Introduction to Parameters and Objects - Building Java Programs: A Back to Basics Approach - page 195

Sometimes you don't just want to draw the outline of a shape; you want to paint
the entire area with a particular color. There are variations of the drawRect and
drawOval methods known as fillRect and fillOval that do exactly that, drawing
a rectangle or oval and filling it in with the current color of paint (the default is
black). Let's change two of the calls in the previous program to be “fill” operations
instead of “draw” operations:

1 // Draws and fills several shapes.
2
3 import java.awt.*;
4
5 public class DrawShapes2 {
6 public static void main(String[] args) {

7 DrawingPanel panel = new DrawingPanel(200, 100);

8
9

Graphics g = panel.getGraphics();

10 g.fillRect(25, 50, 20, 20);

11 g.drawRect(150, 10, 40, 20);

12 g.drawOval(50, 25, 20, 20);

13 g.fillOval(150, 50, 40, 20);

14 }

15 }

Now we get the output shown in Figure 3G.5 instead.

Figure 3G.5 Output of DrawShapes2

Colors
All of the shapes and lines drawn by the preceding programs were black, and all of
the panels had a white background. These are the default colors, but you can change
the background color of the panel, and you can change the color being used by the
Graphics object as many times as you like. To change these colors, you use the stan-
dard Color class, which is part of the java.awt package.