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RE: XP> xhtml-print: RFC3391 interpretation question: how much vi sual sep aration ends a chunk?

From: PARAB,DEEPALI (HP-Boise,ex1) <deepali.parab@hp.com>
Date: Thu, 8 Apr 2004 12:24:31 -0400
Message-ID: <A9D8461BDF1C5446B1FFD5661AB0263B03DB65AA@xboi23.boise.itc.hp.com>
To: "BIGELOW,JIM (HP-Boise,ex1)" <jim.bigelow@hp.com>, www-html-editor@w3.org, Elliott Bradshaw <Elliott.Bradshaw@Zoran.com>, don@lexmark.com
Cc: xp@pwg.org

Hi Jim,
My experience says that its should be,
==================================
</body>
</html>
CHK 0 0 LAST
==================================
The reason is, 
carriage return (ASCII code 0Dh), which positions the cursor to the left
side of the current line of characters, 
line feed (ASCII code 0Ah), which moves the cursor down one line on the
output device.
So if the code is as follows 
===========================
A)
</html><CR><LF>CHK 0 0 LAST then we should get
OR
</html><LF>CHK 0 0 LAST
Then the output would be,
</body>
</html>
CHK 0 0 LAST
===========================
B) But if an additional <LF> (<0a>) is inserted like shown,
</html><CR><LF><LF>CHK 0 0 LAST 
OR
</html><LF><LF>CHK 0 0 LAST 

Then the output would be,
</body>
</html>

CHK 0 0 LAST
==========================
I have observed that PDF file formats (I have worked on then till 1.4
Version) also have this interpretation of CR/LF. Note that this was seen on
windows environment.

Regards,
-Deepali

-----Original Message-----
From: owner-xp@pwg.org [mailto:owner-xp@pwg.org] On Behalf Of BIGELOW,JIM
(HP-Boise,ex1)
Sent: Thursday, April 08, 2004 9:52 AM
To: www-html-editor@w3.org; Elliott Bradshaw; don@lexmark.com
Cc: xp@pwg.org
Subject: XP> xhtml-print: RFC3391 interpretation question: how much visual
sep aration ends a chunk?


I'm looking for opinions on the interpretation of RFC3391 [1] since it is
normatively referenced by XHTML-Print [2].

RFC 3391 says, 
   An Application/Vnd.pwg-multiplexed entity contains a sequence of
   chunks.  Each chunk consists of a chunk header, a chunk payload and a
   CRLF.

     - The chunk header consists of a "CHK" keyword followed by the
       message number, the chunk payload length, whether the chunk is
       the last chunk of a message and, finally, a CRLF.  The length
       field removes the need for boundary strings that Multipart uses.
       (See section 3.1 for the syntax of a chunk header).

     - The chunk payload is a sequence of octets that is either a
       complete message or a part of a message.

     - The CRLF provides visual separation from the following chunk.

There are several situations where a single CRLF does not provide visual
separation since the CRLF added to the document simply terminates a line
rather than adding a empty line.  For example in an XHTML-Print document
didn't contain a terminating CRLF and adding a single CRLF  would give the
result shown below in example 1:

</body>
</html>
CHK 0 0 LAST

Rather than the following, example 2, I expected from reading the spec:

</body>
</html>

CHK 0 0 LAST
   
This could also occur when interleaving images and the root document.  

I think this issue will have a large impact on interoperability between
printers and producers of multiplexed documents.  So I'd like to get  other
people's interpretations of this matter.

If I don't hear from anyone, I'll assume agreement that the multiplexed
document should contain visual separation at the end of the chunk, as in the
example 2.
 

Jim

[1] http://www.ietf.org/rfc/rfc3391.txt
[2] http://www.w3.org/TR/xhtml-print/
Received on Thursday, 8 April 2004 12:25:35 UTC

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