Source

import java.applet.*;
import java.awt.*;

public class AnAppletWithGraphics extends Applet {
	public void paint(Graphics g) {
		g.drawLine(0, 0, 100, 100);
		g.setColor(Color.green);
		g.drawRect(10, 30, 20, 60);
		g.setColor(new Color(100, 50, 210));
		g.fillOval(20, 10, 15, 30);
		g.setColor(Color.red);
		g.drawString("Hi There!", 25, 55);

	}
}

Description and Objective

• Illustrates how to draw graphic shapes in an applet
• How to set the color when drawing graphics

Notes

• Graphic shapes may be drawn when the paint method is invoked
• Most drawing within the context of paint requires the use of the Graphics object passed as a parameter to paint
• The Graphics object also allows you to set the current foreground color
• Text is considered a graphic in the system, and thus text may be drawn as well using the drawString methods of the Graphics object

This Applet's Behavior

• This applet has no instance variables to initialize and requires no other initialization behavior, so no init method is provided.
• The paint method draws several shapes (including text) in several colors onto the applet's surface.
• The setColor method is used to change the 'pen'/'foreground' color.
  • Once set, the color remains only again changed
  • Note: While the foreground color requires a method (i.e., setColor) invoked on the Graphics parameter, the backgeound color is set using a method (setBackground) of the Applet class itself.
• Color constants as well as custom colors are used.
• The drawRect draws an outline of a rectangle in the current color, while the fillRect draws a rectangle whose interior is filled in with the color.

Things to Do

• The Graphics class
  • Which package is it in?
  • Find the various methods used
  • What other useful drawing methods can you find?

1. Code an applet that draws a smiley face
2. Code an applet that accepts two integer parameters.
   • The first, named quantity (assume it will be no more than 4) determines the number of circles to draw. The circles should be drawn adjacent to each other, touching at the single point.
   • The second parameter is the diameter of each circle.
   • Introduce an init method and some instance variables to hold the values of the parameters
3. Same as #1, but now, have the face toggle between a smiley and a frown with each invocation of paint