Re: SVG markup thoughts

Dear All,

Personally I believe inheritance should be kept to a minimum and be the
exception rather than the rule.

As an analogy I refer to experience from working with (presentation) 
MathML, where there is a
similar situation with the mstyle element, that allows to set 
inheritable styles
(very much inspired by LaTeX commands like textbf etc.). Styles can be 
locally
overwritten, partially overwritten, combined from different mstyle 
elements,
some elements only inherit certain style attributes while ignoring 
others etc.

In brief, it can be a real nightmare, in particular if one is trying to 
access
elements of a MathML structure locally. I believe ultimately the same 
thing
would hold for SVG. A well grouped SVG would allow one to access, 
exclusively
focus on or extract subelements. Everything that is only given 
implicitly, will
make life a lot more difficult for these tasks.

I appreciate the argument that authors might be going nuts if they had 
to
specify the same thing over and over again. But again I would refer to 
the
MathML experience, where the number of authors directly writing MathML 
is
actually very low. Most is automatically generated, where it makes 
little
difference if a few redundant attributes have to be added. On the other 
hand,
the number of systems that have to process existing MathML is constantly
growing. And most developers complain about the horrors imposed by 
elements like
mstyle.

Best,
Volker





On 2015-05-14 09:23, Richard Schwerdtfeger wrote:
> Fred, I understand the going nuts, ... but what this also means is
> that if you do the inheritance approach you also have to deal with:
> 
>  - situations where you don't want it inherited
>  - overriding roles on elements that you selectively don't want to
> inherit the role.
> 
>  This is extremely complicated for authors.
> 
>  We would also need to restrict this to specific roles. For widgets
> this will be a disaster.
> 
>  Rich
> 
>  Rich Schwerdtfeger
> 
>  Fred Esch---05/14/2015 09:17:59 AM---Rich, I think it is important to
> be able to inherit the semantic role from an ancestor for three rea
> 
>  From: Fred Esch/Arlington/IBM
>  To: Richard Schwerdtfeger/Austin/IBM@IBMUS, <public-svg-a11y@w3.org>
>  Date: 05/14/2015 09:17 AM
>  Subject: SVG markup thoughts
> 
> -------------------------
> 
>  Rich,
> 
>  I think it is important to be able to inherit the semantic role from
> an ancestor for three reasons. Semantic inheritance avoids bloat, it
> keeps authors from going nuts and simplifies guidance. Whenever you
> bloat your resource, products will argue against a bloated resource
> because it loads slower and takes more memory. We need to allow
> inheritance from any level of ancestor as intermediate groups are
> often generated for a change in style. For example, in the airline
> (delay) chart, the grid lines for the months are grouped by location
> of the text. These groupings are are more space saving than putting
> the attributes in each grid line and we should not discourage non
> semantic groupings.
> 
>  In my markup, when groups should be part of navigation, I provide one
> (or possibly two) of - title, desc, aria- label, labeledby or
> describedby. Non semantic grouping (like the airline chart month grid
> lines for text location) don't have a title, desc, aria- label,
> labeledby or describedby and are ignored by navigation.
> 
>  I am doing markup to support navigation and AT interpretation. Markup
> for media query style changes for low vision, color blind and coga
> will come later. In navigation experiments, regardless of the type of
> graphic, if you have groups that represent features, reasonable things
> happen (using a tree style navigation) when the groupings are done
> well.
> 
>  So if it will be a problem to allow role attribute inheritance, then
> I suggest we create a semantic role or graphic role (g-role)
> attribute.
> 
> Regards,
> 
>  Fred Esch
>  Accessibility, Watson Innovations
>  AARB Complex Visualization Working Group Chair
>  W3C SVG Accessibility Task Force

Received on Friday, 15 May 2015 11:29:07 UTC