Image Magic - Image Levels using Custom Controls

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace LevelsLogic
{
    public class GammaRemap
    {
        private int[] remap;
        private double pshopGamma;      //actually 1/gamma (pShop gamma), valid values 0.10 - 9.99
        private double gamma;           //regular gamma, >= 0.0
        private int    grayGamma;       //where gray (127) is mapped to. 0-255  This is what sets the Gamma
 
        public int[] Remap { get{return remap;} }
        public double PshopGamma { get{return pshopGamma;} }
        public double Gamma { get { return gamma;} }

        public double GrayGamma
        {
            set
            {
                ComputeRemap(value);
            }
        }

        public GammaRemap()
        {
            remap = new int[256];
            for (int i = 0; i <= 255; i++)
                remap[i] = i;
            pshopGamma = 1.0;
            gamma = 1.0;
            grayGamma = 127;
        } //ctor


        //given the value of the gray input slider, compute the remap array
        private void ComputeRemap(double gray_d)
        {
            //most common gray value, if its already been done, do nothing
            if ((int)Math.Floor(gray_d) == 127 && grayGamma==127)
                return;
            grayGamma = (int)Math.Floor(gray_d);
            if (grayGamma <= 0) grayGamma = 1;
            gamma = (Math.Log10(grayGamma/255.0D)) / (Math.Log10(127/255.0D));
            pshopGamma = 1 / gamma;

            for (int i = 0 + 1; i < 256; i++)
            {
                //compute brightness, input adjusted to normalize over black to white
                double inputBrightness = i /255.0D;
                double outputBrightness = Math.Pow(inputBrightness, gamma);
                remap[i] = (int)Math.Floor(outputBrightness * 255);
            }
        } //ComputeRemap()


        public void GammaAdjustRemapArray(int[] srcRemap)
        {
            for (int i = 0; i < 256; i++)
                srcRemap[i] = remap[srcRemap[i]];
        }



    }
}