Re: Ghostscript/GhostPDL 9.22 Release Candidate 1

At 00:31 19/09/2017 +0900, Masamichi Hosoda wrote:

>When you create a PDF document using something like a TeX system
>you may include many small PDF files in the main PDF file.
>It is common for each of the small PDF files to use the same fonts.
>
>If the small PDF files contain embedded full font sets,
>the TeX system includes all of them in the main PDF.
>The main PDF contains duplicates of the same full sets of fonts.
>Therefore, `PDFDontUseFontObjectNum` can remove the duplicates.
>This may considerably reduce the main PDF-file's size.

And if you have multiple subsets, badly named (eg OpenOffice output) then 
you get a final PDF file where some of the text is missing or garbled.

There's no real way to tell the difference, at least by using the font 
object numbers we guarantee correct output.


>There is a tool for using this method of removing duplicate fonts.
>https://www.ctan.org/pkg/extractpdfmark

Not our tool, we don't claim you can do this. Building a tool round an 
unintentional side effect seems less than ideal.


>LilyPond has option `--bigpdfs` for unifying duplicate fonts in this method.

And your point is what ? That's not what the pdfwrite device is intended 
for, and we don't claim you can use it to do that.

As I said, if you think its that useful, then you can add the switch back 
in. In fact, provided you don't change SubsetFonts, the resulting file may 
well be smaller anyway, since the pdfwrite device will only embed that 
portion of each font (which you say is a
complete duplicate) so the resulting two fonts will be smaller than the 
original two fonts.

Risking incorrect output for the minimal benefit of a slightly smaller file 
seems unwise to me.

                 Ken