- From: Aaron M Leventhal <aleventh@us.ibm.com>
- Date: Fri, 11 Apr 2008 10:57:00 +0200
- To: unagi69@concentric.net
- Cc: w3c-wai-pf@w3.org, w3c-wai-pf-request@w3.org, wai-xtech@w3.org
- Message-ID: <OFE935E412.938568AC-ONC1257428.0031257A-C1257428.00315142@us.ibm.com>
I don't understand the definition of the role, especially the describedby
parts. I thought we were just going to use the accessible name for the
math text? When is description used and what should it point to?
Also I don't think we should mention speech, because this is for
conversion to any accessible format -- could also be various types of
Braille, Gardner-style math, etc.
This is for sections that represent math, such as images and ASCII art,
but are not in a formal mathematical language. Such images MUST be labeled
by text that can be converted to an accessible format, using the
describedby property with a reference to a description of the math
expression as it would be spoken. This is designed to facilitate
conversion to speech. The text description should have no special markup
used to control a speech device. Authors MAY store image alternative text
in the image formats themselves. In these scenarios the alternative text
from the image SHOULD also be brought into the text of the document and
referenced by the describedby property.
- Aaron
"Gregory J. Rosmaita" <unagi69@concentric.net>
Sent by: w3c-wai-pf-request@w3.org
04/01/2008 12:03 AM
Please respond to
unagi69@concentric.net
To
<wai-xtech@w3.org>
cc
<w3c-wai-pf@w3.org>
Subject
math role for ARIA - ARIA Subteam Public Meeting Minutes 2008-03-31
[DRAFT]
aloha!
todays' ARIA Subteam meeting was held in a public channel to accomodate
collaborators who are not part of the working group, therefore, the
minutes from today's ARIA Subteam meeting are (a) public and (b) can be
found at:
http://www.w3.org/2008/03/31-aria-math-minutes.html
and as plain text following my signature; the accompanying IRC log can be
accessed via:
http://www.w3.org/2008/03/31-aria-math-irc
as usual, please log any errors, omissions, mis-attributions and mistakes
by replying-to this post on-list
special thanks to neil soiffer for the time he has spent developing and
discussing a math role for ARIA (within PF and the MathML WG) and for his
participation in an hour-and-a-half call today, as well as his offer to
continue collaboration with the PF WG on the math role and the Best
Practices for using the math role... thanks as well to pete brunet of
IBM, for joining to provide insight into IAccessible2 -- the group looks
forward to working with both neil and pete as it moves forward towards
completion...
for background, the term "Expert Handlers" in relation to work being
conducted by the Open Accessibility Workgroup, can be more fully explored
by consulting the use cases document for "Expert Handlers for Specialized
markup" discussed during today's call:
http://a11y.org/uuc
please also take the time to review the accompanying "Strageties, Comments
& Reviews" wiki page, located at:
http://www.linux-foundation.org/en/Accessibility/Handlers/UseCases/Unified/ScratchPad
gregory.
- DRAFT -
ARIA discussion of Math
31 Mar 2008
Agenda
[http://lists.w3.org/Archives/Member/w3c-wai-pf/2008JanMar/0547.html]
See also: IRC log [http://www.w3.org/2008/03/31-aria-math-irc]
Attendees
Present
Al_Gilman, Gregory_Rosmaita, James_Nurthen, Jon_Gunderson,
Lisa_Pappas, Michael_Cooper, Neil_Soiffer, Pete_Brunet,
Rich_Schwerdtfeger, Kenny_Johar, Marc_Silbey, Matt_May
Regrets
Janina_Sajka, Sally_Cain
Chair
Rich_Schwerdtfeger
Scribe
oedipus, Gregory_Rosmaita
Contents
* Topics
1. math role for ARIA 1.0
* Summary of Action Items
_________________________________________________________________
<Rich> scribe: oedipus
<Rich> last irc discussion thread on math:
http://lists.w3.org/Archives/Member/w3c-wai-pf/2008JanMar/0453.html
<MichaelC> Agenda:
http://lists.w3.org/Archives/Member/w3c-wai-pf/2008JanMar/0547.html
(first item only)
<scribe> scribe: Gregory_Rosmaita
<scribe> scribeNick: oedipus
math role for ARIA 1.0
RS: trying to get your math request added to aria; think is great
thing to add; want to 1) meet your needs and 2) provide best practices
for embedding math
... last thread in IRC
<Rich>
http://lists.w3.org/Archives/Member/w3c-wai-pf/2008JanMar/0453.html
AG: 19 March 2008 -- you replied, but bunch of technical details
RS: new math role -- what does it mean? how to use? how to reuse ALT
text? how to handle images?
