TestShapes2.java

/*
    TestShapes2.java
    CIS 260
    2005-11-05
    David Klick

This is the implementation of the TestShapes program as a
    JApplet with the resize problem fixed. Resizing no longer
    blanks out the applet because the repainting works reliably
    now.
*/

/*
<applet code="TestShapes2.class" width="400" height="400">
</applet>
*/

import java.awt.*;
import javax.swing.*;

public class TestShapes2 extends JApplet {
    private Shape[] shapes = new Shape[10];

public void init() {
        // create the 10 randomized shapes to be drawn
        int x, y, r, w, h, n, i;
        for (i=0; i<shapes.length; i++) {
            n = (int) Math.floor(Math.random() * 2);

// this is set as a switch so new cases for new
            //    shapes can be added easily
            switch (n) {
            case 0:
                x = (int) Math.floor(Math.random() * 100) + 150;
                y = (int) Math.floor(Math.random() * 100) + 150;
                r = (int) Math.floor(Math.random() * 150);
                shapes[i] = new Circle(x, y, r);
                break;
            default:
                x = (int) Math.floor(Math.random() * 150);
                y = (int) Math.floor(Math.random() * 150);
                w = (int) Math.floor(Math.random() * (300-x));
                h = (int) Math.floor(Math.random() * (300-y));
                shapes[i] = new Rectangle(x, y, w, h);
            }
        }

// add a component to hold the drawing so that the
        // JApplet will automatically call it to repaint itself
        Container c = getContentPane();
        DrawingArea da = new DrawingArea();
        da.setBackground(Color.WHITE);
        c.add(da);
    }

// This is a simple little class to hold our drawing.
    // We use it to avoid whatever overwriting was happening
    // when we were drawing raw to the JApplet Graphics object.
    class DrawingArea extends JPanel {
        public void paintComponent(Graphics g) {
            super.paintComponent(g);
            for (int i=0; i<shapes.length; i++) {
                shapes[i].draw(g);
            }
        }
    }
}