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Re: Need differentiator between "no alt text provided" and "no alt text necessary"

From: James Craig <jcraig@apple.com>
Date: Mon, 2 Feb 2009 19:10:19 -0800
Cc: Maciej Stachowiak <mjs@apple.com>, public-html@w3.org
Message-Id: <1E7B1771-09C5-4CE9-B506-282D928E47DC@apple.com>
To: Ian Hickson <ian@hixie.ch>

On Feb 2, 2009, at 5:40 PM, Ian Hickson wrote:

> On Mon, 2 Feb 2009, James Craig wrote:
>> On Feb 2, 2009, at 3:39 PM, Ian Hickson wrote:
>>
>>> The very next sentence is:
>>>
>>> If the image is available, the element represents the image  
>>> specified
>>> by the src attribute.
>>>
>>> ...and the Rendering section (which I'm writing as we speak) will  
>>> say
>>> something along the lines of "user agents are expected to render  
>>> <img>
>>> elements as replaced elements showing the image they represent" or  
>>> some
>>> such like.
>>
>> Both of those are fine, but neither adequately defines how a user  
>> agent
>> should "render" the non-visual equivalent of the image. I think  
>> Maciej's
>> wording proposal above does.
>
> The non-image case is handled by the sentence after the one I quote
> above, and will also have detailed text in the rendering section.

Are you referring to the sentence that starts: "If the image is not  
available or if the user agent is not configured to display the image,  
then…"?

If so, that sentence does not address the non-visual equivalent of a  
displayed image. It only addresses the cases of a broken or missing  
image, or the inability to display an image. Those cases are necessary  
but, as far as I can tell, irrelevant to this thread.

Would you be willing to add this clarification (as previously proposed  
by Maciej) of how user agent handle images without an alt attribute?  
Since it's an RFC 2119, I assume it would need to go in a normative  
section.

"User agents MAY (or SHOULD) assume images without an alt attribute  
are a key part of the content lacking a textual equivalent."

That would then clearly indicate the following:

1. <img src="…" alt="">		Presentational image.
2. <img src="…" alt="foo">		Meaningful image, alt text provided.
3. <img src="…">				Meaningful image, no alt text provided.

Currently case #3 is unclear. It might be a meaningful image with no  
alt text provided, or it might be something else entirely. I realize  
that we'll always have authors that do not use alt correctly, but we  
should have a clear definition of what it means when they do.
Received on Tuesday, 3 February 2009 03:11:33 GMT

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