pdf {grDevices} | R Documentation |
pdf
starts the graphics device driver for producing PDF
graphics.
pdf(file = ifelse(onefile, "Rplots.pdf", "Rplot%03d.pdf"),
width, height, onefile, family, title, fonts, version,
paper, encoding, bg, fg, pointsize, pagecentre, colormodel,
useDingbats, useKerning)
file |
a character string giving the name of the file.
For use with |
width , height |
the width and height of the graphics region in
inches. The default values are |
onefile |
logical: if true (the default) allow multiple figures
in one file. If false, generate a file with name containing the page
number for each page. Defaults to |
family |
the font family to be used, see
|
title |
title string to embed as the |
fonts |
a character vector specifying R graphics font family
names for fonts which will be included in the PDF file. Defaults to
|
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. Defaults to |
paper |
the target paper size. The choices are
|
encoding |
the name of an encoding file. See
|
bg |
the initial background color to be used. Defaults to
|
fg |
the initial foreground color to be used. Defaults to
|
pointsize |
the default point size to be used. Strictly
speaking, in bp, that is 1/72 of an inch, but approximately in
points. Defaults to |
pagecentre |
logical: should the device region be centred on the
page? – is only relevant for |
colormodel |
a character string describing the color model:
currently allowed values are |
useDingbats |
logical. Should small circles be rendered
via the Dingbats font? Defaults to |
useKerning |
logical. Should kerning corrections be included in
setting text and calculating string widths? Defaults to |
All arguments except file
default to values given by
pdf.options()
. The ultimate defaults are quoted in the
arguments section.
pdf()
opens the file file
and the PDF commands needed to
plot any graphics requested are sent to that file.
The file
argument is interpreted as a C integer format as used
by sprintf
, with integer argument the page number.
The default gives files ‘Rplot001.pdf’, ..., ‘Rplot999.pdf’,
‘Rplot1000.pdf’, ....
The 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
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 pdfFonts
.)
R does 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: "Times"
(equivalently "serif"
), "Helvetica"
(equivalently
"sans"
) and "Courier"
(equivalently "mono"
).
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): see
embedFonts
. The URW-based families described for
postscript
can be used with viewers
set up to use URW fonts, which is usual with those based on
xpdf
or Ghostscript.
Since embedFonts
makes use of Ghostscript, it should be
able to embed the URW-based families for use with other viewers.
See postscript
for details of encodings, as the internal
code is shared between the drivers. The native PDF encoding is given
in file ‘PDFDoc.enc’.
pdf
writes uncompressed PDF. It is primarily intended for
producing PDF graphics for inclusion in other documents, and
PDF-includers such as pdftex
are usually able to handle
compression.
The PDF produced 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 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 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 par(lwd=)
are in multiples of
1/96 inch. Multiples less than 1 are allowed. pch="."
with
cex = 1
corresponds to a square of side 1/72 inch, which is
also the ‘pixel’ size assumed for graphics parameters such as
"cra"
.
The paper
argument sets the /MediaBox
entry in the file,
which defaults to width
by height
. If it is set to
something other than "special"
, a device region of the
specified size is (by default) centred on the rectangle given by the
paper size: if either width
or height
is less
than 0.1
or too large to give a total margin of 0.5 inch, it is
reset to the corresponding paper dimension minus 0.5. Thus if you
want the default behaviour of postscript
use
pdf(paper="a4r", width=0, height=0)
to centre the device region
on a landscape A4 page with 0.25 inch margins.
When the background colour is fully transparent (as is the initial default value), the PDF produced does not paint the background. Almost all PDF viewers will use a white canvas so the visual effect is if the background were white. This will not be the case when printing onto coloured paper, though.
The default color model is RGB, and model "gray"
maps RGB
colors to greyscale using perceived luminosity (biased towards green).
"cmyk"
outputs in CMYK colorspace. Nothing in R specifies the
interpretation of the RGB or CMYK color spaces, and the simplest
possible conversion to CMYK is used
(http://en.wikipedia.org/wiki/CMYK_color_model#Mapping_RGB_to_CMYK).
This section describes the implementation of the conventions for graphics devices set out in the “R Internals Manual”.
The default device size is 7 inches square.
Font sizes are in big points.
The default font family is Helvetica.
Line widths are as a multiple of 1/96 inch, with no minimum.
Circles of any radius are allowed. Unless useDingbats =
FALSE
, opaque circles of less than 10 big
points radius are rendered using char 108 in the Dingbats font:
all semi-transparent and larger circles using a Bézier
curve for each quadrant.
Colours are interpreted by the viewing/printing application.
If you see problems with postscript output, so remember that the problem is much more likely to be in your viewer as in R. Try another viewer if possible. Symptoms for which the viewer has been at fault are apparent grids on image plots (turn off graphics anti-aliasing in your viewer if you) and missing or incorrect glyphs in text (viewers silently doing font substitution).
Unfortunately the default viewers on most Linux and Mac OS X systems have these problems, and no obvious way to turn off graphics anti-aliasing.
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. This can be circumvented by embedding fonts where possible. Most other viewers substitute fonts, e.g. URW fonts for the standard Helvetica and Times fonts, and these too often have different font metrics from the true fonts.
Acrobat Reader 5.x and later can be extended by support for Asian and (so-called) Central European fonts, and these will be needed for the full use of encodings other than Latin-1. See http://www.adobe.com/products/acrobat/acrrasianfontpack.html for Reader 6.x to 8.x, and http://www.adobe.com/downloads/updates for 9.x.
On some systems the default plotting character pch = 1
is
displayed in some PDF viewers incorrectly as a "q"
character. (These seem to be viewers based on the ‘poppler’ PDF
rendering library). This may be due to incorrect or incomplete mapping
of font names to those used by the system. Adding the following lines
to ‘~/.fonts.conf’ or ‘/etc/fonts/local.conf’ may circumvent
this problem.
<alias binding="same"> <family>ZapfDingbats</family> <accept><family>Dingbats</family></accept> </alias>
pdfFonts
, pdf.options
,
embedFonts
,
Devices
,
postscript
.
cairo_pdf
and (on Mac OS X only) quartz
for other devices that can produce PDF.
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. R News, 6(2):41–47. http://cran.r-project.org/doc/Rnews/Rnews_2006-2.pdf.
## 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)