The LaTeX file generated needs to contain the line
\usepackage{Sweave}, and if this is not present in the
Sweave source file (possibly in a comment), it is inserted by the
RweaveLatex driver. If stylepath = TRUE, a hard-coded
path to the file ‘Sweave.sty’ in the R installation is set in
place of Sweave. The hard-coded path makes the LaTeX file less
portable, but avoids the problem of installing the current version of
‘Sweave.sty’ to some place in your TeX input path. However, TeX
may not be able to process the hard-coded path if it contains spaces
(as it often will under Windows) or TeX special characters. The default for stylepath is now taken from the environment
variable SWEAVE_STYLEPATH_DEFAULT, or is FALSE it that is
unset or empty. If set, it should be exactly TRUE or
FALSE: any other values are taken as FALSE.
The simplest way for frequent Sweave users to ensure that
‘Sweave.sty’ is in the TeX input path is to add
‘R_HOME/share/texmf’ as a ‘texmf tree’ (‘root
directory’ in the parlance of the ‘MiKTeX settings’ utility).
By default, ‘Sweave.sty’ sets the width of all included graphics to:
\setkeys{Gin}{width=0.8\textwidth}.
This setting affects the width size option passed to the
\includegraphics{} directive for each plot file and in turn
impacts the scaling of your plot files as they will appear in your
final document.
Thus, for example, you may set width=3 in your figure chunk and
the generated graphics files will be set to 3 inches in
width. However, the width of your graphic in your final document will
be set to 0.8\textwidth and the height dimension will be
scaled accordingly. Fonts and symbols will be similarly scaled in the
final document.
You can adjust the default value by including the
\setkeys{Gin}{width=...} directive in your ‘.Rnw’ file
after the \begin{document} directive and changing the
width option value as you prefer, using standard LaTeX
measurement values.
If you wish to override this default behavior entirely, you can add a
\usepackage[nogin]{Sweave} directive in your preamble. In this
case, no size/scaling options will be passed to the
\includegraphics{} directive and the height and
width options will determine both the runtime generated graphic
file sizes and the size of the graphics in your final document.
‘Sweave.sty’ also supports the [noae] option, which
suppresses the use of the ae package, the use of which may
interfere with certain encoding and typeface selections. If you have
problems in the rendering of certain character sets, try this option.
As from R 3.1.0 it also supports the [inconsolata] option, to
render monospaced text in inconsolata, the font used by default
for R help pages.
The use of fancy quotes (see sQuote) can cause problems
when setting R output. Either set
options(useFancyQuotes = FALSE) or arrange that LaTeX is
aware of the encoding used (by a \usepackage[utf8]{inputenc}
declaration: Windows users of Sweave from Rgui.exe
will need to replace utf8 by cp1252 or similar) and
ensure that typewriter fonts containing directional quotes are used.
Some LaTeX graphics drivers do not include .png or .jpg
in the list of known extensions. To enable them, add something like
\DeclareGraphicsExtensions{.png,.pdf,.jpg} to the preamble of
your document or check the behavior of your graphics driver. When
both pdf and png are TRUE both files will be
produced by Sweave, and their order in the
DeclareGraphicsExtensions list determines which will be used by
pdflatex.