CL-c2 closure

[Lofton Henderson <lofton@rockynet.com>]

[0] 
http://www.oasis-open.org/committees/download.php/17342/CL-comments.html#CL-c2

INTRODUCTION.  CL-c2 [0] and related (c7, d10) dealt with the change to 
single-picture in WebCGM 2.0.  Specifically, to changes in the fragment 
that limit pictseqno to 1.  In the thread starting at [1], we agreed that 
this was a mistake and no one noticed it before CL -- it was our intent to 
limit number of pictures to 1 in WebCGM 2.0 instances, but there are all 
sorts of legacy questions about fragments coming from non-CGM sources 
(e.g., HTML), etc.  The final conclusion is that we should remove the 
"pictseqno ::= 1" line, and restore to 3.1.2.1 the WebCGM 1.0 rules for 
what to do with an out-of-range pictseqno.

[1] http://lists.oasis-open.org/archives/cgmo-webcgm/200603/msg00048.html

QUESTION.  Does that solution answer the three CL questions (a, b, c) at 
[0]?  Not clearly, in my opinion.

>     *  a.) What does a 2.0 viewer do with an external pseq=2 frag/link 
> into a 2.0 file?
>     * b.) What happens with a 2.0 viewer handling a 1.0 file containing a 
> pseq=2 frag/link?
>     * c.) Can a 2.0 file have a pseq=2 fragment pointing to a 1.0 file?

PROPOSAL.

a.) The 3.1.2.1 rule from 1.0, which we are going to restore to 2.0, says, 
"If the picture sequence value exceeds the number of pictures in the 
metafile, the last picture is displayed."  So our solution answers this 
question.
c.) According to our proposed solution, this is specified -- we are 
removing the "pictseqno=1" restriction from the fragment, and 1.0 files 
could have multiple pictures.  What the 2.0 viewer actually *does* should 
be answered consistently with #b...
b.)  Unclear from our solution.  I see three choices:
b-1.) must support (show 2nd picture);
b-2.) must show picture 1;
b-3.) invoke similar language to what we have used to define deprecation 
(7.2.2):  "...must be supported by conforming 2.0 viewers that support 
conforming 1.0 content."

I recommend b-3.  But I don't really care strongly.  There really isn't any 
multi-picture 1.0 content, so the question is academic, right?

-Lofton.