Java Source Code for Julia Set Plot of Complex Logistic Equation


import java.applet.*;
import java.awt.*;

class logistic_juliaPlot extends Canvas {

	private int maxcol = 399, maxrow = 399, max_colors = 16,
                max_iterations = 256, max_size = 4;
	private Color cmap[];

	private void plot(Graphics g, int x, int y, int color_index) {
		
		g.setColor(cmap[color_index]);
		g.drawLine(x,y, x, y);
	}

	public logistic_juliaPlot() {

            cmap = new Color[max_colors];
            cmap[0] = Color.black;
            cmap[1] = new Color(0, 0, 168);
            cmap[2] = new Color(100, 50, 0);
            cmap[3] = new Color(0, 168, 168);
            cmap[4] = new Color(168, 0, 0);
            cmap[5] = new Color(168, 0, 168);
            cmap[6] = new Color(168, 84, 0);
            cmap[7] = new Color(168, 168, 168);
            cmap[8] = new Color(84, 84, 84);
            cmap[9] = new Color(84, 84, 255);
            cmap[10] = new Color(84, 255, 84);
            cmap[11] = new Color(84, 255, 255);
            cmap[12] = new Color(255, 84, 84);
            cmap[13] = new Color(255, 84, 255);
            cmap[14] = new Color(255, 255, 84);
            cmap[15] = Color.white;
	}

	public void paint(Graphics g) {

		float Q[] = new float[400];
		double Pmax = 1.5, Pmin = -.5, Qmax = .7, Qmin = -.7, A = 1.678, B = .95,
			P, deltaP, deltaQ, X, Y, Xfactor,Yfactor, Xsquare, Ysquare;
		int color, row, col;//(1.68,.95)

		deltaP = (Pmax-Pmin)/(double)(maxcol-1);
		deltaQ = (Qmax-Qmin)/(double)(maxrow-1);
		for (row=0;row<=maxrow;row++) {
			Q[row] = (float)(Qmin+row*deltaQ);
		}
		for (col=0;col<=maxcol;col++) {
			P = Pmin+col*deltaP;
			for(row=0;row<=maxrow;row++){
				X = P; Y = Q[row];
				color = 0;
                                for(color=0; color<=max_iterations-1; color++) {
					Xfactor = X-X*X+Y*Y;
					Yfactor = 2*X*Y-Y;
					X = A*Xfactor+B*Yfactor;
					Y = B*Xfactor-A*Yfactor;
					Xsquare = X*X;
					Ysquare = Y*Y;
					if((Xsquare+Ysquare)>max_size) break;
				}
				plot(g,col,row,(int)(color%max_colors));
			}
		}
	}
	} 

	public class logistic_julia extends Applet {

		private logistic_juliaPlot canvas;
		
		public void init() {

			setLayout(new BorderLayout());
			canvas = new logistic_juliaPlot();
			add("Center", canvas);
			}

	}