Drawing and filling with color in an image?

Question

How to draw an eclipse or a shape in the image (picture)?
I want to whiten (convert to white color) all pixel elements outside the shape, and the pixel elements inside the shape remain the shape.
Pliz give some hints.
Regards,
Chevas

Answer 1

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class Mask extends JPanel
    BufferedImage image;
    public Mask()
        loadImage();
    protected void paintComponent(Graphics g)
        super.paintComponent(g);
        Graphics2D g2 = (Graphics2D)g;
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                            RenderingHints.VALUE_ANTIALIAS_ON);
        int w = getWidth();
        int h = getHeight();
        int imageWidth = image.getWidth();
        int imageHeight = image.getHeight();
        int x = (w - imageWidth)/2;
        int y = (h - imageHeight)/2;
        g2.drawImage(image, x, y, this);
        Area mask = new Area(new Rectangle(0,0,w,h));
        Ellipse2D e = new Ellipse2D.Double(w/6, h/8, w*2/3, h*3/4);
        mask.subtract(new Area(e));
        g2.setPaint(Color.white);
        g2.fill(mask);
    private void loadImage()
        String fileName = "images/owls.jpg";
        try
            URL url = getClass().getResource(fileName);
            image = ImageIO.read(url);
        catch(MalformedURLException mue)
            System.err.println("url: " + mue.getMessage());
        catch(IOException ioe)
            System.err.println("read: " + ioe.getMessage());
    private void saveAsImage()
        int w = getWidth();  // or you could use the width and height
        int h = getHeight(); // of the mask to clip the image...
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = image.createGraphics();
        paint(g2);  // this component paints itself into the new image
        g2.dispose();
        try
            ImageIO.write(image, "jpg", new File("mask.jpg"));
        catch(IOException ioe)
            System.err.println("write: " + ioe.getMessage());
    private JPanel getUIPanel()
        JButton save = new JButton("save");
        save.addActionListener(new ActionListener()
            public void actionPerformed(ActionEvent e)
                saveAsImage();
        JPanel panel = new JPanel();
        panel.add(save);
        return panel;
    public static void main(String[] args)
        Mask mask = new Mask();
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(mask.getUIPanel(), "North");
        f.getContentPane().add(mask);
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
}