[scribus-dev] GSoC project status: PDF/X export

[Thach Tran]

Hi all,

I'm doing PDF/X-1a and PDF/X-4 exporting for Scribus as the moment. I  
have managed to implement these features. You can check out the svn  
repo. at:

https://scribus.svn.sourceforge.net/svnroot/scribus/gsoc2009/pdfexport

Note that the repo. only includes files that I made the changes rather  
than the whole Scribus code base.

As for PDF/X-1a, since this format enforces blind exchange where all  
colors need to be in DeviceCMYK, I have decided to let users export to  
PDF/X-1a only if the Color Management is turned *off* in the  
document's setting as opposed to it to be turned on in exporting PDF/ 
X3. I have tested the output with several simple documents as well as  
some sample documents shipped with Scribus and so far they have all  
passed the PDF/X-1a compliance check (I used the trial version of  
pdfToolbox 4 plug-in of Callas software for Adobe Acrobat, btw). I  
would love to hear some feedback from you guys on your tests.

For PDF/X-4, in general it is an extension of PDF/X-3 which allows  
transparency and layers. So I have be able to preserve transparency  
and layering in PDF/X-4 export as well. However, as I ran the outputs  
through the PDF/X-4 compliance check, several errors were reported.  
Firstly, it said the PDF/X-4 requires the file to have XMP metadata. I  
don't think this is very difficult to do and therefore I'm trying to  
include XMP in the next few days.

Secondly, there're some more problems with fonts which I'm not sure  
how to fix. As an example, below are the reported issues which I have  
encountered from the outputs so far:

1. Width information for glyphs is inconsistent: it is required that  
the glyph widths in the font dictionary and the glyph widths in the  
embedded font are consistent.
2.  Wrong encoding for non-symbolic TrueType font: it is required that  
non-symbolic TrueType fonts use MacRomanEncoding or WinAnsiEncoding  
without any differences. The output I got from Scribus uses  
Differences dictionary extensively for encoding which causes this  
issue, I guess.

My guess would be these are just some of the possible issues since  
there can be many more restrictions in the font usage in PDF/X-4 and  
without getting my hand on the full PDF/X-4 spec, fully supporting PDF/ 
X-4 export would be quite a challenge. I have tried to google around  
for some more details on PDF/X-4 but no luck so far. Hope you guys  
could help.

So, it would be great if I could get some ideas, guys. Thank you very  
much.

Regards,
Thach