//<APPLET CODE="CondShow.class" WIDTH=300 HEIGHT=380></applet>
import java.awt.*;
import java.applet.*;


public class CondShow extends Applet {
	TextField a11,a12,a21,a22,cond;
	ConditionOvalPanel co;
	Jama.Matrix mat;

	public void init(){
		setLayout(new BorderLayout());
		setBackground(Color.white);
		co = new ConditionOvalPanel(10,10);

			ConditionOvalPanel.a11 = 1;
			ConditionOvalPanel.a12 = 0;
			ConditionOvalPanel.a21 = 0;
			ConditionOvalPanel.a22 = 1;
			co.ax1 = (int)(75*1);
			co.ay1 = (int)(75*0);
			co.ax2 = (int)(75*0);
			co.ay2 = (int)(75*1);

		a11 = new TextField(3);
		a12 = new TextField(3);
		a21 = new TextField(3);
		a22 = new TextField(3);

		add("Center",co);

		Panel pControlMain = new Panel();
		pControlMain.setLayout(new BorderLayout());

//----- Control Panel -----//
		Panel pControl = new Panel();

		Panel A = new Panel();
		A.setLayout(new GridLayout(2,2,2,2));
		A.add(a11);
		A.add(a12);
		A.add(a21);
		A.add(a22);

		pControl.add(new Label("A = "));
		pControl.add(A);
		pControl.add(new Label(", cond(A) = "));
		cond = new TextField(4);
		cond.setEditable(false);
		pControl.add(cond);
		pControlMain.add("Center",pControl);
//----- Control Panel -----//

		pControlMain.add("South",new Button("Calculate"));
		add("South",pControlMain);

		reset();
	} // _init()


	public boolean action(Event evt, Object arg){
		if (arg.equals("Calculate")){
			double a[][] = new double[2][2];
			a[0][0]= Double.valueOf(a11.getText()).doubleValue();
			a[0][1]=Double.valueOf(a12.getText()).doubleValue();
			a[1][0]=Double.valueOf(a21.getText()).doubleValue();
			a[1][1]=Double.valueOf(a22.getText()).doubleValue();

			Jama.SingularValueDecomposition svd = new Jama.SingularValueDecomposition(new Jama.Matrix(a));
			cond.setText(""+svd.cond());

			co.ax1 = (int)(75*a[0][0]);
			co.ay1 = (int)(75*a[1][0]);
			co.ax2 = (int)(75*a[0][1]);
			co.ay2 = (int)(75*a[1][1]);
			ConditionOvalPanel.a11 = a[0][0];
			ConditionOvalPanel.a12 = a[0][1];
			ConditionOvalPanel.a21 = a[1][0];
			ConditionOvalPanel.a22 = a[1][1];

			co.repaint();
		}

		return true;
	}

	public void reset(){
		a11.setText("1");
		a12.setText("0");
		a21.setText("0");
		a22.setText("1");
		cond.setText("1");
	}
} // End class

////////////////////////////////////////////////////////////
class ConditionOvalPanel extends Panel {
	int w,
	    h;
	int ovalW,
 	    	     ovalH;

	int ax1=0,ay1=0, ax2=0, ay2=0;
static double a11=0,a12=0,a21=0,a22=0;
	double rangle = 0;
	static boolean bobish = false;

	public ConditionOvalPanel(int w, int h){
		this.w = w;
		this.h = h;
		ovalW = 50;
		ovalH = 50;
		rangle = 0;
	}

	public void paint(Graphics g){
		w = this.size().width;
		h = this.size().height;

		g.setColor(Color.black);
		g.drawLine(0,h/2,w,h/2);
		g.drawLine(w/2,0,w/2,h);

		drawVector(g);

		g.setColor(Color.blue);
		CircleEx.generatePoints(a11,a12,a21,a22,75,75,300,300,g);
	}

	public void drawVector(Graphics g){
		g.setColor(Color.red);

		// Horizontal Vector e1
		drawArrow(w/2,h/2,w/2+ax1,h/2-ay1,g);

		// Vertical Vector e2
		drawArrow(w/2,h/2,w/2+ax2,h/2-ay2,g);
	}


    public void drawArrow(int x1, int y1, int x2, int y2, Graphics g) {

        double d = Math.atan((float)((double)(y1 - y2) / (double)(x1 - x2)));
        if(x1 - x2 < 0)
            d += 3.1415926535897931D;

        g.drawLine(x1, y1, x2, y2);
        g.drawLine(x2, y2, x2 + (int)(Math.cos(d + 0.29999999999999999D) * 10D), y2 + (int)(Math.sin(d + 0.29999999999999999D) * 10D));
        g.drawLine(x2, y2, x2 + (int)(Math.cos(d - 0.29999999999999999D) * 10D), y2 + (int)(Math.sin(d - 0.29999999999999999D) * 10D));
    }


	public boolean mouseDown(Event evt, int x, int y){
		repaint();
		return true;
	}

} // _ConditionOval

//
////////////////////////////////////////////////////////////////////////////////
//
class CircleEx extends Polygon{
	int 	centerX,
		centerY,
		width,
		height;


	public CircleEx(int centerX, int centerY, int width, int height){
		this.centerX = centerX;
		this.centerY = centerY;
	}

	public static void generatePoints(double a11, double a12, double a21, double a22,int lengthX, int lengthY,int width, int height, Graphics g){
		int num_of_points = 360*4;
		double x[] = new double [num_of_points],
		    y[] = new double [num_of_points];
		double theta = num_of_points/360;

		for (int i=0;i<num_of_points;i++){
			x[i] = Math.cos(i*theta);
			y[i] = Math.sin(i*theta);
		}

		double xtemp;

		for (int i=0;i<num_of_points;i++){
			
			xtemp = x[i]*a11+y[i]*a12;
			y[i] = x[i]*a21+y[i]*a22;
			x[i] = -xtemp;

			x[i] = width/2+lengthX*x[i];
			y[i] = height/2+lengthY*y[i];

			g.fillOval((int)Math.round(x[i]),(int)Math.round(y[i]),3,3);
		}
	}
}// End Circle