Run the program below using JDK1.1 under win95 or NT4.0b2. It will
show redisplay problems. The problems don't show when running 1.0.2.

(sorry for the length of the program, I'm in a hurry right now. If you want, let
me know and I'll narrow it down)

- eduardo

========

import java.awt.*;

import java.util.*;
import java.awt.*;

class Clock extends Panel implements Runnable {

    Thread timer = null;
    int lastxs=0, lastys=0, lastxm=0, lastym=0, lastxh=0, lastyh=0;
    MenuBar bar = null;
    
    public Clock() {
        timer = new Thread(this);
        timer.start();
setBackground(Color.pink);
    }

    public Dimension preferredSize() {
return (new Dimension(110,110));
    }

    // Plotpoints allows calculation to only cover 45 degrees of the circle,
    // and then mirror
    
    public void plotpoints(int x0, int y0, int x, int y, Graphics g) {
    
        g.drawLine(x0+x,y0+y,x0+x,y0+y);
        g.drawLine(x0+y,y0+x,x0+y,y0+x);
        g.drawLine(x0+y,y0-x,x0+y,y0-x);
        g.drawLine(x0+x,y0-y,x0+x,y0-y);
        g.drawLine(x0-x,y0-y,x0-x,y0-y);
        g.drawLine(x0-y,y0-x,x0-y,y0-x);
        g.drawLine(x0-y,y0+x,x0-y,y0+x);
        g.drawLine(x0-x,y0+y,x0-x,y0+y);
    }
    
    // Circle is just Bresenham's algorithm for a scan converted circle
    
    public void circle(int x0, int y0, int r, Graphics g) {
        int x,y;
        float d;
    
        x=0;
        y=r;
        d=5/4-r;
        plotpoints(x0,y0,x,y,g);
    
        while (y>x){
            if (d<0) {
                d=d+2*x+3;
                x++;
            }
            else {
                d=d+2*(x-y)+5;
                x++;
                y--;
            }
            plotpoints(x0,y0,x,y,g);
        }
    }
    
    
    // Paint is the main part of the program
    
    public void paint(Graphics g) {

        int xh, yh, xm, ym, xs, ys, s, m, h, xcenter, ycenter;
        String today;
        Date dat = new Date();
    
        s = dat.getSeconds();
        m = dat.getMinutes();
        h = dat.getHours();
        today = dat.toLocaleString();
        xcenter=55;
        ycenter=55;
        
        // a= s* pi/2 - pi/2 (to switch 0,0 from 3:00 to 12:00)
        // x = r(cos a) + xcenter, y = r(sin a) + ycenter
        
        xs = (int)(Math.cos(s * 3.14f/30 - 3.14f/2) * 45 + xcenter);
        ys = (int)(Math.sin(s * 3.14f/30 - 3.14f/2) * 45 + ycenter);
        xm = (int)(Math.cos(m * 3.14f/30 - 3.14f/2) * 40 + xcenter);
        ym = (int)(Math.sin(m * 3.14f/30 - 3.14f/2) * 40 + ycenter);
        xh = (int)(Math.cos((h*30 + m/2) * 3.14f/180 - 3.14f/2) * 30 + xcenter);
        yh = (int)(Math.sin((h*30 + m/2) * 3.14f/180 - 3.14f/2) * 30 + ycenter);
        
        // Draw the circle and numbers
        
        g.setFont(new Font("TimesRoman", Font.PLAIN, 14));
        g.setColor(Color.blue);
        circle(xcenter,ycenter,50,g);
        g.setColor(Color.darkGray);
        g.drawString("9",xcenter-45,ycenter+3);
        g.drawString("3",xcenter+40,ycenter+3);
        g.drawString("12",xcenter-5,ycenter-37);
        g.drawString("6",xcenter-3,ycenter+45);
    
        // Erase if necessary, and redraw
        
        g.setColor(getBackground());
        if (xs != lastxs || ys != lastys) {
            g.drawLine(xcenter, ycenter, lastxs, lastys);
        }
        if (xm != lastxm || ym != lastym) {
            g.drawLine(xcenter, ycenter-1, lastxm, lastym);
            g.drawLine(xcenter-1, ycenter, lastxm, lastym); }
        if (xh != lastxh || yh != lastyh) {
            g.drawLine(xcenter, ycenter-1, lastxh, lastyh);
            g.drawLine(xcenter-1, ycenter, lastxh, lastyh); }
        g.setColor(Color.darkGray);
        g.drawLine(xcenter, ycenter, xs, ys);
        g.setColor(Color.blue);
        g.drawLine(xcenter, ycenter-1, xm, ym);
        g.drawLine(xcenter-1, ycenter, xm, ym);
        g.drawLine(xcenter, ycenter-1, xh, yh);
        g.drawLine(xcenter-1, ycenter, xh, yh);
        lastxs=xs; lastys=ys;
        lastxm=xm; lastym=ym;
        lastxh=xh; lastyh=yh;
    }
    
    public void update(Graphics g) {
        paint(g);
    }

    public Dimension minimumSize() {
return size();
    }

    public void run() {
        while (timer != null) {
            try {
Thread.sleep(1000);
} catch (InterruptedException e){
}
            repaint();
        }
        timer = null;
    }
}


class Main {
    public static void main(String argv[]) {
Frame f = new Frame("Mumble");
Panel p = new Panel();
f.add(p);
f.setLayout(new GridBagLayout());

Clock b1 = new Clock();
b1.resize(100,200);
p.add(b1);

f.resize(300, 250);
f.show();
    }
}