imgdatajoiner.java

jpeg2000算法实现

/*
 * CVS identifier:
 *
 * $Id: ImgDataJoiner.java,v 1.11 2001/01/24 14:58:50 grosbois Exp $
 *
 * Class:                   ImgDataJoiner
 *
 * Description:             Get ImgData from different sources
 *
 *
 *
 * 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;

import jj2000.j2k.*;

/**
 * This class implements the ImgData interface and allows to obtain data from
 * different sources. Here, one source is represented by an ImgData and a
 * component index. The typical use of this class is when the encoder needs
 * different components (Red, Green, Blue, alpha, ...) from different input
 * files (i.e. from different ImgReader objects).
 *
 * <P>All input ImgData must not be tiled (i.e. must have only 1 tile) and the
 * image origin must be the canvas origin. The different inputs can have
 * different dimensions though (this will lead to different subsampling
 * factors for each component).
 *
 * <P>The input ImgData and component index list must be defined when
 * constructing this class and can not be modified later.
 *
 * @see ImgData
 *
 * @see jj2000.j2k.image.input.ImgReader
 * */
public class ImgDataJoiner implements BlkImgDataSrc {

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

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

    /** The number of components in the image */
    private int nc;

    /** The list of input ImgData */
    private BlkImgDataSrc[] imageData;

    /** The component index associated with each ImgData */
    private int[] compIdx;

    /** The subsampling factor along the horizontal direction, for every
     * component */
    private int[] subsX;

    /** The subsampling factor along the vertical direction, for every
     * component */
    private int[] subsY;

    /**
     * Class constructor. Each input BlkImgDataSrc and its component index
     * must appear in the order wanted for the output components.<br>
     *
     * <u>Example:</u> Reading R,G,B components from 3 PGM files.<br>
     * <tt>
     * BlkImgDataSrc[] idList = <br>
     *   {<br>
     *   new ImgReaderPGM(new BEBufferedRandomAccessFile("R.pgm", "r")),<br>
     *   new ImgReaderPGM(new BEBufferedRandomAccessFile("G.pgm", "r")),<br>
     *   new ImgReaderPGM(new BEBufferedRandomAccessFile("B.pgm", "r"))<br>
     *   };<br>
     * int[] compIdx = {0,0,0};<br>
     * ImgDataJoiner idj = new ImgDataJoiner(idList, compIdx);
     * </tt>
     *
     * <p>Of course, the 2 arrays must have the same length (This length is
     * the number of output components). The image width and height are
     * definded to be the maximum values of all the input ImgData.
     *
     * @param imD The list of input BlkImgDataSrc in an array.
     *
     * @param cIdx The component index associated with each ImgData.
     * */
    public ImgDataJoiner(BlkImgDataSrc[] imD, int[] cIdx){
        int i;
        int maxW, maxH;

	// Initializes
	imageData = imD;
	compIdx = cIdx;
	if(imageData.length != compIdx.length)
	    throw new IllegalArgumentException("imD and cIdx must have the"+
					       " same length");

	nc = imD.length;

        subsX = new int[nc];
        subsY = new int[nc];

        // Check that no source is tiled and that the image origin is at the
        // canvas origin.
        for(i=0; i<nc; i++) {
            if (imD[i].getNumTiles() != 1 ||
                imD[i].getULX(cIdx[i]) != 0 || imD[i].getULY(cIdx[i]) != 0) {
                throw
                    new IllegalArgumentException("All input components must, "+
                                                 "not use tiles and must have "+
                                                 "the origin at the canvas "+
                                                 "origin");
            }
        }

        // Guess component subsampling factors based on the fact that the
        // ceil() operation relates the reference grid size to the component's
        // size, through the subsampling factor.

        // Mhhh, difficult problem. For now just assume that one of the
        // subsampling factors is always 1 and that the component width is
        // always larger than its subsampling factor, which covers most of the
        // cases. We check the correctness of the solution once found to chek
        // out hypothesis.

