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A dynamic gradient
/*******************************************************************************
 * Copyright (c) 2000, 2005 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
 *******************************************************************************/

/*
 * Control example snippet: a dynamic gradient
 * 
 * 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.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Listener;
import org.eclipse.swt.widgets.Shell;

public class GradientDynamic {
  static Image oldImage;

  public static void main(String[] args) {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setBackgroundMode(SWT.INHERIT_DEFAULT);

    shell.addListener(SWT.Resize, new Listener() {
      public void handleEvent(Event event) {
        Rectangle rect = shell.getClientArea();
        Image newImage = new Image(display, Math.max(1, rect.width), 1);
        GC gc = new GC(newImage);
        gc.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
        gc.setBackground(display.getSystemColor(SWT.COLOR_BLUE));
        gc.fillGradientRectangle(rect.x, rect.y, rect.width, 1, false);
        gc.dispose();
        shell.setBackgroundImage(newImage);
        if (oldImage != null){
          oldImage.dispose();
        }
        oldImage = newImage;
      }
    });
    shell.pack();
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch())
        display.sleep();
    }
    if (oldImage != null)
      oldImage.dispose();
    display.dispose();
  }
}








18.3.SWT Paint
18.3.1.A dynamic gradientA dynamic gradient
18.3.2.Implement a simple scribble programImplement a simple scribble program
18.3.3.Alpha blendingAlpha blending
18.3.4.A paint canvas.