Hjg.Pngcs.PngWriter.FilterRowSub C# (CSharp) Method

        private void FilterRowSub()
        {
            int i, j;
            for (i = 1; i <= ImgInfo.BytesPixel; i++) {
                rowbfilter[i] = (byte)rowb[i];
            }
            for (j = 1, i = ImgInfo.BytesPixel + 1; i <= ImgInfo.BytesPerRow; i++, j++) {
                rowbfilter[i] = (byte)(rowb[i] - rowb[j]);
            }
        }