Missing ALT attribute for 'photo' oEmbed type - image inside a link - accessibility [#1024470]

Where an image is the only item in a link it requires an ALT attribute. Otherwise, screen readers and other assistive technologies must speak the SRC attribute, which is meaningless (HTML5 specification, 4.8.1.1.2 A link or button containing nothing but the image).

The line in question is, ../oembed/oembedcore.module?..#l408

Line #408 - current:

    $return .= ' ' . l('<img src="' . check_url($embed->url) . '" />', $url, array(...)));

Line #408 - suggested fix (attached):

    	$alttext = empty($embed->title) ? t('Embedded image') : $embed->title;
        if (!empty($embed->provider_name)) {
            $alttext .= t(', on ') . $embed->provider_name;  // Improve for i18n.
        }
        $return .= ' ' . l('<img src="' . check_url($embed->url) . '" alt="'. $alttext .'" />', $url,
                array('html' => TRUE, 'absolute' => TRUE, 'attributes' => array('class' => 'oembed-photo oembed-content')));

Comment	File	Size	Author
#7	1024470-oembed-core-alttags-7-D6.patch	1.19 KB	stuart.crouch
	oembedcore-ALT-attribute-accessibility.module.txt	18.51 KB	nfreear

Comments

Comment #1

nfreear commented 12 January 2011 at 16:57

Note, the above attachment, oembedcore-ALT-attribute-accessibility.module.txt, is from version 6.x-0.8 - line numbers are a bit out (the code fragments above are from HEAD).

The bug applies to D6 and Drupal 7.

I look forward to your response. Cheers,

Nick

Comment #2

Everett Zufelt commented 12 January 2011 at 17:51

I took a look at your suggested change, but am unfamiliar with the module. Can you please provide a brief explanation of title and provider_name?

It does appear that you're on the right track, I just want to make sure that the alt text provided is as good as it can be. Agreed that it likely needs a i18n tidy.

Comment #3

nfreear commented 13 January 2011 at 07:52

Hi Everett,

Thanks for the quick and encouraging response!

Good question. 'title' and 'provider_name' are from the oEmbed standard (http://oembed.com). Taking the embedding of a Flickr image in a blog as an example, provider_name would be 'Flickr', while title is the image's caption or title on Flickr.

The title may be a carefully hand-crafted, meaningful text, or it may be the file-name from the upload eg. DSC12345.jpg. The latter is not great, but given the automated nature of oEmbed, it's probably the best we can do. Alternative suggestions welcome!

The key point is, we need an ALT text, which gives an indication of the content, and the destination of the link (and provides some attribution).

The solution for jquery-oembed may help - note this adds 'author_name' (eg. Flickr user-name),
code.google.com/p/jquery-oembed/.../jquery.oembed.js?r=.#72 code - issue #3.

Best wishes,

Nick

Comment #4

Everett Zufelt commented 13 January 2011 at 08:33

Thanks,

What you have then seems pretty much as good as it can be, given that the data is coming from another source. Curious if the title / provider name has already been check_plain().

Perhaps replacing 'on' with 'from' or 'posted on' would give a bit more context for the provider name.