Hooks & Filters

Bannerize provides WordPress filters that allow developers to customize banner behavior and output. These hooks follow standard WordPress conventions and can be used in your theme’s functions.php or in a custom plugin.

Available Filters

`wp_bannerize_classes`

Modify the CSS classes applied to each banner’s container element.

Signature:


apply_filters('wp_bannerize_classes', array $classes, WP_Post $banner): array

Parameters:

Parameter	Type	Description
`$classes`	`array`	Array of CSS class strings applied to the banner container
`$banner`	`WP_Post`	The WordPress post object for the current banner

Return: An array of CSS class strings.

Example: Add a Class to All Banners


add_filter('wp_bannerize_classes', function ($classes, $banner) {
    $classes[] = 'my-site-banner';
    return $classes;
}, 10, 2);

Example: Add Classes Based on Banner Type


add_filter('wp_bannerize_classes', function ($classes, $banner) {
    $type = get_post_meta($banner->ID, 'banner_type', true);
 
    switch ($type) {
        case 'local':
            $classes[] = 'banner-local-image';
            break;
        case 'remote':
            $classes[] = 'banner-remote-image';
            break;
        default:
            $classes[] = 'banner-html-content';
            break;
    }
 
    return $classes;
}, 10, 2);

Example: Add Campaign Slug as a CSS Class


add_filter('wp_bannerize_classes', function ($classes, $banner) {
    $terms = wp_get_post_terms($banner->ID, 'wp_bannerize_tax', [
        'fields' => 'slugs',
    ]);
 
    if (!is_wp_error($terms)) {
        foreach ($terms as $slug) {
            $classes[] = 'campaign-' . sanitize_html_class($slug);
        }
    }
 
    return $classes;
}, 10, 2);

This adds classes like campaign-sidebar-ads and campaign-holiday-sale to each banner, allowing you to target campaign-specific styles in CSS:


.campaign-holiday-sale {
    border: 2px solid #c41e3a;
    border-radius: 8px;
}

Example: Add Size-Based Classes


add_filter('wp_bannerize_classes', function ($classes, $banner) {
    $width = (int) get_post_meta($banner->ID, 'banner_width', true);
 
    if ($width >= 728) {
        $classes[] = 'banner-large';
    } elseif ($width >= 300) {
        $classes[] = 'banner-medium';
    } else {
        $classes[] = 'banner-small';
    }
 
    return $classes;
}, 10, 2);

Example: Remove a Default Class


add_filter('wp_bannerize_classes', function ($classes, $banner) {
    // Remove a specific class
    $classes = array_filter($classes, function ($class) {
        return $class !== 'unwanted-class';
    });
 
    return array_values($classes);
}, 10, 2);

`wp_bannerize_banners_rank_seed`

Customize the seed value used for randomizing banner order when orderby is set to random.

Signature:


apply_filters('wp_bannerize_banners_rank_seed', int $seed): int

Parameters:

Parameter	Type	Description
`$seed`	`int`	The current randomization seed value

Return: An integer seed value.

This filter is only called when no explicit rank_seed is provided via shortcode attributes, widget settings, or PHP function arguments. If a rank_seed is explicitly set, it takes precedence over this filter.

Example: Change Random Order Every Hour


add_filter('wp_bannerize_banners_rank_seed', function ($seed) {
    // Same seed for the entire hour, changes on the hour
    return (int) date('YmdH');
});

This means all visitors within the same hour see the same “random” banner order. The order changes at the top of each hour.

Example: Change Random Order Daily


add_filter('wp_bannerize_banners_rank_seed', function ($seed) {
    // Same seed for the entire day
    return (int) date('Ymd');
});

Example: Per-User Random Order


add_filter('wp_bannerize_banners_rank_seed', function ($seed) {
    if (is_user_logged_in()) {
        // Each user sees their own consistent random order
        return get_current_user_id();
    }
 
    // Anonymous visitors get a different order each page load
    return $seed;
});

Example: Per-Page Random Order


add_filter('wp_bannerize_banners_rank_seed', function ($seed) {
    // Same random order on each specific page, different across pages
    return crc32(get_permalink());
});

Example: A/B Testing with Two Groups


add_filter('wp_bannerize_banners_rank_seed', function ($seed) {
    // Split visitors into two groups based on IP
    $ip = $_SERVER['REMOTE_ADDR'] ?? '0.0.0.0';
    $group = crc32($ip) % 2; // Returns 0 or 1
 
    return $group === 0 ? 1001 : 1002;
});

Group A (seed 1001) and Group B (seed 1002) will each see a different banner arrangement, but the arrangement is consistent within each group.

Using Filters in Your Theme

Add filter code to your theme’s functions.php file or create a custom plugin:


// In functions.php
add_filter('wp_bannerize_classes', 'my_bannerize_classes', 10, 2);
 
function my_bannerize_classes($classes, $banner) {
    $classes[] = 'my-theme-banner';
    return $classes;
}

If you add filters in your theme’s functions.php, they will be lost when you switch themes. For permanent customizations, consider creating a small custom plugin instead.

Filter Priority

Both filters support WordPress priority levels. A lower number means the filter runs earlier:


// Runs first (priority 5)
add_filter('wp_bannerize_classes', 'early_filter', 5, 2);
 
// Runs second (priority 10, default)
add_filter('wp_bannerize_classes', 'normal_filter', 10, 2);
 
// Runs last (priority 20)
add_filter('wp_bannerize_classes', 'late_filter', 20, 2);

The filter with the highest priority number has the final say on the output.