NS: brought up with MathML WG -- asked if had comments; some of things
we discussed in PF email exchange came up -- restrictions on what type
of math should be placed in a math role; MathML WG felt that a lot of
stuff out, for past compatibility not good to abandon what is being
done today and historically -- mix of TeX and MathML
... none of them are tagged identifying what they are; existing
practice wide-open and that needs to stop
... sniffer trying to find math will be able to tell TeX, MathML, or
similar syntax
... leave open-ended and not specify
... second: subtype "math-tex" -- discarded as bad idea -- to
ambigous; too many TeX variants
... third issue: if math, might not be any alt text in suitable
format, but down the road one could use OCR to pull equation from
image -- already an OCR for math with acuracy in 97% range; again, not
tagged, but open ended
... fourth: didn't care where it is -- BP can say "use alt text or use
image" but one kind of math out there is JSMath -- uses TeX-like base
to create javascripted (inaccessible) math
... don't want to force math into an image that has to be parsed
... no single practice -- math kind of a "wild west" frontier trying
to get integrated into HTML
RS: what does having role="math" help with all formats?
NS: key thing which will allow anyone to do a11y -- 1) given cost of
trying to discover math, having tag iding as math, keys a
sniffer/handler to find and discover format; second) alerts AT that
this is Math and calls a handler to come up with text to speak it,
rather than gibberish
we are in #aria-math for math discussion
switch to #aria-math
NS: MathML WG felt that using attribute value "math" too general
(plot, diagram, formula) want to restrict it more -- suggested
"formula" or MSAAEquation
AG: MSAAEquation was the suggestion
RS: if prefer math, can in API mapping documents map to
role="equation"
NS: not as picky as rest of wg, but thought "equation" restricted it
and was more precise and maps well to what already exists
AG: a) have to channel simon p -- was pressuring us to have this fully
specificied -- thinking that he is building into HTML5 and browser --
challanged that -- this is a flag AT uses to call helper -- it is the
helper that decides how loose or strict it is going to be able to grok
and that above 85% success would be BIG win
... where existing equations are in TeX can do that
... akward thing in that HTML has history of getting into trouble with
putting sloppy definitions in specs which lead to differing/sloppy
implementations; authos have been upset about what happens when their
code hits the browser; strong desire in HTML WG to nail things down
better and have more specific specificiation -- need to distinguish
what role is here -- HTML and base UA not going to do everything for
everyone
NS: math may be embedded in image -- may not even be perceptable to
HTML parser
AG: SimonP would want to be quick -- if you are happy to sniff/ping
inserts and give a sign "math handlers/sniffers" go find and process
this; in accessibility also have problem -- in WCAG developed concept
of accessibly supported technologies -- loose outer defninition
(function performance) then "and furthermore if use this technique
with this technology, value gets through to end user:
s/user;/user;
AG: value of "math" or "equation" is describing intent -- how you
should understand this fragment of content;
... when tell authors what to do, need "and furthermore if you do
this, it is supported" so both a loose and a stricter statement
<kenny> michael, I am using skype for this call today.
NS: should be suggestion in Best Practices that says "this technology
will be exposed/found if you do x with y app" -- would not leave open
ended if starting from scratch, but since ARIA attempting to capture
meaning in current practice and those practices vary greately
RS: mark this as "equation" here are common BP to support
interoperability today, but is there an optional parameter for
"equation" you would want?
