GrayScaleFixed.cs

using System;
 
namespace IdApp.Cv.ColorModels
{
    public static partial class ColorModelOperations
    {
        public static Matrix<int> GrayScaleFixed(this Matrix<uint> M)
        {
            int y, h = M.Height;
            int x, w = M.Width;
            int SrcOffset = M.Start;
            int DestOffset = 0;
            int SrcSkip = M.Skip;
            uint[] Src = M.Data;
            int[] Dest = new int[w * h];
            uint ui;
            int f;
 
            for (y = 0; y < h; y++, SrcOffset += SrcSkip)
            {
                for (x = 0; x < w; x++)
                {
                    ui = Src[SrcOffset++];
 
                    f = 19672 * (int)(ui & 255);
                    ui >>= 8;
                    f += 38620 * (int)(ui & 255);
                    ui >>= 8;
                    f += 7500 * (int)(ui & 255);
 
                    Dest[DestOffset++] = f;
                }
            }
 
            return new Matrix<int>(w, h, Dest);
        }
 
        public static Matrix<int> GrayScaleFixed(this Matrix<byte> M)
        {
            int y, h = M.Height;
            int x, w = M.Width;
            int SrcOffset = M.Start;
            int DestOffset = 0;
            int SrcSkip = M.Skip;
            byte[] Src = M.Data;
            int[] Dest = new int[w * h];
 
            for (y = 0; y < h; y++, SrcOffset += SrcSkip)
            {
                for (x = 0; x < w; x++)
                    Dest[DestOffset++] = 65793 * Src[SrcOffset++];
            }
 
            return new Matrix<int>(w, h, Dest);
        }
 
        public static Matrix<int> GrayScaleFixed(this Matrix<float> M)
        {
            int y, h = M.Height;
            int x, w = M.Width;
            int SrcOffset = M.Start;
            int DestOffset = 0;
            int SrcSkip = M.Skip;
            float[] Src = M.Data;
            int[] Dest = new int[w * h];
 
            for (y = 0; y < h; y++, SrcOffset += SrcSkip)
            {
                for (x = 0; x < w; x++)
                    Dest[DestOffset++] = (int)(0x01000000 * Src[SrcOffset++] + 0.5);
            }
 
            return new Matrix<int>(w, h, Dest);
        }
 
        public static Matrix<int> GrayScaleFixed(this Matrix<int> M)
        {
            return M;
        }
 
        public static IMatrix GrayScaleFixed(this IMatrix M)
        {
            if (M is Matrix<uint> M2)
                return GrayScaleFixed(M2);
            else if (M is Matrix<byte> M3)
                return GrayScaleFixed(M3);
            else if (M is Matrix<float> M4)
                return GrayScaleFixed(M4);
            else if (M is Matrix<int> M5)
                return GrayScaleFixed(M5);
            else
                throw new ArgumentException("Unsupported type: " + M.GetType().FullName, nameof(M));
        }
    }
}