wp_tag_cloud

 * @since 2.8.0 Added the `taxonomy` argument.
 * @since 4.8.0 Added the `show_count` argument.
 *
 * @param array|string $args {
 *     Optional. Array or string of arguments for displaying a tag cloud. See wp_generate_tag_cloud()
 *     and get_terms() for the full lists of arguments that can be passed in `$args`.
 *
 *     @type int    $number    The number of tags to display. Accepts any positive integer
 *                             or zero to return all. Default 0 (all tags).
 *     @type string $link      Whether to display term editing links or term permalinks.
 *                             Accepts 'edit' and 'view'. Default 'view'.
 *     @type string $post_type The post type. Used to highlight the proper post type menu
 *                             on the linked edit page. Defaults to the first post type
 *                             associated with the taxonomy.
 *     @type bool   $echo      Whether or not to echo the return value. Default true.
 * }
 * @return void|string|array Void if 'echo' argument is true, or on failure. Otherwise, tag cloud
 *                           as a string or an array, depending on 'format' argument.
 */
function wp_tag_cloud( $args = '' ) {
	$defaults = array(
		'smallest'   => 8,
		'largest'    => 22,
		'unit'       => 'pt',
		'number'     => 45,
		'format'     => 'flat',
		'separator'  => "\n",
		'orderby'    => 'name',
		'order'      => 'ASC',
		'exclude'    => '',
		'include'    => '',
		'link'       => 'view',
		'taxonomy'   => 'post_tag',
		'post_type'  => '',
		'echo'       => true,
		'show_count' => 0,
	);

	$args = wp_parse_args( $args, $defaults );

	$tags = get_terms(
		array_merge(
			$args,
			array(
				'orderby' => 'count',
				'order'   => 'DESC',
			)
		)
	); // Always query top tags.

	if ( empty( $tags ) || is_wp_error( $tags ) ) {
		return;
	}

	foreach ( $tags as $key => $tag ) {
		if ( 'edit' === $args['link'] ) {
			$link = get_edit_term_link( $tag->term_id, $tag->taxonomy, $args['post_type'] );
		} else {
			$link = get_term_link( intval( $tag->term_id ), $tag->taxonomy );
		}

		if ( is_wp_error( $link ) ) {
			return;
		}

		$tags[ $key ]->link = $link;
		$tags[ $key ]->id   = $tag->term_id;