The beauty of fractals - A simple fractal rendering program done in C#

using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
using System.Threading;
using System.Runtime.Serialization;
using System.Runtime.InteropServices;
using System.Drawing.Imaging;

namespace FracMaster
{
    public class JuliaFractal : Generic2DFractal
    {

        public JuliaFractal()
        {
            pars.SetValue("NAME", "Julia Fractal");
            pars.SetValue("X", 0.5);
            pars.SetValue("Y", -0.2);
            pars.SetValue("XC", 0.0);
            pars.SetValue("YC", 0.0);
            pars.SetValue("W", 4.0);
            pars.SetValue("H", 4.0);
            pars.SetValue("WIDTH", 640);
            pars.SetValue("HEIGHT", 480);
            pars.SetValue("VERSION", "1.0.0");
            pars.SetValue("ITERATIONS", 128);
            pars.SetValue("CAN_BE_INTERPOLATED", 1);
            pars.SetValue("RENDER_INTERPOLATED", 0);
            pars.SetValue("NUM_THREADS", Environment.ProcessorCount);
            Int32[] pal = { -16777108, -16777099, -16777089, -16777079, -16777069, -16777059,
                            -16777050, -16777040, -16777030, -16777020, -16777010, -16777001, 
                            -16776991, -16776981, -16776971, -16776961, -15790081, -14737409, 
                            -13684737, -12632065, -11579393, -10526721, -9474049, -8421377, 
                            -7368705, -6316033, -5263361, -4210689, -3158017, -2105345, -1052673, 
                            -1, -10, -18, -26, -34, -43, -65843, -59, -67, -76, -84, -92, -100,
                            -65900, -65909, -125, -133, -141, -150, -158, -166, -174, -182, -191, 
                            -199, -207, -215, -224, -232, -240, -248, -256, -16777216, -12632257,
                            -12566464, -12500671, -12434878, -12369085, -12303292, -12237499,
                            -12171706, -12105913, -12040120, -11974327, -11908534, -11842741, 
                            -11776948, -11711155, -11645362, -11579569, -11513776, -11447983, 
                            -11382190, -11316397, -11250604, -11184811, -11119018, -11053225, 
                            -10987432, -10921639, -10855846, -10790053, -10724260, -10658467, 
                            -10592674, -10526881, -10461088, -10395295, -10329502, -10263709, 
                            -10197916, -10132123, -10066330, -10000537, -9934744, -9868951, -9803158, 
                            -9737365, -9671572, -9605779, -9539986, -9474193, -9408400, -9342607, 
                            -9276814, -9211021, -9145228, -9079435, -9013642, -8947849, -8882056, 
                            -8816263, -8750470, -8684677, -8618884, -8553091, -16777216, -8421505,
                            -8355712, -8289919, -8224126, -8158333, -8092540, -8026747, -7960954, 
                            -7895161, -7829368, -7763575, -7697782, -7631989, -7566196, -7500403,
                            -7434610, -7368817, -7303024, -7237231, -7171438, -7105645, -7039852,
                            -6974059, -6908266, -6842473, -6776680, -6710887, -6645094, -6579301, 
                            -6513508, -6447715, -6381922, -6316129, -6250336, -6184543, -6118750, 
                            -6052957, -5987164, -5921371, -5855578, -5789785, -5723992, -5658199, 
                            -5592406, -5526613, -5460820, -5395027, -5329234, -5263441, -5197648,
                            -5131855, -5066062, -5000269, -4934476, -4868683, -4802890, -4737097,
                            -4671304, -4605511, -4539718, -4473925, -4408132, -4342339, -4276546, 
                            -4210753, -4144960, -4079167, -4013374, -3947581, -3881788, -3815995, 
                            -3750202, -3684409, -3618616, -3552823, -3487030, -3421237, -3355444,
                            -3289651, -3223858, -3158065, -3092272, -3026479, -2960686, -2894893,
                            -2829100, -2763307, -2697514, -2631721, -2565928, -2500135, -2434342,
                            -2368549, -2302756, -2236963, -2171170, -2105377, -2039584, -1973791, 
                            -1907998, -1842205, -1776412, -1710619, -1644826, -1579033, -1513240, 
                            -1447447, -1381654, -1315861, -1250068, -1184275, -1118482, -1052689, 
                            -986896, -921103, -855310, -789517, -723724, -657931, -592138, -526345, 
                            -460552, -394759, -328966, -263173, -197380, -131587, -16777216 };

