org.eclipse.swt.snippets.Snippet31.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet31.java

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/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.snippets;

/*
 * Tracker example snippet: create a tracker (drag when "torn off")
 *
 * For a list of all SWT example snippets see
 * http://www.eclipse.org/swt/snippets/
 */
import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;

public class Snippet31 {

    static Tracker tracker = null;

    public static void main(String[] args) {
        final Display display = new Display();
        final Shell shell = new Shell(display);
        shell.setText("Snippet 31");
        shell.setSize(200, 200);
        shell.open();
        Listener listener = new Listener() {
            Point point = null;
            static final int JITTER = 8;

            @Override
            public void handleEvent(Event event) {
                switch (event.type) {
                case SWT.MouseDown:
                    point = new Point(event.x, event.y);
                    break;
                case SWT.MouseMove:
                    if (point == null)
                        return;
                    int deltaX = point.x - event.x, deltaY = point.y - event.y;
                    if (Math.abs(deltaX) < JITTER && Math.abs(deltaY) < JITTER) {
                        return;
                    }
                    tracker = new Tracker(display, SWT.NONE);
                    Rectangle rect = display.map(shell, null, shell.getClientArea());
                    rect.x -= deltaX;
                    rect.y -= deltaY;
                    tracker.setRectangles(new Rectangle[] { rect });
                    tracker.open();
                    //FALL THROUGH
                case SWT.MouseUp:
                    point = null;
                    if (tracker != null) {
                        tracker.dispose();
                        tracker = null;
                    }
                    break;
                }
            }
        };
        shell.addListener(SWT.MouseDown, listener);
        shell.addListener(SWT.MouseMove, listener);
        shell.addListener(SWT.MouseUp, listener);
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }
}