[pdftex] very subtle endobj bug in latest pdftex

Ross Moore ross.moore at mq.edu.au
Tue Jun 24 01:10:47 CEST 2014


Hi Reinhard, Akira, and everyone else.


Thanks for looking at this.

On 24/06/2014, at 7:58 AM, Reinhard Kotucha wrote:

> On 2014-06-23 at 12:44:37 +0900, Akira Kakuto wrote:
> 
>> Dear Ross Moore,
>> 
>>>>  <<
>>>>  /I false
>>>>  /K false
>>>>  /CS /DeviceRGB
>>>>  /S /Transparency
>>>>>> endobj
>> 
>> It seems that pdftex in TeX Live 2014 is copying
>> 
>>>> \rendobj
>> 
>> as
>> 
>>>> endobj
>> 
>> ignoring \r.
> 
> Shouldn't it be \n instead of \r anyway?
> 
> The PDF/A standard explicitly forbids \r as a line break.  The problem
> is that if both, \r and \r\n are allowed and the content stream
> contains binary data, it's impossible to determine whether \n is part
> of the line break or part of the content stream.

Yes, but if pdfTeX has already determined that the context makes it 
safe to remove the  \r  (as it seems to have done) then it should be 
possible to check the next character or upcoming key-word, 
to determine that  \n  is indeed required.

One might well ask why the \r  was in the image file in the first 
place. The production of that image has a bit of history, but the
final producer was Adobe Illustrator CS2 – quite an old version
– on a Mac, where \r  is the usual line-end character.

There are dozens of instances of these:  (using  vi )

   ^Mendobj^M636 0 obj<<
and
   >>^Mendobj^M637 0 obj<<

with different object numbers, but only one seems to have
been handled incorrectly. The thing that seems to characterise
this instance is that the object is a Transparency Group setting
a ColorSpace, occurring immediately before the /Info  dictionary,
which was originally created using pdfTeX itself (the PDF page
being later edited in AI).

The same thing happens with 2 other PDF images that I need
for my final full document.


Best of luck tracking this down, Thanh.



But Reinhard makes an interesting point.
Maybe if I use Acrobat Pro to Save As...  PDF/A then the
line-ends will be changed from \r  to \n  and this
problem can be avoided?

Unfortunately it compresses, but I still see plenty of ^M in 
uncompressed portions of the resulting file.
Also, it seems to have changed the colors somewhat.

> 
> Regards,
>  Reinhard



Cheers,

	Ross

------------------------------------------------------------------------
Ross Moore                                       ross.moore at mq.edu.au 
Mathematics Department                           office: E7A-206      
Macquarie University                             tel: +61 (0)2 9850 8955
Sydney, Australia  2109                          fax: +61 (0)2 9850 8114
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