Package org.libtiff.jai.codec

Class XTIFFTileCodecImpl

  • All Implemented Interfaces:
    XTIFFTileCodec
    Direct Known Subclasses:
    XTIFFFaxTileCodec, XTIFFLZWTileCodec, XTIFFPackTileCodec, XTIFFUncompTileCodec
    public abstract class XTIFFTileCodecImpl
extends Object
implements XTIFFTileCodec
    Provides a base class for writing TIFF tile codecs, to be registered with the XTIFFDirectory. This codec allows for both decoding and (optionally) encoding of tiles, and also handles the colorspace conversion in decoding.

    At the minimum you will need to implement the two methods decodeTilePixels() for byte and short data, as well as the methods register() and create(). If your decoder requires additional parameters from the tags, set them up in initializeDecoding(), and initializeEncoding() for encoding.

    To implement encoding, you must override the canEncode() method to return true, and implement encodeTilePixels().

    Author:
    Niles Ritter
    See Also:
    XTIFFTileCodec

    • Field Detail

      • minY

        protected int minY

      • minX

        protected int minX

      • width

        protected int width

      • length

        protected int length

      • numBands

        protected int numBands

      • tileLength

        protected int tileLength

      • tileWidth

        protected int tileWidth

      • compression

        protected int compression

      • sampleSize

        protected int[] sampleSize

      • bitsPerSample

        protected char[] bitsPerSample

      • colormap

        protected char[] colormap

      • isTiled

        protected boolean isTiled

      • decodePaletteAsShorts

        protected boolean decodePaletteAsShorts

      • unitsInThisTile

        protected int unitsInThisTile

      • _bdata

        protected byte[] _bdata

      • _sdata

        protected short[] _sdata

      • bpixvals

        protected byte[] bpixvals

      • spixvals

        protected short[] spixvals

      • dataType

        protected int dataType

      • image_type

        protected int image_type

    • Constructor Detail

      • XTIFFTileCodecImpl

        public XTIFFTileCodecImpl()
        The empty constructor.

    • Method Detail

      • register

        public abstract void register()
        Registration method. Must be implemented by the extended class to register itself with the XTIFFDirectory for all compression codes it supports (e.g Fax codec supports 3 codes).
        Specified by:
        register in interface XTIFFTileCodec
        See Also:
        XTIFFDirectory

      • create

        public abstract XTIFFTileCodec create()
        Implement this to return the corresponding empty codec object.

      • canEncode

        public boolean canEncode()
        Indicate whether this codec can encode data. Override to return true only if your codec implments encoding.

      • initializeDecoding

        public void initializeDecoding()
        The initialization method particular to decoding. Extend for whatever compression-specific information or parameters is needed. The decoding parameter has already been assigned at this point, as well as the XTIFFDirectory parsed from the input stream, and so all XTIFFFields are available.

      • initializeEncoding

        public void initializeEncoding()
        The initialization method particular to encoding. Extend for whatever compression-specific information or parameters is needed. The decoding parameter has already been assigned at this point, as well as the XTIFFDirectory parsed from the input stream, and so all XTIFFFields are available.

      • decodeTilePixels

        public abstract void decodeTilePixels​(byte[] bpixels,
                                      Rectangle rect,
                                      byte[] pixels)
        decode bpixel byte array of data into pixels, packed for 1,2,4 8 bit pixels. Must implment this.
        Parameters:
        bpixels - the byte array of compressed input data
        rect - the rectangular shape of the target pixels
        pixels - the target decompressed pixels.

      • decodeTilePixels

        public abstract void decodeTilePixels​(byte[] bpixels,
                                      Rectangle rect,
                                      short[] pixels)
        decode bpixel byte array of data into pixels, packed for 16 bit pixels. Must implment this.
        Parameters:
        bpixels - the byte array of compressed input data
        rect - the rectangular shape of the target pixels
        pixels - the target decompressed pixels.

