[NTG-context] attachment attaches twice - more research

Michail Vidiassov master at iaas.msu.ru
Sun Feb 20 23:21:15 CET 2011

Dear Developers,

On Sun, 20 Feb 2011, Michail Vidiassov wrote:

> to be precise, the attachment is attached once
> but is listed twice by Adobe Reader.

PDF spec states
An embedded file stream shall be included in a PDF document in one of the 
following ways:
•	Any file specification dictionary in the document may have an EF 
entry that specifies an embedded file stream. The stream data shall still 
be associated with a location in the file system. In particular, this 
method shall be used for file attachment annotations (see, "File 
Attachment Annotations"), which associate the embedded file with a location 
on a page in the document.
•	Embedded file streams may be associated with the document as a 
whole through the EmbeddedFiles entry (PDF 1.4) in the PDF document’s name 
dictionary (see 7.7.4, "Name Dictionary"). The associated name tree shall 
map name strings to file specifications that refer to embedded file streams 
through their EF entries.

while code in lpdf-wid.lua sends everything to EmbeddedFiles - including 
files associated "with a location on a page in the document" as in the 
examples in the originator's post.

For example http://www.microtype.com/showcase/EmbedFiles.pdf
has it done correctly, EmbeddedFiles refers only to that embedded files 
that are not linked to particular icons on pages.

          Sincerely, Michail

PS. did not experiment with patching lpdf-wid.lua myself yet...

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