TarTool example source code file (JFCUtilities.java)

This example TarTool source code file (JFCUtilities.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - TarTool tags/keywords

awt, component, dimension, dimension, event, gui, jfcutilities, jfcutilities, jpopupmenu, mouseevent, mouseevent, point, point, swing

The TarTool JFCUtilities.java source code

/*
** Tim Endres' utilities package.
** Copyright (c) 1997 by Tim Endres
** 
** This program is free software.
** 
** You may redistribute it and/or modify it under the terms of the GNU
** General Public License as published by the Free Software Foundation.
** Version 2 of the license should be included with this distribution in
** the file LICENSE, as well as License.html. If the license is not
** included	with this distribution, you may find a copy at the FSF web
** site at 'www.gnu.org' or 'www.fsf.org', or you may write to the
** Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139 USA.
**
** THIS SOFTWARE IS PROVIDED AS-IS WITHOUT WARRANTY OF ANY KIND,
** NOT EVEN THE IMPLIED WARRANTY OF MERCHANTABILITY. THE AUTHOR
** OF THIS SOFTWARE, ASSUMES _NO_ RESPONSIBILITY FOR ANY
** CONSEQUENCE RESULTING FROM THE USE, MODIFICATION, OR
** REDISTRIBUTION OF THIS SOFTWARE. 
** 
*/

package com.ice.util;

import java.awt.Component;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.Toolkit;
import java.awt.event.MouseEvent;

import javax.swing.JPopupMenu;

/**
 * This is a class that contains useful utility functions related
 * to the JFC (Swing).
 */

public class
JFCUtilities
	{
	/**
	 * Swing 1.0 and 1.1 have a horrible bug with respect to popup menus.
	 * Namely that they are not adjusted to be kept on-screen.
	 * Here, we ensure that the popup is properly located.
	 * This method will continue to work even after Sun fixes Swing...
	 * However, because there is a case where we estimate the size of
	 * the popup menu, one could make the argument to noop this method
	 * when the bug is finally fixed.
	 */

	static public Point
	computePopupLocation( MouseEvent event, Component rel, JPopupMenu popup )
		{
		Dimension psz = popup.getSize();
		Dimension ssz = Toolkit.getDefaultToolkit().getScreenSize();
		Point gLoc = rel.getLocationOnScreen();
		Point result = new Point( event.getX(), event.getY() );

		gLoc.x += event.getX();
		gLoc.y += event.getY();

		if ( psz.width == 0 || psz.height == 0 )
			{
			// DRAT! Now we need to "estimate"...
			int items = popup.getSubElements().length;
			psz.height = ( items * 22 );
			psz.width = 100;
			}

		psz.height += 5;

		if ( (gLoc.x + psz.width) > ssz.width )
			{
			result.x -= (( gLoc.x + psz.width) - ssz.width);
			if ( (gLoc.x + result.x) < 0 )
				result.x = -(gLoc.x + event.getX());
			}

		if ( (gLoc.y + psz.height) > ssz.height )
			{
			result.y -= (( gLoc.y + psz.height) - ssz.height);
			if ( (gLoc.y + result.y) < 0 )
				result.y = -gLoc.y;
			}

		return result;
		}

	}