NS: 2 things: 1) where is the math going to be found; 2) give me a
strong clue as to what type of math i need to deal with
(self-discoverable)
... with TeX similar, but different -- one thing not well understood
about TeX was written without logical parser -- doesn't tokenize
things but tokenizes each character
... some variants of TeX tokenize elements; things like that make TeX
an open ended thing
... would be nice to specify that, but 20 variantsof TeX and many
implementations follow custom rules
AG: took first pass at approach: didn't address "casting to a dialect"
but did point to where can find; put encoded math in ALT attribute one
pattern has to be looked for (proably a search list); what is new in
ARIA is "describedby" points to something for people or machines --
could point to a machine understandable -- could develop conventions
for TeX -- ways to put into meta data (use SCRIPT that not displayed,
ask what type of script, get return) -- hav
RS: describedby like a long desc for area in document
... can hide with CSS or have visible; gets mapped to accessible
description in a11y APIs so one can extract text if needed;
... suggestion on how to process math object? OCR it, use description
(describedby)
... can't specify TeX because too many variants
NS: right
... question i have which hasn't been answered by PF is "how important
is compatibility with existing use cases?" -- is goal of ARIA to
change and constrain use of math to make more accessible or just
trying to describe current usage
RS: ARIA about interoperability with platform a11y APIs -- everything
needs to be obtained through APIs; could say, if use ARIA, this is how
you should use it for math -- if in best interest of industry -- use
of ARIA might direct them to a more consistent use of math on web
NS: driving factor on some, but not all, putting math in HTML is
terseness; some use TeX-like notation that uses javascript to
"prettify" -- wikipedia/wikimedia has extension that creates TeX from
ascii notation or to describe image containing math
... JSMath -- if javascript really doing writing, could put out more
description
... maybe verbosity is not an issue on second thought -- tool will
generate extra stuff
AG: wikipedia case where site doing patern driven transform is good
likelihood of uptake thing -- getting JSMath library to generate more
stuff would rate down
NS: working with us
AG: maybe will work with us like dojo
... everyone in end cares about character count -- not just mobile
providers; wasted chars not good idea -- if put TeX in alt and mark
with role then should work -- content devlopers who want to put in
different flavors of TeX, that we have the "try harder" coding
patterns we target for when more than just an image and alt text
JRG: ideally what is most accesible way to put math on web
NS: MathML -- works with XHTML no problem, but problem with HTML -- if
you only use IE, can put in HTML document and IE extention mechanism
will handle it, but nothing in firefox or safari
RS: role="equation" - source equals "URI for mathML" and let AT suck
it out
NS: URIs have 2000 character limits?
AG: good question
RS: here is URI for source of that, don't need alt text -- if you
understand MathML go get it
AG: problem when src used to point to math image
RS: can handle that
AG: HLink versus XLink wars
NS: essentially 1 thing saying let's make it explicit and put on image
or embed tag -- MathML WG trying to make math more interoperable --
people carry around images, but leave alt text behind; embedding in
image safe way to go -- always there
... extractable from image, not dependent on alt -- TeX part of image
... not bad idea to have attribute that make these things obvious, but
worry about fragility of extraction method
RS: like to have 2 vehicles in BP: role="equation" -- in BP say "store
equivalent text in image"
NS: here are 3 or 4 ways that are supported by most extraction techs
... 1 would be ALT text (current practice); other would be using
"describedby" and other in image itself
RS: no URL to mathml equiv
NS: not sure
AG: should be supported
GJR: strong plus one
AG: if provider has equation in MathML, need to know -- want to use
that if present
RS: mathML equiv to give URL (optional parameter)
NS: why just MathML? if to make discovery easy, shouldn't be limited
to MathML -- just URL of equivalent
RS: server could tell media type when pull down TeX
NS: is a text format
MC: datatype or new mime-type property?
AG: has to be tested to make sure current implementations of OBJECT
won't break; if put in OBJECT and make MathML first choice, that is
the Best Practice possible; problem is whith mime-types for MathML
NS: persued and rejected by MathML WG
AG: problem: UA can't determine ahead of time if can process MathML --
doesn't know MathML is MathML until gets it
RS: right
NS: sigh, right
... though OBJECT has own problems
AG: matter of debate -- tantek told us it has been fixed; HTML5
faction against it (VIDEO, AUDIO, etc.) -- shouldn't lose cascading
fallback idea; want to wait to have highest and best form avialable
... issues: need mime-type identifier; need extractor for TeX in image
<kenny> Do we know if any screen readers today support LaTex?
