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Java > Open Source Codes > org > jfree > layout > CenterLayout


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * -----------------
28  * CenterLayout.java
29  * -----------------
30  * (C) Copyright 2000-2005, by Object Refinery Limited.
31  *
32  * Original Author: David Gilbert (for Object Refinery Limited);
33  * Contributor(s): -;
34  *
35  * $Id: CenterLayout.java,v 1.6 2005/11/16 15:58:40 taqua Exp $
36  *
37  * Changes (from 5-Nov-2001)
38  * -------------------------
39  * 05-Nov-2001 : Changed package to com.jrefinery.layout.* (DG);
40  * 10-Oct-2002 : Fixed errors reported by Checkstyle (DG);
41  *
42  */
43
44 package org.jfree.layout;
45
46 import java.awt.Component JavaDoc;
47 import java.awt.Container JavaDoc;
48 import java.awt.Dimension JavaDoc;
49 import java.awt.Insets JavaDoc;
50 import java.awt.LayoutManager JavaDoc;
51 import java.io.Serializable JavaDoc;
52
53 /**
54  * A layout manager that displays a single component in the center of its
55  * container.
56  *
57  * @author David Gilbert
58  */
59 public class CenterLayout implements LayoutManager JavaDoc, Serializable JavaDoc {
60
61     /** For serialization. */
62     private static final long serialVersionUID = 469319532333015042L;
63     
64     /**
65      * Creates a new layout manager.
66      */
67     public CenterLayout() {
68     }
69
70     /**
71      * Returns the preferred size.
72      *
73      * @param parent the parent.
74      *
75      * @return the preferred size.
76      */
77     public Dimension JavaDoc preferredLayoutSize(final Container JavaDoc parent) {
78
79         synchronized (parent.getTreeLock()) {
80             final Insets JavaDoc insets = parent.getInsets();
81             if (parent.getComponentCount() > 0) {
82                 final Component JavaDoc component = parent.getComponent(0);
83                 final Dimension JavaDoc d = component.getPreferredSize();
84                 return new Dimension JavaDoc(
85                     (int) d.getWidth() + insets.left + insets.right,
86                     (int) d.getHeight() + insets.top + insets.bottom
87                 );
88             }
89             else {
90                 return new Dimension JavaDoc(
91                     insets.left + insets.right, insets.top + insets.bottom
92                 );
93             }
94         }
95
96     }
97
98     /**
99      * Returns the minimum size.
100      *
101      * @param parent the parent.
102      *
103      * @return the minimum size.
104      */
105     public Dimension JavaDoc minimumLayoutSize(final Container JavaDoc parent) {
106
107         synchronized (parent.getTreeLock()) {
108             final Insets JavaDoc insets = parent.getInsets();
109             if (parent.getComponentCount() > 0) {
110                 final Component JavaDoc component = parent.getComponent(0);
111                 final Dimension JavaDoc d = component.getMinimumSize();
112                 return new Dimension JavaDoc(d.width + insets.left + insets.right,
113                                  d.height + insets.top + insets.bottom);
114             }
115             else {
116               return new Dimension JavaDoc(insets.left + insets.right,
117                                    insets.top + insets.bottom);
118             }
119         }
120
121     }
122
123     /**
124      * Lays out the components.
125      *
126      * @param parent the parent.
127      */
128     public void layoutContainer(final Container JavaDoc parent) {
129
130         synchronized (parent.getTreeLock()) {
131             if (parent.getComponentCount() > 0) {
132                 final Insets JavaDoc insets = parent.getInsets();
133                 final Dimension JavaDoc parentSize = parent.getSize();
134                 final Component JavaDoc component = parent.getComponent(0);
135                 final Dimension JavaDoc componentSize = component.getPreferredSize();
136                 final int xx = insets.left + (
137                     Math.max((parentSize.width - insets.left - insets.right
138                                       - componentSize.width) / 2, 0)
139                 );
140                 final int yy = insets.top + (
141                     Math.max((parentSize.height - insets.top - insets.bottom
142                                       - componentSize.height) / 2, 0));
143                 component.setBounds(xx, yy, componentSize.width,
144                         componentSize.height);
145             }
146         }
147
148     }
149
150     /**
151      * Not used.
152      *
153      * @param comp the component.
154      */
155     public void addLayoutComponent(final Component JavaDoc comp) {
156         // not used.
157 }
158
159     /**
160      * Not used.
161      *
162      * @param comp the component.
163      */
164     public void removeLayoutComponent(final Component JavaDoc comp) {
165         // not used
166 }
167
168     /**
169      * Not used.
170      *
171      * @param name the component name.
172      * @param comp the component.
173      */
174     public void addLayoutComponent(final String JavaDoc name, final Component JavaDoc comp) {
175         // not used
176 }
177
178     /**
179      * Not used.
180      *
181      * @param name the component name.
182      * @param comp the component.
183      */
184     public void removeLayoutComponent(final String JavaDoc name, final Component JavaDoc comp) {
185         // not used
186 }
187
188 }
189
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