BitMiracle.LibTiff.Classic.TiffRgbaImage.gtTileSeparate C# (CSharp) Method

        private static bool gtTileSeparate(TiffRgbaImage img, int[] raster, int offset, int width, int height)
        {
            int tilesize = img.tif.TileSize();
            byte[] buf = new byte[(img.alpha != 0 ? 4 : 3) * tilesize];

            int p0 = 0;
            int p1 = p0 + tilesize;
            int p2 = p1 + tilesize;
            int pa = (img.alpha != 0 ? (p2 + tilesize) : -1);

            FieldValue[] result = img.tif.GetField(TiffTag.TILEWIDTH);
            int tileWidth = result[0].ToInt();

            result = img.tif.GetField(TiffTag.TILELENGTH);
            int tileHeight = result[0].ToInt();

            int flip = img.setorientation();
            int y;
            int rasterShift;
            if ((flip & FLIP_VERTICALLY) != 0)
            {
                y = height - 1;
                rasterShift = -(tileWidth + width);
            }
            else
            {
                y = 0;
                rasterShift = -(tileWidth - width);
            }

            bool ret = true;
            for (int row = 0; row < height; )
            {
                int rowstoread = tileHeight - (row + img.row_offset) % tileHeight;
                int nrow = (row + rowstoread > height ? height - row : rowstoread);
                for (int col = 0; col < width; col += tileWidth)
                {
                    if (img.tif.ReadTile(buf, p0, col + img.col_offset, row + img.row_offset, 0, 0) < 0 && img.stoponerr)
                    {
                        ret = false;
                        break;
                    }

                    if (img.tif.ReadTile(buf, p1, col + img.col_offset, row + img.row_offset, 0, 1) < 0 && img.stoponerr)
                    {
                        ret = false;
                        break;
                    }

                    if (img.tif.ReadTile(buf, p2, col + img.col_offset, row + img.row_offset, 0, 2) < 0 && img.stoponerr)
                    {
                        ret = false;
                        break;
                    }

                    if (img.alpha != 0)
                    {
                        if (img.tif.ReadTile(buf, pa, col + img.col_offset, row + img.row_offset, 0, 3) < 0 && img.stoponerr)
                        {
                            ret = false;
                            break;
                        }
                    }

                    int pos = ((row + img.row_offset) % tileHeight) * img.tif.TileRowSize();

                    if (col + tileWidth > width)
                    {
                        // Tile is clipped horizontally.
                        // Calculate visible portion and skewing factors.
                        int npix = width - col;
                        int bufferShift = tileWidth - npix;

                        img.putSeparate(img, raster, offset + y * width + col, rasterShift + bufferShift,
                            col, y, npix, nrow,
                            buf, p0 + pos, p1 + pos, p2 + pos, img.alpha != 0 ? (pa + pos) : -1, bufferShift);
                    }
                    else
                    {
                        img.putSeparate(img, raster, offset + y * width + col, rasterShift,
                            col, y, tileWidth, nrow,
                            buf, p0 + pos, p1 + pos, p2 + pos, img.alpha != 0 ? (pa + pos) : -1, 0);
                    }
                }

                y += ((flip & FLIP_VERTICALLY) != 0 ? -nrow : nrow);
                row += nrow;
            }

            if ((flip & FLIP_HORIZONTALLY) != 0)
            {
                for (int line = 0; line < height; line++)
                {
                    int left = offset + line * width;
                    int right = left + width - 1;

                    while (left < right)
                    {
                        int temp = raster[left];
                        raster[left] = raster[right];
                        raster[right] = temp;
                        left++;
                        right--;
                    }
                }
            }

            return ret;
        }