Chapter 2, Problem 23RE

Explanation of Solution

Calling “paintComponent ()” method:

• The “paintComponent ()” is a method used in the Java programming language.
• This method is called whenever the user wants to redraw the diagram.
• When a window becomes resized or visible, the system automatically calls the “paintComponent ()” method for all area of the screen which have to be redrawn.

Example:

Consider an example for the “paintComponent ()” method as follows:

//include the required header files

import javax.swing.JComponent;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.geom.Ellipse2D;

//definition of "Ellipse" class

public class Ellipse extends JComponent

{

    //definition of "paintComponent" method

    public void paintComponent(Graphics g)

    {

        //create an object for "Graphics2D"

        Graphics2D g2 = (Graphics2D) g;

/*declare the required variables and call the required methods*/

        double wid = getWidth();

        double ht = getHeight();

        //create an object for "Ellipse2D"

Ellipse2D o = new Ellipse2D...

Explanation of Solution

Occurrence of “paintComponent()” method:

• A graphic object is the argument to the “paintComponent()”method.

  The “repaint ()” method is used to refresh the screen...