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

public class orbits extends Applet implements Runnable, ActionListener{
	// Applet for plotting orbits. Stefan Emet 1998.
	TextField	TextField_parameter_a, TextField_parameter_b, 
				TextField_X_0;
	Choice		Choice_function; 
	Button		Button_Draw, Button_Continue, Button_Stop; 
	Thread		Thread_RUN;
	Panel		Panel_top, Panel_right, Panel_right_param,  
				Panel_bottom, Panel_X_0, Panel_Buttons;
	Label		Label_top, Label_parameter_a, Label_parameter_b, Label_X_0;
  	figure		figure_plot;	// class figure controls the plotting 
	figure_text	figure_text_f;	// class Function_text updates the function texts  
	boolean		CLEAR_figure=true, DRAW_ORBIT, FIRST, CONTINUE;
	int			ACTIVE_FUNCTION=0, t=0,	// time: t		 
				x_pix_inc=30, x_pix_ind=0, run=0,click=0;
	final static int COSINE=0,NONLINEAR=1,LOGISTIC=2,LINEAR=3;
	double		a=0.5, b=1, X_0=0, X_t;	// system: X_t, X_0 
	String[]	Function = {"Cos( X(t) )","0.5 ( X(t)^3 + X(t) )",
							"a X(t) ( 1-X(t) )","a X(t) + b"};
	
public void init() {
	setLayout(new BorderLayout(5,5));	// sets the main-border
	Panel_top = new Panel();
	Label_top = new Label("The forward-orbit of a chosen map");
	Panel_top.add(Label_top);
	add("North",Panel_top);

	Panel_right = new Panel();
	Panel_right.setLayout(new GridLayout(0,1,5,5));
	Panel_right.add(new Label("Choose function"));
	Choice_function = new Choice();		// allocate memory for the 
	Choice_function.addItem("cos(x)");
	Choice_function.addItem(".5(x^3+x)");
	Choice_function.addItem("a x (1-x)");
	Choice_function.addItem("a x + b");
	//Choice_function.addActionListener(this);
	Panel_right.add(Choice_function);
 	Panel_right_param = new Panel();
	Panel_right_param.setLayout(new GridLayout(2,2,3,3));
	Panel_right_param.add(Label_parameter_a = new Label("a :"));
	Panel_right_param.add(TextField_parameter_a = new TextField(""+a,3));
	Panel_right_param.add(Label_parameter_b = new Label("b :"));
	Panel_right_param.add(TextField_parameter_b = new TextField(""+b,3));
	Panel_right.add(Panel_right_param);
	Panel_right.add(new Label(" "));
	add("East",Panel_right);	// puts the Choice-menu and parameter-field to the right

	Panel_bottom = new Panel();
	Panel_bottom.setLayout(new GridLayout(1,0,5,5)); // 1-row 
	figure_text_f = new figure_text(this);
	Panel_bottom.add(figure_text_f);
	Panel_X_0 = new Panel();
	Panel_X_0.add(new Label("X(0) :"));
	Panel_X_0.add(TextField_X_0 = new TextField(""+X_0,3));
	Panel_bottom.add(Panel_X_0);
	Panel_Buttons = new Panel();
	Panel_Buttons.setLayout(new GridLayout(1,0,3,3));
	Panel_Buttons.add(Button_Draw= new Button("Draw"));
	Panel_Buttons.add(Button_Stop= new Button("Stop"));
	Panel_Buttons.add(Button_Continue= new Button("Continue"));
       Button_Draw.addActionListener(this);
       Button_Stop.addActionListener(this);
       Button_Continue.addActionListener(this);
	Panel_bottom.add(Panel_Buttons);
	add("South",Panel_bottom);

