/** * CVS identifier: * * $Id: ImgReader.java,v 1.2 2002/07/23 12:23:28 grosbois Exp $ * * Class:                   ImgReader * * Description:             Generic interface for image readers (from *                          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.input;import jj2000.j2k.image.*;import jj2000.j2k.*;import java.io.*;/** * This is the generic interface to be implemented by all image file (or other * resource) readers for different image file formats. * * <p>An ImgReader behaves as an ImgData object. Whenever image data is * requested through the getInternCompData() or getCompData() methods, the * image data will be read (if it is not buffered) and returned. Implementing * classes should not buffer large amounts of data, so as to reduce memory * usage.</p> * * <p>This class sets the image origin to (0,0). All default implementations * of the methods assume this.</p> * * <p>This class provides default implementations of many methods. These * default implementations assume that there is no tiling (i.e., the only tile * is the entire image), that the image origin is (0,0) in the canvas system * and that there is no component subsampling (all components are the same * size), but they can be overloaded by the implementating class if need * be.</p> * */public abstract class ImgReader implements BlkImgDataSrc {    /** The width of the image */    protected int w;    /** The height of the image */    protected int h;    /** The number of components in the image */    protected int nc;    /**     * Closes the underlying file or network connection from where the     * image data is being read.     *     * @exception IOException If an I/O error occurs.     */    public abstract void close() throws IOException;    /**     * Returns the width of the current tile in pixels, assuming there is     * no-tiling. Since no-tiling is assumed this is the same as the width of     * the image. The value of <tt>w</tt> is returned.     *     * @return The total image width in pixels.     * */    public int getTileWidth() {        return w;    }    /**     * Returns the overall height of the current tile in pixels, assuming     * there is no-tiling. Since no-tiling is assumed this is the same as the     * width of the image. The value of <tt>h</tt> is returned.     *     * @return The total image height in pixels.  */    public int getTileHeight() {        return h;    }    /** Returns the nominal tiles width */    public int getNomTileWidth() {        return w;    }    /** Returns the nominal tiles height */    public int getNomTileHeight() {        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. The     * value of <tt>w</tt> is returned.     *     * @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. The     * value of <tt>h</tt> is returned.     *     * @return The total image's height in pixels.     * */    public int getImgHeight() {        return h;    }    /**     * Returns the number of components in the image. The value of <tt>nc</tt>     * is returned.     *     * @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 C-1)     *     * @return The horizontal subsampling factor of component 'c'     *     * @see jj2000.j2k.image.ImgData     * */    public int getCompSubsX(int c) {        return 1;    }    /**     * 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 C-1)     *     * @return The vertical subsampling factor of component 'c'     *     * @see jj2000.j2k.image.ImgData     * */    public int getCompSubsY(int c) {        return 1;    }    /**     * Returns the width in pixels of the specified tile-component. This     * default implementation assumes no tiling and no component subsampling     * (i.e., all components, or components, have the same dimensions in     * pixels).     *     * @param t Tile index     *     * @param c The index of the component, from 0 to C-1.     *     * @return The width in pixels of component <tt>c</tt> in tile<tt>t</tt>.     * */    public int getTileCompWidth(int t,int c) {        if(t!=0) {            throw new Error("Asking a tile-component width for a tile index"+                            " greater than 0 whereas there is only one tile");        }        return w;    }    /**     * Returns the height in pixels of the specified tile-component. This     * default implementation assumes no tiling and no component subsampling     * (i.e., all components, or components, have the same dimensions in     * pixels).     *     * @param t The tile index     *     * @param c The index of the component, from 0 to C-1.     *     * @return The height in pixels of component <tt>c</tt> in tile     * <tt>t</tt>.     * */    public int getTileCompHeight(int t,int c) {        if(t!=0) {            throw new Error("Asking a tile-component width for a tile index"+                            " greater than 0 whereas there is only one tile");        }        return h;    }    /**     * Returns the width in pixels of the specified component in the overall     * image. This default implementation assumes no component, or component,     * subsampling (i.e. all components have the same dimensions in pixels).     *     * @param c The index of the component, from 0 to C-1.     *     * @return The width in pixels of component <tt>c</tt> in the overall     * image.     * */    public int getCompImgWidth(int c) {        return w;    }    /**     * Returns the height in pixels of the specified component in the overall     * image. This default implementation assumes no component, or component,     * subsampling (i.e. all components have the same dimensions in pixels).     *     * @param c The index of the component, from 0 to C-1.     *     * @return The height in pixels of component <tt>c</tt> in the overall     * image.     * */    public int getCompImgHeight(int c) {        return h;    }    /**     * Changes the current tile, given the new coordinates. An     * IllegalArgumentException is thrown if the coordinates do not correspond     * to a valid tile. This default implementation assumes no tiling so the     * only valid arguments are x=0, y=0.     *     * @param x The horizontal coordinate of the tile.     *     * @param y The vertical coordinate of the new tile.     * */    public void setTile(int x, int y) {        if (x!=0 || y != 0) {            throw new IllegalArgumentException();        }    }    /**     * Advances to the next tile, in standard scan-line order (by rows then     * columns). A NoNextElementException is thrown if the current tile is the     * last one (i.e. there is no next tile). This default implementation     * assumes no tiling, so NoNextElementException() is always thrown.     * */    public void nextTile() {        throw new NoNextElementException();    }    /**     * Returns the coordinates of the current tile. This default     * implementation assumes no-tiling, so (0,0) is returned.     *     * @param co If not null this object is used to return the information. If     * null a new one is created and returned.     *     * @return The current tile's coordinates.     * */    public Coord getTile(Coord co) {        if (co != null) {            co.x = 0;            co.y = 0;            return co;        }        else {            return new Coord(0,0);        }    }    /**     * Returns the index of the current tile, relative to a standard scan-line     * order. This default implementations assumes no tiling, so 0 is always     * returned.     *     * @return The current tile's index (starts at 0).     * */    public int getTileIdx() {        return 0;    }    /**     * Returns the horizontal coordinate of the upper-left corner of the     * specified component in the current tile.     *     * @param c The component index.     * */    public int getCompULX(int c) {        return 0;    }    /**     * Returns the vertical coordinate of the upper-left corner of the     * specified component in the current tile.     *     * @param c The component index.     * */    public int getCompULY(int c) {        return 0;    }    /** Returns the horizontal tile partition offset in the reference grid */    public int getTilePartULX() {        return 0;    }    /** Returns the vertical tile partition offset in the reference grid */    public int getTilePartULY() {        return 0;    }    /**     * Returns the horizontal coordinate of the image origin, the top-left     * corner, in the canvas system, on the reference grid.     *     * @return The horizontal coordinate of the image origin in the canvas     * system, on the reference grid.     * */    public int getImgULX() {        return 0;    }    /**     * Returns the vertical coordinate of the image origin, the top-left     * corner, in the canvas system, on the reference grid.     *     * @return The vertical coordinate of the image origin in the canvas     * system, on the reference grid.     * */    public int getImgULY() {        return 0;    }    /**     * Returns the number of tiles in the horizontal and vertical     * directions. This default implementation assumes no tiling, so (1,1) is     * always returned.     *     * @param co If not null this object is used to return the information. If     * null a new one is created and returned.     *     * @return The number of tiles in the horizontal (Coord.x) and vertical     * (Coord.y) directions.     * */    public Coord getNumTiles(Coord co) {        if (co != null) {            co.x = 1;            co.y = 1;            return co;        }        else {            return new Coord(1,1);        }    }    /**     * Returns the total number of tiles in the image. This default     * implementation assumes no tiling, so 1 is always returned.     *     * @return The total number of tiles in the image.     * */    public int getNumTiles() {        return 1;    }    /**     * Returns true if the data read was originally signed in the specified     * component, false if not.     *     * @param c The index of the component, from 0 to C-1.     *     * @return true if the data was originally signed, false if not.     * */    public abstract boolean isOrigSigned(int c);}