public void scrollToAttribute(Attribute a) {
    if (!a.getDescriptor().getConfig().equals(getConfig())) {
      logger.fine("Cannot scroll to attribute that isn't attached to this type of descriptor");
      return;
    }
    int rowIndex = getCurrentModel().getRowForDescriptor(a.getDescriptor());
    int colIndex = getCurrentModel().getColumnForAttribute(a);
    JScrollPane scrollPane = (JScrollPane) this.getComponent(0);
    JViewport viewport = (JViewport) scrollPane.getViewport();
    EnhancedTable table = (EnhancedTable) viewport.getView();

    // This rectangle is relative to the table where the
    // northwest corner of cell (0,0) is always (0,0).
    Rectangle rect = table.getCellRect(rowIndex, colIndex, true);

    // The location of the viewport relative to the table
    Point pt = viewport.getViewPosition();

    // Translate the cell location so that it is relative
    // to the view, assuming the northwest corner of the
    // view is (0,0)
    rect.setLocation(rect.x - pt.x, rect.y - pt.y);

    // Scroll the area into view
    viewport.scrollRectToVisible(rect);
  }
  /**
   * Method to check that the current position is in the viewing area and if not scroll to center
   * the current position if possible
   */
  public void checkScroll() {
    // get the x and y position in pixels
    int xPos = (int) (colIndex * zoomFactor);
    int yPos = (int) (rowIndex * zoomFactor);

    // only do this if the image is larger than normal
    if (zoomFactor > 1) {

      // get the rectangle that defines the current view
      JViewport viewport = scrollPane.getViewport();
      Rectangle rect = viewport.getViewRect();
      int rectMinX = (int) rect.getX();
      int rectWidth = (int) rect.getWidth();
      int rectMaxX = rectMinX + rectWidth - 1;
      int rectMinY = (int) rect.getY();
      int rectHeight = (int) rect.getHeight();
      int rectMaxY = rectMinY + rectHeight - 1;

      // get the maximum possible x and y index
      int macolIndexX = (int) (picture.getWidth() * zoomFactor) - rectWidth - 1;
      int macolIndexY = (int) (picture.getHeight() * zoomFactor) - rectHeight - 1;

      // calculate how to position the current position in the middle of the viewing
      // area
      int viewX = xPos - (int) (rectWidth / 2);
      int viewY = yPos - (int) (rectHeight / 2);

      // reposition the viewX and viewY if outside allowed values
      if (viewX < 0) viewX = 0;
      else if (viewX > macolIndexX) viewX = macolIndexX;
      if (viewY < 0) viewY = 0;
      else if (viewY > macolIndexY) viewY = macolIndexY;

      // move the viewport upper left point
      viewport.scrollRectToVisible(new Rectangle(viewX, viewY, rectWidth, rectHeight));
    }
  }