[Rd] vignettes: problems with PDF compaction

[Michael Friendly]

[Env: OS: Win Xp; R 2.15.2; IDE: eclipse/StatET]

Each time I update my heplots package, I get warnings from R CMD check
on R-Forge,

* checking sizes of PDF files under ‘inst/doc’ ... WARNING
   ‘gs+qpdf’ made some significant size reductions:
      compacted ‘HE-examples.pdf’ from 739Kb to 366Kb

and upon submission to CRAN, a message from maintainers:

On CRAN now: but again there were warnings about significant size
reductions in PDF compaction, which should really be fixed on your end.

however, I am unable to find what to do to fix this on my end. In my 
package directory,
I have the vignette sources all under vignettes/, with copies of the 
.pdf and .Rnw
under inst/doc for historical reasons. [Q: can I now safely delete the 
copies under
inst/doc ?]

inst/doc/
HE-examples.pdf
HE-examples.Rnw
vignettes/
HE-examples.pdf
HE-examples.Rnw
HE-examples.bib
fig/
...

I have qpdf installed:
 > Sys.which(Sys.getenv("R_QPDF", "qpdf"))
qpdf
"c:\\Rtools\\bin\\qpdf.exe"
 >

but, if I try to run it on the vignettes/HE-examples.pdf file, nothing 
happens:

 > 
tools::compactPDF("C:/Documents/workspace/heplots/vignettes/HE-examples.pdf")
 >

Since vignettes are re-built from sources and then installed into 
inst/doc, I don't see why
PDF compaction cannot be run as part of the build process. That is, if
R CMD check --as-cran detects a problem, shouldn't there be some option for
R CMD build that would run gs+qpdf to correct it?

The idea of vignettes for R packages is a good thing, but, this problem 
(and others with vignettes) discourages me from using vignettes in 
packages, a bad thing.

-- 
Michael Friendly     Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University      Voice: 416 736-2100 x66249 Fax: 416 736-5814
4700 Keele Street    Web:   http://www.datavis.ca
Toronto, ONT  M3J 1P3 CANADA