[scribus-dev] GSOC: PDF Embedding

[Thach Tran]

Hi all,

Most of the pieces for preflighting the embedded PDFs are in place  
right now. It would be really great if you could try it out and send  
me your feedbacks/thoughts. The url for the svn repo is https://scribus.svn.sourceforge.net/svnroot/scribus/gsoc2009/pdfexport

It could detect the incompatible color usages (e.g. using DeviceRGB  
while our overall document is PDF/X, etc), transparency, non-embedded  
fonts, and too low/high resolution of images in the embedded PDFs.  
Most of the inspection code is in pdf_analyzer.cpp; and  
documentchecker.cpp will use this code to report the appropriate  
preflight errors.
One thing I'm not sure how to accomplish right now is how would I  
force the PDFs to be rasterized when there're issues. This is because  
the exporting code takes place in pdflib_core while the preflighting  
process is in another place. Any suggestion?

Regards,
Thach

On 3 Jul 2009, at 23:22, Andreas Vox wrote:
> Hi Thach!
>
> I think the first thing should be to find out what colorspaces are  
> used in
> the PDF.
> In addition it might also worth to check for used/embedded fonts and
> transparency.
>
> I suggest a new sourcefile with code that uses Podofo to read the  
> PDF and
> records:
>
> - colorspace and transparency settings (blendmode, softmask, alpha) in
> graphic states
> - use of G, g, RG, rg, K, and k operators
> - colorspaces and resolution of bitmap images
>
> This code can then used by the preflighter to warn the user about  
> issues. In
> my view that should be enough to remove the "EXPERIMENTAL" flag from  
> PDF
> embedding. We can also enforce rasterizing the PDF to fix the  
> colorspace and
> compatibility issues.
>
> Later you/we can extend the code to fix colorpace issues or embed  
> missing
> fonts. The PDF reading code may also evolve into a PDF import function
> later.
>
> /Andreas