	figure_plot = new figure(this);
	add("Center", figure_plot);
}
public double f(double x){
	switch (ACTIVE_FUNCTION) {
	case COSINE:		return Math.cos(x);			
	case NONLINEAR:		return 0.5*(Math.pow(x,3)+x);
	case LOGISTIC:		return a*x*(1-x);
	case LINEAR:		return a*x+b;
	}
	return 0;
}
public void run(){
	t=0; x_pix_ind=0;
	X_t = X_0 = Double.valueOf(TextField_X_0.getText()).doubleValue();
	a = Double.valueOf(TextField_parameter_a.getText()).doubleValue();
	b = Double.valueOf(TextField_parameter_b.getText()).doubleValue();
	FIRST = true; 
	while (DRAW_ORBIT){		  
		if (x_pix_ind % x_pix_inc == 0){
			X_t=f(X_t);
			t++;
		}	
		figure_plot.repaint(); 
		try { Thread.sleep(50);}	// try{} catch -block slows down the drawings 
		catch ( InterruptedException e ) {}
		x_pix_ind++; 
	}
}
public void start(){
	if (Thread_RUN==null){
		Thread_RUN=new Thread(this);
	}
		Thread_RUN.start();		// calls the run -method
}
public void stop(){
	Thread_RUN.stop();
	DRAW_ORBIT=false;
	Thread_RUN=null;			// the thread to null
}
/*public boolean lostFocus(Event e, Object arg){
	showStatus("Lost !");
	return false;
}
public boolean gotFocus(Event e, Object arg){
	showStatus("Got Focus !");
	return false;
} */
public void actionPerformed(ActionEvent e){
	Object source=e.getSource();
	if (source.equals(Choice_function)){
		ACTIVE_FUNCTION=Choice_function.getSelectedIndex();	
		set_CLEAR(true);		  
		DRAW_ORBIT=false;		  
		figure_text_f.repaint();			
	}			
	else if(source.equals(Button_Draw)){
		stop();
		set_CLEAR(true);		
		DRAW_ORBIT=true;
		Button_Draw.setEnabled(false);
		Button_Continue.setEnabled(false);
		Button_Stop.setEnabled(true);
		start();
	}
	else if(source.equals(Button_Stop)){
		Button_Draw.setEnabled(true);
		Button_Continue.setEnabled(true);
		Button_Stop.setEnabled(false);
		Thread_RUN.suspend();
	}
	else if(source.equals(Button_Continue)){
		Button_Continue.setEnabled(false);
		Button_Stop.setEnabled(true);
		Thread_RUN.resume(); 
	}
}
public void set_CLEAR(boolean set){
	CLEAR_figure=set;
}
public void set_FIRST(boolean set){
	FIRST=set;
}
public void set_x_pix_ind(int set){
	x_pix_ind=set;
}
}	// class orbits


class figure extends Canvas {
	orbits	orbit;
	double	y_pix_inc;
	int		figure_WIDTH, figure_HEIGHT, AXES_WIDTH, AXES_HEIGHT,
			AXES_x0=15, AXES_y0=20,	ii=1,
			x_pix, y_pix, y_pix_a, y_pix_b;

