Accord.Imaging.Filters.AdditiveNoise.ProcessFilter C# (CSharp) Method

        protected override unsafe void ProcessFilter(UnmanagedImage image, Rectangle rect)
        {
            int pixelSize = (image.PixelFormat == PixelFormat.Format8bppIndexed) ? 1 : 3;

            int startY = rect.Top;
            int stopY = startY + rect.Height;

            int startX = rect.Left * pixelSize;
            int stopX = startX + rect.Width * pixelSize;

            int offset = image.Stride - (stopX - startX);

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

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

            // for each line
            for (int y = startY; y < stopY; y++)
            {
                // for each pixel
                for (int x = startX; x < stopX; x++, ptr++)
                {
                    *ptr = Math.Max((byte)0, Math.Min((byte)255, (byte)(*ptr + generator.Generate())));
                }
                ptr += offset;
            }
        }
    }