０８１７ - プログラム倉庫

import java.awt.*;
import java.awt.event.*;
import java.awt.image.*;
import javax.swing.*;

class game0817 extends JComponent implements MouseMotionListener {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().add(new game0817());
frame.setBounds(0,0,400,300);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

Image image;
public game0817() {
addMouseMotionListener(this);
image = new BufferedImage(400, 300, BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(new Color(0xFF, 0xFF, 0xFF));
g.fillRect(0, 0, 400, 300);
}
public void paintComponent(Graphics g) {
g.drawImage(image, 0, 0, this);
}

public void mouseDragged(MouseEvent e) {
Graphics g = image.getGraphics();
g.setColor(new Color(0, 0, 0));
g.fillOval(e.getX() - 5, e.getY() - 5, 5 , 5);
repaint();
}
public void mouseMoved(MouseEvent e) {}
}