- From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
- Date: Wed, 18 Aug 2010 20:27:32 +0200
- To: Mark Birbeck <mark.birbeck@webbackplane.com>
- Cc: Ivan Herman <ivan@w3.org>, Shane P McCarron <shane@aptest.com>, martin@weborganics.co.uk, W3C RDFa WG <public-rdfa-wg@w3.org>
Mark Birbeck, Wed, 18 Aug 2010 16:23:54 +0100:
> I'm not ignoring your email Leif. :) In fact I was in the middle of
> replying when I saw Ivan's response below, and since I think he has
> captured perfectly the current stage of the debate, I won't run the
> risk of causing confusion!
I do not think that *not* thinking about @alt when you makes use of a
concrete RDFa vocabulary, makes you create better @alt texts. I will
illustrate that by looking at some code of yours: [1]
1.<div about="#me" typeof="foaf:Person">
2. <span property="foaf:name">Mark Birbeck</span>
3. <a rel="foaf:weblog"
href="http://internet-apps.blogspot.com/">
XForms and Internet
4. Applications</a>
5. <a rel="foaf:knows" href="http://www.w3.org/People/Ivan/#me">
Ivan Herman</a>
6. <span rel="foaf:img">
7. <img
src="http://www.formsplayer.com/files/pictures/picture-11.jpg"
8. alt="Picture of Mark Birbeck"/>
9. </span>
10.</div>
Critique: A user with a non-visual user agent will have to read the
name "Mark Birbeck" twice - once as foaf:name and once inside @alt. But
given that the above construct/microformat is foaf:Person, then why
should it be necessary to repeat the name? Repeated text is can be a
boring for screen reader users. Also, a word such as "picture" also
isn't very telling.
If you took your use of @alt into the overall picture when creating you
foaf:Person microformat, then it is possible that you could have gotten
rid of the repetition, perhaps you could have had an entirely empty
@alt, and perhaps you could - if RDFa supported it - constructed a
useful triple with @alt as object.
Examples.
(1) Empty @alt example + no repetition:
<span role="img">
<span property='foaf:name'>Mark Birbeck</span>
<span rel='foaf:img'>
<img src='http://www.example.com/i.png' alt=''/>
</span>
</span>
(2) Non-empty @alt with useful info + no repetition + another triple.
<span role="img">
<span property='foaf:name'>Mark Birbeck</span>
<span rel='foaf:img'>
<img src='http://www.example.com/i.png'
property='foaf:Image'
alt='Portrait photo.'
content="Portrait photo" />
</span>
</span>
(3) The result in (2) can actually be achieved without using @role or
extra span elements:
<span rel='foaf:img'>
<img src='http://www.example.com/i.png'
property='foaf:Image'
alt='Portrait photo'
content="Portrait photo" />
</span>
Of course, the reason I repeat @alt inside @content, is due to how RDFa
works today.
[1]
http://webbackplane.com/mark-birbeck/blog/2009/04/getting-started-with-rdfa
--
leif halvard silli
Received on Wednesday, 18 August 2010 18:28:10 UTC