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[Jongware]
[Jongware]
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Formal representation missing items?

Aug 2, 2012 3:00 AM

Tags: #pdf #formal #representation

The "Formal Representation of PDF 1.7" document from Acrobat X is very interesting, but it appears to be missing a few parts. What is the official status of this document? Advisory? Internal Use? Summary? Eyes Only, Accidentally Included?

 

I haven't got around checking it in detail, but I found not all supported Filter abbreviations are listed under InlineImageDict, only the ones that have DecodeParms.

 

(Possibly the abbreviations should be listed under StreamDict as well. PDFRef 1.7 says in the Implementation Notes

 

Acrobat viewers accept the abbreviated filter names shown in Table H.1 in addition to the standard ones. Although the abbreviated names are intended for use only in the context of inline images [..], they are also accepted as filter names in any stream object.

 

but ISO32000-1:2008 states "These abbreviations are valid only in inline images; they shall not be used in image XObjects." -- one of the rare cases where the Adobe and ISO spec differ. Perhaps this Formal Rep describes ISO, and not the general Acrobat viewer behavior.)

559 Views   2 Replies   Latest reply: [Jongware], Aug 2, 2012 6:05 AM
 
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  • lrosenth
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    1. lrosenth,
    Aug 2, 2012 4:54 AM   in reply to [Jongware]
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    If you referring to the PDF that is included with the Acrobat package, it is undocumented and unsupported for use by 3rd parties.

     

    However, the ISO 32000 committee is working on defining a formal grammar for PDF.  If that is something that you are interested in, you should contact your national representative and join the committee.  It's free!

     
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  • [Jongware]
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    2. [Jongware],
    Aug 2, 2012 6:05 AM   in reply to lrosenth
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    Thanks, Leonard!

     

    Nah, I'm just on the receiving end of specs. I ran across this document testing my homegrown PDF reading library and got intrigued because Everything You Always Wanted To Know (etc.) seemed to be in there!

     

    Even though everything is written out in excruciating detail in the ISO doc, it's scattered about in 756 pages of butt ugly 10pt Arial. Quite a difference with Adobe's own nicely designed version ... and the ISO one lacks the all-important index as well! (Also, after reading a hundred pages with at least a dozen occurrences of "shall" each my eyes start to water.)

     

    I'm going to use your *very* useful list as a shortcut but I'll make sure to cross-reference everything against the full specifications.

     
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