ACTION: revise 3.3.1. Media Types and Fragment Identifier Semantics

Hello ,

First sentence of the story is fine

>> In one of his XHTML pages, Dirk links to an image that Nadia has
>> published on the Web. He creates a hypertext link with <a
>> href="http://www.example.com/images/nadia#hat">Nadia's hat</a>.

Insert a new second sentence

Emma views Dirk's XHTML page in her Web browser and follows the link.
The HTML implementation in her browser removes the fragment from the URI
and requests the image "http://www.example.com/images/nadia"

Continue with existing story

>> Nadia serves an SVG representation of the image (with Internet media
>> type "image/svg+xml"), so the authoritative interpretation of the
>> fragment identifier "hat" depends on the SVG specification.

Add new sentence:

Emma's Web browser starts up an SVG implementation to view the image. It
passes it the original URI including the fragment,
"http://www.example.com/images/nadia#hat" to this implementation,
causing a view of the hat to be displayed rather than the complete
image.


Delete entire first paragraph after story, starting "Per[URI] ..."

Insert a new paragraph as follows:

Note that the HTML implementation in Emma's browser did not need to
<em>understand the syntax or semantics</em> of the SVG fragment (nor
does the SVG implementation have to understand HTML, WebCGM, RDF ...
fragment syntax or semantics; it merely had to recognize the # delimiter
from the URI syntax [URI] and remove the fragment when requesting the
resource. This orthogonality is an important feature of Web
architecture.

Thoughts and comments:

There is a whole related issue that fetching the SVG file, sticking it
in some local cache and passing that local address rather than the
actual Web address will cause relative URIs in the SVG file to break.
The implementation needs the entire original URI, not just the fragment.

I'm not sure whether to discuss it here or to merely leave it hinted at
in the "passes the original URI".

I also don't want to give the impression that the SVG implementation
re-requests the resource.

It occurs to me that the point about not understanding could be made
with a complex-looking fragment than a bare ID. For example,
#viewBox(20,30,8,6)

Apart from these issues, the rest of 3.3.1 makes sense with the revised
story and intro para.

This completes my action item.


-- 
 Chris Lilley                    mailto:chris@w3.org
 Chair, W3C SVG Working Group
 Member, W3C Technical Architecture Group

Received on Monday, 19 July 2004 15:05:25 UTC