Improve accessibility ( a11y ) of oik and oik-fields

[bobbingwide]

It's probably also necessary to remove the title= attribute from <img> tags.

Well, it's been a long time since I looked at accessibility of oik's code.
Having run WAVE against oik-plugins.com I thought it was time to add an alt attribute to the Featured image field displayed by the [bw_field] shortcode.

I changed bw_fields_get_featured_image() to access the alt text for the featured image (using the same code as in wp_get_attachment_image() ), then passed this to retimage().

$alt = trim( strip_tags( get_post_meta( $thumbnail_id, '_wp_attachment_image_alt', true ) ) );
$thumbnail = retimage( "featured", $thumbnail[0], $alt );

This worked but I got the WAVE Alert: Redundant title text due to having both title and alt attributes.

So I need to

• change retimage() as well
• or call wp_get_attachment_image instead.

Originally posted by @bobbingwide in #79

[bobbingwide]

Another WAVE error is Empty link when displaying noderef fields which are empty.
In this example there is no API ref value set for the [bw_logo] shortcode. The current code displays a '#'.

<div class="bw_metadata _oik_sc_func">
<span class="label _oik_sc_func">API ref</span>
<span class="sep">: </span>
<span class="value">
<a class="bw_link" href="#"></a>
</span>
</div>

Note: The API ref field is defined in oik-shortcodes as a sctext field. It used to be a noderef

bw_register_field( "_oik_sc_func", "sctext", "API ref", array( "#type" => "oik_api",  "#theme" => true, '#theme_null' => false ) );

• The field value is [bw_link 5893]
• Post ID 5893 does not exist.
• bw_link() calls retlink()
• retlink() sets the URL to # if it's not set.
• it therefore returns an empty link