Re: ISSUE-2147 (external-refs confusing): Section on externally referenced documents confusing [Last Call: SVG 1.2 Tiny ]

Hi, Folks-

That section of the spec is indeed pretty poorly written, with lots of
repetition.  I cleaned it up and reordered it, though I didn't make as
many changes as Cyril.  The attached file has the original, Cyril's
reworking, and my rough draft.

I don't have a feel strongly about any of the content, though I agree
the section needs a revision.

Regards-
-Doug


Cyril Concolato wrote (on 10/14/08 4:54 AM):
> Hi all,
> 
> SVG Working Group Issue Tracker a écrit :
>>
>> ISSUE-2147 (external-refs confusing): Section on externally referenced
>> documents confusing [Last Call: SVG 1.2 Tiny ]
>>
>> http://www.w3.org/Graphics/SVG/WG/track/issues/2147
>>
>> Raised by: Doug Schepers
>> On product: Last Call: SVG 1.2 Tiny
>> Cyril Concolato
>> <http://lists.w3.org/Archives/Public/www-svg/2008Oct/0110.html>:
>> [[
>> * Section 14.1.6 Externally referenced documents The section is quite
>> hard to read and it's not easy to understand the difference between
>> the processing of primary and resource documents. For example, instead
>> of copy/pasting the "conceptual processing model" of primary documents
>> for resource documents could you just give one unique paragraph? Could
>> you highlight in the text the common points and differences? For
>> example with the following structure
>> definitions:
>>  - primary document: referenced as a whole (no fragment). In SVG Tiny
>> 1.2, it only concerns 'a', 'animation' and 'foreignObject' (as per
>> restriction)
>>  - resource documents: referenced using a fragment identifier. In SVG
>> Tiny 1.2, it only concerns 'use' and 'foreignObject' (as per restriction)
>> common points:
>>  - processing is that events are fired, scripts are executed, ...
>> differences:
>>  - resource documents are loaded only once per primary document
>>  - primary documents may be loaded multiple times
> I attach a modified version of that section which I have rewritten
> according to the above plan. I tried not to remove any important text or
> nor added any new idea. However, I propose to remove the sentence in red.
> 
>> Could you also answer the following points:
>>  - What about "externally referenced media" ? Does a primary document
>> maintain a dictionnary of media resources? If a video is refered twice
>> in the scene does this lead to two different ressources?
> For this point, I suggest to add:
> "Similarly to primary documents, multiple references to the same
> external media lead to separate media timeline."
> 
> It does not mention loading because in some cases (short clips), you
> might load and decode them only once.
> The above sentence means that the following code will, at time 5,
> display 2 different frames of the same video:
> <video x="0" y="0" width="100" height="100" xml:id="v1" begin="0"
> xlink:href="http://www.example.org/myvideo.mp4"/>
> <video x="0" y="100" width="100" height="100" xml:id="v2" begin="5"
> xlink:href="http://www.example.org/myvideo.mp4"/>
> 
> 
>>  - What about externally referenced scripts ? 
> Here I just want to clarify that if two scripts in the same scripting
> context point to the same script file, then the script is loaded only
> once. I propose the following sentence:
> 
> "Similarly to resource documents, in the case of multiple references, in
> the same scripting context, to the same external script file, the script
> file is processed once."