/*
* $RCSfile: BlkImgDataSrc.java,v $
* $Revision: 1.1 $
* $Date: 2005/02/11 05:02:11 $
* $State: Exp $
*
* Class: BlkImgDataSrc
*
* Description: Defines methods to transfer image data in blocks.
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphal Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Flix 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;
/**
* This interface defines the methods to transfer image data in blocks,
* without following any particular order (random access). This interface does
* not define the methods to access the image characteristics, such as width,
* height, number of components, tiles, etc., or to change the current
* tile. That is provided by other interfaces such as ImgData.
*
* <P>This interface has the notion of a current tile. All data, coordinates
* and dimensions are always relative to the current tile. If there is only
* one tile then it is equivalent as having no tiles.
*
* <P>A block of requested data may never cross tile boundaries. This should
* be enforced by the implementing class, or the source of image data.
*
* <P>This interface defines the methods that can be used to retrieve image
* data. Implementing classes need not buffer all the image data, they can ask
* their source to load the data they need.
*
* @see ImgData
* */
public interface BlkImgDataSrc extends ImgData {
/**
* Returns the position of the fixed point in the specified component, or
* equivalently the number of fractional bits. This is the position of the
* least significant integral (i.e. non-fractional) bit, which is
* equivalent to the number of fractional bits. For instance, for
* fixed-point values with 2 fractional bits, 2 is returned. For
* floating-point data this value does not apply and 0 should be
* returned. Position 0 is the position of the least significant bit in
* the data.
*
* @param c The index of the component.
*
* @return The position of the fixed-point, which is the same as the
* number of fractional bits. For floating-point data 0 is returned.
* */
public int getFixedPoint(int c);
/**
* Returns, in the blk argument, a block of image data containing the
* specifed rectangular area, in the specified component. The data is
* returned, as a reference to the internal data, if any, instead of as a
* copy, therefore the returned data should not be modified.
*
* <P>The rectangular area to return is specified by the 'ulx', 'uly', 'w'
* and 'h' members of the 'blk' argument, relative to the current
* tile. These members are not modified by this method. The 'offset' and
* 'scanw' of the returned data can be arbitrary. See the 'DataBlk' class.
*
* <P>This method, in general, is more efficient than the 'getCompData()'
* method since it may not copy the data. However if the array of returned
* data is to be modified by the caller then the other method is probably
* preferable.
*
* <P>If possible, the data in the returned 'DataBlk' should be the
* internal data itself, instead of a copy, in order to increase the data
* transfer efficiency. However, this depends on the particular
* implementation (it may be more convenient to just return a copy of the
* data). This is the reason why the returned data should not be modified.
*
* <P>If the data array in <tt>blk</tt> is <tt>null</tt>, then a new one
* is created if necessary. The implementation of this interface may
* choose to return the same array or a new one, depending on what is more
* efficient. Therefore, the data array in <tt>blk</tt> prior to the
* method call should not be considered to contain the returned data, a
* new array may have been created. Instead, get the array from
* <tt>blk</tt> after the method has returned.
*
* <P>The returned data may have its 'progressive' attribute set. In this
* case the returned data is only an approximation of the "final" data.
*
* @param blk Its coordinates and dimensions specify the area to return,
* relative to the current tile. Some fields in this object are modified
* to return the data.
*
* @param c The index of the component from which to get the data.
*
* @return The requested DataBlk
*
* @see #getCompData
* */
public DataBlk getInternCompData(DataBlk blk, int c);
/**
* Returns, in the blk argument, a block of image data containing the
* specifed rectangular area, in the specified component. The data is
* returned, as a copy of the internal data, therefore the returned data
* can be modified "in place".
*
* <P>The rectangular area to return is specified by the 'ulx', 'uly', 'w'
* and 'h' members of the 'blk' argument, relative to the current
* tile. These members are not modified by this method. The 'offset' of
* the returned data is 0, and the 'scanw' is the same as the block's
* width. See the 'DataBlk' class.
*
* <P>This method, in general, is less efficient than the
* 'getInternCompData()' method since, in general, it copies the
* data. However if the array of returned data is to be modified by the
* caller then this method is preferable.
*
* <P>If the data array in 'blk' is 'null', then a new one is created. If
* the data array is not 'null' then it is reused, and it must be large
* enough to contain the block's data. Otherwise an 'ArrayStoreException'
* or an 'IndexOutOfBoundsException' is thrown by the Java system.
*
* <P>The returned data may have its 'progressive' attribute set. In this
* case the returned data is only an approximation of the "final" data.
*
* @param blk Its coordinates and dimensions specify the area to return,
* relative to the current tile. If it contains a non-null data array,
* then it must be large enough. If it contains a null data array a new
* one is created. Some fields in this object are modified to return the
* data.
*
* @param c The index of the component from which to get the data.
*
* @see #getInternCompData
* */
public DataBlk getCompData(DataBlk blk, int c);
}
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