Graphics.cs

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Fractal
{
    public class Graphics
    {
        public Color HsvToRgb(double hue, double saturation, double value)
        {
            int hi = Convert.ToInt32(Math.Floor(hue / 60.0)) % 6;
            double f = hue / 60.0 - Math.Floor(hue / 60.0);

            value = value * 255;
            int p = Convert.ToInt32(value * (1 - saturation));
            int q = Convert.ToInt32(value * (1 - f * saturation));
            int v = Convert.ToInt32(value);
            int t = Convert.ToInt32(value * (1 - (1 - f) * saturation));

            if (hi == 0)
                return Color.FromArgb(255, (byte)(v*255.0), (byte)(t * 255.0), (byte)(p * 255.0));
            else if (hi == 1)
                return Color.FromArgb(255, (byte)(q * 255.0), (byte)(v * 255.0), (byte)(p * 255.0));
            else if (hi == 2)
                return Color.FromArgb(255, (byte)(p * 255.0), (byte)(v * 255.0), (byte)(t * 255.0));
            else if (hi == 3)
                return Color.FromArgb(255, (byte)(p * 255.0), (byte)(q * 255.0), (byte)(v * 255.0));
            else if (hi == 4)
                return Color.FromArgb(255, (byte)(t * 255.0), (byte)(p * 255.0), (byte)(v * 255.0));
            else
                return Color.FromArgb(255, (byte)(v * 255.0), (byte)(p * 255.0), (byte)(q * 255.0));
        }

        public void HsvToRgb(double h, double S, double V, out int r, out int g, out int b)
        {
            double H = h;
            while (H < 0) { H += 360; };
            while (H >= 360) { H -= 360; };
            double R, G, B;
            if (V <= 0)
            { R = G = B = 0; }
            else if (S <= 0)
            {
                R = G = B = V;
            }
            else
            {
                double hf = H / 60.0;
                int i = (int)Math.Floor(hf);
                double f = hf - i;
                double pv = V * (1 - S);
                double qv = V * (1 - S * f);
                double tv = V * (1 - S * (1 - f));
                switch (i)
                {

                    // Red is the dominant color

                    case 0:
                        R = V;
                        G = tv;
                        B = pv;
                        break;

                    // Green is the dominant color

                    case 1:
                        R = qv;
                        G = V;
                        B = pv;
                        break;
                    case 2:
                        R = pv;
                        G = V;
                        B = tv;
                        break;

                    // Blue is the dominant color

                    case 3:
                        R = pv;
                        G = qv;
                        B = V;
                        break;
                    case 4:
                        R = tv;
                        G = pv;
                        B = V;
                        break;

                    // Red is the dominant color

                    case 5:
                        R = V;
                        G = pv;
                        B = qv;
                        break;

                    // Just in case we overshoot on our math by a little, we put these here. Since its a switch it won't slow us down at all to put these here.

                    case 6:
                        R = V;
                        G = tv;
                        B = pv;
                        break;
                    case -1:
                        R = V;
                        G = pv;
                        B = qv;
                        break;

                    // The color is not defined, we should throw an error.

                    default:
                        //LFATAL("i Value error in Pixel conversion, Value is %d", i);
                        R = G = B = V; // Just pretend its black/white
                        break;
                }
            }
            r = Clamp((int)(R * 255.0));
            g = Clamp((int)(G * 255.0));
            b = Clamp((int)(B * 255.0));
        }

        private int Clamp(int i)
        {
            if (i < 0) return 0;
            if (i > 255) return 255;
            return i;
        }
    }
}