Name: sg39081 Date: 02/20/98


/*
 * Here's the problem: Basically, Lightweight Containers have a lot of
 * trouble dealing with Heavyweights. Now, we already know about the
 * fact that Z-buffering doesn't work because Heavyweights are always
 * painted on top of Lightweights. But the problem we've run across here
 * is that a Heavyweight which is larger than its Lightweight Container
 * is not properly cropped.
 *
 * In this demonstration we use the HotJavaBrowserBean because our
 * program uses that Bean - we are attempting to maximize the Bean, and
 * place it in a JScrollPane, thus allowing us to control the appearance
 * of the scrollbars. (To be honest, we are using our own Lightweight
 * ScrollPane, but JScrollPane shows the same behavior.) If you wanted
 * to, you could also demonstrate the problem using Panel rather than
 * the browser bean.
 *
 * There are two ways to fix this problem: the browser bean could be
 * composed of a lightweight Panel and a lightweight ScrollPane (say
 * JPanel and JScrollPane - or any other lightweight version), rather
 * than the Panel and ScrollPane it currently uses, thus making it a
 * Lightweight; or Lightweight Containers could somehow be made to
 * properly clip their Heavyweight components. This second option
 * seems much less likely to even be possible. The first option seems
 * like a fairly easy fix. Also, it would allow us to double-buffer
 * the HTML component quite easily.
 *
 * David Levine, ###@###.###
 * Dario Laverde, ###@###.###
 *
 */
 
public class LightHeavy
{
    public final static int LIGHTWEIGHTDEMO = 0;
    public final static int HEAVYWEIGHTDEMO = 1;
    
    // Change this from LIGHTWEIGHTDEMO to HEAVYWEIGHTDEMO to see both cases.
    public static int aType = LIGHTWEIGHTDEMO;
    
    public static void main( String[] args)
    {
        switch( aType)
        {
            case HEAVYWEIGHTDEMO:
            {
                //This uses all heavyweights, and works
                Frame aFrame = new Frame( "LightHeavy");
                aFrame.setLayout( null);
                aFrame.setBounds( 100, 100, 300, 300);
                aFrame.setBackground( Color.black);
                ScrollPane aPane = new ScrollPane( );
                HotJavaBrowserBean aBrowser = new HotJavaBrowserBean( );
                aBrowser.setBounds( 0, 0, 180, 2500);
                aPane.add( aBrowser);
                aPane.setBounds( 40, 40, 200, 200);
                aFrame.add( aPane);
                aFrame.show( );
                try
                {
                    aBrowser.setDocumentURL( new URL("http://java.sun.com/"));
                }
                catch( Exception e)
                {
                }
                break;
            }
            case LIGHTWEIGHTDEMO:
            {
                // This adds a heavyweight to a lightweight scrollpane, and is not cropped correctly
                Frame aFrame = new Frame( "LightHeavy");
                aFrame.setLayout( null);
                aFrame.setBounds( 100, 100, 300, 300);
                aFrame.setBackground( Color.black);
                JScrollPane aPane = new JScrollPane( );
                HotJavaBrowserBean aBrowser = new HotJavaBrowserBean( );
                aBrowser.setBounds( 0, 0, 180, 2500);
                aPane.setViewportView( aBrowser);
                aPane.setBounds( 40, 40, 200, 200);
                aFrame.add( aPane);
                aFrame.show( );
                try
                {
                    aBrowser.setDocumentURL( new URL("http://java.sun.com/"));
                }
                catch( Exception e)
                {
                }
                break;
            }
            default:
                break;
        }
    }
}
(Review ID: 22695)
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