Interpreting relative references in OPC

[Rex Jaeschke]

As the liaison between OpenXML and OpenXPS, I forwarded Murata-san's mail
below to the XPS folks. Below is the response I received from the Ecma TC46
chairman, Brian Clubb.

Rex


-----Original Message-----
From: Brian Clubb [mailto:Brian.Clubb at microsoft.com] 
Sent: Thursday, May 17, 2012 2:02 PM
To: Rex Jaeschke
Subject: RE: Interpreting relative references in OPC

Rex,

This seems to be incorrect.  OXPS requires relative URIs (see sections
9.1.2, 9.1.3, 9.1.4, 10 of spec).  Microsoft's XPS allowed either relative
or absolute paths.  I am concerned they are looking at the wrong kind of XPS
file here.

Thanks!
Brian



-----Original Message-----
From: eb2mmrt at gmail.com [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA
Makoto
Sent: Tuesday, May 15, 2012 9:35 PM
To: SC34
Subject: Interpreting relative references in OPC

Dear colleagues,

If my memory is correct, resolution of relative references within OPC is an
issue.
ODF and EPUB both did reasonably good jobs.

EPUB3 http://idpf.org/epub/30/spec/epub30-ocf.html#sec-container-iri
ODF 1.2
http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part3.html#__
RefHeading__752821_826425813

In my understanding, after unzipping OPC, every relative reference will be
broken, and this has not caused any real problems.  But, in EPUB3, unzipping
do not break relative references except for those in the META-INF directory,
which is only for packaging.
This is also intentional, since synergy with the Web world and the e-book
world is highly important for EPUB.  I am not sure about ODF 1.2.

Interestingly, XPS implementations always appear to use absolute-path
references (which always begin with "/") as references, while OOXML
implementations appear to use relative-path references (which do not begin
with "/").


Regards,
Makoto