001: /*
002: * $RCSfile: CBlkQuantDataSrcEnc.java,v $
003: * $Revision: 1.1 $
004: * $Date: 2005/02/11 05:02:20 $
005: * $State: Exp $
006: *
007: * Class: CBlkQuantDataSrcEnc
008: *
009: * Description: Interface that defines a source of
010: * quantized wavelet data to be transferred in a
011: * code-block by code-block basis.
012: *
013: *
014: *
015: * COPYRIGHT:
016: *
017: * This software module was originally developed by Raphaël Grosbois and
018: * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
019: * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
020: * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
021: * Centre France S.A) in the course of development of the JPEG2000
022: * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
023: * software module is an implementation of a part of the JPEG 2000
024: * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
025: * Systems AB and Canon Research Centre France S.A (collectively JJ2000
026: * Partners) agree not to assert against ISO/IEC and users of the JPEG
027: * 2000 Standard (Users) any of their rights under the copyright, not
028: * including other intellectual property rights, for this software module
029: * with respect to the usage by ISO/IEC and Users of this software module
030: * or modifications thereof for use in hardware or software products
031: * claiming conformance to the JPEG 2000 Standard. Those intending to use
032: * this software module in hardware or software products are advised that
033: * their use may infringe existing patents. The original developers of
034: * this software module, JJ2000 Partners and ISO/IEC assume no liability
035: * for use of this software module or modifications thereof. No license
036: * or right to this software module is granted for non JPEG 2000 Standard
037: * conforming products. JJ2000 Partners have full right to use this
038: * software module for his/her own purpose, assign or donate this
039: * software module to any third party and to inhibit third parties from
040: * using this software module for non JPEG 2000 Standard conforming
041: * products. This copyright notice must be included in all copies or
042: * derivative works of this software module.
043: *
044: * Copyright (c) 1999/2000 JJ2000 Partners.
045: */
046:
047: package jj2000.j2k.quantization.quantizer;
048:
049: import jj2000.j2k.wavelet.analysis.*;
050: import jj2000.j2k.entropy.encoder.*;
051: import jj2000.j2k.wavelet.*;
052: import jj2000.j2k.image.*;
053:
054: /**
055: * This interface defines a source of quantized wavelet coefficients and
056: * methods to transfer them in a code-block by code-block basis. In each call
057: * to 'getNextCodeBlock()' or 'getNextInternCodeBlock()' a new code-block is
058: * returned. The code-blocks are returned in no specific order.
059: *
060: * <p>This class is the source of data for the entropy coder. See the
061: * 'EntropyCoder' class.</p>
062: *
063: * <p>Code-block data is returned in sign-magnitude representation, instead of
064: * the normal two's complement one. Only integral types are used. The sign
065: * magnitude representation is more adequate for entropy coding. In sign
066: * magnitude representation, the most significant bit is used for the sign (0
067: * if positive, 1 if negative) and the magnitude of the coefficient is stored
068: * in the next M most significant bits. The rest of the bits (least
069: * significant bits) can contain a fractional value of the quantized
070: * coefficient. The number 'M' of magnitude bits is communicated in the
071: * 'magbits' member variable of the 'CBlkWTData'.</p>
072: *
073: * <p>Note that no more of one object may request data, otherwise one object
074: * would get some of the data and another one another part, in no defined
075: * manner.</p>
076: *
077: * @see ForwWTDataProps
078: * @see CBlkWTDataSrc
079: * @see Quantizer
080: * @see EntropyCoder
081: * */
082: public interface CBlkQuantDataSrcEnc extends ForwWTDataProps {
083:
084: /**
085: * Returns the next code-block in the current tile for the specified
086: * component, as a copy (see below). The order in which code-blocks are
087: * returned is not specified. However each code-block is returned only
088: * once and all code-blocks will be returned if the method is called 'N'
089: * times, where 'N' is the number of code-blocks in the tile. After all
090: * the code-blocks have been returned for the current tile calls to this
091: * method will return 'null'.
092: *
093: * <p>When changing the current tile (through 'setTile()' or 'nextTile()')
094: * this method will always return the first code-block, as if this method
095: * was never called before for the new current tile.</p>
096: *
097: * <p>The data returned by this method is always a copy of the internal
098: * data of this object, if any, and it can be modified "in place" without
099: * any problems after being returned. The 'offset' of the returned data is
100: * 0, and the 'scanw' is the same as the code-block width. See the
101: * 'CBlkWTData' class.</p>
102: *
103: * <p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
104: * contain the coordinates of the top-left corner of the block, with
105: * respect to the tile, not the subband.</p>
106: *
107: * @param c The component for which to return the next code-block.
108: *
109: * @param cblk If non-null this object will be used to return the new
110: * code-block. If null a new one will be allocated and returned. If the
111: * "data" array of the object is non-null it will be reused, if possible,
112: * to return the data.
113: *
114: * @return The next code-block in the current tile for component 'c', or
115: * null if all code-blocks for the current tile have been returned.
116: *
117: * @see CBlkWTData
118: * */
119: public CBlkWTData getNextCodeBlock(int c, CBlkWTData cblk);
120:
121: /**
122: * Returns the next code-block in the current tile for the specified
123: * component. The order in which code-blocks are returned is not
124: * specified. However each code-block is returned only once and all
125: * code-blocks will be returned if the method is called 'N' times, where
126: * 'N' is the number of code-blocks in the tile. After all the code-blocks
127: * have been returned for the current tile calls to this method will
128: * return 'null'.
129: *
130: * <p>When changing the current tile (through 'setTile()' or 'nextTile()')
131: * this method will always return the first code-block, as if this method
132: * was never called before for the new current tile.</p>
133: *
134: * <p>The data returned by this method can be the data in the internal
135: * buffer of this object, if any, and thus can not be modified by the
136: * caller. The 'offset' and 'scanw' of the returned data can be
137: * arbitrary. See the 'CBlkWTData' class.</p>
138: *
139: * <p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
140: * contain the coordinates of the top-left corner of the block, with
141: * respect to the tile, not the subband.</p>
142: *
143: * @param c The component for which to return the next code-block.
144: *
145: * @param cblk If non-null this object will be used to return the new
146: * code-block. If null a new one will be allocated and returned. If the
147: * "data" array of the object is non-null it will be reused, if possible,
148: * to return the data.
149: *
150: * @return The next code-block in the current tile for component 'n', or
151: * null if all code-blocks for the current tile have been returned.
152: *
153: * @see CBlkWTData
154: * */
155: public CBlkWTData getNextInternCodeBlock(int c, CBlkWTData cblk);
156: }
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