GradientSelection.java Source code

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Here is the source code for GradientSelection.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 org.eclipse.swt.snippets;
/* 
 * Table example snippet: Draw a custom gradient selection
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 * 
 * @since 3.2
 */

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.Region;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Table;
import org.eclipse.swt.widgets.TableColumn;
import org.eclipse.swt.widgets.TableItem;

public class GradientSelection {
    public static void main(String[] args) {
        final Display display = new Display();
        Shell shell = new Shell(display);
        shell.setText("Custom gradient selection for Table");
        shell.setLayout(new FillLayout());
        final Table table = new Table(shell, SWT.MULTI | SWT.FULL_SELECTION);
        table.setHeaderVisible(true);
        table.setLinesVisible(true);
        int columnCount = 3;
        for (int i = 0; i < columnCount; i++) {
            TableColumn column = new TableColumn(table, SWT.NONE);
            column.setText("Column " + i);
        }
        int itemCount = 8;
        for (int i = 0; i < itemCount; i++) {
            TableItem item = new TableItem(table, SWT.NONE);
            item.setText(new String[] { "item " + i + " a", "item " + i + " b", "item " + i + " c" });
        }
        /*
         * NOTE: MeasureItem, PaintItem and EraseItem are called repeatedly.
         * Therefore, it is critical for performance that these methods be as
         * efficient as possible.
         */
        table.addListener(SWT.EraseItem, new Listener() {
            public void handleEvent(Event event) {
                if ((event.detail & SWT.SELECTED) != 0) {
                    GC gc = event.gc;
                    Rectangle area = table.getClientArea();
                    /*
                     * If you wish to paint the selection beyond the end of last column,
                     * you must change the clipping region.
                     */
                    int columnCount = table.getColumnCount();
                    if (event.index == columnCount - 1 || columnCount == 0) {
                        int width = area.x + area.width - event.x;
                        if (width > 0) {
                            Region region = new Region();
                            gc.getClipping(region);
                            region.add(event.x, event.y, width, event.height);
                            gc.setClipping(region);
                            region.dispose();
                        }
                    }
                    gc.setAdvanced(true);
                    if (gc.getAdvanced())
                        gc.setAlpha(127);
                    Rectangle rect = event.getBounds();
                    Color foreground = gc.getForeground();
                    Color background = gc.getBackground();
                    gc.setForeground(display.getSystemColor(SWT.COLOR_RED));
                    gc.setBackground(display.getSystemColor(SWT.COLOR_LIST_BACKGROUND));
                    gc.fillGradientRectangle(0, rect.y, 500, rect.height, false);
                    // restore colors for subsequent drawing
                    gc.setForeground(foreground);
                    gc.setBackground(background);
                    event.detail &= ~SWT.SELECTED;
                }
            }
        });
        for (int i = 0; i < columnCount; i++) {
            table.getColumn(i).pack();
        }
        table.setSelection(table.getItem(0));
        shell.setSize(500, 200);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}