MC: putting mathML in attributes means using escape characters
AG: TeX in alt rather than MathML
<kenny> Thanks gregory.
AG: if load into IFRAME, how is communicated to UA that this thing
contains math -- application/xml+mathml -- if can't process XML move
onto something else
NS: not going to work right now
GJR: MC can WCAG2 address the author's best practice by advising that
TeX be embeded in an image
AG: interim technique; also want to fix the web so highest and best
math (MathML) can be documented as object and served to users
NS: MathML in HTML5 -- consensus that math will be in HTML5 --
probably MathML in some as yet unkown/specified form
... want to discourage hacks
AG: agree -- just trying to separate 2 issues: need role now so
something can be processed and
GJR: need to take info to WCAG and ATAG
RS: if alt text not in document, are you going to pull alt text out of
image and map to a11y api?
NS: don't think UA itself would do sniffing (although would be great
if would) -- UA's not the ones that turn MathML into speech, AT
vendors don't want to handle MathML directly, so would have to use
Expert Handler (http://a11y.org/handlers) -- there is pllugin for IE
that allows speech -- AT essential to getting braille support
... developed tech to go out and pull the alt text out, paste into
equation editor; port that back into viewer -- take the TeX translate
to MathML then run through MathML to Speech and MahtML to braille
engines -- very doable; current limitation -- plugin calls for MathML
and need to do javascript on imagesand scan of page to determine what
math is there in what form
... if have role="math" could limit search
AG: summarize: if the user has a png format for their picture of
equation and put embedded meta-data in png, not expect browser to put
into API as accessible description -- can take alt text and processed
as usual; if mathML in embedded, math helper might write good
description into accessibility API
NS: ARIA exported to AT, javascript that binds will do translation and
in case of UAs not serving up dom, can rewrite page AT should pick up
... alt text put out as value field in MSAA?
RS: no, AccessibleName and helpInformation -- MSAA has description API
(equiv of help) IA2 has relationships that understand "describedby";
don't know what UIAutomation plans
NS: whatever written, write correctly, even if in alt
RS: wearing AT vendor hat, if TeX embedded in image, would want to
know that if don't have TeX plugin
NS: what is loud and clear from AT vendors is "we're not dealing with
math; you do that, tell us what to put out, and we'll support it" not
going to search DOM, will speak if is there -- don't want to fetch
image and parse it
RS: 2 things: 1) either can put a describedby as technique or a tool
can fulfill that role; 2) HTML5 people will not like URL pointing
NS: HTML5 people will tell you that they will handle math as text/html
-- dubious at this point if possible
... describedby field in TeX or MathML -- if had javascript that looks
for math and outputs speech, is it still "describedby"?
AG: describedby takes list of IDs -- have to revisit what UAs do with
concatonated methods
... can't do this on fly, but are things can write into DOM that can
capture (SSML)
NS: with MSAA can't use SSML, have to use straight text
... as long as you come up with soulition that describedby is machine
field, need to id field that needs priority to generate speech,
braille, etc.
AG: hoemwork item, but this discussion has GREATLY cleared up the
issues; thought going to take directoy to APIs -- if put back into
DOM, have to rethink thorugh fully so AT ends up with it
NS: found varying levels of commitment from AT vendors: base level -
have MSAA interface, but that is limited to string of text (can't put
braille in that -- text you put in isn't braille you get out in math)
-- that's why have to expose handler interface to all UAs all ATs all
platforms; minimum base is ability to take math code and output speech
RS: braille involves fight with AT
NS: we dont' speak things, we return text for speech and braille
engines
AG: take back to ATs -- knee-jerk reaction is that that is part of
procedure call on dispatching expert handler -- should know if have
braille device and follow user's preference; Fluid Project beating on
W3C elsewhere, so will be a W3C user prefernces in context that can be
exposed
RS: don't want future equivalent for MathML
... "equation" or "math"
LP: preference for math -- it's shorter
NS: MathML prefered equation, personally don't care
AG: can live with either -- math good idea now -- authors will relate
better to math - will think equation doesn't always apply
RS: can say in description "this is a math equation"
NS: not equations, expressions, but...
