docs: function(x, y) {
              if (typeof x === "number" && typeof y === "number") {
                  var center = this.pos2px(x, y);
                  Crafty.viewport._x =
                      -center.left +
                      Crafty.viewport.width / 2 -
                      this._tile.width / 2;
                  Crafty.viewport._y =
                      -center.top +
                      Crafty.viewport.height / 2 -
                      this._tile.height / 2;
                  return this;
              } else {
                  return {
                      top:
                          -Crafty.viewport._y +
                          Crafty.viewport.height / 2 -
                          this._tile.height / 2,
                      left:
                          -Crafty.viewport._x +
                          Crafty.viewport.width / 2 -
                          this._tile.width / 2
                  };
              }
          }