The R Project SVN R

\name{postscript}

\alias{postscript}

\alias{ps.options}

%\alias{.PostScript.Options}

\alias{.ps.prolog}

\concept{encoding}

\title{PostScript Graphics}

\description{

  \code{postscript} starts the graphics device driver for producing

  PostScript graphics.

  The auxiliary function \code{ps.options} can be used to set and view

  (if called without arguments) default values for the arguments to

  \code{postscript}.

}

\synopsis{

postscript(file = ifelse(onefile, "Rplots.ps", "Rplot\%03d.ps"),

           onefile = TRUE, family, title = "R Graphics Output", \dots)

ps.options(\dots, reset = FALSE, override.check = FALSE)

}

%% The definitive doc is the source :-)

%% 	../../../main/devices.c  &   ../../../unix/devPS.c

\usage{

postscript(file = ifelse(onefile, "Rplots.ps", "Rplot\%03d.ps"),

           onefile = TRUE,

           paper, family, encoding, bg, fg,

           width, height, horizontal, pointsize,

           pagecentre, print.it, command, title = "R Graphics Output")

% paper, horizontal, width, height, family, pointsize, bg, fg)

ps.options(paper, horizontal, width, height, family, encoding,

           pointsize, bg, fg,

           onefile = TRUE, print.it = FALSE, append = FALSE,

           reset = FALSE, override.check = FALSE)

}

\arguments{

  \item{file}{a character string giving the name of the file.  If it is

    \code{""}, the output is piped to the command given by

    the argument \code{command}.

#ifdef unix

    If it is \code{"|cmd"}, the output is piped to the command given

    by \file{cmd}.

#endif

    For use with \code{onefile=FALSE} give a \code{printf} format such

    as \code{"Rplot\%03d.ps"} (the default in that case).

  }

%  \item{\dots}{further options for \code{postscript()}.}

  \item{paper}{the size of paper in the printer.  The choices are

    \code{"a4"}, \code{"letter"}, \code{"legal"} and

    \code{"executive"} (and these can be capitalized).

    Also, \code{"special"} can be used, when the \code{width}

    and \code{height} specify the paper size.  A further choice is

    \code{"default"}, which is the default.  If this is selected, the

    papersize is taken from the option \code{"papersize"}

    if that is set and to \code{"a4"} if it is unset or empty.}

  \item{horizontal}{the orientation of the printed image, a

    logical. Defaults to true, that is landscape orientation on paper

    sizes with width less than height.}

  \item{width, height}{the width and height of the graphics region in

    inches.  The default is to use the entire page less a 0.25 inch

    border on each side.}

  \item{family}{the font family to be used.  EITHER a single character

    string OR a character vector of length

    four or five.  See the section \sQuote{Families}.}

  \item{encoding}{the name of an encoding file. Defaults to

#ifdef unix

"ISOLatin1.enc"

#endif

#ifdef windows

"WinAnsi.enc"

#endif

    in the \file{R\_HOME/afm} directory, which is used

    if the path does not contain a path separator.  An extension

    \code{".enc"} can be omitted.}

  \item{pointsize}{the default point size to be used.}

  \item{bg}{the default background color to be used.

    If \code{"transparent"} (or an equivalent specification), no

    background is painted.}

  \item{fg}{the default foreground color to be used.}

  \item{onefile}{logical: if true (the default) allow multiple figures

    in one file.  If false, generate a file name containing the page

    number and use an EPSF header and no \code{DocumentMedia} comment.}

  \item{pagecentre}{logical: should the device region be centred on the

    page: defaults to true.}

  \item{print.it}{logical: should the file be printed when the device is

    closed?  (This only applies if \code{file} is a real file name.)}

  \item{command}{the command to be used for \dQuote{printing}.  Defaults to

    option \code{"printcmd"}; this can also be selected as

    \code{"default"}.}

  \item{append}{logical; currently \bold{disregarded}; just there for

    compatibility reasons.}

  \item{reset, override.check}{logical arguments passed to

    \code{\link{check.options}}.  See the Examples.}

  \item{title}{title string to embed in the file.}

}

\details{

  \code{postscript} opens the file \code{file} and the PostScript

  commands needed to plot any graphics requested are stored in that

  file.  This file can then be printed on a suitable device to obtain

  hard copy.

