org.eclipse.swt.snippets.Snippet9.java Source code

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Here is the source code for org.eclipse.swt.snippets.Snippet9.java

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/*******************************************************************************
 * Copyright (c) 2000, 2016 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;

/*
 * Composite example snippet: scroll a child control automatically
 *
 * 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 Snippet9 {

    public static void main(String[] args) {
        Display display = new Display();
        final Shell shell = new Shell(display, SWT.SHELL_TRIM | SWT.H_SCROLL | SWT.V_SCROLL);
        shell.setText("Snippet 9");
        final Composite composite = new Composite(shell, SWT.BORDER);
        composite.setSize(700, 600);
        final Color red = display.getSystemColor(SWT.COLOR_RED);
        composite.addPaintListener(e -> {
            e.gc.setBackground(red);
            e.gc.fillOval(5, 5, 690, 590);
        });
        final ScrollBar hBar = shell.getHorizontalBar();
        hBar.addListener(SWT.Selection, e -> {
            Point location = composite.getLocation();
            location.x = -hBar.getSelection();
            composite.setLocation(location);
        });
        final ScrollBar vBar = shell.getVerticalBar();
        vBar.addListener(SWT.Selection, e -> {
            Point location = composite.getLocation();
            location.y = -vBar.getSelection();
            composite.setLocation(location);
        });
        shell.addListener(SWT.Resize, e -> {
            Point size = composite.getSize();
            Rectangle rect = shell.getClientArea();
            hBar.setMaximum(size.x);
            vBar.setMaximum(size.y);
            hBar.setThumb(Math.min(size.x, rect.width));
            vBar.setThumb(Math.min(size.y, rect.height));
            int hPage = size.x - rect.width;
            int vPage = size.y - rect.height;
            int hSelection = hBar.getSelection();
            int vSelection = vBar.getSelection();
            Point location = composite.getLocation();
            if (hSelection >= hPage) {
                if (hPage <= 0)
                    hSelection = 0;
                location.x = -hSelection;
            }
            if (vSelection >= vPage) {
                if (vPage <= 0)
                    vSelection = 0;
                location.y = -vSelection;
            }
            composite.setLocation(location);
        });
        shell.setSize(600, 500);
        shell.open();
        while (!shell.isDisposed()) {
            if (!display.readAndDispatch())
                display.sleep();
        }
        display.dispose();
    }

}