\HeaderA{pdf}{PDF Graphics Device}{pdf}
\keyword{device}{pdf}
\begin{Description}\relax
\code{pdf} starts the graphics device driver for producing PDF
graphics.
\end{Description}
\begin{Usage}
\begin{verbatim}
pdf(file = ifelse(onefile, "Rplots.pdf", "Rplot%03d.pdf"),
    width = 6, height = 6, onefile = TRUE, family = "Helvetica",
    title = "R Graphics Output", fonts = NULL, version = "1.1",
    paper = "special", encoding, bg, fg, pointsize, pagecentre)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{file}] a character string giving the name of the file.
For use with \code{onefile=FALSE} give a C integer format such
as \code{"Rplot\%03d.pdf"} (the default in that case).
(See \code{\LinkA{postscript}{postscript}} for further details.)

\item[\code{width, height}] the width and height of the graphics region in
inches.
\item[\code{onefile}] logical: if true (the default) allow multiple figures
in one file.  If false, generate a file name containing the page
number.
\item[\code{family}] the font family to be used, see \code{\LinkA{postscript}{postscript}}.
\item[\code{title}] title string to embed in the file.
\item[\code{fonts}] a character vector specifying \R{} graphics font family
names for fonts which will be included in the PDF file.
\item[\code{version}] a string describing the PDF version that will be
required to view the output.  This is a minimum, and will be
increased (with a warning) if necessary.
\item[\code{paper}] the target paper size.  The choices are
\code{"a4"}, \code{"letter"}, \code{"legal"} (or \code{"us"}) and
\code{"executive"} (and these can be capitalized), or \code{"a4r"}
and \code{"USr"} for rotated (\sQuote{landscape}).
The default is \code{"special"}, which means that the \code{width}
and \code{height} specify the paper size.  A further choice is
\code{"default"}; if this is selected, the
papersize is taken from the option \code{"papersize"}
if that is set and as \code{"a4"} if it is unset or empty.
\item[\code{encoding}] the name of an encoding file.  See
\code{\LinkA{postscript}{postscript}} for details.
\item[\code{bg}] the default background color to be used.
\item[\code{fg}] the default foreground color to be used.
\item[\code{pointsize}] the default point size to be used.  Strictly
speaking, in bp, that is 1/72 of an inch, but approximately in points.
\item[\code{pagecentre}] logical: should the device region be centred on the
page? -- defaults to true, but is only relevant for
\code{paper != "special"}.
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
\code{pdf()} opens the file \code{file} and the PDF commands needed to
plot any graphics requested are sent to that file.

The \code{file} argument is interpreted as a C integer format as used
by \code{\LinkA{sprintf}{sprintf}}, with integer argument the page number.
The default gives files \file{Rplot001.pdf}, \dots, \file{Rplot999.pdf},
\file{Rplot1000.pdf}, \dots.

The \code{family} argument can be used to specify a PDF-specific
font family as the initial/default font for the device.

If a device-independent \R{} graphics font family is specified (e.g., via
\code{par(family=)} in the graphics package), the PDF device makes use
of the PostScript font mappings to convert the \R{} graphics font family
to a PDF-specific font family description.  (See the
documentation for \code{\LinkA{pdfFonts}{pdfFonts}}.)

\R{} does \emph{not} embed fonts in the PDF file, so it is only
straightforward to use mappings to the font families that can be
assumed to be available in any PDF viewer: \code{"Times"}
(equivalently \code{"serif"}), \code{"Helvetica"} (equivalently
\code{"sans"}), \code{"Courier"} (equivalently \code{"mono"}) and
\code{"Symbol"} (equivalently \code{"symbol"}).  Other families may be
specified, but it is the user's responsibility to ensure that these
fonts are available on the system and third-party software, e.g.,
ghostscript, may be required to embed the fonts so that the PDF can be
included in other documents (e.g., LaTeX).  The URW-based families
described for \code{\LinkA{postscript}{postscript}} can be used with viewers such
as GSView which are based on URW fonts.

See \code{\LinkA{postscript}{postscript}} for details of encodings, as the internal
code is shared between the drivers.  The native PDF encoding is given
in file \file{PDFDoc.enc}.

\code{pdf} writes uncompressed PDF.  It is primarily intended for
producing PDF graphics for inclusion in other documents, and
PDF-includers such as \code{pdftex} are usually able to handle
compression.

At present the PDF is fairly simple, with each page being represented
as a single stream.  The \R{} graphics model does not distinguish
graphics objects at the level of the driver interface.

The \code{version} argument declares the version of PDF that gets
produced.  The version must be at least 1.4 for semi-transparent
output to be understood, and at least 1.3 if CID fonts are to be used:
if these features are used the version number will be increased (with
a warning).  Specifying a low version number (as the default) is
useful if you want to produce PDF output that can be viewed on older
or non-Adobe PDF viewers.  (PDF 1.4 requires Acrobat 5 or later.)

Line widths as controlled by \code{par(lwd=)} are in multiples of
1/96 inch.  Multiples less than 1 are allowed.  \code{pch="."} with
\code{cex = 1} corresponds to a square of side 1/72 inch, which is
also the \sQuote{pixel} size assumed for graphics parameters such as
\code{"cra"}.
\end{Details}
\begin{Note}\relax
Acrobat Reader does not use the fonts specified but rather emulates
them from multiple-master fonts.  This can be seen in imprecise
centering of characters, for example the multiply and divide signs in
Helvetica.

Acrobat Reader 5.x and later can be extended by support for Asian and
(so-called) Central European fonts (the latter only for 7.x and
later), and this will be needed for the full use of encodings other
than Latin-1. See
\url{http://www.adobe.com/products/acrobat/acrrasianfontpack.html}.
\end{Note}
\begin{SeeAlso}\relax
\code{\LinkA{pdfFonts}{pdfFonts}},
\code{\LinkA{embedFonts}{embedFonts}},
\code{\LinkA{Devices}{Devices}},
\code{\LinkA{postscript}{postscript}}

More details of font families and encodings and especially handling
text in a non-Latin-1 encoding and embedding fonts can be found in

Paul Murrell and Brian Ripley (2006) Non-standard fonts in PostScript
and PDF graphics. \emph{R News}, 6(2):41--47.
\url{http://cran.r-project.org/doc/Rnews/Rnews_2006-2.pdf}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
## Not run: 
## Test function for encodings
TestChars <- function(encoding="ISOLatin1", ...)
{
    pdf(encoding=encoding, ...)
    par(pty="s")
    plot(c(-1,16), c(-1,16), type="n", xlab="", ylab="", xaxs="i", yaxs="i")
    title(paste("Centred chars in encoding", encoding))
    grid(17, 17, 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.
TestChars("ISOLatin2")
## this does not view properly in older viewers.
TestChars("ISOLatin2", family="URWHelvetica")
## works well for viewing in gs-based viewers, and often in xpdf.
## End(Not run)\end{ExampleCode}
\end{Examples}

