/*
 * ColorRing.java
 *
 * Copyright (C) 1999 by Hiroshi Yuki.
 * All rights reserved.
 * <hyuki@hyuki.com>
 * http://www.hyuki.com/jb/
 */

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

public class ColorRing extends Applet {
    int mousex = 0;
    int mousey = 0;
    final int R = 10;
    int dr = 1, dg = 2, db = 3;
    Color color = Color.white;

    private void nextColor() {
        int r = color.getRed();
        int g = color.getGreen();
        int b = color.getBlue();
        if (r + dr >= 256 || r + dr < 0) dr = -dr;
        if (g + dg >= 256 || g + dg < 0) dg = -dg;
        if (b + db >= 256 || b + db < 0) db = -db;
        r = (r + dr) % 256;
        g = (g + dg) % 256;
        b = (b + db) % 256;
        color = new Color(r, g, b);
    }
    public boolean mouseDrag(Event e, int x, int y) {
        mousex = x;
        mousey = y;
        repaint();
        return true;
    }
    public boolean mouseDown(Event e, int x, int y) {
        Dimension d = size();
        Graphics g = getGraphics();
        mousex = x;
        mousey = y;
        g.setColor(Color.white);
        g.fillRect(0, 0, d.width, d.height);
        repaint();
        return true;
    }
    public void update(Graphics g) {
        paint(g);
    }
    public void paint(Graphics g) {
        g.setColor(color);
        g.drawOval(mousex - R, mousey - R, 2 * R, 2 * R);
        nextColor();
    }
}