Initial data commit

Task/Color-wheel/C-sharp/color-wheel.cs

@@ -0,0 +1,66 @@
+// constructor of main window
+// in MainWindow.xaml just create <Image Name="imgMain" />
+public MainWindow()
+{
+    InitializeComponent();
+    RenderOptions.SetBitmapScalingMode(imgMain, BitmapScalingMode.HighQuality);
+    imgMain.Source = new WriteableBitmap(480, 480, 96, 96, PixelFormats.Bgr32, null);
+    // using slider you can change saturation and call DrawHue with different level
+    DrawHue(100);
+}
+
+void DrawHue(int saturation)
+{
+    var bmp = (WriteableBitmap)imgMain.Source;
+
+    int centerX = (int)bmp.Width / 2;
+    int centerY = (int)bmp.Height / 2;
+    int radius = Math.Min(centerX, centerY);
+    int radius2 = radius - 40;
+
+    bmp.Lock();
+    unsafe{
+        var buf = bmp.BackBuffer;
+        IntPtr pixLineStart;
+        for(int y=0; y < bmp.Height; y++){
+            pixLineStart = buf + bmp.BackBufferStride * y;
+            double dy = (y - centerY);
+            for(int x=0; x < bmp.Width; x++){
+                double dx = (x - centerX);
+                double dist = Math.Sqrt(dx * dx + dy * dy);
+                if (radius2 <= dist && dist <= radius) {
+                    double theta = Math.Atan2(dy, dx);
+                    double hue = (theta + Math.PI) / (2.0 * Math.PI);
+                    *((int*)(pixLineStart + x * 4)) = HSB_to_RGB((int)(hue * 360), saturation, 100);
+                }
+            }
+        }
+    }
+    bmp.AddDirtyRect(new Int32Rect(0, 0, 480, 480));
+    bmp.Unlock();
+}
+
+static int HSB_to_RGB(int h, int s, int v)
+{
+    var rgb = new int[3];
+
+    var baseColor = (h + 60) % 360 / 120;
+    var shift = (h + 60) % 360 - (120 * baseColor + 60 );
+    var secondaryColor = (baseColor + (shift >= 0 ? 1 : -1) + 3) % 3;
+
+    //Setting Hue
+    rgb[baseColor] = 255;
+    rgb[secondaryColor] = (int) ((Math.Abs(shift) / 60.0f) * 255.0f);
+
+    //Setting Saturation
+    for (var i = 0; i < 3; i++)
+        rgb[i] += (int) ((255 - rgb[i]) * ((100 - s) / 100.0f));
+
+    //Setting Value
+    for (var i = 0; i < 3; i++)
+        rgb[i] -= (int) (rgb[i] * (100-v) / 100.0f);
+
+    return RGB2int(rgb[0], rgb[1], rgb[2]);
+}
+
+public static int RGB2int(int r, int g, int b) => r << 16 | g << 8 | b;