001: /*
002: * $RCSfile: BlkImgDataSrc.java,v $
003: * $Revision: 1.1 $
004: * $Date: 2005/02/11 05:02:11 $
005: * $State: Exp $
006: *
007: * Class: BlkImgDataSrc
008: *
009: * Description: Defines methods to transfer image data in blocks.
010: *
011: *
012: *
013: * COPYRIGHT:
014: *
015: * This software module was originally developed by Raphaël Grosbois and
016: * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
017: * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
018: * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
019: * Centre France S.A) in the course of development of the JPEG2000
020: * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
021: * software module is an implementation of a part of the JPEG 2000
022: * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
023: * Systems AB and Canon Research Centre France S.A (collectively JJ2000
024: * Partners) agree not to assert against ISO/IEC and users of the JPEG
025: * 2000 Standard (Users) any of their rights under the copyright, not
026: * including other intellectual property rights, for this software module
027: * with respect to the usage by ISO/IEC and Users of this software module
028: * or modifications thereof for use in hardware or software products
029: * claiming conformance to the JPEG 2000 Standard. Those intending to use
030: * this software module in hardware or software products are advised that
031: * their use may infringe existing patents. The original developers of
032: * this software module, JJ2000 Partners and ISO/IEC assume no liability
033: * for use of this software module or modifications thereof. No license
034: * or right to this software module is granted for non JPEG 2000 Standard
035: * conforming products. JJ2000 Partners have full right to use this
036: * software module for his/her own purpose, assign or donate this
037: * software module to any third party and to inhibit third parties from
038: * using this software module for non JPEG 2000 Standard conforming
039: * products. This copyright notice must be included in all copies or
040: * derivative works of this software module.
041: *
042: * Copyright (c) 1999/2000 JJ2000 Partners.
043: * */
044: package jj2000.j2k.image;
045:
046: /**
047: * This interface defines the methods to transfer image data in blocks,
048: * without following any particular order (random access). This interface does
049: * not define the methods to access the image characteristics, such as width,
050: * height, number of components, tiles, etc., or to change the current
051: * tile. That is provided by other interfaces such as ImgData.
052: *
053: * <P>This interface has the notion of a current tile. All data, coordinates
054: * and dimensions are always relative to the current tile. If there is only
055: * one tile then it is equivalent as having no tiles.
056: *
057: * <P>A block of requested data may never cross tile boundaries. This should
058: * be enforced by the implementing class, or the source of image data.
059: *
060: * <P>This interface defines the methods that can be used to retrieve image
061: * data. Implementing classes need not buffer all the image data, they can ask
062: * their source to load the data they need.
063: *
064: * @see ImgData
065: * */
066: public interface BlkImgDataSrc extends ImgData {
067:
068: /**
069: * Returns the position of the fixed point in the specified component, or
070: * equivalently the number of fractional bits. This is the position of the
071: * least significant integral (i.e. non-fractional) bit, which is
072: * equivalent to the number of fractional bits. For instance, for
073: * fixed-point values with 2 fractional bits, 2 is returned. For
074: * floating-point data this value does not apply and 0 should be
075: * returned. Position 0 is the position of the least significant bit in
076: * the data.
077: *
078: * @param c The index of the component.
079: *
080: * @return The position of the fixed-point, which is the same as the
081: * number of fractional bits. For floating-point data 0 is returned.
082: * */
083: public int getFixedPoint(int c);
084:
085: /**
086: * Returns, in the blk argument, a block of image data containing the
087: * specifed rectangular area, in the specified component. The data is
088: * returned, as a reference to the internal data, if any, instead of as a
089: * copy, therefore the returned data should not be modified.
090: *
091: * <P>The rectangular area to return is specified by the 'ulx', 'uly', 'w'
092: * and 'h' members of the 'blk' argument, relative to the current
093: * tile. These members are not modified by this method. The 'offset' and
094: * 'scanw' of the returned data can be arbitrary. See the 'DataBlk' class.
095: *
096: * <P>This method, in general, is more efficient than the 'getCompData()'
097: * method since it may not copy the data. However if the array of returned
098: * data is to be modified by the caller then the other method is probably
099: * preferable.
100: *
101: * <P>If possible, the data in the returned 'DataBlk' should be the
102: * internal data itself, instead of a copy, in order to increase the data
103: * transfer efficiency. However, this depends on the particular
104: * implementation (it may be more convenient to just return a copy of the
105: * data). This is the reason why the returned data should not be modified.
106: *
107: * <P>If the data array in <tt>blk</tt> is <tt>null</tt>, then a new one
108: * is created if necessary. The implementation of this interface may
109: * choose to return the same array or a new one, depending on what is more
110: * efficient. Therefore, the data array in <tt>blk</tt> prior to the
111: * method call should not be considered to contain the returned data, a
112: * new array may have been created. Instead, get the array from
113: * <tt>blk</tt> after the method has returned.
114: *
115: * <P>The returned data may have its 'progressive' attribute set. In this
116: * case the returned data is only an approximation of the "final" data.
117: *
118: * @param blk Its coordinates and dimensions specify the area to return,
119: * relative to the current tile. Some fields in this object are modified
120: * to return the data.
121: *
122: * @param c The index of the component from which to get the data.
123: *
124: * @return The requested DataBlk
125: *
126: * @see #getCompData
127: * */
128: public DataBlk getInternCompData(DataBlk blk, int c);
129:
130: /**
131: * Returns, in the blk argument, a block of image data containing the
132: * specifed rectangular area, in the specified component. The data is
133: * returned, as a copy of the internal data, therefore the returned data
134: * can be modified "in place".
135: *
136: * <P>The rectangular area to return is specified by the 'ulx', 'uly', 'w'
137: * and 'h' members of the 'blk' argument, relative to the current
138: * tile. These members are not modified by this method. The 'offset' of
139: * the returned data is 0, and the 'scanw' is the same as the block's
140: * width. See the 'DataBlk' class.
141: *
142: * <P>This method, in general, is less efficient than the
143: * 'getInternCompData()' method since, in general, it copies the
144: * data. However if the array of returned data is to be modified by the
145: * caller then this method is preferable.
146: *
147: * <P>If the data array in 'blk' is 'null', then a new one is created. If
148: * the data array is not 'null' then it is reused, and it must be large
149: * enough to contain the block's data. Otherwise an 'ArrayStoreException'
150: * or an 'IndexOutOfBoundsException' is thrown by the Java system.
151: *
152: * <P>The returned data may have its 'progressive' attribute set. In this
153: * case the returned data is only an approximation of the "final" data.
154: *
155: * @param blk Its coordinates and dimensions specify the area to return,
156: * relative to the current tile. If it contains a non-null data array,
157: * then it must be large enough. If it contains a null data array a new
158: * one is created. Some fields in this object are modified to return the
159: * data.
160: *
161: * @param c The index of the component from which to get the data.
162: *
163: * @see #getInternCompData
164: * */
165: public DataBlk getCompData(DataBlk blk, int c);
166: }
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