Which wordpress function is the caption shortcode linked to?

Question

I have used this code in my page content to try and output an image + caption with a custom caption class and id...

[caption id="my-caption-id" class="my-caption-class" align="alignnone" width="399"]<img src="whatever.jpg" alt="whatever" width="399" height="600" /> My caption text[/caption]

...but the caption's id and class names are not being output.

After some digging around, I found the img_caption_shortcode function in wp-includes/media.php which handles the id and class attributes of the [caption] shortcode but, after some experimenting, it seems this function is not executed with the [caption] shortcode...

So does anyone know which function the [caption] shortcode is linked to? (and / or how to get the class and id attributes to be output on a caption?)

I'm using WordPress 3.9.2 .

Answer 1

You should try this on a default theme (without any plugins), to see if that makes any difference.

Your shortcode example:

[caption id="my-caption-id" class="my-caption-class" align="alignnone" width="399"]
    <img src="whatever.jpg" alt="whatever" width="399" height="600" /> 
    My caption text
[/caption]

gives this output:

<div id="my-caption-id" 
     style="width: 409px" 
     class="wp-caption alignnone my-caption-class">
    <img src="whatever.jpg" alt="whatever" width="399" height="600">
    <p class="wp-caption-text">My caption text</p>
</div>

on the Twenty Twelve theme. It's just a little bit formatted to make it easier to read here.

So the caption id and classes are displayed in the output.

Update:

It looks like your theme is overriding the image caption via:

// Remove default inline style of wp-caption
add_shortcode('wp_caption', 'fixed_img_caption_shortcode');
add_shortcode('caption', 'fixed_img_caption_shortcode');

in the /library/cleanup.php file.