[pdftex] pdftex core dump when including certain pdf files

Werner LEMBERG wl at gnu.org
Wed Jul 20 08:05:14 CEST 2016

> Did you try to merge different font subsets into one (subsetted fonts
> already exist in the files)

Yes, by including PDF snippets into a larger texinfo document created
by pdftex (or xetex).  I tried then to execute

  ps2pdf pdftex-output.pdf out.pdf

which indeed reduces the file size and the number of subsetted fonts
by 30%, but there is a problem that makes all links disappear...  We
have to further investigate.

> or did you try to convince Ghostscript to insert missing fonts (PDF
> files contain only references to external fonts e.g., /FontName, but
> no physical font, subsetted or not)?

I'm not there yet, but this is the ultimate goal.

> In the latter case Ghostscript must be able to find the fonts.

Yes, I really hope that!

> [...]  If you say
>  > too much information is already lost during the subsetting process
> I assume that your PDF files already contain font subsets.

Yes, this is current setup.

> But what I have in mind is that you create PDF files which don't
> contain any fonts at all but only the information which font
> (/FontName) should be used.

Exactly this is my plan also.

> Then Ghostscript can insert the fonts.  And it certainly creates
> subsets by default.  AFAIK it even converts Type 1 fonts to CFF in
> order to save space.  I don't know ATM what Ghostscript does if
> multiple files are merged which all have references to one and the
> same font but I'm confident that it does something very useful.
> Isn't this exactly what you want to achieve?  Create zillions of
> files which don't contain any fonts at all, merge them, and finally
> insert the fonts in order to make the document portable?


> I must admit that I don't know anything about LilyPond except that
> musicians like it.  Presumably it creates PostScript code and
> converts it to PDF.  Right?

Yes.  We have to modify lilypond to not embed the font resources into
the PS file but to collect them in a directory.


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