Java Tutorial/Swing/JWindow

Center window

   <source lang="java">

/*

* Copyright (c) 1998-2002 Carnegie Mellon University.  All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* THIS SOFTWARE IS PROVIDED BY CARNEGIE MELLON UNIVERSITY ``AS IS"" AND
* ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY
* NOR ITS EMPLOYEES BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

import java.awt.*; public abstract class Win {

   public static void center (Window window, Component ref) {
       position (window, ref, 0.5, 0.5);
   }
   public static void position (Window frame, Component ref, 
                                double xfrac, double yfrac) {
       Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
       Dimension size = frame.getSize();
       Dimension refSize = (ref != null) 
           ? ref.getSize() 
           : screenSize;
       Point origin = (ref != null)
           ? ref.getLocationOnScreen () 
           : new Point (0, 0);
       int x = origin.x + relativePoint (xfrac, refSize.width, size.width);
       int y = origin.y + relativePoint (yfrac, refSize.height, size.height);
       // make sure frame is entirely on screen
       x = Math.max (0, Math.min (screenSize.width - size.width, x));
       y = Math.max (0, Math.min (screenSize.height - size.height, y));
       
       frame.setLocation (x, y);
   }
   static int relativePoint (double frac, int parentLength, int childLength) {
       if (frac < 0)
           return (int) (frac * childLength);
       else if (frac > 1)
           return (int) (parentLength + (frac - 2) * childLength);
       else
           return (int) (frac * (parentLength - childLength));
   }

   public static Frame findFrame (Component comp) {
       for (; comp!=null; comp = comp.getParent ())
           if (comp instanceof Frame) {
               return (Frame)comp;
           }
       return null;
   }
   public static Frame findFrameOrMakeFrame (Component parent) {
       return (parent != null) ? findFrame (parent) : new Frame ();
   }
       

}</source>

Center Within Parent

   <source lang="java">

/*

* Copyright (C) 2001-2004 Colin Bell
* colbell@users.sourceforge.net
*
* 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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

import java.awt.ruponent; import java.awt.Container; import java.awt.Dimension; import java.awt.FontMetrics; import java.awt.Frame; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.Insets; import java.awt.Point; import java.awt.Rectangle; import java.awt.Toolkit; import java.awt.Window; import java.awt.geom.Rectangle2D; import java.beans.PropertyVetoException; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JInternalFrame; import javax.swing.SwingUtilities; /**

* Common GUI utilities accessed via static methods.
* 
* @author 
*/

public class GUIUtils {

 private static JFrame _mainFrame;
 /**
  * Centers wind within its parent. If it has no parent then
  * center within the screen. If centering would cause the title bar to go
  * above the parent (I.E. cannot see the titlebar and so cannot move the
  * window) then move the window down.
  * 
  * @param wind
  *          The Window to be centered.
  * 
  * @throws IllegalArgumentException
  *           If wind is null.
  */
 public static void centerWithinParent(Window wind) {
   if (wind == null) {
     throw new IllegalArgumentException("null Window passed");
   }
   final Container parent = wind.getParent();
   if (parent != null && parent.isVisible()) {
     center(wind, new Rectangle(parent.getLocationOnScreen(), parent.getSize()));
   } else {
     centerWithinScreen(wind);
   }
 }
 /**
  * Centers passed internal frame within its desktop area. If centering would
  * cause the title bar to go off the top of the screen then move the window
  * down.
  * 
  * @param frame
  *          The internal frame to be centered.
  * 
  * @throws IllegalArgumentException
  *           If frame is null.
  */
 public static void centerWithinDesktop(JInternalFrame frame) {
   if (frame == null) {
     throw new IllegalArgumentException("null JInternalFrame passed");
   }
   final Container parent = frame.getDesktopPane();
   if (parent != null && parent.isVisible()) {
     center(frame, new Rectangle(new Point(0, 0), parent.getSize()));
   }
 }
 /**
  * Centers wind within the screen. If centering would cause the
  * title bar to go off the top of the screen then move the window down.
  * 
  * @param wind
  *          The Window to be centered.
  * 
  * @throws IllegalArgumentException
  *           If wind is null.
  */
 public static void centerWithinScreen(Window wind) {
   if (wind == null) {
     throw new IllegalArgumentException("null Window passed");
   }
   final Toolkit toolKit = Toolkit.getDefaultToolkit();
   final Rectangle rcScreen = new Rectangle(toolKit.getScreenSize());
   final Dimension windSize = wind.getSize();
   final Dimension parentSize = new Dimension(rcScreen.width, rcScreen.height);
   if (windSize.height > parentSize.height) {
     windSize.height = parentSize.height;
   }
   if (windSize.width > parentSize.width) {
     windSize.width = parentSize.width;
   }
   center(wind, rcScreen);
 }
 /**
  * Centers wind within the passed rectangle.
  * 
  * @param wind
  *          The Window to be centered.
  * @param rect
  *          The rectangle (in screen coords) to center wind
  *          within.
  * 
  * @throws IllegalArgumentException
  *           If Window or Rectangle is null.
  */
 private static void center(Component wind, Rectangle rect) {
   if (wind == null || rect == null) {
     throw new IllegalArgumentException("null Window or Rectangle passed");
   }
   Dimension windSize = wind.getSize();
   int x = ((rect.width - windSize.width) / 2) + rect.x;
   int y = ((rect.height - windSize.height) / 2) + rect.y;
   if (y < rect.y) {
     y = rect.y;
   }
   wind.setLocation(x, y);
 }

}</source>

Difference between JFrame and JWindow

   <source lang="java">

import javax.swing.JFrame; import javax.swing.JWindow; public class Main {

 public static void main(String[] args) {
   JFrame f = new JFrame("The Frame");
   f.setSize(300, 300);
   f.setLocation(100, 100);
   JWindow w = new JWindow();
   w.setSize(300, 300);
   w.setLocation(500, 100);
   f.setVisible(true);
   w.setVisible(true);
 }

}</source>

Extending JWindow

If you need to extend JWindow, the class has two protected methods of importance:

   <source lang="java">

protected void windowInit() protected JRootPane createRootPane()</source>

Have borders on a JWindow/JFrame

   <source lang="java">

import java.awt.FlowLayout; import javax.swing.JButton; import javax.swing.JPanel; import javax.swing.JWindow; public class Main{

 public static void main(String s[]) {
   JWindow win = new JWindow();
   JPanel pan = new JPanel();
   win.add(pan, "Center");
   pan.setLayout(new FlowLayout());
   pan.add(new JButton("Hello"));
   win.setSize(200, 200);
   win.setVisible(true);
 }

}</source>