KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > MandelbrotPlot


1 import java.applet.*;
2 import java.awt.*;
3 import java.awt.event.*;
4 import java.awt.image.MemoryImageSource JavaDoc;
5 import JSci.maths.Complex;
6 import JSci.maths.chaos.*;
7
8 /**
9 * Plot of the Mandelbrot set.
10 * @author Mark Hale
11 * @version 1.1
12 */
13 public final class MandelbrotPlot extends Applet {
14         private final int colorTable[]=new int[22];
15         private final int range[]={1,10,20,30,40,50,60,70,80,90,100,200,300,400,500,600,700,800,900,1000};
16         private final int N=2000;
17         private Image mandelbrotImage;
18         private Image imageBuffer;
19
20         /**
21         * Initialise the applet.
22         */
23         public void init() {
24                 // create colour palette
25 for(int i=0;i<colorTable.length;i++)
26                         colorTable[i]=grey(255-10*i);
27                 // draw Mandelbrot set to an image buffer
28 mandelbrotImage=drawMandelbrot();
29                 // mouse listener
30 addMouseListener(new MouseAdapter() {
31                         public void mouseClicked(MouseEvent evt) {
32                                 if(imageBuffer==mandelbrotImage) {
33                                         final int width=getSize().width;
34                                         final int height=getSize().height;
35                                         final Complex z=new Complex(evt.getX()*3.0/width-2.0,1.25-evt.getY()*2.5/height);
36                                         imageBuffer=drawJulia(z);
37                                         System.err.println(z.toString());
38                                         showStatus("Click to return to Mandelbrot set");
39                                 } else {
40                                         imageBuffer=mandelbrotImage;
41                                         showStatus("Click to generate a Julia set");
42                                 }
43                                 repaint();
44                         }
45                 });
46         }
47         public void start() {
48                 imageBuffer=mandelbrotImage;
49                 showStatus("Click to generate a Julia set");
50         }
51         public void paint(Graphics g) {
52                 g.drawImage(imageBuffer,0,0,this);
53         }
54         private Image drawMandelbrot() {
55                 final int width=getSize().width;
56                 final int height=getSize().height;
57                 final MandelbrotSet set=new MandelbrotSet();
58                 double x,y;
59                 int pixels[]=new int[width*height];
60                 int index=0;
61                 for(int j=0;j<height;j++) {
62                         for(int i=0;i<width;i++) {
63                                 x=i*3.0/width-2.0;
64                                 y=1.25-j*2.5/height;
65                                 pixels[index++]=colorLookup(set.isMember(x,y,N));
66                         }
67                 }
68                 return createImage(new MemoryImageSource JavaDoc(width,height,pixels,0,width));
69         }
70         private Image drawJulia(Complex z) {
71                 final int width=getSize().width;
72                 final int height=getSize().height;
73                 final JuliaSet set=new JuliaSet(z);
74                 double x,y;
75                 int pixels[]=new int[width*height];
76                 int index=0;
77                 for(int j=0;j<height;j++) {
78                         for(int i=0;i<width;i++) {
79                                 x=i*4.0/width-2.0;
80                                 y=1.25-j*2.5/height;
81                                 pixels[index++]=colorLookup(set.isMember(x,y,N));
82                         }
83                 }
84                 return createImage(new MemoryImageSource JavaDoc(width,height,pixels,0,width));
85         }
86         /**
87         * Returns a RGBA value.
88         */
89         private int colorLookup(int n) {
90                 if(n==0) {
91                         return 0xff000000; // black
92 } else {
93                         for(int i=0;i<range.length-1;i++) {
94                                 if(n>=range[i] && n<range[i+1])
95                                         return colorTable[i];
96                         }
97                         return 0xffffffff; // white
98 }
99         }
100         /**
101         * Returns a grey RGBA value.
102         */
103         private static int grey(int n) {
104                 return 0xff000000 | n<<16 | n<<8 | n;
105         }
106 }
107
108
Popular Tags