Re: Reduce size of PDF files when inc. in *TeX docs (issue 194090043 by address@hidden)

[Knut Petersen]

On 15.01.2015 10:45, address@hidden wrote:
> Reliable?  If I remember correctly, the tool used for combining the
> fonts (ppdfsizeopt.py) 

Ghostscript does the font merging.

> fails on the PDF files from PDFLaTeX, so there
> must be an additional iteration through GhostScript.  This additional
> iteration will reencode and resample included bitmap graphics at some
> command line option dependent resolution, correct? 

pdfsizeopt.py does some optimization of the remaining fonts, it tries to
find better compression for images, etc.

> What happens with hyperlinks?  Has anybody checked those?

BTW: All this has been documented in the commit message of the git-formatted
patch sent to lilypond-devel:

Internal hyperlinks are fully preserved with current ghostscript git master.

External hyperlinks (GoToR) _to_ a file processed this way are broken.
Fixing this would require major changes to ghostscript.

External hyperlinks _from_ a file processed this way to other pdfs are
preserved if the reader program isn't broken (acroread is not broken
in this respect, evince is).

For more details see Ghostscript bug #695747 
<http://bugs.ghostscript.com/show_bug.cgi?id=695747#c22>

> At any rate, I've taken a look at the description of pdfsizeopt, and it
> would appear that it is optimized for working on PDF files created by
> PDFTeX.  That would imply that it would be
> a) really a good idea to get along without using Ghostscript as an
> intermediary.  That seems like it would require fixing pdfsizeopt.  Its
> project page contains a link "Doesn't pdfsizeopt work with your PDF?
> Report the issue".  Now there is a remarkable dearth of names on the web
> pages, but from other projects and content under this account and the
> account's name I should be surprised if this project is not owned by
> Szabó Péter.  And I should be surprised if he does not manage to fix the
> problem when reported or suggest a full quality workaround.
> b) in a similar vein, I'd ask Péter for suggestions about the best
> course for having the font compaction work without blowing up the
> intermediate files all too much.  Of course I am speculating on him just
> making pdfsizeopt do all the work, but even if not, he'll be likely to
> come up with a good plan.

The pdfsizeopt.py problems we run into (at least issues 2 and 18) are reported
since 2009, and a fix is still missing.  No, I won't rely on Peter to enhance 
and fix
his tool fast.

ghostscript is the tool that does the main work, pdfsizeopt.py is an option.


cu,
 Knut