docs: function (cfg) {
          if (arguments.length === 0) { var components = (this.css ('transform') || '').match (/^matrix\((.+\))$/)
              if (components) {
                  var m = components[1].split (',').map (parseFloat)
                  return new Transform ({ a: m[0], b: m[1], c: m[2], d: m[3], e: m[4], f: m[5] }) }
              else {
                  return Transform.identity } }
          else {
              return this.css ('transform', (_.isStrictlyObject (cfg) && (
                  (cfg.translate ? ('translate(' + cfg.translate.x + 'px,' + cfg.translate.y + 'px) ') : '') +
                  (cfg.rotate ? ('rotate(' + cfg.rotate + 'rad) ') : '') +
                  (cfg.scale ? ('scale(' + (new Vec2 (cfg.scale).separatedWith (',')) + ')') : ''))) || '') } }