Data commit

Task/Mandelbrot-set/C-sharp/mandelbrot-set.cs

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+using System;
+using System.Drawing;
+using System.Drawing.Imaging;
+using System.Threading;
+using System.Windows.Forms;
+
+/// <summary>
+/// Generates bitmap of Mandelbrot Set and display it on the form.
+/// </summary>
+public class MandelbrotSetForm : Form
+{
+    const double MaxValueExtent = 2.0;
+    Thread thread;
+
+    static double CalcMandelbrotSetColor(ComplexNumber c)
+    {
+        // from http://en.wikipedia.org/w/index.php?title=Mandelbrot_set
+        const int MaxIterations = 1000;
+        const double MaxNorm = MaxValueExtent * MaxValueExtent;
+
+        int iteration = 0;
+        ComplexNumber z = new ComplexNumber();
+        do
+        {
+            z = z * z + c;
+            iteration++;
+        } while (z.Norm() < MaxNorm && iteration < MaxIterations);
+        if (iteration < MaxIterations)
+            return (double)iteration / MaxIterations;
+        else
+            return 0; // black
+    }
+
+    static void GenerateBitmap(Bitmap bitmap)
+    {
+        double scale = 2 * MaxValueExtent / Math.Min(bitmap.Width, bitmap.Height);
+        for (int i = 0; i < bitmap.Height; i++)
+        {
+            double y = (bitmap.Height / 2 - i) * scale;
+            for (int j = 0; j < bitmap.Width; j++)
+            {
+                double x = (j - bitmap.Width / 2) * scale;
+                double color = CalcMandelbrotSetColor(new ComplexNumber(x, y));
+                bitmap.SetPixel(j, i, GetColor(color));
+            }
+        }
+    }
+
+    static Color GetColor(double value)
+    {
+        const double MaxColor = 256;
+        const double ContrastValue = 0.2;
+        return Color.FromArgb(0, 0,
+            (int)(MaxColor * Math.Pow(value, ContrastValue)));
+    }
+
+    public MandelbrotSetForm()
+    {
+        // form creation
+        this.Text = "Mandelbrot Set Drawing";
+        this.BackColor = System.Drawing.Color.Black;
+        this.BackgroundImageLayout = System.Windows.Forms.ImageLayout.Stretch;
+        this.MaximizeBox = false;
+        this.StartPosition = FormStartPosition.CenterScreen;
+        this.FormBorderStyle = FormBorderStyle.FixedDialog;
+        this.ClientSize = new Size(640, 640);
+        this.Load += new System.EventHandler(this.MainForm_Load);
+    }
+
+    void MainForm_Load(object sender, EventArgs e)
+    {
+        thread = new Thread(thread_Proc);
+        thread.IsBackground = true;
+        thread.Start(this.ClientSize);
+    }
+
+    void thread_Proc(object args)
+    {
+        // start from small image to provide instant display for user
+        Size size = (Size)args;
+        int width = 16;
+        while (width * 2 < size.Width)
+        {
+            int height = width * size.Height / size.Width;
+            Bitmap bitmap = new Bitmap(width, height, PixelFormat.Format24bppRgb);
+            GenerateBitmap(bitmap);
+            this.BeginInvoke(new SetNewBitmapDelegate(SetNewBitmap), bitmap);
+            width *= 2;
+            Thread.Sleep(200);
+        }
+        // then generate final image
+        Bitmap finalBitmap = new Bitmap(size.Width, size.Height, PixelFormat.Format24bppRgb);
+        GenerateBitmap(finalBitmap);
+        this.BeginInvoke(new SetNewBitmapDelegate(SetNewBitmap), finalBitmap);
+    }
+
+    void SetNewBitmap(Bitmap image)
+    {
+        if (this.BackgroundImage != null)
+            this.BackgroundImage.Dispose();
+        this.BackgroundImage = image;
+    }
+
+    delegate void SetNewBitmapDelegate(Bitmap image);
+
+    static void Main()
+    {
+        Application.Run(new MandelbrotSetForm());
+    }
+}
+
+struct ComplexNumber
+{
+    public double Re;
+    public double Im;
+
+    public ComplexNumber(double re, double im)
+    {
+        this.Re = re;
+        this.Im = im;
+    }
+
+    public static ComplexNumber operator +(ComplexNumber x, ComplexNumber y)
+    {
+        return new ComplexNumber(x.Re + y.Re, x.Im + y.Im);
+    }
+
+    public static ComplexNumber operator *(ComplexNumber x, ComplexNumber y)
+    {
+        return new ComplexNumber(x.Re * y.Re - x.Im * y.Im,
+            x.Re * y.Im + x.Im * y.Re);
+    }
+
+    public double Norm()
+    {
+        return Re * Re + Im * Im;
+    }
+}