CenterLayout.java

/*
    GNU GENERAL LICENSE
    Copyright (C) 2006 The Lobo Project. Copyright (C) 2014 - 2017 Lobo Evolution

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public
    License as published by the Free Software Foundation; either
    verion 3 of the License, or (at your option) any later version.

    This program 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
    General License for more details.

    You should have received a copy of the GNU General Public
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
    

    Contact info: lobochief@users.sourceforge.net; ivan.difrancesco@yahoo.it
 */
/*
 * Created on Mar 19, 2005
 */
package org.lobobrowser.util.gui;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;

/**
 * The Class CenterLayout.
 *
 * @author J. H. S.
 */
public class CenterLayout implements LayoutManager {
    /*
     * (non-Javadoc)
     * @see java.awt.LayoutManager#addLayoutComponent(java.lang.String,
     * java.awt.Component)
     */
    @Override
    public void addLayoutComponent(String arg0, Component arg1) {
    }
    
    /*
     * (non-Javadoc)
     * @see java.awt.LayoutManager#removeLayoutComponent(java.awt.Component)
     */
    @Override
    public void removeLayoutComponent(Component arg0) {
    }
    
    /*
     * (non-Javadoc)
     * @see java.awt.LayoutManager#preferredLayoutSize(java.awt.Container)
     */
    @Override
    public Dimension preferredLayoutSize(Container arg0) {
        Insets insets = arg0.getInsets();
        int count = arg0.getComponentCount();
        if (count > 0) {
            Dimension d = arg0.getComponent(0).getPreferredSize();
            return new Dimension(d.width + insets.left + insets.right,
                    d.height + insets.top + insets.bottom);
        } else {
            return new Dimension(insets.left + insets.right,
                    insets.top + insets.bottom);
        }
    }
    
    /*
     * (non-Javadoc)
     * @see java.awt.LayoutManager#minimumLayoutSize(java.awt.Container)
     */
    @Override
    public Dimension minimumLayoutSize(Container arg0) {
        Insets insets = arg0.getInsets();
        int count = arg0.getComponentCount();
        if (count > 0) {
            Dimension d = arg0.getComponent(0).getMinimumSize();
            return new Dimension(d.width + insets.left + insets.right,
                    d.height + insets.top + insets.bottom);
        } else {
            return new Dimension(insets.left + insets.right,
                    insets.top + insets.bottom);
        }
    }
    
    /*
     * (non-Javadoc)
     * @see java.awt.LayoutManager#layoutContainer(java.awt.Container)
     */
    @Override
    public void layoutContainer(Container container) {
        int count = container.getComponentCount();
        if (count > 0) {
            Component child = container.getComponent(0);
            Insets insets = container.getInsets();
            int availWidth = container.getWidth() - insets.left - insets.right;
            int availHeight = container.getHeight() - insets.top
                    - insets.bottom;
            Dimension preferredSize = child.getPreferredSize();
            double preferredWidth = preferredSize.getWidth();
            double preferredHeight = preferredSize.getHeight();
            int width;
            int height;
            int x;
            int y;
            if (preferredWidth < availWidth) {
                x = (int) Math.round(
                        insets.left + ((availWidth - preferredWidth) / 2));
                width = (int) Math.round(preferredWidth);
            } else {
                x = insets.left;
                width = availWidth;
            }
            if (preferredHeight < availHeight) {
                y = (int) Math.round(
                        insets.top + ((availHeight - preferredHeight) / 2));
                height = (int) Math.round(preferredHeight);
            } else {
                y = insets.top;
                height = availHeight;
            }
            child.setBounds(x, y, width, height);
        }
    }
    
    /** The instance. */
    private static CenterLayout instance = new CenterLayout();
    
    /** Gets the instance.
	 *
	 * @return the instance
	 */
    public static CenterLayout getInstance() {
        return instance;
    }
}