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List:       lyx-devel
Subject:    Re: serious Problems with UserGuide on current macOS
From:       Guenter Milde <milde () users ! sf ! net>
Date:       2017-08-29 19:28:14
Message-ID: oo4f8e$cps$1 () blaine ! gmane ! org
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On 2017-08-29, mn wrote:
> On 29.08.17 11:25, Guenter Milde wrote:

> > > The end of this will mail will list the generated warning from the linux
> > > tests.

...

> > > pdfTeX warning: pdflatex (file ./1_usr_share_lyx_images_file-open.pdf):
> > > PDF inclusion: multiple pdfs with page group included in a single page
> > > <./2_usr_share_lyx_images_buffer-write.pdf

> > OTOH, with inkscape as converter I did not see these warings and the
> > UserGuide exported here did work no Mike's Mac.

> > ...


> > So we have as reasons:

> > * Multiple PDF inclusions on one page (like the many small icons in the
> > UserGuide). No problem with just one included icon.

> > * Conversion of these PDFs via rsvg (an internet search for the error
> > message showed other examples inclduing Sage and MS Office)

> > * The Mac PDF viewer 
> > (but there are reports of Acrobat having problems with
> > "multiple pdfs with page group included in a single page", too)

> > The page
> > https://tex.stackexchange.com/questions/76273/multiple-pdfs-with-page-group-included-in-a-single-page-warning
> >  gives a detailled explanation of the warning and consequences as well as
> > possible workarounds.

> That discussion on tex.SE left me wondering.
> From my understanding this is a now chain of three different but
> amplifying bugs?

> A bug in the converters, a bug in pdftex and one in macOS?

Not necessarily bugs but problems that all toghether result in the dramatic
fail.

The warning from pdflatex is not as spurious as some people think - it can
lead to failure of the PDF viewer.

> I haven't found a formula yet but this will affect other PDFs produced
> with LyX (well LaTeX).

Yes. Pre-conditions are 

* inclusion of PDFs that define "page groups"
* in in close succession, so that they end up on one output page.

> How should this be addressed now for current LyX users?

Document 

* that generated PDFs may fail with the Mac preview app,
* that the warning about "multiple pdfs with page group included in a single
  page" is an indicator of a real problem
* that using inkscape as SVG converter may help.

Think about preferences/detection order of SVG converters.

Upload a UserGuide with inkscape-generated inclusions to the wiki.  


  

> And after reading of those superfluous nestings on tex.SE I compared the
> UserGuide.pdf from Guenter with those produced on my systems.
> Guenters is 1.9MB, mine are 1.6MB.
> Looks to me there is some serious case of bloat in there on top of it all.

This is most probably up to the many included icons.

> Using the popular ghostscript filter to reduce file sizes these swell up
> even more. But after first linearization and then optimization the buggy
> rsvg-using PDF can be reduced to ~900kB (although for that I had to
> force \pdfminorversion=4). And that then also displays fine!


> #
> Since almost all PDFs from LyX are really huge in comparison to other
> PDF producers: which of these alterations could be introduced into the
> LyX workflow to generally produce smaller files.
> #

Also, font inclusion may play a role. The user guide uses many different
families of an embedded font. OTOH, many other applications do not embed the
standard Postcript fonts (LaTeX may be configured to do so, too -- producing
smaller files at the risk of deficient viewing/printing experience in case
the fonts are missing on the target machine/printer.


> In case the above wasn't clear enough:
> one possible but very cumbersome workaround for users on OS X wanting to
> display UserGuide.pdf in Preview.app-like viewers is to apply the
> \pdfminorversion=4 to the preamble and get a defective PDF. This
> defective file can then be post-processed resulting in a much smaller
> file that does display in Preview.app.
> I had no such success with the default values or \pdfminorversion= >4

This does not sound like an approach easily turned in robust automatic
post-processing, though.

Günter


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