import java.awt.*;
import java.applet.Applet;
import java.awt.image.BufferedImage;

public class MandelbrotFractal extends Applet {
	
	private int height = 500;
	private int width = 500;
	private Color [][] picture;
	private BufferedImage image;
	
	private Generator gen;
	
	public void init() {
		gen = new Generator();
		gen.render();
		image = matrixToImage(picture);
	}
	
	public void paint(Graphics g) {
		g.drawImage(image, 0, 0, this);
	}
	
	private BufferedImage matrixToImage(Color[][] matrix) {
		BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		for (int i = 0; i < height; ++i) 
			for (int k = 0; k < width; ++k)
				image.setRGB(k, i, matrix[i][k].getRGB());
		return image;
	}
	
	
	private class Generator {
		private Complex[][] complex;	
		private Color[] colors;
		
		public Generator() {
			generateColors();
		}

		public Color[][] render() {
			
			mesh();
			picture = new Color[height][width];
			int pixelSize = 1;
			

			int nextIm = pixelSize/2;
			for(int i = 0; i < height; i++) {
			
				int nextRe = pixelSize/2;
				for(int j = 0; j < width; j++) {
				
					Complex c = new Complex(0, 0);
					int iterations=0;
					
					while(c.getAbs2() < 4 && iterations<199) {
						c.mul(c);
						c.add(complex[nextIm][nextRe]);
						iterations++;
					}
					
					if(iterations == 199)
						picture[0][j] = Color.BLACK;
					else
						picture[0][j] = colors[iterations];

					nextRe += pixelSize;
					
				}
				
				nextIm += pixelSize;
				
			}
			
			return picture;
			
		}

		private void mesh() {
			complex = new Complex[height][width];
			double minRe = -2.4;
			double maxRe = 0.8;
			double minIm = -1.4;
			double maxIm = 1.4;
			double dRe = (maxRe - minRe) / width;
			double dIm = (maxIm - minIm) / height;
			for(int i = 0; i < height; i++)
				for(int j = 0; j < width; j++)
					complex[i][j] = new Complex(minRe + j*dRe, maxIm - i*dIm);
		}
		
		private void generateColors() {
			colors = new Color[200];
			int red = 255;
			int green = 255;
			int blue = 255;
			for(int k = 0; k < 40; k++){ // -> röd
				colors[k] = new Color(red,green,blue);
				blue -= 5;
				green -= 5;
			}
			for(int k = 0; k < 40; k++){ // -> gul
				colors[40+k] = new Color(red,green,blue);
				green += 5;
			}
			for(int k = 0; k < 40; k++){ // -> vit
				colors[80+k] = new Color(red,green,blue);
				blue += 5;
			}
			for(int k = 0; k < 40; k++){ // -> turkos
				colors[120+k] = new Color(red,green,blue);
				red -= 5;
			}
			for(int k = 0; k < 40; k++){ // -> blå
				colors[160+k] = new Color(red,green,blue);
				green -= 5;
			}
		}
	}

	class Complex {

		private double re, im;
		
		public Complex(double re, double im) {
			this.re = re;
			this.im = im;
		}
		
		public double getRe() {
			return re;
		}
		
		public double getIm() {
			return im;
		}
		
		public double getAbs2() {
			return re*re + im*im;
		}
		
		public void add(Complex c) {
			re += c.getRe();
			im += c.getIm();
		}
		
		public void mul(Complex c) {
			double r1 = re;
			double i1 = im;
			double r2 = c.getRe();
			double i2 = c.getIm();
			
			re = r1*r2 - i1*i2;
			im = r1*i2 + i1*r2;
		}
			
	}
}