I understood that the --compact-vignettes option in the Build Tools/Build Source Package -- R CMD check additional options would run
tools::compactPDF over the PDF files in inst/doc (and its subdirectories) to losslessly compress them (https://cran.r-project.org/doc/manuals/R-exts.html#Checking-and-building-packages). However, the warning I am getting says:
- checking sizes of PDF files under ‘inst/doc’ ... WARNING
‘gs+qpdf’ made some significant size reductions:
compacted ‘shiny_app_use.pdf’ from 3054Kb to 711Kb
consider running tools::compactPDF(gs_quality = "ebook") on these files
I need some guidance and would appreciate an explanation of what is happening.