/**
* Fractal Waffle
* a Sierpinski Gasket Java applet
* by Jay Tomlin, January 1997
* http://ezinfo.ucs.indiana.edu/~ltomlin
* ltomlin@indiana.edu
*/


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

public class FractalWaffle extends Applet {

// Define the class variables
Panel chalkboard, controls;
BorderLayout border;
Scrollbar iterations;
Button redraw;
TextField showIterations;

// Define and draw widgets 

public void init() {
        chalkboard = new Panel(); // for the gasket
        controls = new Panel(); // to set the number of iterations
        iterations = new Scrollbar(Scrollbar.VERTICAL, 3, 2, 0, 6);
        showIterations = new TextField(2);
        showIterations.setEditable(false);
        redraw = new Button("Redraw");  
        controls.add(new Label("Iterations: "));
        controls.add(showIterations);
        controls.add(iterations);
        controls.add(redraw);
        border = new BorderLayout();
        setLayout(border); // for the applet itself
        add("Center", chalkboard);
        add("South", controls);
        show();
        showIterations.setText("0");
        iterations.setValue(0);
} // ends init()

public void start() { }

// other class methods


void drawGasket(int iter) {
        
        Graphics g = chalkboard.getGraphics();
        Rectangle r = chalkboard.bounds();

        Double J = new Double(iter);
        double j = J.doubleValue();

        double colwidth, rowheight, rectWidth, rectHeight;
        
        try{ colwidth = r.width/(Math.pow(3.0,j));}
                catch (ArithmeticException e) {colwidth=0;}
        try{  rowheight = r.height/(Math.pow(3.0,j));}
                catch (ArithmeticException e) {rowheight=0;}
        try{  rectWidth = r.width/(Math.pow(3.0,j-1));}
                catch (ArithmeticException e) {rectWidth=0;}
        try{  rectHeight = r.height/(Math.pow(3.0,j-1));}
                catch (ArithmeticException e) {rectHeight=0;}
        
        Double Holes; // the number of white squares per row for this iteration
        try { Holes = new Double(Math.pow(3.0, j-1));}
                catch (ArithmeticException e) { Holes = new Double(0);}
        
        int holes = Holes.intValue();
        int x,y;
        g.setColor(Color.white);

        for (y=0; y<holes; y++) {
                for (x=0; x<holes; x++) {

                        double X1 = (x * rectWidth) + colwidth;
                        double Y1 = (y * rectHeight) + rowheight;
                        
                        Double DX1 = new Double(X1);
                        Double DY1 = new Double(Y1);
                        Double W = new Double(colwidth);
                        Double H = new Double(rowheight);

                        int x1 = DX1.intValue();
                        int y1 = DY1.intValue();
                        int w = W.intValue();
                        int h = H.intValue();
                        g.fillRect(x1, y1, w, h); 
                } // ends for(x)
        } // ends for(y)  


} // ends drawGasket


public boolean handleEvent(Event e) { // button clicks et al
        if (e.id == Event.ACTION_EVENT) { if (e.target == redraw) {
                int j = iterations.getValue();
                eraseBoard();
                for (int i=1; i<=j; i++) {
                        drawGasket(i);
                        } // ends for()
                }} else if (    e.id == Event.SCROLL_LINE_UP ||
                                        e.id == Event.SCROLL_LINE_DOWN ||
                                        e.id == Event.SCROLL_PAGE_UP ||
                                        e.id == Event.SCROLL_PAGE_DOWN ||
                                        e.id == Event.SCROLL_ABSOLUTE) {
                        Integer Iterations = new Integer(iterations.getValue());
                        showIterations.setText(Iterations.toString());
                } else { 
                 return super.handleEvent(e);}// ends if
        return true;
} // ends action()


void eraseBoard(){
        Graphics g = chalkboard.getGraphics();
        Rectangle r=chalkboard.bounds();
        g.setColor(Color.black);
        g.fillRect(r.x, r.y, r.width, r.height);
} // ends eraseBaord()


} // ends class FractalWaffle  :-)