org.eclipse.jst.server.jetty.ui/src/org/eclipse/jst/server/jetty/ui/internal/SWTUtil.java

/*******************************************************************************
 * Copyright (c) 2003, 2005 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - Initial API and implementation
 *     Angelo Zerr <angelo.zerr@gmail.com> - Jetty packages
 *******************************************************************************/
package org.eclipse.jst.server.jetty.ui.internal;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;

/**
 * SWT Utility class.
 */
public class SWTUtil
{
    private static FontMetrics _fontMetrics;

    protected static void initializeDialogUnits(Control testControl)
    {
        // Compute and store a font metric
        GC gc = new GC(testControl);
        gc.setFont(JFaceResources.getDialogFont());
        _fontMetrics = gc.getFontMetrics();
        gc.dispose();
    }

    /**
     * Returns a width hint for a button control.
     */
    protected static int getButtonWidthHint(Button button)
    {
        int widthHint = Dialog.convertHorizontalDLUsToPixels(_fontMetrics,IDialogConstants.BUTTON_WIDTH);
        return Math.max(widthHint,button.computeSize(SWT.DEFAULT,SWT.DEFAULT,true).x);
    }

    /**
     * Create a new button with the standard size.
     * 
     * @param comp
     *            the component to add the button to
     * @param label
     *            the button label
     * @return a button
     */
    public static Button createButton(Composite comp, String label)
    {
        Button b = new Button(comp,SWT.PUSH);
        b.setText(label);
        
        if (_fontMetrics == null)
        {
            initializeDialogUnits(comp);
        }
        
        GridData data = new GridData(GridData.HORIZONTAL_ALIGN_FILL);
        data.widthHint = getButtonWidthHint(b);
        b.setLayoutData(data);
        return b;
    }
}