[NTG-pdftex] [ pdftex-Bugs-362 ] pdfobj produces extra /Filter for object streams with own filter

[noreply at sarovar.org]

Bugs item #362, was opened at 2005-06-02 12:55
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Category: None
Group: v1.21a
Status: Open
Resolution: None
Priority: 5
Submitted By: Jens Elstner (daguy)
Assigned to: Nobody (None)
Summary: pdfobj produces extra /Filter for object streams with own filter

Initial Comment:
When I use the following code with pdftex and 
activated compression

\pdfcompresslevel=9
\pdfobj stream%
attr{/Filter/ASCIIHexDecode/FunctionType 0/Encode[0 
255]/BitsPerSample 8/Domain[0 1]/Size[2]/Range[0 1 0 1 
0 1 0 1]/Decode[0 1 0 1 0 1 0 1]}%
{00000000FFFFFFFF}%  output tint function

The generated pdf file contains the object as shown 
below

3 0 obj <<
/Filter/ASCIIHexDecode/FunctionType 0/Encode[0 
255]/BitsPerSample 8/Domain[0 1]/Size[2]/Range[0 1 0 1 
0 1 0 1]/Decode[0 1 0 1 0 1 0 1]
/Length 17        
/Filter /FlateDecode
>>
stream
x┌30Ç
'7'c
endobj

The compression added an extra /Filter line and 
produces an error or does not work the way it was 
intended anymore.

Proposed fix for this would be to check the <attr-
spec> for /Filter and omit any compression if a user 
filter function is present already.

Yours sincerely,

Jens Elstner

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Comment By: Heiko Oberdiek (oberdiek)
Date: 2005-06-02 14:52

Message:
Logged In: YES 
user_id=1276

Hello,

not a fix, just a workaround:

\begingroup
  \pdfcompresslevel=0 % then pdfTeX does not
                      % add /Filter itself
  \immediate\pdfobj stream attr{/Filter/...}{...}\relax
\endgroup

Yours sincerely
  Heiko <oberdiek at uni-freiburg.de>

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