Show category tags WordPress. Code example

function get_tags_in_cat( $cat_id ) {
	$posts = get_posts( array( 'category' => $cat_id, 'numberposts' => -1 ) );
	$tags  = array();

	foreach ( $posts as $post ) {
		$post_tags = get_the_tags( $post->ID );
		if ( ! empty( $post_tags ) )
			foreach ( $post_tags as $tag )
				$tags[ $tag->term_id ] = $tag->name;
	}
	asort( $tags );
	return $tags;
}