Introduction to Parameters and Objects - Building Java Programs: A Back to Basics Approach - page 196

Table 3G.3 Color Constants

Color.BLACK Color.GREEN Color.RED

Color.BLUE Color.LIGHT_GRAY Color.WHITE

Color.CYAN Color.MAGENTA Color.YELLOW

Color.DARK_GRAY Color.ORANGE

Color.GRAY Color.PINK

There are a number of predefined colors that you can refer to directly. They are
defined as class constants in the Color class (a lot like the constants we used in Chapter
2). The names of these constants are all in uppercase and are self-explanatory. To refer to
one of these colors, you have to precede it with the class name and a dot, as in
Color.GREEN or Color.BLUE . The predefined Color constants are listed in Table 3G.3.
As mentioned earlier, the DrawingPanel object has a method that can be used to
change the background color that covers the entire panel:

<panel>.setBackground(<color>);

Likewise, the Graphics object has a method that can be used to change the cur-
rent color that draws or fills shapes and lines:

g.setColor(<color>);

Calling setColor is like dipping your paintbrush in a different color of paint.
From that point on, all drawing and filling will be done in the specified color. For
example, here is another version of the previous program that uses a cyan (light blue)
background color and fills in the oval and square with white instead of black:

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

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

8 panel.setBackground(Color.CYAN);

9
10 Graphics g = panel.getGraphics();

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

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

13 g.setColor(Color.WHITE);

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

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

16 }

17 }