twodash", where "blank" uses
‘invisible lines’ (i.e., doesn't draw them).
Alternatively, a string of up to 8 characters (from c(1:9,
"A":"F")) may be given, giving the length of line segments
which are alternatively drawn and skipped. See section
‘Line Type Specification’ below.
Some functions such as lines accept a vector of values
which are recycled. Other uses will take just the first value if
a vector of length greater than one is supplied.
lwd1. The interpretation is device-specific,
and some devices do not implement line widths less than one.
(Some functions such as lines accept a vector of values
which are recycled. Other uses will take just the first value if
a vector of length greater than one is supplied.)
maic(bottom,
left, top, right) which gives the margin size specified in
inches.marc(bottom,
left, top, right) which gives the number of lines of margin to be
specified on the four sides of the plot.
The default is c(5, 4, 4, 2) + 0.1.mexmex is a character size expansion factor
which is used to describe coordinates in the margins of plots.
Note that this does not change the font size, rather specifies the
size of font used to convert between mar and mai,
and between oma and omi.
mfcol, mfrowc(nr, nc).
Subsequent figures will be drawn in an nr-by-nc
array on the device by columns (mfcol), or
rows (mfrow), respectively.
In a layout with exactly two rows and columns the base value of
"cex" is reduced by a factor of 0.83: if there are three or
more of either rows or columns, the reduction factor is 0.66.
Consider the alternatives, layout and
split.screen.
mfgc(i, j)
where i and j indicate which figure in an array of
figures is to be drawn next (if setting) or is being drawn (if
enquiring). The array must already have been set by mfcol
or mfrow.
For compatibility with S, the form c(i, j, nr, nc) is also
accepted, when nr and nc should be the current
number of rows and number of columns. Mismatches will be ignored,
with a warning.
mgpmex units) for the axis
title, axis labels and axis line.
The default is c(3, 1, 0).mkhpch is an integer.
Completely ignored currently.
newFALSE. If set to
TRUE, the next high-level plotting command (actually
plot.new) should not clean the frame before
drawing “as if it was on a new device”.omac(bottom, left, top,
right) giving the size of the outer margins in lines of text.omdc(x1, x2, y1, y2)
giving the outer margin region in NDC (= normalized device
coordinates), i.e., as fraction (in [0,1]) of the device
region.omic(bottom, left, top,
right) giving the size of the outer margins in inches.pchpoints for possible values and their interpretation.
pin(width,height),
in inches.pltc(x1, x2, y1, y2)
giving the coordinates of the plot region as fractions of the
current figure region.pspointsize argument of most devices, this does not change
the relationship between mar and mai (nor oma
and omi), but it does scale cin and csi.
What is meant by ‘pointsize’ is device-specific, but most devices mean a multiple of 1bp, that is 1/72 of an inch.
pty"s" generates a square plotting region and
"m" generates the maximal plotting region.smosrtcrt.
tcktck >= 0.5 it is interpreted as a fraction of the
relevant side, so if
tck = 1 grid lines are drawn. The default setting
(tck = NA) is to use tcl = -0.5 (see below).tcl-0.5;
setting tcl = NA sets tck = -0.01 which is S' default.usrc(x1, x2, y1, y2)
giving the extremes of the user coordinates of the plotting
region. When a logarithmic scale is in use (i.e.,
par("xlog") is true, see below), then the x-limits will be
10 ^ par("usr")[1:2]. Similarly for the y-axis.
xaxpc(x1, x2, n) giving
the coordinates of the extreme tick marks and the number of
intervals between tick-marks when par("xlog") is false.
Otherwise, when log coordinates are active, the three
values have a different meaning: For a small range, n is
negative, and the ticks are as in the linear case,
otherwise, n is in 1:3, specifying a case number,
and x1 and x2 are the lowest and highest power of 10
inside the user coordinates, 10 ^ par("usr")[1:2]. (The
"usr" coordinates are log10-transformed here!)
See axTicks() for a pure R implementation of this.
This parameter is reset when a user coordinate system is set up,
for example by starting a new page or by calling
plot.window or setting par("usr"): n
is taken from par("lab"). It affects the default behaviour
of subsequent calls to axis for sides 1 or 3.
xaxs"r", "i",
"e", "s", "d". The styles are generally
controlled by the range of data or xlim, if given.
Style "r" (regular) first extends the data range by 4
percent and then finds an axis with pretty labels that fits within
the range.
Style "i" (internal) just finds an axis with pretty labels
that fits within the original data range.
Style "s" (standard) finds an axis with pretty labels
within which the original data range fits.
