import java.applet.*;
import java.awt.event.*;
import java.awt.*;

public class applet_doubleBuffering extends Applet implements MouseMotionListener {
    Graphics bufferGraphics; // The object we will use to write with instead of the standard screen graphics
    Image offscreen; // The image that will contain everything that has been drawn on bufferGraphics.
    Dimension dim;
    int curX, curY;
    
    public void init() {
        dim = getSize();
        addMouseMotionListener(this);
        setBackground(Color.blue);
        offscreen = createImage(dim.width,dim.height); // Create an offscreen image to draw on
        bufferGraphics = offscreen.getGraphics(); // everything that is drawn by bufferGraphics will be written on the offscreen image.
    }
    
    public void paint(Graphics g) {
        bufferGraphics.setFont(new Font("Arial",Font.BOLD,28));
        bufferGraphics.clearRect(0,0,dim.width,dim.width);
        bufferGraphics.setColor(Color.white);
        bufferGraphics.drawString("Double-buffered",10,35);
        bufferGraphics.setFont(new Font("Arial",Font.BOLD,18));
        bufferGraphics.setColor(Color.yellow);
        bufferGraphics.drawString("Drawing is first done to an",10,70);
        bufferGraphics.drawString("offscreen image, and when all",10,95);
        bufferGraphics.drawString("is done, the offscreen image",10,120);
        bufferGraphics.drawString("is drawn on the screen.",10,145);
        bufferGraphics.setColor(Color.red);
        bufferGraphics.fillRect(curX,curY,20,20);
        g.drawImage(offscreen,0,0,this); // draw the offscreen image to the screen like a normal image.
    }
    
    public void update(Graphics g) {
        paint(g);
    }
    
    public void mouseMoved(MouseEvent evt) {
        curX = evt.getX();
        curY = evt.getY();
        repaint();
    }
    
    public void mouseDragged(MouseEvent evt) {
    }
}