WriteEncodedTile() public method

Encodes and writes a tile of data to an open TIFF file/stream.

WriteEncodedTile encodes count bytes of raw data from buffer and append the result to the end of the specified tile. Note that the value of tile is a "raw tile number". That is, the caller must take into account whether or not the data are organized in separate planes (TiffTag.PLANARCONFIG = PlanarConfig.SEPARATE). ComputeTile automatically does this when converting an (x, y, z, plane) coordinate quadruple to a tile number.

There must be space for the data. The function clamps individual writes to a tile to the tile size, but does not (and can not) check that multiple writes to the same tile were performed.

A correct value for the TiffTag.IMAGELENGTH tag must be setup before writing; WriteEncodedTile does not support automatically growing the image on each write (as O:BitMiracle.LibTiff.Classic.Tiff.WriteScanline does).

The library writes encoded data using the native machine byte order. Correctly implemented TIFF readers are expected to do any necessary byte-swapping to correctly process image data with value of TiffTag.BITSPERSAMPLE tag greater than 8.

public WriteEncodedTile ( int tile, byte buffer, int count ) : int
tile int The zero-based index of the tile to write.
buffer byte The buffer with image data to be encoded and written.
count int The maximum number of tile bytes to be read from /// .
return int
Tiff Class Documentation
Esempio n. 1
0
        static bool cvt_by_tile(Tiff inImage, Tiff outImage, int width, int height)
        {
            int tile_width = 0;
            int tile_height = 0;

            FieldValue[] result = inImage.GetField(TiffTag.TILEWIDTH);
            if (result != null)
            {
                tile_width = result[0].ToInt();

                result = inImage.GetField(TiffTag.TILELENGTH);
                if (result != null)
                    tile_height = result[0].ToInt();
            }

            if (result == null)
            {
                Tiff.Error(inImage.FileName(), "Source image not tiled");
                return false;
            }

            outImage.SetField(TiffTag.TILEWIDTH, tile_width);
            outImage.SetField(TiffTag.TILELENGTH, tile_height);

            // Allocate tile buffer
            int raster_size = multiply(tile_width, tile_height);
            int rasterByteSize = multiply(raster_size, sizeof(int));
            if (raster_size == 0 || rasterByteSize == 0)
            {
                Tiff.Error(inImage.FileName(),
                    "Can't allocate buffer for raster of size {0}x{1}", tile_width, tile_height);
                return false;
            }

            int[] raster = new int[raster_size];
            byte[] rasterBytes = new byte[rasterByteSize];

            // Allocate a scanline buffer for swapping during the vertical mirroring pass.
            // (Request can't overflow given prior checks.)
            int[] wrk_line = new int[tile_width];

            // Loop over the tiles.
            for (int row = 0; row < height; row += tile_height)
            {
                for (int col = 0; col < width; col += tile_width)
                {
                    // Read the tile into an RGBA array
                    if (!inImage.ReadRGBATile(col, row, raster))
                        return false;

                    // For some reason the ReadRGBATile() function chooses the lower left corner
                    // as the origin. Vertically mirror scanlines.
                    for (int i_row = 0; i_row < tile_height / 2; i_row++)
                    {
                        int topIndex = tile_width * i_row * sizeof(int);
                        int bottomIndex = tile_width * (tile_height - i_row - 1) * sizeof(int);

                        Buffer.BlockCopy(raster, topIndex, wrk_line, 0, tile_width * sizeof(int));
                        Buffer.BlockCopy(raster, bottomIndex, raster, topIndex, tile_width * sizeof(int));
                        Buffer.BlockCopy(wrk_line, 0, raster, bottomIndex, tile_width * sizeof(int));
                    }

                    // Write out the result in a tile.
                    int tile = outImage.ComputeTile(col, row, 0, 0);
                    Buffer.BlockCopy(raster, 0, rasterBytes, 0, rasterByteSize);
                    if (outImage.WriteEncodedTile(tile, rasterBytes, rasterByteSize) == -1)
                        return false;
                }
            }

            return true;
        }