RasterImageTest.java Source code

Introduction

Here is the source code for RasterImageTest.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.Color;
import java.awt.EventQueue;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.WritableRaster;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;

/**
 * This program demonstrates how to build up an image from individual pixels.
 * @version 1.13 2007-08-16
 * @author Cay Horstmann
 */
public class RasterImageTest {
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                JFrame frame = new RasterImageFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

/**
 * This frame shows an image with a Mandelbrot set.
 */
class RasterImageFrame extends JFrame {
    public RasterImageFrame() {
        setTitle("RasterImageTest");
        setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
        BufferedImage image = makeMandelbrot(DEFAULT_WIDTH, DEFAULT_HEIGHT);
        add(new JLabel(new ImageIcon(image)));
    }

    /**
     * Makes the Mandelbrot image.
     * @param width the width
     * @parah height the height
     * @return the image
     */
    public BufferedImage makeMandelbrot(int width, int height) {
        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
        WritableRaster raster = image.getRaster();
        ColorModel model = image.getColorModel();

        Color fractalColor = Color.red;
        int argb = fractalColor.getRGB();
        Object colorData = model.getDataElements(argb, null);

        for (int i = 0; i < width; i++)
            for (int j = 0; j < height; j++) {
                double a = XMIN + i * (XMAX - XMIN) / width;
                double b = YMIN + j * (YMAX - YMIN) / height;
                if (!escapesToInfinity(a, b))
                    raster.setDataElements(i, j, colorData);
            }
        return image;
    }

    private boolean escapesToInfinity(double a, double b) {
        double x = 0.0;
        double y = 0.0;
        int iterations = 0;
        while (x <= 2 && y <= 2 && iterations < MAX_ITERATIONS) {
            double xnew = x * x - y * y + a;
            double ynew = 2 * x * y + b;
            x = xnew;
            y = ynew;
            iterations++;
        }
        return x > 2 || y > 2;
    }

    private static final double XMIN = -2;
    private static final double XMAX = 2;
    private static final double YMIN = -2;
    private static final double YMAX = 2;
    private static final int MAX_ITERATIONS = 16;
    private static final int DEFAULT_WIDTH = 400;
    private static final int DEFAULT_HEIGHT = 400;
}