[Rd] Failure to get compactPDF to compact a pdf file

[John Maindonald]

Quoting from the R-2.14.1 help page for compactPDF:
"
This by default makes use of 'qpdf', available from <URL:
    http://qpdf.sourceforge.net/> (including as a Windows binary) and
    included with the CRAN Mac OS X distribution of R.  If 'gs_cmd' is
    non-empty, GhostScript will used instead.
"

The defaults are:
compactPDF(paths, qpdf = Sys.getenv("R_QPDF", "qpdf"),
               gs_cmd = Sys.getenv("R_GSCMD", ""),
               gs_quality = c("printer", "ebook", "screen"),
               gs_extras = character())

> Sys.getenv("R_QPDF", "qpdf")
[1] "/Library/Frameworks/R.framework/Resources/bin/qpdf"
> Sys.getenv("R_GSCMD", "")
[1] ""
> 

Thus, as far as I can see, compactPDF is set up (on my system) to use qpdf to compress.

I take it then that the "Writing R Extensions manual [2.14.1 (2011-12-22)] is anticipating what is in R-devel:
"
The --compact-vignettes option will run tools::compactPDF over the PDF files in inst/doc (and its subdirectories) to losslessly compress them. This is not enabled by default (it can be selected by environment variable _R_BUILD_COMPACT_VIGNETTES_) and needs qpdf(http://qpdf.sourceforge.net/) to be available.
"

John Maindonald             email: john.maindonald at anu.edu.au
phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
Centre for Mathematics & Its Applications, Room 1194,
John Dedman Mathematical Sciences Building (Building 27)
Australian National University, Canberra ACT 0200.
http://www.maths.anu.edu.au/~johnm

On 24/01/2012, at 11:22 PM, Prof Brian Ripley wrote:

> On 24/01/2012 08:30, John Maindonald wrote:
>> I am failing to get compactPDF to make any change to a pdf file
>> that, a/c to the message from the CRAN upload site, can be very
>> substantially compacted.  Any ideas what may be wrong?
> 
> AFAICS you are quoting a message from R-devel, which tries to find 'gs' for you.  In R 2.14.1 you need to tell compactPDF where it is (assuming you do have it installed): see its help.
> 
>> I have also tried recreating the pdf file.  I also tried
>> R CMD build --resave-data --compact-vignettes DAAG
> 
> Again, in R-devel you can do R CMD build --compact-vignettes=gs (assuming that is in your path or R_GSCMD is set), but not in R 2.14.1.
> 
> But I have already told you directly (and been ignored) that the problem is the excessive resolution of the embedded bitmap image which needs to be down-sampled.
> 
> 
>> The data files compact alright (but I get the 'significantly better compression'
>> warning message that might suggest that this is not happening), but the pdf
>> file appears to go into the package unmodified.
>> 
>> <<<<
>>> tools::compactPDF('/Users/johnm/packages/DAAG/inst/doc/', gs_quality = "ebook")
>>> dir('/Users/johnm/packages/DAAG/inst/doc/')
>> [1] "rockArt.pdf"
>>> sessionInfo()
>> R version 2.14.1 (2011-12-22)
>> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>> 
>> locale:
>> [1] C
>> 
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>> 
>> loaded via a namespace (and not attached):
>> [1] tools_2.14.1
>>>>>> 
>> 
>>> From the Unix command line:
>> jhm:doc johnm$ ls -lt /Users/johnm/packages/DAAG/inst/doc
>> total 1368
>> -rw-r--r--@ 1 johnm  staff  696762  2 Aug 12:35 rockArt.pdf
>> 
>> Message from the CRAN upload site:
>> 
>> * checking sizes of PDF files under ‘inst/doc’ ... NOTE
>> ‘gs’ made some significant size reductions:
>>    compacted ‘rockArt.pdf’ from 680Kb to 58Kb
>> consider running tools::compactPDF(gs_quality = "ebook") on these files
>> 
>> John Maindonald             email: john.maindonald at anu.edu.au
>> phone : +61 2 (6125)3473    fax  : +61 2(6125)5549
>> Centre for Mathematics&  Its Applications, Room 1194,
>> John Dedman Mathematical Sciences Building (Building 27)
>> Australian National University, Canberra ACT 0200.
>> http://www.maths.anu.edu.au/~johnm
>> 
>> ______________________________________________
>> R-devel at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-devel
> 
> 
> -- 
> Brian D. Ripley,                  ripley at stats.ox.ac.uk
> Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
> University of Oxford,             Tel:  +44 1865 272861 (self)
> 1 South Parks Road,                     +44 1865 272866 (PA)
> Oxford OX1 3TG, UK                Fax:  +44 1865 272595