How to get Sweave to put graphics in separate folder AND name them after the Rnw file

Question

I've seen a few questions about this, but can't work out how to do what I want.

By default, Sweave creates graphics by concatenating the name of the Rnw file and the name of the graphic object label.

From this question (Make Sweave + RweaveHTML put all graphics in a specified folder) If I want all my graphics in the folder foo and to be named bar-graphic I can use

\SweaveOpts{prefix.string=foo/bar}

But how can I get the graphics in folder foo but named rnwfile-graphic ?

Answer 1

OK, this probably should be assigned to the innermost circle of hell, but the only way I know of to get the name of the currently running script is to use (abuse?) the source reference attached to functions. Consider this Sweave chunk in a file foo.Rnw

<<>>=
foo <- function(x) {x}
srcref <- attr(body(foo), "srcref")[[1]]
attr(srcref, "srcfile")$filename
@

When I process foo.Rnw with Sweave I get:

\begin{Schunk}
\begin{Sinput}
> foo <- function(x) {
+     x
+ }
> srcref <- attr(body(foo), "srcref")[[1]]
> attr(srcref, "srcfile")$filename
\end{Sinput}
\begin{Soutput}
[1] "foo.Rnw"
attr(,"encoding")
[1] "ASCII"
\end{Soutput}
\end{Schunk}

You could make a dummy function at the top of your Sweave file, pull out the $filename from the source reference, and process it to remove the extension, e.g.:

> sub("\\.Rnw", "", "foo.Rnw")
[1] "foo"

and then build up the string needed for prefix.string, with say

<<>>=
fname <- sub("\\.Rnw", "", attr(srcref, "srcfile")$filename)
prefix.string <- paste("foo/", fname, "-graphic", sep = "")
@

\SweaveOpts{prefix.string=\Sexpr{prefix.string}}

where prefix.string contains the built up path and prefix.

Here is a complete example:

<<>>=
foo <- function(x) {x}
srcref <- attr(body(foo), "srcref")[[1]]
attr(srcref, "srcfile")$filename
@

<<>>=
fname <- sub("\\.Rnw", "", attr(srcref, "srcfile")$filename)
prefix.string <- paste("foo/", fname, "-graphic", sep = "")
@

\SweaveOpts{prefix.string=\Sexpr{prefix.string}}

<<fig=TRUE>>=
plot(1:10)
@

that when processed by Sweave gives:

\begin{Schunk}
\begin{Sinput}
> foo <- function(x) {
+     x
+ }
> srcref <- attr(body(foo), "srcref")[[1]]
> attr(srcref, "srcfile")$filename
\end{Sinput}
\begin{Soutput}
[1] "foo.Rnw"
attr(,"encoding")
[1] "ASCII"
\end{Soutput}
\end{Schunk}

\begin{Schunk}
\begin{Sinput}
> fname <- sub("\\.Rnw", "", attr(srcref, "srcfile")$filename)
> prefix.string <- paste("foo/", fname, "-graphic", sep = "")
\end{Sinput}
\end{Schunk}



\begin{Schunk}
\begin{Sinput}
> plot(1:10)
\end{Sinput}
\end{Schunk}
\includegraphics{foo/foo-graphic-003}

Tweak that as you see fit.