        // Look for max width and height.
        maxW = 0;
        maxH = 0;
	for(i=0; i<nc; i++) {
	    if(imD[i].getCompImgWidth(cIdx[i]) > maxW)
		maxW = imD[i].getCompImgWidth(cIdx[i]);
	    if(imD[i].getCompImgHeight(cIdx[i]) > maxH)
		maxH = imD[i].getCompImgHeight(cIdx[i]);
	}
        // Set the image width and height as the maximum ones
	w = maxW;
	h = maxH;

        // Now get the sumsampling factors and check the subsampling factors,
        // just to see if above hypothesis were correct.
        for (i=0; i<nc; i++) {
            // This calculation only holds if the subsampling factor is less
            // than the component width
            subsX[i] = (maxW + imD[i].getCompImgWidth(cIdx[i])-1) /
                imD[i].getCompImgWidth(cIdx[i]);
            subsY[i] = (maxH + imD[i].getCompImgHeight(cIdx[i])-1) /
                imD[i].getCompImgHeight(cIdx[i]);
            if ((maxW+subsX[i]-1)/subsX[i] !=
                imD[i].getCompImgWidth(cIdx[i]) ||
                (maxH+subsY[i]-1)/subsY[i] !=
                imD[i].getCompImgHeight(cIdx[i])) {
                throw new Error("Can not compute component subsampling "+
                                "factors: strange subsampling.");
            }
        }
    }

    /**
     * Returns the overall width of the current tile in pixels. This is the
     * tile's width without accounting for any component subsampling.
     *
     * @return The total current tile's width in pixels.
     * */
    public int getWidth(){
	return w;
    }

    /**
     * Returns the overall height of the current tile in pixels. This is the
     * tile's height without accounting for any component subsampling.
     *
     * @return The total current tile's height in pixels.
     * */
    public int getHeight(){
	return h;
    }

    /**
     * Returns the overall width of the image in pixels. This is the image's
     * width without accounting for any component subsampling or tiling.
     *
     * @return The total image's width in pixels.
     * */
    public int getImgWidth(){
	return w;
    }

    /**
     * Returns the overall height of the image in pixels. This is the image's
     * height without accounting for any component subsampling or tiling.
     *
     * @return The total image's height in pixels.
     * */
    public int getImgHeight(){
	return h;
    }

    /**
     * Returns the number of components in the image.
     *
     * @return The number of components in the image.
     * */
    public int getNumComps(){
	return nc;
    }

    /**
     * Returns the component subsampling factor in the horizontal direction,
     * for the specified component. This is, approximately, the ratio of
     * dimensions between the reference grid and the component itself, see the
     * 'ImgData' interface desription for details.
     *
     * @param c The index of the component (between 0 and N-1)
     *
     * @return The horizontal subsampling factor of component 'c'
     *
     * @see ImgData
     * */
    public int getCompSubsX(int c) {
        return subsX[c];
    }

    /**
     * Returns the component subsampling factor in the vertical direction, for
     * the specified component. This is, approximately, the ratio of
     * dimensions between the reference grid and the component itself, see the
     * 'ImgData' interface desription for details.
     *
     * @param c The index of the component (between 0 and N-1)
     *
     * @return The vertical subsampling factor of component 'c'
     *
     * @see ImgData
     * */
    public int getCompSubsY(int c) {
        return subsY[c];
    }


    /**
     * Returns the width in pixels of the specified component in the
     * current tile.
     *
     * @param c The index of the component, from 0 to N-1.
     *
     * @return The width in pixels of component <tt>c</tt> in the current
     * tile.
     * */
    public int getCompWidth(int c){
	return imageData[c].getCompWidth(compIdx[c]);
    }

    /**
     * Returns the height in pixels of the specified component in the current
     * tile.
     *
     * @param c The index of the component, from 0 to N-1.
     *
     * @return The height in pixels of component <tt>c</tt> in the current
     * tile.
     * */
    public int getCompHeight(int c){
	return imageData[c].getCompHeight(compIdx[c]);
    }

    /**
     * Returns the width in pixels of the specified component in the overall
     * image.
     *
     * @param c The index of the component, from 0 to N-1.
     *
     * @return The width in pixels of component <tt>c</tt> in the overall
     * image.
     * */
    public int getCompImgWidth(int c){
	return imageData[c].getCompImgWidth(compIdx[c]);
    }

    /**
     * Returns the height in pixels of the specified component in the
     * overall image.
     *
     * @param n The index of the component, from 0 to N-1.
     *
     * @return The height in pixels of component <tt>n</tt> in the overall
     * image.