            pars.SetValue("PALETTE", pal);
        }

        public override void Configure()
        {
            Generic2DFractalSettings dia = new Generic2DFractalSettings();
            dia.FractalType = "FracMaster.JuliaFractal";
            dia.Parameters = (IFractalParameters)this.Parameters.Clone();
            
            if (dia.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                this.Parameters = dia.Parameters;
            }
        }

        override protected void PartialRender(object P)
        {
            object[] o = (object[])P;
            int offset = (int)o[0];
            int lines = (int)o[1];
            int[] dst = (int[])o[2];
            RenderResult.RenderStatus status_clbk = (RenderResult.RenderStatus)o[3];
            AutoResetEvent completed = (AutoResetEvent)o[4];

            int width = (int)pars.GetValue("WIDTH");
            int heigth = (int)pars.GetValue("HEIGHT");
            int iterations = (int)pars.GetValue("ITERATIONS") - 1;
            Int32[] Palette = (Int32[])pars.GetValue("PALETTE");
            int RenderInterpolated = (Int32)pars.GetValue("RENDER_INTERPOLATED",0);
           
            double W = (double)pars.GetValue("W");
            double H = (double)pars.GetValue("H");
            double X = (double)pars.GetValue("X");
            double Y = (double)pars.GetValue("Y");
            double XC = (double)pars.GetValue("XC");
            double YC = (double)pars.GetValue("YC");
            double r1 = 0;
            double i1 = 0;
            double r1pow2 = 0;
            double i1pow2 = 0;
            double rpow = 0;
            double rlastpow = 0;
            int iter = 0;
            int idx = 0;
            double xs = (X - W / 2.0);
            double ys = (Y - H / 2.0);
            double xd = W / (double)width;
            double yd = H / (double)heigth;
            double y1 = ys + yd * offset;

            for (int y = offset; y < offset + lines; y++)
            {
                idx = y * width;
                double x1 = xs;

                for (int x = 0; x < width; x++)
                {
                    iter = 0;
                    r1 = x1;
                    i1 = y1;
                    r1pow2 = x1*x1;
                    i1pow2 = y1*y1;

                    rpow = 0;
                    rlastpow = 0;
                    while ((iter < iterations) && (rpow < 4))
                    {
                        r1pow2 = r1 * r1;
                        i1pow2 = i1 * i1;
                        i1 = 2 * i1 * r1 + YC;
                        r1 = r1pow2 - i1pow2 + XC;
                        rlastpow = rpow;
                        rpow = r1pow2 + i1pow2;
                        iter++;                         
                    }

                    if (RenderInterpolated == 1)
                    {
                        double count_f = iter + (4 - rlastpow) / (rpow - rlastpow) - 1;
                        int factor = (int)((1.0 - (iter - count_f)) * 255);
                        dst[idx++] = Utils.InterpolateColors(Palette[(iter - 1)%Palette.Length], Palette[iter%Palette.Length], factor);
                    }
                    else
                    {
                        iter = iter % Palette.Length;
                        dst[idx++] = Palette[iter];
                    }
                    
                    x1 += xd;
                }
                y1 += yd;
                lines_rendered++;
                if (lines_rendered % 40 == 0)
                {
                    status_clbk(100.0f * ((float)lines_rendered) / heigth);
                }
            }
            completed.Set();
        }
         
    }
}