[Rd] pdf default version

[Kevin Wright]

R has had the ability to generate pdfs with transparent colors for a
couple of years now using pdf(..., version="1.4").

By default, Sweave uses just 'pdf' (without version 1.4), so a hack is
needed when using Sweave to create pdfs with transparent colors.  See
http://tolstoy.newcastle.edu.au/R/help/04/11/6655.html

I would find my work process simpler if R defaulted to generating PDFs
using version="1.4".  The help page for R's pdf command says there is
a risk of some older pdf viewers not being able to view newer PDFs.
Does anyone have a feeling for how big a risk this is?  I tried for a
while to search google for pdf metadata and the distribution of pdf
documents of different versions, but could find nothing useful to
report.

The PDF 1.4 specification appears to have been published in November, 2001.

Is updating pdf() to version="1.4" feasible?

Discussions on this topic will be watched with interest.

Kevin Wright