Center that window on the given desktop. : SwingUtilities « Swing « Java Tutorial

 * $Id:,v 1.16 2009/05/25 16:37:52 kschaefe Exp $
 * Copyright 2004 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import java.awt.GraphicsDevice;
import java.awt.GraphicsEnvironment;
import java.awt.MouseInfo;
import java.awt.Point;
import java.awt.Rectangle;

import javax.swing.JInternalFrame;

 * Encapsulates various utilities for windows (ie: <code>Frame</code> and
 * <code>Dialog</code> objects and descendants, in particular).
 * @author Richard Bair
public class Utils {
   * <p/>
   * Returns the <code>Point</code> at which a window should be placed to
   * center that window on the given desktop.
   * </p>
   * <p/>
   * Some thought was taken as to whether to implement a method such as this,
   * or to simply make a method that, given a window, will center it.  It was
   * decided that it is better to not alter an object within a method.
   * </p>
   * @param window  The window (JInternalFrame) to calculate the center point
   *                for.  This object can not be null.
   * @return the <code>Point</code> at which the window should be placed to
   *         center that window on the given desktop
  public static Point getPointForCentering(JInternalFrame window) {
      try {
          //assert window != null;
          Point mousePoint = MouseInfo.getPointerInfo().getLocation();
          GraphicsDevice[] devices = GraphicsEnvironment
          for (GraphicsDevice device : devices) {
              Rectangle bounds = device.getDefaultConfiguration().getBounds();
              //check to see if the mouse cursor is within these bounds
              if (mousePoint.x >= bounds.x && mousePoint.y >= bounds.y
                  && mousePoint.x <= (bounds.x + bounds.width)
                  && mousePoint.y <= (bounds.y + bounds.height)) {
                  //this is it
                  int screenWidth = bounds.width;
                  int screenHeight = bounds.height;
                  int width = window.getWidth();
                  int height = window.getHeight();
                  return new Point(((screenWidth - width) / 2) + bounds.x,
                                      ((screenHeight - height) / 2) + bounds
      } catch (Exception e) {
      return new Point(0, 0);

14.127.1.Getting the JFrame of a Component
14.127.2.Convert a coordinate relative to a component's bounds to screen coordinates
14.127.3.Convert a coordinate on a screen to a coordinate relative to a component's bounds
14.127.4.Handle long-running tasks in a Swing application
14.127.5.Get the JFrame by getting the root of a component
14.127.6.Positions the specified frame at a relative position in the screen, where 50% is considered to be the center of the screen.
14.127.7.Positions the specified frame in the middle of the screen.
14.127.8.Positions the specified frame at a random location on the screen while ensuring that the
14.127.9.Get Window from a component
14.127.10.Center that window on the given desktop.
14.127.11.Get All Components in a container
14.127.12.Get Point For Centering
14.127.13.Is Within Parent
14.127.14.Show the given frame as modal to the specified owner
14.127.15.Change the sizes of all the passed buttons to be the size of the largest one.
14.127.16.Get Screen Bounds For
14.127.17.Returns the offset of the bracket matching the one at the specified offset of the document