[R] vignettes: .png graphics or pre-compiled .pdf

[Michael Friendly]

Achim Zeileis wrote:
> On Fri, 13 Nov 2009, Michael Friendly wrote:
>
>> Alternatively, is there a way to generate .png graphs from the .Rnw 
>> file so that those are used in building
>> the .pdf for the package?  AFAICS, \SweaveOpts{} offers only the 
>> choices of eps/pdf = {TRUE/FALSE}.
>
> Yes, but you can call the png() device yourself within the code chunk
>
> <<>>=
> png(file = "fig1.png", ...)
> ...
> dev.off()
> @
>
> and then put
>
> \includegraphics{fig1}
>
> manually into the LaTeX. It's certainly not as nice as Sweave's 
> automatic handling of figures but will work and still keep the file 
> self-contained.
> Z
>
Thanks, Achim

This works, but has the infelicitous effect that both the png() call and 
dev.off(), with its output appear in the vignette (with echo=TRUE)

% do .png manually ...
<<fig1cpng, fig=TRUE, pdf=FALSE, eval=TRUE, echo=TRUE, debug=TRUE, 
results=verbatim, include=FALSE>>=
png(file="figs/fig-fig1c.png", width=4, height=4, units="in", res=72)
 # plot stuff ...
dev.off()
@

I suppose I could break this up into 3 chunks as follows, but is there 
some other way, either with R or LaTeX constructs?

<<echo=FALSE>>=
png(file="figs/fig-fig1c.png", width=4, height=4, units="in", res=72)
@
<<fig1cpng, fig=TRUE, pdf=FALSE, eval=TRUE, echo=TRUE, debug=TRUE, 
results=verbatim, include=FALSE>>=
# plot stuff  ...
@
<<echo=FALSE>>=
dev.off()
@


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Michael Friendly     Email: friendly AT yorku DOT ca 
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