1 /*
   2  * Copyright (c) 1998, 2003, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.swing.plaf.basic;
  27 
  28 
  29 import java.awt.*;
  30 import java.io.*;
  31 
  32 /**
  33   * Center-positioning layout manager.
  34   * @author Tom Santos
  35   * @author Steve Wilson
  36   */
  37 class CenterLayout implements LayoutManager, Serializable {
  38     public void addLayoutComponent(String name, Component comp) { }
  39     public void removeLayoutComponent(Component comp) { }
  40 
  41     public Dimension preferredLayoutSize( Container container ) {
  42         Component c = container.getComponent( 0 );
  43         if ( c != null ) {
  44             Dimension size = c.getPreferredSize();
  45             Insets insets = container.getInsets();
  46 
  47             return new Dimension(size.width + insets.left + insets.right,
  48                                  size.height + insets.top + insets.bottom);
  49         }
  50         else {
  51             return new Dimension( 0, 0 );
  52         }
  53     }
  54 
  55     public Dimension minimumLayoutSize(Container cont) {
  56         return preferredLayoutSize(cont);
  57     }
  58 
  59     public void layoutContainer(Container container) {
  60         if (container.getComponentCount() > 0) {
  61             Component c = container.getComponent(0);
  62             Dimension pref = c.getPreferredSize();
  63             int containerWidth = container.getWidth();
  64             int containerHeight = container.getHeight();
  65             Insets containerInsets = container.getInsets();
  66 
  67             containerWidth -= containerInsets.left +
  68                               containerInsets.right;
  69             containerHeight -= containerInsets.top +
  70                                containerInsets.bottom;
  71 
  72             int left = (containerWidth - pref.width) / 2 +
  73                             containerInsets.left;
  74             int right = (containerHeight - pref.height) / 2 +
  75                             containerInsets.top;
  76 
  77             c.setBounds(left, right, pref.width, pref.height);
  78         }
  79     }
  80 }