将JFrame内容另存为.png

Question

I am currently developing a 2D game in Java (I use a JFrame). I would like to, when a certain button is pressed, save the content of the frame and store it in an image. For the moment, I use the following code:

Robot robot = new Robot();
Rectangle screenSize = new Rectangle(display.getFrame().getX() + 3, display.getFrame().getY() + 26, handler.getWidth(), handler.getHeight());

BufferedImage screenShot = robot.createScreenCapture(screenSize);   ImageIO.write(screenShot,File("D:\\Programming\\First2DGame\\res\\textures\\Screenshot.png"));

The problem is that this takes a screenshot of a portion of the screen , and not of the frame itself . This means that if, for example, I move my window to the bottom right of the screen, I receive a discord notification and then I press my button, the notification will be present in the screenshot.

I have already searched a bit, a I tried this code:

 try
        {
            BufferedImage image = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
            Graphics2D graphics2D = image.createGraphics();
            frame.paint(graphics2D);
            ImageIO.write(image,"jpeg", new File("D:\\Programming\\First2DGame\\res\\textures\\Screenshot.png"));
        }
        catch(Exception e)
        {
            e.printStackTrace;
        }
    }

    protected void paintComponent(Graphics g)
    {
        g.drawRect(50,50,50,50);
    }

but the result is a white window:

Do you perhaps know how to create a screenshot of only the frame ?

Answer 1

I think the example code you showed is pretty much the right...
Can you test it with the code below? :D If you remove contentPane.printAll(g2d) As you showed, only the white window

public class ImageSaveTest extends JFrame {

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

    public ImageSaveTest() {
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLayout(new BorderLayout());

        JPanel panel = new JPanel();
        panel.setPreferredSize(new Dimension(300, 300));
        panel.setLayout(new GridBagLayout());

        JLabel label = new JLabel("Hello! StackOverflow(Press Enter)");
        label.setFont(new Font("Default", Font.BOLD, 15));

        panel.add(label);
        add(panel);
        setVisible(true);
        pack();

        addKeyListener(new KeyAdapter() {
            @Override
            public void keyPressed(KeyEvent e) {
                System.out.println(e.getKeyCode());
                if(e.getKeyCode() == KeyEvent.VK_ENTER) {
                    try {
                        Container contentPane = getContentPane();
                        BufferedImage image = new BufferedImage(contentPane.getWidth(), contentPane.getHeight(),
                                BufferedImage.TYPE_INT_RGB);
                        Graphics2D g2d = image.createGraphics();
                        contentPane.printAll(g2d);
                        g2d.dispose();

                        // replace this path to your image
                        ImageIO.write(image, "jpeg", new File("Your Path/Print.png"));
                    } catch (IOException ex) {
                        // Exception Handling
                    }
                }
            }
        });
    }
}