Change Wordpress default gallery output

Question

I am looking to use the Wordpress gallery shortcut but I want to tie the output into the Foundation Orbit plugin (to make a slider). This is the HTML I am looking to output:

<div class="slideshow-wrapper">
    <div class="preloader"></div>
    <ul data-orbit>
        <li>
            <img src="img1.png" alt="bla bla bla" />
        </li>
        <li>
            <img src="img2.png" alt="bla bla bla" />
        </li>
        <li>
            <img src="img3.png" alt="bla bla bla" />
        </li>
        <li>
            <img src="img4.png" alt="bla bla bla" />
        </li>
    </ul>
</div>

Is it possible to put something in functions.php (or similar) to achieve this?

Answer 1

Yes, indeed. Quite a while ago I've found this code and have been using it ever since. It's great to customize WP's default gallery to whatever you want.

There's a filter to post_gallery which you can use to customize all default WP galleries. Here's a sample of the code I use adapted to the template you provided. I've cleared it up as much as possible.

The first part of the function is pretty much gallery attachments handling, so you'll probably just want to change the latter half, the one that determines the output of your gallery template (follow the comments):

add_filter('post_gallery', 'my_post_gallery', 10, 2);
function my_post_gallery($output, $attr) {
    global $post;

    if (isset($attr['orderby'])) {
        $attr['orderby'] = sanitize_sql_orderby($attr['orderby']);
        if (!$attr['orderby'])
            unset($attr['orderby']);
    }

    extract(shortcode_atts(array(
        'order' => 'ASC',
        'orderby' => 'menu_order ID',
        'id' => $post->ID,
        'itemtag' => 'dl',
        'icontag' => 'dt',
        'captiontag' => 'dd',
        'columns' => 3,
        'size' => 'thumbnail',
        'include' => '',
        'exclude' => ''
    ), $attr));

    $id = intval($id);
    if ('RAND' == $order) $orderby = 'none';

    if (!empty($include)) {
        $include = preg_replace('/[^0-9,]+/', '', $include);
        $_attachments = get_posts(array('include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby));

        $attachments = array();
        foreach ($_attachments as $key => $val) {
            $attachments[$val->ID] = $_attachments[$key];
        }
    }

    if (empty($attachments)) return '';

    // Here's your actual output, you may customize it to your need
    $output = "<div class=\"slideshow-wrapper\">\n";
    $output .= "<div class=\"preloader\"></div>\n";
    $output .= "<ul data-orbit>\n";

    // Now you loop through each attachment
    foreach ($attachments as $id => $attachment) {
        // Fetch the thumbnail (or full image, it's up to you)
//      $img = wp_get_attachment_image_src($id, 'medium');
//      $img = wp_get_attachment_image_src($id, 'my-custom-image-size');
        $img = wp_get_attachment_image_src($id, 'full');

        $output .= "<li>\n";
        $output .= "<img src=\"{$img[0]}\" width=\"{$img[1]}\" height=\"{$img[2]}\" alt=\"\" />\n";
        $output .= "</li>\n";
    }

    $output .= "</ul>\n";
    $output .= "</div>\n";

    return $output;
}

Just paste it to your functions.php file and modify to adapt it to your need. I'm pretty sure it'll work for you as it have worked for me :)