Re: Visible MetaData == "Visible to whom?" was Re: Design Principles

Maciej Stachowiak wrote, quote:
Thus, visible metadata reduces the need for browser involvement in  
web innovation.
unquote

whilst i understand your argument maciej, visible is in the eye, 
ear, fingertip or whatever else is available to the user.

the point of the discussion, as i read it, between invisible and 
visible metadata would be better threaded as: perceptible versus 
hidden metadata -- that is, metadata which isn't necessarily 
exposed, but which provides a programmatic option for:

A. user cognizance of the presence of the hidden metadata, 
without which exposition of the hidden metadata, is impossible;

B. knowledge of the existence of, and access to, the otherwise 
imperceptible metadata; no matter what modality through which 
the document has been parsed and presented to the user, the 
intended functionality of hidden metadata depends upon a 
programmatic cue from the user agent, which can either be 
communicated directly to the user interacting with the user 
agent or processed as a programmatic switch which then effects,
and is affected by, user defined settings and options, as well 
as triggering appropriate switches in third-party software, 
such as a screen-reader.

which is why the A element has become, by default, and may well 
remain, the catch-all element for exposition of otherwise hidden 
metadata, targets, or options: it remains the only ubiquitously 
supported means of pointing to a target, such as a longdesc page, 
and enabling the user to obtain the target document or other 
associated metadata resources.

i had to use the A element to encase an IMG declaration which 
contained an identical target, pointed to through use of the 
LONGDESC attribute, before mainstream assisstive technologies 
began to recognize and support IMG elements for which LONGDESC 
has been described, but i shouldn't have had to wait so long for 
an assisstive technology vendor to implement support for an 
interactive attribute such as LONGDESC -- support for LONGDESC 
(which can provide meta- and micro- data) should be available to 
any users of all user agents, as part of their conformance to the 
specification...

yes, i associate the LONGDESC explicitly with the IMG it describes, 
but i also use A extensively (admittedly as a hack) to make the IMG 
element an actionable item, even though that is what LONGDESC is 
intended to provide the user in a transparent manner - that is, 
recognition of, and support for, invisible metadata.which can be made 
quote visible unquote - or, rather, perceptible - to the tools which 
the user is currently using; optimallly, LONGDESC would be 
universally supported at the user agent level, for not everyone who 
needs or wants a LONGDESC will be using a screen reader or other 
assisstive technology, so the option to access quote invisible 
unquote metadata or additional information about an IMG, OBJECT, or 
other actionable elements (such as Q) must be presented to all users
 at the user agent level, upon user request, but the request cannot 
be made if the user has no means of first being informed of the 
existence of the metadata defined for the document, as well as a 
means of accessing the specified target resource.

in the end, the backplane mechanics should provide the user with 
a choice: automatically detect changes in lang and take appropriate, 
user-defined action -- such as either automatically switching to a 
more suitable natural language (for the purpose of visual, aural, 
and tactile rendering, based on user defined client side preferences, 
which i believe to be raman's prefered method), or setting the user 
agent to generate a choice of perceptible and actionable options.
(which could take the form of flags automatically associated with an 
actionable icon - and appropriate ALT text - to allow for manual 
choice, in this case, of a more suitable natural language.iteration 
for a particular user.


gregory j. rosmaita

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Received on Thursday, 29 March 2007 20:27:08 UTC