Sorting Masonry Gallery by random

Hi folks,

I had the problem of sorting a masonry gallery by random – inclunding using the ‘load more’-functionality. It took a bit of digging into the source code, but I want to give others the results as a hint. In my special case I want to have all images sorted into a special WP Media Folder as well as the post image used in a portfolio item. You may adapt the solution to Your specific needs:

add_filter('avia_masonry_entries_query', 'avia_gallery_image_query', 10, 2);

function avia_gallery_image_query($query, $params)
{
	// Matches on empty masonry galleries which are not Portfolio Masonry
	if ($params['ids'] == null && (!isset ($params ['taxonomy']) || $params ['taxonomy'] != 'portfolio_entries'))
    {        
		// First call - then then 'post__in' is set, but empty
		if (isset ($query ['post__in']))
		{
			// Get al my portfolio categories
			$terms = array();
			$allTax = get_terms('portfolio_entries');
			foreach($allTax as $tax) 
			{
				$terms[] = $tax->term_id;
			}

			// Register the WP Media Folder category - doesn't work without
            register_taxonomy('wpmf-category', 'attachment', array('hierarchical'=>true,'show_in_nav_menus'=>false,'show_ui'=>false));

			// Get all the images that match the root folder 'galerie' as well as all portfolio-items
			$available = new WP_Query
            (
				array
				(
					'posts_per_page' => -1,
					'post_status'     => array ( 'publish', 'inherit'),
					'post_type'     => array ( 'attachment', 'portfolio' ),
					'post_parent'   => null,        
					'tax_query'    => array
							(
								array
								(            
									'taxonomy' => 'portfolio_entries',
									'field'    => 'id',
									'terms'    => $terms,
									'operator' => 'IN'
								),
								'relation' => 'OR',
								array
								(            
									'taxonomy' => 'wpmf-category',
									'field'    => 'slug',
									'terms'    => array ( 'galerie' ),
									'operator' => 'IN'
								),                                
							),
						'fields'        => 'ids'
            ));

			// Place it into a session variable
			$_SESSION['gallery'] = $available->posts;

			// Sort it by random
			shuffle ($_SESSION['gallery']);
		}

		// Reset all relevant query parameters and set the IN-Clause to the found items and sort them by the random order as done before
		$query ['post__in'] = $_SESSION['gallery'];
		$query ['orderby'] = 'post__in';
		$query ['order'] = 'ASC';
		$query ['tax_query'] = null;
		$query ['post_status'] = 'any';
		$query ['post_type'] = 'any';
		$query ['post_mime_type'] = null;
		$query ['post_parent'] = null;

		// Don't let any sort plugin modify what we want
		remove_all_filters('posts_orderby');
    }
    else
    {
		// Reset the session variable
		$_SESSION['gallery'] = array ();
    }

    return $query;

}