Introduction to Parameters and Objects - Building Java Programs: A Back to Basics Approach - page 194

Notice that the first two values passed to drawRect and drawOval are coordi-
nates, while the next two values are a width and a height. For example, here is a short
program that draws two rectangles and two ovals:

1 // Draws several shapes.
2
3 import java.awt.*;
4
5 public class DrawShapes1 {
6 public static void main(String[] args) {

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

8
9

Graphics g = panel.getGraphics();

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

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

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

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

14 }

15 }

Figure 3G.4 shows the output of the program.

Figure 3G.4 Output of DrawShapes1

The first rectangle has its upper-left corner at the coordinates (25, 50). Its width
and height are each 20, so this is a square. The coordinates of its lower-right corner
would be (45, 70), or 20 more than the (x, y) coordinates of the upper-left corner. The
program also draws a rectangle with its upper-left corner at (150, 10) that has a width
of 40 and a height of 20 (wider than it is tall). The bounding rectangle of the first oval
has upper-left coordinates (50, 25) and a width and height of 20. In other words, it's a
circle. The bounding rectangle of the second oval has upper-left coordinates (150,
50), a width of 40, and a height of 20 (it's an oval that is wider than it is tall).