More Conditionals and Loops - Java Software Solutions: Foundations of Program Design - page 290

LISTING 6.8 continued

public class BoxesPanel extends JPanel
{
private final int NUM_BOXES = 50, THICKNESS = 5, MAX_SIDE = 50;
private final int MAX_X = 350, MAX_Y = 250;
private Random generator;

//-----------------------------------------------------------------
// Sets up the drawing panel.
//-----------------------------------------------------------------
public BoxesPanel ()
{
generator = new Random();

setBackground (Color.black);
setPreferredSize ( new Dimension(400, 300));
}

//-----------------------------------------------------------------
// Paints boxes of random width and height in a random location.
// Narrow or short boxes are highlighted with a fill color.
//-----------------------------------------------------------------
public void paintComponent(Graphics page)
{
super .paintComponent (page);

int x, y, width, height;

for ( int count = 0; count < NUM_BOXES; count++)
{
x = generator.nextInt(MAX_X) + 1;
y = generator.nextInt(MAX_Y) + 1;

width = generator.nextInt(MAX_SIDE) + 1;
height = generator.nextInt(MAX_SIDE) + 1;

if (width <= THICKNESS) // check for narrow box
{
page.setColor (Color.yellow);
page.fillRect (x, y, width, height);
}
else
if (height <= THICKNESS) // check for short box
{