javaswingjframetransparencytranslucency

How to make a transparent JFrame but keep everything else the same?


I want to make the JFrame transparent, but the image on top of it to be non-transparent. This is what I have now:

enter image description here

Does anyone know a way to make only the JFrame transparent?

Here's my code:

import javax.swing.*;
import java.awt.*;
import com.sun.awt.AWTUtilities;
import static java.awt.GraphicsDevice.WindowTranslucency.*;

public class SplashDemo extends JFrame
{
    public SplashDemo()
    {
        setUndecorated(true);
        setSize(200, 200);

        add(new JLabel(new ImageIcon("puppy2.png"))); 
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setVisible(true);

        setOpacity(0.85f);      
    }

     public static void main(String[] args) 
     {
        new SplashDemo();
     }
}

Solution

  • Basically, you need to make a transparent window and a translucent content pane. This will mean anything added to the content pane will continue to be rendered without additional alphering...

    enter image description here

    public class TranscluentWindow {
    
        public static void main(String[] args) {
            new TranscluentWindow();
        }
    
        public TranscluentWindow() {
            EventQueue.invokeLater(new Runnable() {
                @Override
                public void run() {
                    try {
                        try {
                            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                        } catch (Exception ex) {
                        }
    
                        JWindow frame = new JWindow();
                        frame.setAlwaysOnTop(true);
                        frame.addMouseListener(new MouseAdapter() {
                            @Override
                            public void mouseClicked(MouseEvent e) {
                                if (e.getClickCount() == 2) {
                                    SwingUtilities.getWindowAncestor(e.getComponent()).dispose();
                                }
                            }
                        });
                        frame.setBackground(new Color(0,0,0,0));
                        frame.setContentPane(new TranslucentPane());
                        frame.add(new JLabel(new ImageIcon(ImageIO.read(getClass().getResource("/Puppy.png")))));
                        frame.pack();
                        frame.setLocationRelativeTo(null);
                        frame.setVisible(true);
                    } catch (IOException ex) {
                        ex.printStackTrace();
                    }
    
                }
            });
        }
    
        public class TranslucentPane extends JPanel {
    
            public TranslucentPane() {
                setOpaque(false);
            }
    
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g); 
    
                Graphics2D g2d = (Graphics2D) g.create();
                g2d.setComposite(AlphaComposite.SrcOver.derive(0.85f));
                g2d.setColor(getBackground());
                g2d.fillRect(0, 0, getWidth(), getHeight());
    
            }
    
        }
    
    }