SWTUtil.java

/*******************************************************************************
 * Copyright (c) 2006 Business Objects Software Limited and others.
 * All rights reserved. 
 * This file is 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:
 *     Business Objects Software Limited - initial API and implementation based on Eclipse 3.1.2 code for
 *                             /org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/util/SWTUtil.java
 *                           Eclipse source is available at: http://www.eclipse.org/downloads/
 *******************************************************************************/

/*
 * SWTUtil.java
 * Creation date: Jan 20, 2006.
 * By: Edward Lam
 */
package org.openquark.cal.eclipse.ui.util;


import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.graphics.Point;
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;

import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.core.runtime.Assert;

/**
 * Utility class to simplify access to some SWT resources. 
 * 
 * @author Edward Lam
 */
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) {
        if (button.getFont().equals(JFaceResources.getDefaultFont())) {
            button.setFont(JFaceResources.getDialogFont());
        }
        PixelConverter converter = new PixelConverter(button);
        int widthHint = converter.convertHorizontalDLUsToPixels(IDialogConstants.BUTTON_WIDTH);
        return Math.max(widthHint, button.computeSize(SWT.DEFAULT, SWT.DEFAULT, true).x);
    }
    
    /**
     * 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       button button for which to set the dimension hint
     */
    public static void setButtonDimensionHint(Button button) {
        Dialog.applyDialogFont(button);
        Assert.isNotNull(button);
        Object gd = button.getLayoutData();
        if (gd instanceof GridData) {
            ((GridData)gd).widthHint = getButtonWidthHint(button);
        }
    }
    
    public static void setDialogSize(Dialog dialog, int width, int height) {
        Point computedSize = dialog.getShell().computeSize(SWT.DEFAULT, SWT.DEFAULT);
        width = Math.max(computedSize.x, width);
        height = Math.max(computedSize.y, height);
        dialog.getShell().setSize(width, height);
    }
}