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/*
* $RCSfile: ImgReader.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:14 $
* $State: Exp $
*
* Class: ImgReader
*
* Description: Generic interface for image readers (from
* file or other resource)
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix 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 java.awt.Point;
import java.io.IOException;
import jj2000.j2k.NoNextElementException;
import jj2000.j2k.image.BlkImgDataSrc;
/**
* This is the generic interface to be implemented by all image file (or other
* resource) readers for different image file formats.
*
* 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.
*
* This class sets the image origin to (0,0). All default implementations
* of the methods assume this.
*
* 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.
* */
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 w 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 h 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 w 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 h 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 nc
* 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 c in tilet.
* */
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 c in tile
* t.
* */
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 c 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 c 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 Point getTile(Point co) {
if (co != null) {
co.x = 0;
co.y = 0;
return co;
}
else {
return new Point(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 (Point.x) and vertical
* (Point.y) directions.
* */
public Point getNumTiles(Point co) {
if (co != null) {
co.x = 1;
co.y = 1;
return co;
}
else {
return new Point(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);
}