/*  Illustrates the use of the:
        Color constructor Color(int, int, int)
        increment operator
*/
import java.awt.*;
import java.applet.*;
import java.awt.event.*;    // import the window event package

public class redblueboard extends Applet implements ActionListener {
    Label sizeL = new Label("Edge length"),
          numL    = new Label("Number");
    TextField sizeT = new TextField("40", 2),
              numT    = new TextField("8", 2);

    int num = 8,
        size = 40;      // size of square

    public void init() {
        add(numL);    add(numT);
        add(sizeL); add(sizeT);
        // "this" applet handles ActionEvents for all TextFields
        sizeT.addActionListener( this );
        numT.addActionListener( this );
    }

    public void paint(Graphics g) {
        int col,
            xOffset = 40,   // horizontal offset from left
            yOffset = 40,
            delta = 255/num;   // vertical offset from top
            Color c;

        int row = -1;
        while (++row < num) {
            col = -1;
            while (++col < num) {
                if ((row + col) % 3 == 0)
                    c = new Color(row* delta, 0, col*delta);
                else if ((row + col) % 3 == 1)
                    c = new Color(0, col*delta, row*delta);
                else
                    c = Color.black;
                g.setColor(c);
                g.fillRect(xOffset + col*size, yOffset + row*size, size, size);
            }
        }
    }
    public void actionPerformed( ActionEvent e ) {
        size = Integer.parseInt( sizeT.getText() );
        num  = Integer.parseInt( numT.getText() );
        repaint();
    }
}