org.eclipse.gyrex.admin.ui.internal.helper.SwtUtil.java Source code

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Here is the source code for org.eclipse.gyrex.admin.ui.internal.helper.SwtUtil.java

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/*******************************************************************************
 * Copyright (c) 2000, 2012 IBM Corporation, AGETO Service GmbH 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
 *     Gunnar Wagenknecht - copied from JDT and adapted to Gyrex
 *******************************************************************************/
package org.eclipse.gyrex.admin.ui.internal.helper;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.dialogs.IDialogConstants;
import org.eclipse.jface.layout.PixelConverter;
import org.eclipse.jface.resource.JFaceResources;
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.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Control;
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;

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

    /**
     * The default visible item count for {@link Combo}s. Workaround for
     * https://bugs.eclipse.org/bugs/show_bug.cgi?id=245569 .
     * 
     * @see Combo#setVisibleItemCount(int)
     * @since 3.5
     */
    public static final int COMBO_VISIBLE_ITEM_COUNT = 30;

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

    /**
     * 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.
     * 
     * @param widget
     *            the widget
     * @return the shell for the given widget
     */
    public static Shell getShell(final 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;
    }

    public static int getTableHeightHint(final Table table, final 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;
    }

    public static GridLayout newLayoutNoMargins(final int columns) {
        final GridLayout layout = new GridLayout(columns, false);
        layout.marginWidth = 0;
        layout.marginHeight = 0;
        return layout;
    }

    /**
     * Adds an accessibility listener returning the given fixed name.
     * 
     * @param control
     *            the control to add the accessibility support to
     * @param text
     *            the name
     */
    public static void setAccessibilityText(final Control control, final String text) {
        //      control.getAccessible().addAccessibleListener(new AccessibleAdapter() {
        //         @Override
        //         public void getName(final AccessibleEvent e) {
        //            if (e.childID == ACC.CHILDID_SELF) {
        //               e.result = text;
        //            }
        //         }
        //      });
    }

    /**
     * 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
     *            the button for which to set the dimension hint
     */
    public static void setButtonDimensionHint(final Button button) {
        Assert.isNotNull(button);
        final Object gd = button.getLayoutData();
        if (gd instanceof GridData) {
            ((GridData) gd).widthHint = getButtonWidthHint(button);
            ((GridData) gd).horizontalAlignment = GridData.FILL;
        }
    }

    /**
     * Sets the default visible item count for {@link Combo}s. Workaround for
     * https://bugs.eclipse.org/bugs/show_bug.cgi?id=7845 .
     * 
     * @param combo
     *            the combo
     * @see Combo#setVisibleItemCount(int)
     * @see #COMBO_VISIBLE_ITEM_COUNT
     * @since 3.5
     */
    public static void setDefaultVisibleItemCount(final Combo combo) {
        combo.setVisibleItemCount(COMBO_VISIBLE_ITEM_COUNT);
    }

}