docs: function (geometry) {
              var boundary = this._boundary;
              if (boundary) {
                  var boundaryGeometry = boundary;
                  if (boundary == ariaUtilsDom.VIEWPORT) {
                      var viewportSize = ariaUtilsDom._getViewportSize();
                      boundaryGeometry = {
                          x: 0,
                          y: 0,
                          width: viewportSize.width,
                          height: viewportSize.height
                      };
                  }
                  var deltaLeft = geometry.x - boundaryGeometry.x;
                  var deltaTop = geometry.y - boundaryGeometry.y;
                  var deltaRight = boundaryGeometry.x + boundaryGeometry.width - geometry.x - geometry.width;
                  var deltaBottom = boundaryGeometry.y + boundaryGeometry.height - geometry.y - geometry.height;
                  if (deltaLeft < 0) {
                      geometry.x -= deltaLeft;
                      geometry.width += deltaLeft;
                  }
                  if (deltaTop < 0) {
                      geometry.y -= deltaTop;
                      geometry.height += deltaTop;
                  }
                  if (deltaRight < 0) {
                      geometry.width += deltaRight;
                  }
                  if (deltaBottom < 0) {
                      geometry.height += deltaBottom;
                  }
              }
              return geometry;
          }