org.eclipse.cdt.debug.internal.ui.SWTUtil.java Source code

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Here is the source code for org.eclipse.cdt.debug.internal.ui.SWTUtil.java

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/*******************************************************************************
 * Copyright (c) 2005, 2010 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
 *******************************************************************************/
package org.eclipse.cdt.debug.internal.ui;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Caret;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Menu;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Widget;

/**
 * Utility class to simplify access to some SWT resources.
 */
public class SWTUtil {

    /**
     * Returns the standard display to be used. The method first checks, if the
     * thread calling this method has an associated disaply. If so, this
     * display is returned. Otherwise the method returns the default display.
     */
    public static Display getStandardDisplay() {
        Display display;
        display = Display.getCurrent();
        if (display == null)
            display = Display.getDefault();
        return display;
    }

    /**
     * Returns the shell for the given widget. If the widget doesn't represent
     * a SWT object that manage a shell, <code>null</code> is returned.
     * 
     * @return the shell for the given widget
     */
    public static Shell getShell(Widget widget) {
        if (widget instanceof Control)
            return ((Control) widget).getShell();
        if (widget instanceof Caret)
            return ((Caret) widget).getParent().getShell();
        if (widget instanceof DragSource)
            return ((DragSource) widget).getControl().getShell();
        if (widget instanceof DropTarget)
            return ((DropTarget) widget).getControl().getShell();
        if (widget instanceof Menu)
            return ((Menu) widget).getParent().getShell();
        if (widget instanceof ScrollBar)
            return ((ScrollBar) widget).getParent().getShell();
        return null;
    }

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

    /**
     * Returns a height hint for a button control.
     */
    //   public static int getButtonHeigthHint( Button button ) {
    //      PixelConverter converter = new PixelConverter( button );
    //      return converter.convertVerticalDLUsToPixels( IDialogConstants.BUTTON_HEIGHT );
    //   }

    /**
     * Sets width and height hint for the button control. <b>Note:</b> This
     * is a NOP if the button's layout data is not an instance of <code>GridData</code>.
     * 
     * @param the button for which to set the dimension hint
     */
    public static void setButtonDimensionHint(Button button) {
        Assert.isNotNull(button);
        Object gd = button.getLayoutData();
        if (gd instanceof GridData) {
            ((GridData) gd).widthHint = getButtonWidthHint(button);
            ((GridData) gd).horizontalAlignment = GridData.FILL;
        }
    }
}