figure(orbits pointer){
	super();
	orbit = pointer;
}
public void paint(Graphics g){
	figure_WIDTH=getSize().width;	// the width of the Plot-window				
	figure_HEIGHT=getSize().height;	// the height of the Plot-window
	AXES_WIDTH=figure_WIDTH-29; 	// width of the axes in the Plot-window
	AXES_HEIGHT=figure_HEIGHT-39;	// height of the axes in the Plot-window
	update(g);
}
public void update(Graphics g){
	if (orbit.CLEAR_figure){
		orbit.set_CLEAR(false);		 
		g.setColor(Color.white);
		g.fillRect(0,0,figure_WIDTH,figure_HEIGHT);
		g.setColor(Color.black);
		g.drawRect(0,0,figure_WIDTH-1,figure_HEIGHT-1);
		axis(g);
	}
	if (orbit.FIRST){
		orbit.set_FIRST(false);
		x_pix=AXES_x0;
		y_pix=y_pix_a=y_pix_b=y_pixel(orbit.X_0);
	}
	if (orbit.DRAW_ORBIT){ // draw the orbit one step forward
		draw(g);		
		if (orbit.x_pix_ind % AXES_WIDTH == 0){
			orbit.set_CLEAR(true);
			x_pix=AXES_x0;
		}
		else
			x_pix++;
	}
}	// update
public void axis(Graphics g){
	g.drawRect(AXES_x0,AXES_y0,AXES_WIDTH,AXES_HEIGHT);
	g.drawString("X(t)",AXES_x0+1,AXES_y0-3);g.drawString("t",AXES_x0+AXES_WIDTH+2,AXES_y0+AXES_HEIGHT+10);
	switch (orbit.ACTIVE_FUNCTION) {
	case orbit.COSINE:	g.drawString("1",AXES_x0-8,AXES_y0+4); g.drawLine(AXES_x0-2,AXES_y0,AXES_x0+2,AXES_y0);
			g.drawString("0",AXES_x0-8,AXES_y0+(int)(0.5*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.5*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.5*AXES_HEIGHT));
			g.drawString("-1",AXES_x0-10,AXES_y0+AXES_HEIGHT+4); g.drawLine(AXES_x0-2,AXES_y0+AXES_HEIGHT,AXES_x0+2,AXES_y0+AXES_HEIGHT);
			break;	
	case orbit.NONLINEAR:	g.drawString("+Inf",AXES_x0-15,AXES_y0+5);
			g.drawString("1",AXES_x0-8,AXES_y0+(int)(0.2*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.2*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.2*AXES_HEIGHT));
			g.drawString("0",AXES_x0-8,AXES_y0+(int)(0.5*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.5*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.5*AXES_HEIGHT));
			g.drawString("-1",AXES_x0-10,AXES_y0+(int)(0.8*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.8*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.8*AXES_HEIGHT));
			g.drawString("-Inf",AXES_x0-15,AXES_y0+AXES_HEIGHT+5);
			break;
	case orbit.LOGISTIC:	g.drawString("1",AXES_x0-8,AXES_y0+(int)(0.2*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.2*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.2*AXES_HEIGHT));
			g.drawString("0",AXES_x0-8,AXES_y0+(int)(0.8*AXES_HEIGHT)+4); g.drawLine(AXES_x0-2,AXES_y0+(int)(0.8*AXES_HEIGHT),AXES_x0+2,AXES_y0+(int)(0.8*AXES_HEIGHT));
			g.drawString("-Inf",AXES_x0-15,AXES_y0+AXES_HEIGHT+5);
			break;
	case orbit.LINEAR:	
			break;
	}
}
public void draw(Graphics g){
	if ((orbit.x_pix_ind % orbit.x_pix_inc)==0){
		y_pix_a=y_pix_b;			// update the y_points
		y_pix_b=y_pixel(orbit.X_t);	// the next point
		y_pix_inc=(double)(y_pix_b-y_pix_a)/(orbit.x_pix_inc);
		cross(g,x_pix,y_pix_a);		// put a cross at the point (t,X(t)) 
		g.drawLine(x_pix,AXES_y0+AXES_HEIGHT-2,x_pix,AXES_y0+AXES_HEIGHT+2);
		g.drawString(""+(orbit.t-1), x_pix-3,AXES_y0+AXES_HEIGHT+13);
	}
	else{
		g.drawLine(x_pix,y_pix,x_pix+1,y_pix_a+(int)((orbit.x_pix_ind % orbit.x_pix_inc)*y_pix_inc));
		y_pix=y_pix_a+(int)((orbit.x_pix_ind % orbit.x_pix_inc)*y_pix_inc);
	}
} 	
public void cross(Graphics g, int x, int y){
	g.setColor(Color.red);
	g.drawLine(x-1,y-1,x+1,y+1);
	g.drawLine(x-1,y+1,x+1,y-1);
	g.setColor(Color.black);
}
public int y_pixel(double in){
	int y_pix_value=0;
	switch (orbit.ACTIVE_FUNCTION) {
	case orbit.COSINE:		y_pix_value = (int)(0.5*AXES_HEIGHT*(1-in));
				break;
	case orbit.NONLINEAR:	y_pix_value = 
				(in > 1) ?		(int)(AXES_HEIGHT*0.18*(1-Math.min((double)(in/100000),1)))
				:(	(in < -1) ? (int)(AXES_HEIGHT*(0.82+0.18*(Math.min((double)(-in/100000),1.0))))
					:			(int)(AXES_HEIGHT*(0.2+0.3*(1-in))));					
				break;
	case orbit.LOGISTIC:	y_pix_value = 
				(in > 1) ?		(int)(AXES_HEIGHT*0.2*(1-Math.min((double)(in/10),1)))
				:(	(in < 0) ?	(int)(AXES_HEIGHT*(0.82+0.18*(Math.min((double)(-in/100000),1.0))))
					:			(int)(AXES_HEIGHT*(0.2+0.6*(1-in))));
				break;
	case orbit.LINEAR:		
				break;
	}
	return (AXES_y0+y_pix_value);
}
}	// class figure	


class figure_text extends Canvas {
	orbits orbit;

figure_text(orbits pointer){
	super();
	orbit = pointer;
}
public void paint(Graphics g){
	g.drawString("X(t+1) = "+orbit.Function[orbit.ACTIVE_FUNCTION],10,20);
}
}	// class figure_text