SimpleBufferedImageDemo.java Source code

Introduction

Here is the source code for SimpleBufferedImageDemo.java

Source

import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.Container;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.MediaTracker;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.border.TitledBorder;

public class SimpleBufferedImageDemo extends JFrame {
    DisplayCanvas canvas;

    JRadioButton buffButton, nonBuffButton;

    JButton displayButton, clearButton;

    public SimpleBufferedImageDemo() {
        super();
        Container container = getContentPane();

        canvas = new DisplayCanvas();
        container.add(canvas);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(2, 2));
        panel.setBorder(new TitledBorder("Select an Option and Display Image..."));

        buffButton = new JRadioButton("Buffered");
        buffButton.addActionListener(new ButtonListener());
        nonBuffButton = new JRadioButton("Non-Buffered", true);
        nonBuffButton.addActionListener(new ButtonListener());
        ButtonGroup group = new ButtonGroup();
        group.add(buffButton);
        group.add(nonBuffButton);

        displayButton = new JButton("Display");
        displayButton.addActionListener(new ButtonListener());
        clearButton = new JButton("Clear");
        clearButton.addActionListener(new ButtonListener());

        panel.add(nonBuffButton);
        panel.add(buffButton);
        panel.add(displayButton);
        panel.add(clearButton);

        container.add(BorderLayout.SOUTH, panel);

        addWindowListener(new WindowEventHandler());
        pack();
        setVisible(true);
    }

    class WindowEventHandler extends WindowAdapter {
        public void windowClosing(WindowEvent e) {
            System.exit(0);
        }
    }

    public static void main(String arg[]) {
        new SimpleBufferedImageDemo();
    }

    class ButtonListener implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            Object obj = e.getSource();

            if (obj instanceof JRadioButton) {
                JRadioButton button = (JRadioButton) obj;
                if (button.equals(buffButton)) {
                    canvas.buffered = true;
                } else if (button.equals(nonBuffButton)) {
                    canvas.buffered = false;
                }
            }

            if (obj instanceof JButton) {
                JButton button = (JButton) obj;
                if (button.equals(displayButton)) {
                    canvas.display = true;
                    canvas.repaint();
                } else if (button.equals(clearButton)) {
                    canvas.clear = true;
                    canvas.repaint();
                }
            }
        }
    }
}

class DisplayCanvas extends Canvas {
    boolean display = false;

    boolean clear = false;

    boolean buffered = false;

    Image displayImage;

    DisplayCanvas() {
        displayImage = Toolkit.getDefaultToolkit().getImage("largeJava2sLogo.jpg");

        MediaTracker mt = new MediaTracker(this);
        mt.addImage(displayImage, 1);
        try {
            mt.waitForAll();
        } catch (Exception e) {
            System.out.println("Exception while loading.");
        }

        if (displayImage.getWidth(this) == -1) {
            System.out.println("No *.jpg file");
            System.exit(0);
        }
        setBackground(Color.white);
        setSize(400, 225);
    }

    public void paint(Graphics g) {
        Graphics2D g2D = (Graphics2D) g;

        if (display) {
            if (buffered) {
                BufferedImage bi = (BufferedImage) createImage(getWidth(), getHeight());

                // Draw into the memory buffer.
                for (int i = 0; i < getWidth(); i = i + displayImage.getWidth(this)) {
                    for (int j = 0; j < getHeight(); j = j + displayImage.getHeight(this)) {
                        bi.createGraphics().drawImage(displayImage, i, j, this);
                    }
                }
                // Draw the buffered Image on to the screen
                g2D.drawImage(bi, 0, 0, this);
            }
            // This block of code draws the texture directly onto the screen.
            else if (!buffered) {
                for (int i = 0; i < getWidth(); i = i + displayImage.getWidth(this)) {
                    for (int j = 0; j < getHeight(); j = j + displayImage.getHeight(this)) {
                        g2D.drawImage(displayImage, i, j, this);
                    }
                }
            }
            display = false;
        } else if (clear) {
            g2D.setColor(Color.white);
            g2D.clearRect(0, 0, getWidth(), getHeight());
            clear = false;
        }
    }
}