  A postscript plot can be printed via \code{postscript} in two ways.

  \enumerate{

    \item Setting \code{print.it = TRUE} causes the command given in

    argument \code{command} to be called with argument \code{"file"}

    when the device is closed.

    Note that the plot file is not deleted unless \code{command} arranges to

    delete it.

    \item \code{file=""} or \code{file="|cmd"} can be used to print

    using a pipe on systems that support \file{popen}.  Failure to open the

    command will probably be reported to the terminal but not to

    \file{popen}, in which case close the device by \code{dev.off}

    immediately.

  }

#ifdef windows

  Only the first of these will work on Windows, and the default

  \code{"printcmd"} is empty and will give an error if \code{print.it=TRUE}

  is used.  Suitable commands to spool a PostScript file to a printer

  can be found in \file{RedMon} suite available from

  \url{http://www.cs.wisc.edu/~ghost/index.html}.  The command will be run

  in a minimized window.   GSView 4.x provides

  \file{gsprint.exe} which may be even more convenient (it requires

  GhostScript version 6.0 or later).

#endif

  The postscript produced by \R is EPS (\emph{Encapsulated PostScript})

  compatible, and can be included into other documents, e.g., into

  LaTeX, using \code{\includegraphics{<filename>}}.  For use in this way

  you will probably want to set \code{horizontal = FALSE, onefile = FALSE,

    paper = "special"}.

  Most of the PostScript prologue used is taken from the \R character

  vector \code{.ps.prolog}.  This is marked in the output, and can be

  changed by changing that vector.  (This is only advisable for

  PostScript experts: the standard version is in

  \code{namespace:graphics}.)

  \code{ps.options} needs to be called before calling \code{postscript},

  and the default values it sets can be overridden by supplying

  arguments to \code{postscript}.

}

\section{Families}{

  The argument \code{family} specifies the font family to be used.

  In normal use it is one of \code{"AvantGarde"},

  \code{"Bookman"}, \code{"Courier"}, \code{"Helvetica"},

  \code{"Helvetica-Narrow"}, \code{"NewCenturySchoolbook"},

  \code{"Palatino"} or \code{"Times"}, and refers to the standard

  Adobe PostScript fonts of those names which are included (or cloned)

  in all common PostScript devices.

  Many PostScript emulators (including those based on

  \code{ghostscript}) use the URW equivalents of these fonts, which are

  \code{"URWGothic"}, \code{"URWBookman"}, \code{"NimbusMon"},

  \code{"NimbusSan"}, \code{"NimbusSanCond"}, \code{"CenturySch"},

  \code{"URWPalladio"} and \code{"NimbusRom"} respectively.  If your

  PostScript device is using URW fonts, you will obtain access to more

  characters and more appropriate metrics by using these names.  To make

  these easier to remember, \code{"URWHelvetica" == "NimbusSan"} and

  \code{"URWTimes" == "NimbusRom"} are also supported.

  It is also possible to specify \code{family="ComputerModern"}. This

  is intended to use with the Type 1 versions of the TeX CM fonts.  It

  will normally be possible to include such output in TeX or LaTeX

  provided it is processed with \code{dvips -Ppfb -j0} or the equivalent

  on your system. (\code{-j0} turns off font subsetting.)

  If the second form of argument \code{"family"} is used, it should be a

  character vector of four or five paths to Adobe Font Metric files for

  the regular, bold, italic, bold italic and (optionally) symbol fonts to

  be used.  If these paths do not contain the file separator, they are

  taken to refer to files in the \R directory \file{R\_HOME/afm}.  Thus the

  default Helvetica family can be specified by \code{family =

    c("hv______.afm",

    "hvb_____.afm", "hvo_____.afm", "hvbo____.afm", "sy______.afm")}.

  It is the user's responsibility to check that suitable fonts are made

  available, and that they contain the needed characters when

  re-encoded.  The fontnames used are taken from the \code{FontName}

  fields of the afm files.  The software including the PostScript plot

  file should either embed the font outlines (usually from \file{.pfb}

  or \file{.pfa} files) or use DSC comments to instruct the print

  spooler to do so.

