AForge.Imaging.Filters.HueModifierRelative.ProcessFilter C# (CSharp) Method

        protected unsafe override void ProcessFilter(UnmanagedImage image, Rectangle rect)
        {
            int pixelSize = Bitmap.GetPixelFormatSize(image.PixelFormat) / 8;

            int startX = rect.Left;
            int startY = rect.Top;
            int stopX = startX + rect.Width;
            int stopY = startY + rect.Height;
            int offset = image.Stride - rect.Width * pixelSize;
            bool exclude = false;

            RGB rgb = new RGB();
            HSL hsl = new HSL();

            // do the job
            byte* ptr = (byte*)image.ImageData.ToPointer();

            // allign pointer to the first pixel to process
            ptr += (startY * image.Stride + startX * pixelSize);

            // for each row
            for (int y = startY; y < stopY; y++)
            {
                // for each pixel
                for (int x = startX; x < stopX; x++, ptr += pixelSize)
                {
                    rgb.Red = ptr[RGB.R];
                    rgb.Green = ptr[RGB.G];
                    rgb.Blue = ptr[RGB.B];

                    exclude = false;
                    if (keepBW)
                    {
                        if (rgb.Red == 0 && rgb.Green == 0 && rgb.Blue == 0)
                            exclude = true;
                        if (rgb.Red == 255 && rgb.Green == 255 && rgb.Blue == 255)
                            exclude = true;
                    }

                    if(!exclude)
                    {
                        // convert to HSL
                        AForge.Imaging.HSL.FromRGB(rgb, hsl);

                        // modify hue value
                        hsl.Hue += hue;

                        // convert back to RGB
                        AForge.Imaging.HSL.ToRGB(hsl, rgb);

                        ptr[RGB.R] = rgb.Red;
                        ptr[RGB.G] = rgb.Green;
                        ptr[RGB.B] = rgb.Blue;
                    }
                }
                ptr += offset;
            }
        }