descent.internal.ui.util.SWTUtil.java Source code

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Here is the source code for descent.internal.ui.util.SWTUtil.java

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/*******************************************************************************
 * Copyright (c) 2000, 2006 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 descent.internal.ui.util;

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.Table;
import org.eclipse.swt.widgets.Widget;

import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.util.Assert;

/**
 * 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) {
        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);
    }

    /**
     * Returns a height hint for a button control.
     */
    public static int getButtonHeigthHint(Button button) {
        if (button.getFont().equals(JFaceResources.getDefaultFont()))
            button.setFont(JFaceResources.getDialogFont());
        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).heightHint = getButtonHeigthHint(button);
            ((GridData) gd).widthHint = getButtonWidthHint(button);
        }
    }

    public static int getTableHeightHint(Table table, int rows) {
        if (table.getFont().equals(JFaceResources.getDefaultFont()))
            table.setFont(JFaceResources.getDialogFont());
        int result = table.getItemHeight() * rows + table.getHeaderHeight();
        if (table.getLinesVisible())
            result += table.getGridLineWidth() * (rows - 1);
        return result;
    }

}