Question

I have a Java swing application where I’ve created an ImageIcon with a picture and displayed it to a screen. I did that by loading a URL as an ImageIcon and placing it in the Java Swing window as a label.

Now I need to place ‘markers’ on the image with other images.
In context: Place a picture of an eye on someones face over their eye.

I’d appreciate anyone who can point my in the right direction or give me some SSCCE code to work from.

What is the best manner to place ‘markers’ on an ImageIcon Java Swing?

Answer 1

The basic concept is, you need a temporary image onto which you can paint the master/base image and the marker.

1. Create a new BufferedImage. This would typically be the same size as the master image, but doesn’t have to be.
2. Paint the master image onto BufferedImage
3. Paint the marker onto the BufferedImage
4. Create a new ImageIcon using the BufferedImage
5. Apply the ImageIcon to the label…

public class PaintIcon {

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

    public PaintIcon() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                JFrame frame = new JFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new PaintPane());
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class PaintPane extends JPanel {

        private JLabel label;
        private int state = 0;

        private BufferedImage disk;
        private BufferedImage play;
        private BufferedImage pause;
        private BufferedImage stop;

        public PaintPane() {

            setLayout(new GridBagLayout());
            add((label = new JLabel()));

            try {
                disk = ImageIO.read(getClass().getResource("/cd.png"));
                play = ImageIO.read(getClass().getResource("/media_play.png"));
                pause = ImageIO.read(getClass().getResource("/media_pause.png"));
                stop = ImageIO.read(getClass().getResource("/media_stop.png"));
            } catch (Exception e) {
                e.printStackTrace();
            }

            updateState();

            label.addMouseListener(new MouseAdapter() {
                @Override
                public void mouseClicked(MouseEvent e) {
                    state++;
                    if (state > 2) {
                        state = 0;
                    }
                    updateState();
                }
            });
        }

        protected void updateState() {
            BufferedImage base = new BufferedImage(disk.getWidth(), disk.getHeight(), BufferedImage.TYPE_INT_ARGB);
            Graphics2D g2d = base.createGraphics();
            g2d.drawImage(disk, 0, 0, this);
            BufferedImage marker = null;
            switch (state) {
                case 0:
                    marker = stop;
                    break;
                case 1:
                    marker = play;
                    break;
                case 2:
                    marker = pause;
                    break;
            }
            int x = disk.getWidth() - marker.getWidth();
            int y = disk.getHeight() - marker.getHeight();
            g2d.drawImage(marker, x, y, this);
            g2d.dispose();

            label.setIcon(new ImageIcon(base));
        }
    }
}