      • encodeTilePixels

        public int encodeTilePixels​(int[] pixels,
                            Rectangle rect,
                            byte[] bpixels)
        encode the tile in pixels into bpixels and return the byte size of the compressed data. Override this method if canEncode() = true;
        Parameters:
        pixels - input pixels
        rect - the array dimensions of samples
        bpixels - the target array of compressed byte data

      • initialize

        public void initialize()
        The method for initializing information common to both encoder and decoder.

      • getLongField

        protected long getLongField​(int fld)
        A common utility method for accessing the XTIFFFields in the current image directory.

      • register

        public void register​(int comp)
        This method may be used by the implementations register() method to register itself with the XTIFFDirectory.
        See Also:
        XTIFFDirectory

      • setupSourceImage

        protected void setupSourceImage​(RenderedImage img)
        One-time common image parameter setup
        Parameters:
        img - the source image that will be encoded into a TIFF formatted stream, or the TIFF image from which Raster tiles will be decoded.

      • encode

        public int encode​(RenderedImage img,
                  Rectangle rect,
                  byte[] bpixels)
        Encode the data into buffer and return byte count Normally you will not need to override this method, but instead implement the encodeTilePixels() method.
        Specified by:
        encode in interface XTIFFTileCodec

      • setupBufferForEncoding

        protected void setupBufferForEncoding()
        One-time setup for encoding

      • getTilePixels

        protected void getTilePixels​(Rectangle rect)
        Get the portion of tile fitting into buffer. You probably won't need to override this.
        Parameters:
        rect - the region to extract from image.

      • getCompressedTileSize

        public int getCompressedTileSize​(RenderedImage im)
        If derived classes can make a better estimate for the maximum size of a compressed tile, they should override this, which assumes conservatively that it won't be worse than twice the original size.
        Specified by:
        getCompressedTileSize in interface XTIFFTileCodec
        Parameters:
        im - the rendered image containing the image data

      • setupBufferForDecoding

        protected void setupBufferForDecoding()
        One-time setup for encoding. Some configurations require a temp array for unpacking 16-bit palette data.

      • decode

        public WritableRaster decode​(RenderedImage img,
                             Rectangle newRect,
                             byte[] bpixels)
        Decode a rectangle of data stored in bpixels into a raster tile. Usually you will not need to override this, but instead implement the decodeTilePixels methods.
        Specified by:
        decode in interface XTIFFTileCodec

      • decodeColor

        protected void decodeColor​(Rectangle newRect)
        Postprocess the uncompressed color data into the appropriate display color model. This implementation Does a number of things:
        • For RGB color, reverse to BGR which apparently is faster for Java 2D display
        • For one-bit WHITE_IS_ZERO data, flip the values so that they will look correct
        • If the decodePaletteAsShorts flag is true then unpack the bits and apply the lookup table, as 16-bit lookup is not supported in JAI.
        Override this if you have other color types.
        See Also:
        XTIFFDecodeParam

      • decodeTilePixels

        protected void decodeTilePixels​(byte[] bpixels,
                                Rectangle newRect)
        Decode a tile of data into either byte or short pixel buffers. Override this if you have other buffer types (e.g. int)

      • setTilePixels

        protected WritableRaster setTilePixels​(Rectangle rect)
        Take the values from the buffer and store them in a WritableRaster object.

      • unpackShorts

        protected void unpackShorts​(byte[] byteArray,
                            short[] output,
                            int shortCount)
        A useful Method to interpret a byte array as shorts. Method depends on whether the bytes are stored in a big endian or little endian format.

      • decodeColor

        protected void decodeColor​(byte[] bpix,
                           short[] sdata,
                           Rectangle newRect)
        Decode short pixel data, or interpret palette data as short from byte.

      • decodeColor

        protected void decodeColor​(short[] spix,
                           short[] sdata,
                           Rectangle newRect)
        Decode short color data, or interpret palette data as short.

      • decodeColor

        protected void decodeColor​(byte[] bpix,
                           byte[] bdata,
                           Rectangle newRect)
        Decode byte color data