RS: math expression in definition
<Al> +1
+1
<Rich> +1
<kenny> +1
LP +1
<Jon> +1
raman gave +1 to "math" on list
RESOLUTION: ARIA will use math role type; in definition will state
that this is a "math expression"
rssagent make minutes
RS: describedby a universal property, right?
MC: yes
RS: don't have to say antyhing explicit in spec about math, but a BP
thing; have to compose best practices section 1) alternative text
embedded in image, third party app extracts info and load
"describedby" with that info, or may speak, or author may but in
"describedby" himslef
NS: describedby -- words to speak or what should be written into DOM
using existing API bindings
AG: need to get AaronL (mozilla) and SimonP (opera) in on this
RS: best way to speak it (as long as not changing voice dynamics) ==
that way AT doesn't have to think alot to deliver to TTS or braille
device
NS: machine encoding shouldn't be part of "describedby"
AG: how does API binding respect cascade of acceptable forms
NS: someone could manually use field -- need to know if field exists
AG: action/homework item: UA best practice for AT helper (expert
handler -- if writes back into DOM, how to do it)
... need browser brothers to address this
RS: if start putting other markup in there, going to go bonkers
AG: are we going to say if TeX in image and can figure how to say that
can overwrite ALT and go with that -- haven't been considering that
piece of problem
NS: 2 ways: 1) we say "override ALT or describedby" and put in
description AT can pick up: 2) tighter binding -- id as Math -- call
expert handler, and that will tell us what to say -- that fall back
position is needed -- may be rewriting ALT or describedby -- should
process, put back into DOM
AG: for PF, in terms of browsers binding DOM to API, much plainer if
return to AT that called handler than figuring out override; don't
want to overwrite something suitable to speak that is only handled by
handler; handler api has to return best advoice on how to speak or
braille expression
RS: what is best practice: how does an AT know that an expert
handler/plugin (MathPlayer - works only in IE)
NS: have to work with each AT vendor to tell them "when you get to
this node, use our interfaces" when you get to our interface, then
speak, highlight, braille-output
... plug-in a dll that gets into registry
... want standard way that says "here is how you work with expert
handler" rather than one-off solutions
AG: browsers look like going to implement ARIA, will be refelected in
accessibleRole in API -- if use a11y API can bootstrap off of that,
determine if math and then ask for help
RS: preferential way to look at describedby or alt -- that would be
what is to be spoken
NS: JavaScript solution is a cross-platform base fallback -- can't
give highlighting or braille currnetly; if could write SSML into math
speech, would be much better, but if stuck with plain text, fake it
with commas and periods and other klduges
AG: small SSML implementations not available yet
RS: if use describedby method should be processable in speech
NS: exactly what i did with MSAA/SAPI5 -- value field with plain text
... like RS' solution
RS: need to put something in best practices -- don't need to do
anything special with UA devs
AG: have in our vocab "valuetext" -- if make "valuetext" apply to math
role, have place to stuff it
RS: [ponders] --
NS: can it be a long string?
RS: yes
... currently valuetext associated with valuemax valuemin etc.
AG: document has tools to deal with it attribute by attribute -- math
role has this property: "valuetext" defaults to how to say, can also
put in how to braille
RS: in HTML what is maximum lenght of string
AG: have to look for it
... generic limit on strings 255
MC: anything directed towards human should be in an element
RS: between 2 tags can be as long as want
AG: that points to describedby over valuetext -- problem: have to work
with AT so that role="math" goies straight to describedby and prcess
it in its entirety
RS: think have enought to write something up
ACTION ARIA Editors: write up proposal for role="math" and best
practices for its use
<kenny> bye
NS: happy to participate as needed
Summary of Action Items
[End of minutes]
--------------------------------------------------------------
You cannot depend on your eyes when your imagination is out of
focus. -- Mark Twain
--------------------------------------------------------------
Gregory J. Rosmaita: unagi69@concentric.net
Camera Obscura: http://www.hicom.net/~oedipus/
Oedipus' Online Complex: http://my.opera.com/oedipus
--------------------------------------------------------------
Received on Friday, 11 April 2008 08:59:25 UTC