FormLayoutHelper.java

/**
 * This file Copyright (c) 2005-2008 Aptana, Inc. This program is
 * dual-licensed under both the Aptana Public License and the GNU General
 * Public license. You may elect to use one or the other of these licenses.
 * 
 * This program is distributed in the hope that it will be useful, but
 * AS-IS and WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, TITLE, or
 * NONINFRINGEMENT. Redistribution, except as permitted by whichever of
 * the GPL or APL you select, is prohibited.
 *
 * 1. For the GPL license (GPL), you can redistribute and/or modify this
 * program under the terms of the GNU General Public License,
 * Version 3, as published by the Free Software Foundation.  You should
 * have received a copy of the GNU General Public License, Version 3 along
 * with this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * 
 * Aptana provides a special exception to allow redistribution of this file
 * with certain other free and open source software ("FOSS") code and certain additional terms
 * pursuant to Section 7 of the GPL. You may view the exception and these
 * terms on the web at http://www.aptana.com/legal/gpl/.
 * 
 * 2. For the Aptana Public License (APL), this program and the
 * accompanying materials are made available under the terms of the APL
 * v1.0 which accompanies this distribution, and is available at
 * http://www.aptana.com/legal/apl/.
 * 
 * You may view the GPL, Aptana's exception and additional terms, and the
 * APL in the file titled license.html at the root of the corresponding
 * plugin containing this source file.
 * 
 * Any modifications to this file must keep this entire header intact.
 */
package com.aptana.ide.server.ui.launchConfigurations;

import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.widgets.Control;

/**
 * FormLayoutHelper
 */
public final class FormLayoutHelper
{
	/**
	 * FormLayoutHelper
	 */
	private FormLayoutHelper()
	{
	}
	
	/**
	 * valignMiddle
	 * 
	 * @param targetControl
	 * @param anchorControl
	 */
	public static void valignMiddle(Control targetControl, Control anchorControl)
	{
		FormData data = getFormData(targetControl);
		int heightDelta = targetControl.getSize().y - anchorControl.getSize().y;
		int middleOffset = (int) (heightDelta / 2f);
		data.top = new FormAttachment(anchorControl, middleOffset, SWT.TOP);
	}

	private static FormData getFormData(Control control)
	{
		Object layoutData = control.getLayoutData();
		if (layoutData == null)
		{
			layoutData = new FormData();
			control.setLayoutData(layoutData);
			return (FormData) layoutData;
		}
		if (layoutData instanceof FormData)
		{
			return (FormData) layoutData;
		}
		else
		{
			throw new IllegalStateException("control is not using a form layout"); //$NON-NLS-1$
		}
	}
}