centerlayout.java

java jdk 1.4的源码

/*
 * @(#)CenterLayout.java	1.10 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.swing.plaf.basic;


import java.awt.*;
import java.io.*;

/**
  * Center-positioning layout manager.
  * @version 1.10 01/23/03
  * @author Tom Santos
  * @author Steve Wilson
  */
class CenterLayout implements LayoutManager, Serializable {
    public void addLayoutComponent(String name, Component comp) { }
    public void removeLayoutComponent(Component comp) { }

    public Dimension preferredLayoutSize( Container container ) {
	Component c = container.getComponent( 0 );
	if ( c != null ) {
	    Dimension size = c.getPreferredSize();
	    Insets insets = container.getInsets();
	    size.width += insets.left + insets.right;
	    size.height += insets.top + insets.bottom;
	    return size;
	}
	else {
	    return new Dimension( 0, 0 );
	}
    }

    public Dimension minimumLayoutSize(Container cont) {
    	return preferredLayoutSize(cont);
    }

    public void layoutContainer(Container container) {
	try {
	   Component c = container.getComponent( 0 );

           c.setSize( c.getPreferredSize() );
	   Dimension size = c.getSize();
           Dimension containerSize = container.getSize();
	   Insets containerInsets = container.getInsets();
	   containerSize.width -= containerInsets.left + containerInsets.right;
	   containerSize.height -= containerInsets.top + containerInsets.bottom;
	   int componentLeft = (containerSize.width / 2) - (size.width / 2);
	   int componentTop = (containerSize.height / 2) - (size.height / 2);
	   componentLeft += containerInsets.left;
	   componentTop += containerInsets.top;

	    c.setBounds( componentLeft, componentTop, size.width, size.height );
	 }
         catch( Exception e ) {
         }
    }
}