Java – JFrame has the same shape as image / program running in the background

My problem is very simple, the solution is definitely not I am looking for a way to shape a JFrame, just like the image it will display By shape, I mean with alpha= The shape of 0 pixels I have found a working example using the generalpath object, but it has created ~ 110000 "nodes" for about 500 * 400 images, so it takes more than 2 minutes to start JFrame, which is definitely not an ideal effect. It should be started within 2 seconds

Thank you for your time

Solution

Personally, I will abandon the shape of the window instead of the transparent window, which is easier for what you want to do

And use the close button (see the lower left corner)

The red border around the image is intentional because it shows the "window" boundary

This depends on Java 1.7 or Java 1.6_ 10. Check in the code

public class TransparentFrame {

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

    public TransparentFrame() {
        EventQueue.invokelater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (Exception ex) {
                }

                JFrame frame = new JFrame("Testing");
                frame.setUndecorated(true);
                frame.setContentPane(new ContentPane());

                String version = System.getProperty("java.version");
                System.out.println(version);
                if (version.startsWith("1.7")) {
                    frame.setBackground(new Color(0,0));
                } else if (version.startsWith("1.6")) {
                    if (supportsPerAlphaPixel()) {
                        setOpaque(frame,false);
                    } else {
                        System.out.println("Per Pixel Alphering is not support with Java " + version);
                        System.exit(1);
                    }
                } else {
                    System.out.println("Per Pixel Alphering is not support with Java " + version);
                    System.exit(1);
                }
                frame.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new ImagePane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static boolean supportsPerAlphaPixel() {

        boolean support = false;

        try {

            Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
            support = true;

        } catch (Exception exp) {
        }

        return support;

    }

    public static void setOpaque(Window window,boolean opaque) {

        try {

            Class<?> awtUtilsClass = Class.forName("com.sun.awt.AWTUtilities");
            if (awtUtilsClass != null) {

                Method method = awtUtilsClass.getmethod("setWindowOpaque",Window.class,boolean.class);
                method.invoke(null,window,opaque);

            }

        } catch (Exception exp) {
        }

    }

    public class ContentPane extends JPanel {

        public ContentPane() {
            setOpaque(false);
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            g.setColor(Color.RED);
            g.drawRect(0,getWidth() - 1,getHeight() - 1);
        }
    }

    public class ImagePane extends JPanel {

        private BufferedImage background;
        private BufferedImage offImage;
        private Ellipse2D offButton;
        private boolean mouseIn;

        public ImagePane() {
            setOpaque(false);
            try {
                background = ImageIO.read(new File("tamagotchi400.png"));
                offImage = ImageIO.read(new File("powerSmall.png"));
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            offButton = new Ellipse2D.Float(212,330,25,25);
            MouseAdapter handler = new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    if (e.getClickCount() == 1 && e.getButton() == MouseEvent.BUTTON1) {
                        if (offButton.contains(e.getPoint())) {
                            Window window = SwingUtilities.getWindowAncestor(ImagePane.this);
                            if (window != null) {
                                window.dispose();
                            }
                        }
                    }
                }

                @Override
                public void mouseMoved(MouseEvent e) {
                    Cursor cursor = Cursor.getDefaultCursor();
                    if (offButton.contains(e.getPoint())) {
                        cursor = Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
                    }
                    setCursor(cursor);
                }

                @Override
                public void mouseEntered(MouseEvent e) {
                    mouseIn = true;
                    repaint();
                }

                @Override
                public void mouseExited(MouseEvent e) {
                    mouseIn = false;
                    repaint();
                }
            };
            addMouseListener(handler);
            addMouseMotionListener(handler);
        }

        @Override
        public Dimension getPreferredSize() {
            return background == null ? new Dimension(400,400) : new Dimension(background.getWidth(),background.getHeight());
        }

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            if (background != null) {
                Graphics2D g2d = (Graphics2D) g.create();
                int x = (getWidth() - background.getWidth()) / 2;
                int y = (getHeight() - background.getHeight()) / 2;
                g2d.drawImage(background,x,y,this);
                if (mouseIn && offImage != null) {
                    g2d.drawImage(offImage,(int) offButton.getX(),(int) offButton.getY(),this);
                }
                g2d.dispose();
            }
        }
    }
}