ido

import java.awt.AWTEvent;
import java.awt.Canvas;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.GraphicsEnvironment;
import java.awt.Transparency;
import java.awt.event.KeyEvent;
import java.awt.image.BufferStrategy;
import java.awt.image.BufferedImage;

import javax.swing.JFrame;
import javax.swing.JPanel;

public class Example extends Canvas {
    static final int KEYS = 65536;

    int font_height = 10;
    int width_in_chars = 80;
    int height_in_chars = 40;

    BufferStrategy strategy;
    BufferedImage buffer;
    boolean keys[];

    public Example() {
        Font font = new Font(Font.MONOSPACED, Font.PLAIN, font_height);
        keys = new boolean[KEYS];

        int win_width = width_in_chars * getFontMetrics(font).charWidth(' ');
        int win_height = height_in_chars * font_height;

        JFrame f = new JFrame();
        JPanel p = (JPanel) f.getContentPane();

        p.setPreferredSize(new Dimension(win_width, win_width));
        p.setLayout(null);

        setBounds(0, 0, win_width, win_height);
        p.add(this);

        f.pack();
        f.setResizable(false);
        f.setTitle("Example Project");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setVisible(true);
        f.setFont(font);
        f.setLocationRelativeTo(null);

        createBufferStrategy(2);
        strategy = getBufferStrategy();

        GraphicsConfiguration gc = GraphicsEnvironment
                .getLocalGraphicsEnvironment().getDefaultScreenDevice()
                .getDefaultConfiguration();
        buffer = gc.createCompatibleImage(win_width, win_height,
                Transparency.OPAQUE);

        setIgnoreRepaint(true);
        enableEvents(AWTEvent.KEY_EVENT_MASK);
    }

    void mainLoop() {
        while (!keys[KeyEvent.VK_ESCAPE]) {
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) { }

            // draw on buffer
            buffer.getGraphics().drawLine(0, 0, 100, 100);

            // blit buffer to screen
            Graphics2D g = (Graphics2D) strategy.getDrawGraphics();
            paint(g);
            g.dispose();
            strategy.show();
        }
    }

    @Override
    public void paint(Graphics g) {
        g.drawImage(buffer, 0, 0, this);
    }

    @Override
    public void processKeyEvent(KeyEvent e) {
        keys[e.getKeyCode()] = e.getID() == KeyEvent.KEY_PRESSED;
    }

    public static void main(String[] args) {
        new Example().mainLoop();
    }
}