eu.esdihumboldt.hale.ui.util.viewer.BrowserColumnViewerTip.java Source code

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Here is the source code for eu.esdihumboldt.hale.ui.util.viewer.BrowserColumnViewerTip.java

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/*
 * Copyright (c) 2012 Data Harmonisation Panel
 * 
 * All rights reserved. This program and the accompanying materials are made
 * available under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the License,
 * or (at your option) any later version.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution. If not, see <http://www.gnu.org/licenses/>.
 * 
 * Contributors:
 *     HUMBOLDT EU Integrated Project #030962
 *     Data Harmonisation Panel <http://www.dhpanel.eu>
 */

package eu.esdihumboldt.hale.ui.util.viewer;

import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseTrackAdapter;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Shell;

import eu.esdihumboldt.hale.ui.util.tip.BrowserTip;

/**
 * Enables a tool tip for a {@link ColumnViewer}
 * 
 * @author Simon Templer
 * @partner 01 / Fraunhofer Institute for Computer Graphics Research
 * @version $Id$
 */
public abstract class BrowserColumnViewerTip {

    private final BrowserTip tip;

    private final ColumnViewer viewer;

    private Shell toolShell = null;

    private ViewerCell toolCell = null;

    private int tipCharThreshold = 10;

    /**
     * Constructor
     * 
     * @param viewer the viewer
     * @param width the maximum tip width
     * @param height the maximum tip height
     * @param plainText if the tip text is plain text or HTML
     */
    public BrowserColumnViewerTip(ColumnViewer viewer, int width, int height, boolean plainText) {
        super();

        this.viewer = viewer;

        viewer.getControl().addMouseTrackListener(new MouseTrackAdapter() {

            @Override
            public void mouseHover(MouseEvent e) {
                showToolTip(e.x - 1, e.y - 1);
            }

        });

        tip = new BrowserTip(width, height, plainText);
        tip.setHeightAdjustment(5);
    }

    /**
     * Show tooltip for the cell at the given position
     * 
     * @param x the widget relative x ordinate
     * @param y the widget relative y ordinate
     */
    protected void showToolTip(int x, int y) {
        ViewerCell cell = viewer.getCell(new Point(x, y));

        if (toolCell != null && toolCell.equals(cell) && BrowserTip.toolTipVisible(toolShell)) {
            // tooltip already visible -> do nothing
            return;
        }

        toolCell = cell;
        BrowserTip.hideToolTip(toolShell);

        if (cell != null) {
            Object element = cell.getElement();
            int col = cell.getColumnIndex();

            /**
             * It would be very nice if we could get the column from the viewer
             * and the attached label provider, but the getViewerColumn method
             * is only package visible
             */

            String text = cell.getText();

            String tipText = getToolTip(element, col, text);

            if (tipText != null && !tipText.isEmpty() && tipText.length() >= tipCharThreshold) {
                Rectangle cellBounds = cell.getBounds();
                //            toolShell = tip.showToolTip(viewer.getControl(), x, y, tipText);
                toolShell = tip.showToolTip(viewer.getControl(), cellBounds.x, cellBounds.y + cellBounds.height,
                        tipText, cellBounds, viewer.getControl());
            }
        }
    }

    /**
     * Get the tool tip for a viewer cell
     * 
     * @param element the element defining the viewer row
     * @param col the column index
     * @param text the cell text
     * 
     * @return the tool tip, <code>null</code> if no tool tip shall be shown
     */
    protected abstract String getToolTip(Object element, int col, String text);

}