public static function get_instance()
 {
     if (!self::$instance) {
         self::$instance = new DT_Shortcode_Photos_Masonry();
     }
     return self::$instance;
 }
                } else {
                    $attributes['proportion'] = '';
                }
            }
            return $attributes;
        }
        protected function setup_config()
        {
            $config =& $this->config;
            $atts =& $this->atts;
            $config->set('template', 'media');
            $config->set('layout', 'masonry');
            $config->set('load_style', 'default');
            $config->set('justified_grid', false);
            $config->set('full_width', false);
            $config->set('item_padding', $atts['padding']);
            $config->set('image_layout', $atts['proportion'] ? 'resize' : 'original');
            $config->set('thumb_proportions', $atts['proportion']);
            $config->set('show_excerpts', $atts['show_excerpt']);
            $config->set('show_titles', $atts['show_title']);
            $content_visible = $atts['show_title'] || $atts['show_excerpt'];
            $config->set('post.preview.content.visible', $content_visible);
            $config->set('post.preview.description.style', $content_visible ? 'under_image' : 'disabled');
            $config->set('post.preview.load.effect', $atts['loading_effect']);
            $config->set('post.preview.width.min', $atts['column_width']);
            $config->set('template.columns.number', $atts['columns']);
        }
    }
    // create shortcode
    DT_Shortcode_Photos_Masonry::get_instance();
}