}

\section{Encodings}{

  Encodings describe which glyphs are used to display the character codes

  (in the range 0--255).  By default \R uses ISOLatin1 encoding, and

  the examples for \code{\link{text}} are in that encoding.  However,

  the encoding used on machines running \R may well be different, and by

  using the \code{encoding} argument the glyphs can be matched to

  encoding in use.

  None of this will matter if only ASCII characters (codes 32--126) are

  used as all the encodings agree over that range.  Some encodings are

  supersets of ISOLatin1, too.  However, if accented and special

  characters do not come out as you expect, you may need to change the

  encoding.  Three other encodings are supplied with \R:

  \code{"WinAnsi.enc"} and \code{"MacRoman.enc"} correspond to the

  encodings normally used on Windows and MacOS (at least by Adobe), and

  \code{"PDFDoc.enc"} is the first 256 characters of the Unicode

  encoding, the standard for PDF.

  If you change the encoding, it is your responsibility to ensure that

  the PostScript font contains the glyphs used.  One issue here is the Euro

  symbol which is in the WinAnsi and MacRoman encodings but may well not

  be in the PostScript fonts.  (It is in the URW variants; it is not in

  the supplied Adobe Font Metric files.)

  There is one exception.  Character 45 (\code{"-"}) is always set

  as minus (its value in Adobe ISOLatin1) even though it is hyphen in

  the other encodings.  Hyphen is available as character 173 (octal

  0255) in ISOLatin1.

}

\references{

  Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)

  \emph{The New S Language}.

  Wadsworth \& Brooks/Cole.

}

\seealso{

  \code{\link{Devices}},

  {\code{\link{check.options}} which is called from both

    \code{ps.options} and \code{postscript}}.

}

\author{

  Support for Computer Modern fonts is based on a contribution by

  Brian D'Urso \email{durso@hussle.harvard.edu}.

}

\examples{

\dontrun{

# open the file "foo.ps" for graphics output

postscript("foo.ps")

# produce the desired graph(s)

dev.off()              # turn off the postscript device

#ifdef unix

postscript("|lp -dlw")

# produce the desired graph(s)

dev.off()              # plot will appear on printer

#endif

#ifdef windows

options(printcmd='redpr -P"\\\\markov\\lw"')

postscript(file=tempfile("Rps."), print.it=TRUE)

# produce the desired graph(s)

dev.off()              # send plot file to the printer

#endif

# for URW PostScript devices

postscript("foo.ps", family = "NimbusSan")

## for inclusion in Computer Modern TeX documents, perhaps

postscript("cm_test.eps", width = 4.0, height = 3.0,

           horizontal = FALSE, onefile = FALSE, paper = "special",

           family = "ComputerModern")

## The resultant postscript file can be used by dvips -Ppfb -j0.

## To test out encodings, you can use

TestChars <- function(encoding="ISOLatin1", family="URWHelvetica")

{

    postscript(encoding=encoding, family=family)

    par(pty="s")

    plot(c(0,15), c(0,15), type="n", xlab="", ylab="")

    title(paste("Centred chars in encoding", encoding))

    grid(15, 15, lty=1)

    for(i in c(32:255)) {

	x <- i %% 16

	y <- i %/% 16

	points(x, y, pch=i)

    }

    dev.off()

}

## there will be many warnings. We use URW to get a complete enough

## set of font metrics.

TestChars()

TestChars("ISOLatin2")

TestChars("WinAnsi")

}

\dontshow{

xx <- seq(0, 7, length=701)

yy <- sin(xx)/xx; yy[1] <- 1

plot(xx,yy)                     # produce the desired graph(s)

}

ps.options(bg = "pink")

utils::str(ps.options(reset = TRUE))

### ---- error checking of arguments: ----

ps.options(width=0:12, onefile=0, bg=pi)

# override the check for 'onefile', but not the others:

utils::str(ps.options(width=0:12, onefile=1, bg=pi,

                      override.check = c(FALSE,TRUE,FALSE)))

}

\keyword{device}