/* SpiralApplet.java - draws spiral patterns */

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

class Spiral {
	//class variables
 	float angstep;
	float radstep;
	int numsteps;
	int maxColor;
	Dimension size;
	Color colors[];

	//constructor
	public Spiral() {
		maxColor = 6;
		colors = new Color[7];
		colors[0] = new Color(255, 0, 0);	
		colors[1] = new Color(255, 255, 0);	
		colors[2] = new Color(0, 255, 0);	
		colors[3] = new Color(255, 0, 255);	
		colors[4] = new Color(0, 0, 255);	
		colors[5] = new Color(255, 128, 0);	
		colors[6] = new Color(0, 255, 255);	
	}

	//set the pattern's parameters
	public void setParms() {
		maxColor = 6;
		float drift = 0;
		Random r = new Random();
		int type = 2 + (int)(r.nextFloat() * (float)6);
		float mid = (float)6.283 / (float)type;
		switch (type) {
			case 2:
				type = 9 + (int)(r.nextFloat() * (float)20);
				mid = (float)6.283 * (float)type / (float)(type * 2 + 1);
				drift = (float).004;
				radstep = (float)2 + r.nextFloat() * (float)4 * (float)type / (float)20;
				numsteps = 200 + type * 35;
			break;
			case 3:
				drift = (float).05;
				radstep = (float)1 + r.nextFloat() * (float)4;			
				numsteps = (int)((float)size.width / radstep);
			break;
			case 4:
				drift = (float).04;
				radstep = (float)1 + r.nextFloat() * (float)2.5;			
				numsteps = (int)((float)size.width / radstep);
			break;
			case 5:
				drift = (float).02;
				radstep = (float)1 + r.nextFloat() * (float)1.4;			
				numsteps = (int)((float)size.width / radstep);
			break;
			case 6:
				drift = (float).017;
				radstep = (float)1 + r.nextFloat() * (float).8;			
				numsteps = (int)((float)size.width / radstep);
			break;
			case 7:
				drift = (float).016;
				radstep = (float).9 + r.nextFloat() * (float).5;			
				numsteps = (int)((float)size.width / radstep);
				maxColor = 5;
			break;
			case 8:
				drift = (float).015;
				radstep = (float).8 + r.nextFloat() * (float).4;			
				numsteps = (int)((float)size.width / radstep);
			break;
		}
		angstep = mid + (r.nextFloat() - (float).5) * drift;
	}		

	//receive window size from applet
	public void setSize(Dimension size) {
		this.size = size;
	}

	//draw pattern
	public void paint(Graphics g) {
		int xold, yold;
		int xcent = size.width / 2;		
		int ycent = size.height / 2;
		int xnew = xcent;
		int ynew = ycent;
		float rad = 0;
		float ang = 0;
		int c = 0;
		for (int i=0; i<numsteps; i++) {
			xold = xnew;
			yold = ynew;
			rad = rad + radstep;
			ang = ang + angstep;
			xnew = xcent + (int)(rad * Math.cos(ang));
			ynew = ycent + (int)(rad * Math.sin(ang));
			g.setColor(colors[c]);
			c++;
			if (c > maxColor) c = 0;
			g.drawLine(xold, yold, xnew, ynew);
		}
	}
}

public class SpiralApplet extends java.applet.Applet implements Runnable {
	//instance variables
	Thread t = null;
	private Spiral sp;
	private long bedtime;
	private Button quitButton, autoButton, newButton, fastButton, slowButton;
	private boolean auto, painting;

	//initialise applet
	public void init() {
		this.setBackground(Color.black);
		this.setLayout(new BorderLayout());
		Panel p = new Panel();
		p.setBackground(Color.lightGray);
		p.setLayout(new FlowLayout());
		p.add(autoButton = new Button("auto/man"));
		p.add(newButton = new Button("new pattern"));
		p.add(fastButton = new Button("faster"));
		p.add(slowButton = new Button("slower"));
		this.add("North", p);
		auto = true;
		painting = false;
		setButtons();
		bedtime = (long)2001;
	}

	public void run() {
		t.setPriority(Thread.NORM_PRIORITY);
		while (t != null) {
			if (auto) newPattern();
			try {
				Thread.sleep(bedtime);
			}
			catch (InterruptedException e) {}
		}
	}

	public void start() {
		if (t == null) {
			t = new Thread(this);
			t.start();
		}
	}

	public void stop() {
		if (t != null) {
			t.stop();
			t = null;
		}
	}

	private void newPattern() {
		if (sp == null) sp = new Spiral();
		if (!painting) {
			painting = true;
			sp.setSize(size());
			sp.setParms();

			//workaround for netscape gold ??????
			if (this.getBackground() != Color.black) this.setBackground(Color.black);

			repaint();
		}
	}

	private void setButtons() {
		if (auto) {
			newButton.disable();
			fastButton.enable();
			slowButton.enable();
		}
		else {
			newButton.enable();
			fastButton.disable();
			slowButton.disable();
		}
	}			

	public void paint(Graphics g) {
		painting = true;
		if (sp != null) {
			sp.setSize(size());
			sp.paint(g);
		}
		painting = false;
	}	

	public boolean action(Event e, Object o) {
		if (e.target == autoButton) {
			auto = !auto;
			setButtons();
			return true;
		}
		else if ((e.target == newButton) && (!auto)) {
			newPattern();
			return true;
		}
		else if (e.target == fastButton) {
			if (bedtime > (long)1000) bedtime -= (long)1000;
			return true;
		}
		else if (e.target == slowButton) {
			bedtime += (long)1000;
			return true;
		}
		return super.action(e, o);
	}
}