Style "e" (extended) is like style "s", except that
it is also ensures that there is room for plotting symbols within
the bounding box.
Style "d" (direct) specifies that the current axis should
be used on subsequent plots.
(Only "r" and "i" styles are currently
implemented)xaxt"n" suppresses plotting of the axis. The
standard value is "s": for compatibility with S values
"l" and "t" are accepted but are equivalent to
"s": any value other than "n" implies plotting.xloglog in
plot.default). If TRUE, a logarithmic scale
is in use (e.g., after plot(*, log = "x")).
For a new device, it defaults to FALSE, i.e., linear scale.xpdNA.
If FALSE, all plotting is clipped to the plot region, if
TRUE, all plotting is clipped to the figure region, and if
NA, all plotting is clipped to the device region.yaxpc(y1, y2, n) giving
the coordinates of the extreme tick marks and the number of
intervals between tick-marks unless for log coordinates, see
xaxp above.yaxsxaxs above.yaxt"n" suppresses plotting.ylogxlog above.
Colors can be specified in several different ways. The simplest way is
with a character string giving the color name (e.g., "red"). A
list of the possible colors can be obtained with the function
colors. Alternatively, colors can be specified directly in
terms of their RGB components with a string of the form "#RRGGBB"
where each of the pairs RR, GG, BB consist of two
hexadecimal digits giving a value in the range 00 to FF.
Colors can also be specified by giving an index into a small table of
colors, the palette. This provides compatibility with
S. Index 0 corresponds to the background color.
Additionally, "transparent" or (integer) NA is
transparent, useful for filled areas (such as the background!),
and just invisible for things like lines or text.
The functions rgb, hsv, hcl,
gray and rainbow
provide additional ways of generating colors.
Line types can either be specified by giving an index into a small
built-in table of line types (1 = solid, 2 = dashed, etc, see
lty above) or directly as the lengths of on/off stretches of
line. This is done with a string of an even number (up to eight)
of characters, namely non-zero
(hexadecimal) digits which give the lengths in consecutive positions
in the string. For example, the string "33" specifies three
units on followed by three off and "3313" specifies three units
on followed by three off followed by one on and finally three off.
The ‘units’ here are (on most devices) proportional to
lwd, and with lwd = 1 are in pixels or points.
The five standard dash-dot line types (lty = 2:6) correspond to
c("44", "13", "1343", "73", "2262").
Note that NA is not a valid value for lty.
Prior to R 2.4.0, zero hex digits were accepted and handled in a
device-dependent way, e.g. X11() mapped them to one, pdf()
regarded zero as terminating the string and windows() gave a
zero-length stretch.
The effect of restoring all the (settable) graphics parameters as
in the examples is hard to predict if the device has been resized.
Several of them are attempting to set the same things in different
ways, and those last in the alphabet will win. In particular, the
settings of mai, mar, pin, plt and
pty interact, as do the outer margin settings, the figure
layout and figure region size.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
Murrell, P. (2005) R Graphics. Chapman & Hall/CRC Press.
plot.default for some high-level plotting parameters;
colors;
options for other setup parameters;
graphic devices x11, postscript and
setting up device regions by layout and
split.screen.
op <- par(mfrow = c(2, 2), # 2 x 2 pictures on one plot
pty = "s") # square plotting region,
# independent of device size
## At end of plotting, reset to previous settings:
par(op)
## Alternatively,
op <- par(no.readonly = TRUE) # the whole list of settable par's.
## do lots of plotting and par(.) calls, then reset:
par(op)
par("ylog") # FALSE
plot(1 : 12, log = "y")
par("ylog") # TRUE
plot(1:2, xaxs = "i") # 'inner axis' w/o extra space
par(c("usr", "xaxp"))
( nr.prof <-
c(prof.pilots=16,lawyers=11,farmers=10,salesmen=9,physicians=9,
mechanics=6,policemen=6,managers=6,engineers=5,teachers=4,
housewives=3,students=3,armed.forces=1))
par(las = 3)
barplot(rbind(nr.prof)) # R 0.63.2: shows alignment problem
par(las = 0)# reset to default
## 'fg' use:
plot(1:12, type = "b", main="'fg' : axes, ticks and box in gray",
fg = gray(0.7), bty="7" , sub=R.version.string)
ex <- function() {
old.par <- par(no.readonly = TRUE) # all par settings which
# could be changed.
on.exit(par(old.par))
## ...
## ... do lots of par() settings and plots
## ...
invisible() #-- now, par(old.par) will be executed
}
ex()