/*
Fractal Dimension of Galaxies
A Java program to calculate the Fractal Dimension of Galaxies.
This program reads the galaxy from a gif file and then
calculates the fractal dimension for each contour.
Slide the bar to select the intensity contour for which you want
to calculate the fractal dimension.
*/
import java.lang.*;
import java.applet.*;
import java.awt.*;
import java.awt.image.*;
public class F3 extends Applet {
Image orig, contour; // the original and contour versions of the image
int scrollint=0;
int scrollintold=0;
Timer timer= new Timer(this);
Scrollbar s = new Scrollbar(Scrollbar.HORIZONTAL,10,10,0,255);
int width=256,height=256;
int decimal=0,fract=0,cont=0;
int[] box1 = new int [256];
int[] box2 = new int [256];
int[] box3 = new int [256];
/**
* Load the image. Create a new image that is a contour version of it, using
* a FilteredImageSource, ImageProducer and a the ContourFilter class, below.
*/
public void init() {
setLayout(new BorderLayout() );
orig = this.getImage(this.getCodeBase(), "galax.gif");
ImageFilter filter = new ContourFilter(20);
ImageProducer producer = new FilteredImageSource(orig.getSource(), filter);
contour = this.createImage(producer);
add("North",s);
timer.start();
fractInit(orig);
}
public void step() {
scrollintold=scrollint;
scrollint=s.getValue();
if(scrollint != scrollintold) {
ImageFilter filter = new ContourFilter(scrollint);
ImageProducer producer = new FilteredImageSource(orig.getSource(), filter);
contour = this.createImage(producer);
fractDim(scrollint);
repaint();
}
}
public void fractDim(int i) {
double bbb;
bbb=(double) box2[i]/((double) box3[i]);
bbb=Math.log(bbb)/Math.log(2);
decimal=(int) bbb;
bbb=( (bbb-(double) decimal)*100.+0.5);
fract= (int) bbb;
cont=i;
}
public void fractInit(Image im) {
try {
//grab pixels and precompute for fractDim
int[] pgPixels = new int [width*height];
PixelGrabber pg = new PixelGrabber(im,0,0,
width,height,pgPixels,0,width);
if(pg.grabPixels() && ((pg.status() & ImageObserver.ALLBITS) !=0))
{
int level=0;
int max3,max2,max1,min3,min2,min1;
int x,y;
for(int iiii=0;iiii<(width>>3);iiii++){
for(int jjjj=0;jjjj<(height>>3);jjjj++){
min3=256;max3=0;
for(int iii=0;iii<=1;iii++){
for(int jjj=0;jjj<=1;jjj++){
min2=256;max2=0;
for(int ii=0;ii<=1;ii++){
for(int jj=0;jj<=1;jj++){
min1=256;max1=0;
for(int i=0;i<=1;i++){
for(int j=0;j<=1;j++){
x=i+(ii<<1)+(iii<<2)+(iiii<<3);
y=width*(j+(jj<<1)+(jjj<<2)+(jjjj<<3));
level=pgPixels[x+y]&0xff;
max1=Math.max(max1,level);
min1=Math.min(min1,level);
// System.out.println(" "+level);
// System.out.println(" "+x+" "+y+" "+level);
}
}
// System.out.println(">"+max1+" "+min1);
for(int m = min1; m<=max1;m++){
box1[m]++;
}
max2=Math.max(max1,max2);
min2=Math.min(min1,min2);
}
}
max3=Math.max(max3,max2);
min3=Math.min(min3,min2);
for(int m=min2;m<=max2;m++){
box2[m]++;
}
// System.out.println(">>"+max2+" "+min2);
}
}
for(int m=min3;m<=max3;m++){
box3[m]++;
}
}
}
}
}catch (InterruptedException e) {e.printStackTrace();}
return;
}
/* override update to reduce flickering */
public void update(Graphics g){
g.setColor(getBackground());
g.fillRect(300,282,556,300);
g.setColor(getForeground());
paint(g);
}
public void paint(Graphics g) {
g.drawImage(orig, 25, 25, this);
g.drawImage(contour, 300, 25, this);
g.drawString("Fractal Dimension = "+decimal+"."+fract+" level= "+cont
,300,300);
}
}
/** Filter an image by averaging its colors */
class ContourFilter extends RGBImageFilter {
static int ilevel;
public ContourFilter(int ilev) { canFilterIndexColorModel = true;ilevel=ilev; }
public int filterRGB(int x, int y, int rgb) {
int a = rgb & 0xff000000;
int r = rgb & 0xff0000;
int g = rgb & 0x00ff00;
int b = rgb & 0x0000ff;
int avg=((r>>16)+(g>>8)+b)/3;
r=0;
g=0;
b=0;
if(avg>ilevel) r=255<<16;
if(avg==ilevel) g=255<<8;
if(ilevel>avg) b=255;
return a | r | g | b;
}
}
class Timer extends Thread {
F3 myapplet;
public Timer(F3 myapplet){
this.myapplet=myapplet ;
setPriority(MIN_PRIORITY);
}
public void run() {
for(;;){
myapplet.step();
yield();
try{sleep(100L);} catch(InterruptedException e){;}
}
}
}
/*
*/