imgwriter.java

jpeg2000编解码

/*
 * CVS identifier:
 *
 * $Id: ImgWriter.java,v 1.1.1.1 2002/07/22 09:26:51 grosbois Exp $
 *
 * Class:                   ImgWriter
 *
 * Description:             Generic interface for all image writer
 *                          classes (to file or other resource)
 *
 *
 *
 * COPYRIGHT:
 * 
 * This software module was originally developed by Rapha雔 Grosbois and
 * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
 * Askel鰂 (Ericsson Radio Systems AB); and Bertrand Berthelot, David
 * Bouchard, F閘ix Henry, Gerard Mozelle and Patrice Onno (Canon Research
 * Centre France S.A) in the course of development of the JPEG2000
 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
 * software module is an implementation of a part of the JPEG 2000
 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
 * Systems AB and Canon Research Centre France S.A (collectively JJ2000
 * Partners) agree not to assert against ISO/IEC and users of the JPEG
 * 2000 Standard (Users) any of their rights under the copyright, not
 * including other intellectual property rights, for this software module
 * with respect to the usage by ISO/IEC and Users of this software module
 * or modifications thereof for use in hardware or software products
 * claiming conformance to the JPEG 2000 Standard. Those intending to use
 * this software module in hardware or software products are advised that
 * their use may infringe existing patents. The original developers of
 * this software module, JJ2000 Partners and ISO/IEC assume no liability
 * for use of this software module or modifications thereof. No license
 * or right to this software module is granted for non JPEG 2000 Standard
 * conforming products. JJ2000 Partners have full right to use this
 * software module for his/her own purpose, assign or donate this
 * software module to any third party and to inhibit third parties from
 * using this software module for non JPEG 2000 Standard conforming
 * products. This copyright notice must be included in all copies or
 * derivative works of this software module.
 * 
 * Copyright (c) 1999/2000 JJ2000 Partners.
 *  */
package jj2000.j2k.image.output;

import jj2000.j2k.image.*;
import jj2000.j2k.util.*;
import jj2000.j2k.*;

import java.io.*;

/**
 * This is the generic interface to be implemented by all image file (or other
 * resource) writers for different formats.
 *
 * <p>Each object inheriting from this class should have a source ImgData
 * object associated with it. The image data to write to the file is obtained
 * from the associated ImgData object. In general this object would be
 * specified at construction time.</p>
 *
 * <p>Depending on the actual type of file that is written a call to any
 * write() or writeAll() method will write data from one component, several
 * components or all components. For example, a PGM writer will write data
 * from only one component (defined in the constructor) while a PPM writer
 * will write 3 components (normally R,G,B).</p>
 * */
public abstract class ImgWriter {

    /** The defaukt height used when writing strip by strip in the 'write()'
     * method. It is 64. */
    public final static int DEF_STRIP_HEIGHT = 64;

    /** The source ImagaData object, from where to get the image data */
    protected BlkImgDataSrc src;

    /** The width of the image */
    protected int w;

    /** The height of the image */
    protected int h;

    /**
     * Closes the underlying file or netwrok connection to where the data is
     * written. The implementing class must write all buffered data before
     * closing the file or resource. Any call to other methods of the class
     * become illegal after a call to this one.
     *
     * @exception IOException If an I/O error occurs.
     * */
    public abstract void close() throws IOException;

    /**
     * Writes all buffered data to the file or resource. If the implementing
     * class does onot use buffering nothing should be done.
     *
     * @exception IOException If an I/O error occurs.
     * */
    public abstract void flush() throws IOException;

    /**
     * Flushes the buffered data before the object is garbage collected. If an
     * exception is thrown the object finalization is halted, but is otherwise
     * ignored.
     *
     * @exception IOException If an I/O error occurs. It halts the
     * finalization of the object, but is otherwise ignored.
     *
     * @see Object#finalize
     * */
    public void finalize() throws IOException {
        flush();
    }

    /**
     * Writes the source's current tile to the output. The requests of data
     * issued by the implementing class to the source ImgData object should be
     * done by blocks or strips, in order to reduce memory usage.
     *
     * <p>The implementing class should only write data that is not
     * "progressive" (in other words that it is final), see DataBlk for
     * details.</p>
     *
     * @exception IOException If an I/O error occurs.
     *
     * @see DataBlk
     * */
    public abstract void write() throws IOException;

    /**
     * Writes the entire image or only specified tiles to the output. The
     * implementation in this class calls the write() method for each tile
     * starting with the upper-left one and proceding in standard scanline
     * order. It changes the current tile of the source data.
     *
     * @exception IOException If an I/O error occurs.
     *
     * @see DataBlk
     * */
    public void writeAll() throws IOException {
        // Find the list of tile to decode.
        Coord nT = src.getNumTiles(null);

        // Loop on vertical tiles
        for(int y=0; y<nT.y; y++){
            // Loop on horizontal tiles
            for(int x=0; x<nT.x; x++){
		src.setTile(x,y);
		write();
            } // End loop on horizontal tiles            
        } // End loop on vertical tiles
    }

    /**
     * Writes the data of the specified area to the file, coordinates are
     * relative to the current tile of the source.
     *
     * <p>The implementing class should only write data that is not
     * "progressive" (in other words that is final), see DataBlk for
     * details.</p>
     *
     * @param ulx The horizontal coordinate of the upper-left corner of the
     * area to write, relative to the current tile.
     *
     * @param uly The vertical coordinate of the upper-left corner of the area
     * to write, relative to the current tile.
     *
     * @param width The width of the area to write.
     *
     * @param height The height of the area to write.
     *
     * @exception IOException If an I/O error occurs.
     * */
    public abstract void write(int ulx, int uly, int w, int h) 
        throws IOException;

}