postscript             package:graphics             R Documentation

PostScript Graphics

Description:

     'postscript' starts the graphics device driver for producing
     PostScript graphics.

     The auxiliary function 'ps.options' can be used to set and view
     (if called without arguments) default values for the arguments to
     'postscript'.

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")

     ps.options(paper, horizontal, width, height, family, encoding,
                pointsize, bg, fg,
                onefile = TRUE, print.it = FALSE, append = FALSE,
                reset = FALSE, override.check = FALSE)

Arguments:

    file: a character string giving the name of the file.  If it is
          '""', the output is piped to the command given by the
          argument 'command'. If it is '"|cmd"', the output is piped to
          the command given by 'cmd'.

          For use with 'onefile=FALSE' give a 'printf' format such as
          '"Rplot%03d.ps"' (the default in that case). 

   paper: the size of paper in the printer.  The choices are '"a4"',
          '"letter"', '"legal"' and '"executive"' (and these can be
          capitalized). Also, '"special"' can be used, when the 'width'
          and 'height' specify the paper size.  A further choice is
          '"default"', which is the default.  If this is selected, the
          papersize is taken from the option '"papersize"' if that is
          set and to '"a4"' if it is unset or empty.

horizontal: the orientation of the printed image, a logical. Defaults
          to true, that is landscape orientation on paper sizes with
          width less than height.

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.

  family: the font family to be used.  EITHER a single character string
          OR a character vector of length four or five.  See the
          section 'Families'.

encoding: the name of an encoding file. Defaults to "ISOLatin1.enc" in
          the 'R_HOME/afm' directory, which is used if the path does
          not contain a path separator.  An extension '".enc"' can be
          omitted.

pointsize: the default point size to be used.

      bg: the default background color to be used. If '"transparent"'
          (or an equivalent specification), no background is painted.

      fg: the default foreground color to be used.

 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 'DocumentMedia' comment.

pagecentre: logical: should the device region be centred on the page:
          defaults to true.

print.it: logical: should the file be printed when the device is
          closed?  (This only applies if 'file' is a real file name.)

 command: the command to be used for "printing".  Defaults to option
          '"printcmd"'; this can also be selected as '"default"'.

  append: logical; currently *disregarded*; just there for
          compatibility reasons.

reset, override.check: logical arguments passed to 'check.options'. 
          See the Examples.

   title: title string to embed in the file.

Details:

     'postscript' opens the file '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 'postscript' in two ways.

        1.  Setting 'print.it = TRUE' causes the command given in
           argument 'command' to be called with argument '"file"' when
           the device is closed. Note that the plot file is not deleted
           unless 'command' arranges to delete it.

        2.  'file=""' or 'file="|cmd"' can be used to print using a
           pipe on systems that support 'popen'.  Failure to open the
           command will probably be reported to the terminal but not to
           'popen', in which case close the device by 'dev.off'
           immediately.

     The postscript produced by R is EPS (_Encapsulated PostScript_)
     compatible, and can be included into other documents, e.g., into
     LaTeX, using '\includegraphics{<filename>}'.  For use in this way
     you will probably want to set 'horizontal = FALSE, onefile =
     FALSE, paper = "special"'.

     Most of the PostScript prologue used is taken from the R character
     vector '.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
     'namespace:graphics'.)

     'ps.options' needs to be called before calling 'postscript', and
     the default values it sets can be overridden by supplying
     arguments to 'postscript'.

Families:

     The argument 'family' specifies the font family to be used. In
     normal use it is one of '"AvantGarde"', '"Bookman"', '"Courier"',
     '"Helvetica"', '"Helvetica-Narrow"', '"NewCenturySchoolbook"',
     '"Palatino"' or '"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 'ghostscript')
     use the URW equivalents of these fonts, which are '"URWGothic"',
     '"URWBookman"', '"NimbusMon"', '"NimbusSan"', '"NimbusSanCond"',
     '"CenturySch"', '"URWPalladio"' and '"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, '"URWHelvetica" ==
     "NimbusSan"' and '"URWTimes" == "NimbusRom"' are also supported.

     It is also possible to specify '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 'dvips -Ppfb -j0' or the equivalent
     on your system. ('-j0' turns off font subsetting.)

     If the second form of argument '"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
     'R_HOME/afm'.  Thus the default Helvetica family can be specified
     by '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 'FontName' fields of the afm files.  The
     software including the PostScript plot file should either embed
     the font outlines (usually from '.pfb' or '.pfa' files) or use DSC
     comments to instruct the print spooler to do so.

     The '.afm' files for the first four fonts do not need to be in the
     correct encoding, but that for the symbol font must be.

     When 'family="ComputerModern"' is used, the italic/bold-italic
     fonts used are slanted fonts ('cmsl10' and 'cmbxsl10').  To use
     text italic fonts instead, use 'family = c("CM_regular_10.afm",
     "CM_boldx_10.afm", "cmti10.afm", "cmbxti10.afm",
     "CM_symbol_10.afm")'.

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 'text' are in that encoding.  However, the
     encoding used on machines running R may well be different, and by
     using the '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: '"WinAnsi.enc"' and '"MacRoman.enc"' correspond to the
     encodings normally used on Windows and MacOS (at least by Adobe),
     and '"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 ('"-"') 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.

Author(s):

     Support for Computer Modern fonts is based on a contribution by
     Brian D'Urso durso@hussle.harvard.edu.

References:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

See Also:

     'Devices', {'check.options' which is called from both 'ps.options'
     and 'postscript'}.

Examples:

     ## Not run: 
     # open the file "foo.ps" for graphics output
     postscript("foo.ps")
     # produce the desired graph(s)
     dev.off()              # turn off the postscript device
     postscript("|lp -dlw")
     # produce the desired graph(s)
     dev.off()              # plot will appear on printer

     # 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 
             y <- i 
             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")
     ## End(Not run)


     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)))

