Re: Moving objects on GlassPane ignores setLocation()

From:
Icarus <kristian.heidmann@web.de>
Newsgroups:
comp.lang.java.programmer
Date:
Sat, 2 Aug 2008 12:50:41 -0700 (PDT)
Message-ID:
<74c1a766-54f4-4b46-8ed6-53fbbd1b937d@r66g2000hsg.googlegroups.com>
I just tried to change the code back to the "overriding
paintComponent" approach and what the heck, it's working! After I've
spent a day trying this out, I'm doing practically the same thing and
it is working fine!

I am still curious how I could get the JLabel approach working, but at
least I don't have the pressure of a deadline on me, and so you don't
need to break your back over it to help me. For those who are
inerested, and if you don't mind the german names, I used this:

import javax.swing.*;

import java.awt.*;
import java.awt.event.AWTEventListener;
import java.awt.event.MouseEvent;
import java.awt.image.BufferedImage;

@SuppressWarnings("serial")
public class VersteckteGlassPane extends JPanel implements
AWTEventListener {
    private final JFrame vaterfenster;
    private Point altePosition = new Point();
    private Point aktPosition = new Point();
    private BufferedImage bild;

    public VersteckteGlassPane(JFrame vaterfenster) {
        super(null);
        this.vaterfenster = vaterfenster;
        setOpaque(false);
    }

    public void setPosition(Point aktPosition) {
     this.altePosition = this.aktPosition;
        this.aktPosition = aktPosition;
    }

    public void setBild(BufferedImage bild){
     this.bild = bild;
    }

    public Rectangle getRepaintBereich() {
        int x = (int)aktPosition.getX();
        int y = (int)aktPosition.getY();

        int x2 = (int)altePosition.getX();
        int y2 = (int)altePosition.getY();

        int breite = bild.getWidth();
        int hoehe = bild.getHeight();

        return new Rectangle(x, y, breite, hoehe).union(new
Rectangle(x2, y2, breite, hoehe));
    }

    protected void paintComponent(Graphics g) {
     if (bild == null || !isVisible()) {
            return;
        }

        Graphics2D g2 = (Graphics2D) g.create();
 
g2.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER,
1.0f));
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);

        int x = (int) (aktPosition.getX());
        int y = (int) (aktPosition.getY());

        g2.drawImage(bild, x, y, (int)bild.getWidth(),
(int)bild.getHeight(), null);
    }

    public void eventDispatched(AWTEvent event) {

    if ((event instanceof MouseEvent) && (this.bild != null)) {
            MouseEvent me = (MouseEvent) event;

        Point aktPosition;
        if (me.getID() != MouseEvent.MOUSE_EXITED ||
me.getComponent() != vaterfenster) {
            MouseEvent converted =
SwingUtilities.convertMouseEvent(me.getComponent(), me,
vaterfenster.getGlassPane());
            aktPosition = converted.getPoint();

            this.setPosition(aktPosition);
            this.repaint(this.getRepaintBereich());
        }
        }
    }

    public void registriere(boolean registriere) {

        if(registriere){
            Toolkit.getDefaultToolkit().addAWTEventListener(this,
                AWTEvent.MOUSE_MOTION_EVENT_MASK |
AWTEvent.MOUSE_EVENT_MASK);
        }
        else{
            Toolkit.getDefaultToolkit().
                removeAWTEventListener(this);
        }
    }
}

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