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CSJ2K.j2k.wavelet.analysis.ForwardWT

ForwardWT Class

This abstract class represents the forward wavelet transform functional block. The functional block may actually be comprised of several classes linked together, but a subclass of this abstract class is the one that is returned as the functional block that performs the forward wavelet transform.

       <p>This class assumes that data is transferred in code-blocks, as defined
       by the 'CBlkWTDataSrc' interface. The internal calculation of the wavelet
       transform may be done differently but a buffering class should convert to
       that type of transfer.</p>
Inheritance
ForwardWT
Namespace: CSJ2K.j2k.wavelet.analysis
Assembly: C1.WPF.PdfViewer.4.6.2.dll
Syntax
public abstract class ForwardWT : ImgDataAdapter, ForwWT, WaveletTransform, CBlkWTDataSrc, ForwWTDataProps, ImgData

Constructors

Name Description
ForwardWT(ImgData)

Initializes this object for the specified number of tiles 'nt' and components 'nc'.

Fields

Name Description
OPT_PREFIX

The prefix for wavelet transform options: 'W'

WT_DECOMP_DYADIC

ID for the dyadic wavelet tree decomposition (also called "Mallat" in JPEG 2000): 0x00.

Properties

Name Description
CbULX

Returns the horizontal offset of the code-block partition. Allowable values are 0 and 1, nothing else.

CbULY

Returns the vertical offset of the code-block partition. Allowable values are 0 and 1, nothing else.

ParameterInfo

Returns the parameters that are used in this class and implementing classes. It returns a 2D String array. Each of the 1D arrays is for a different option, and they have 3 elements. The first element is the option name, the second one is the synopsis and the third one is a long description of what the parameter is. The synopsis or description may be 'null', in which case it is assumed that there is no synopsis or description of the option, respectively. Null may be returned if no options are supported.

Methods

Name Description
createInstance(BlkImgDataSrc, ParameterList, EncoderSpecs)

Creates a ForwardWT object with the specified filters, and with other options specified in the parameter list 'pl'.

getAnSubbandTree(int, int)

Returns a reference to the root of subband tree structure representing the subband decomposition for the specified tile-component.

getDataType(int, int)

Return the data type of this CBlkWTDataSrc for the given component in the current tile. Its value should be either DataBlk.TYPE_INT or DataBlk.TYPE_FLOAT but can change according to the current tile-component.

getDecomp(int, int)

Returns the wavelet tree decomposition. Only WT_DECOMP_DYADIC is supported by JPEG 2000 part I.

getDecompLevels(int, int)

Returns the number of decomposition levels that are applied to obtain the LL band, in the specified tile-component. A value of 0 means that no wavelet transform is applied.

getFixedPoint(int)

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.

getHorAnWaveletFilters(int, int)

Returns the horizontal analysis wavelet filters used in each level, for the specified tile-component. The first element in the array is the filter used to obtain the lowest resolution (resolution level 0) subbands (i.e. lowest frequency LL subband), the second element is the one used to generate the resolution level 1 subbands, and so on. If there are less elements in the array than the number of resolution levels, then the last one is assumed to repeat itself.

       <p>The returned filters are applicable only to the specified component
       and in the current tile.</p><p>The resolution level of a subband is the resolution level to which a
       subband contributes, which is different from its decomposition
       level.</p>
getImplementationType(int)

Returns the implementation type of this wavelet transform (WT_IMPL_LINE or WT_IMPL_FRAME) for the specified component, in the current tile.

getNextCodeBlock(int, CBlkWTData)

Returns the next code-block in the current tile for the specified component, as a copy (see below). The order in which code-blocks are returned is not specified. However each code-block is returned only once and all code-blocks will be returned if the method is called 'N' times, where 'N' is the number of code-blocks in the tile. After all the code-blocks have been returned for the current tile calls to this method will return 'null'.

       <p>When changing the current tile (through 'setTile()' or 'nextTile()')
       this method will always return the first code-block, as if this method
       was never called before for the new current tile.</p><p>The data returned by this method is always a copy of the internal
       data of this object, if any, and it can be modified "in place" without
       any problems after being returned. The 'offset' of the returned data is
       0, and the 'scanw' is the same as the code-block width.  The 'magbits'
       of the returned data is not set by this method and should be
       ignored. See the 'CBlkWTData' class.</p><p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
       contain the coordinates of the top-left corner of the block, with
       respect to the tile, not the subband.</p>
getNextInternCodeBlock(int, CBlkWTData)

Returns the next code-block in the current tile for the specified component. The order in which code-blocks are returned is not specified. However each code-block is returned only once and all code-blocks will be returned if the method is called 'N' times, where 'N' is the number of code-blocks in the tile. After all the code-blocks have been returned for the current tile calls to this method will return 'null'.

       <p>When changing the current tile (through 'setTile()' or 'nextTile()')
       this method will always return the first code-block, as if this method
       was never called before for the new current tile.</p><p>The data returned by this method can be the data in the internal
       buffer of this object, if any, and thus can not be modified by the
       caller. The 'offset' and 'scanw' of the returned data can be
       arbitrary. The 'magbits' of the returned data is not set by this method
       and should be ignored. See the 'CBlkWTData' class.</p><p>The 'ulx' and 'uly' members of the returned 'CBlkWTData' object
       contain the coordinates of the top-left corner of the block, with
       respect to the tile, not the subband.</p>
getVertAnWaveletFilters(int, int)

Returns the vertical analysis wavelet filters used in each level, for the specified tile-component. The first element in the array is the filter used to obtain the lowest resolution (resolution level 0) subbands (i.e. lowest frequency LL subband), the second element is the one used to generate the resolution level 1 subbands, and so on. If there are less elements in the array than the number of resolution levels, then the last one is assumed to repeat itself.

       <p>The returned filters are applicable only to the specified component
       and in the current tile.</p><p>The resolution level of a subband is the resolution level to which a
       subband contributes, which is different from its decomposition
       level.</p>
isReversible(int, int)

Returns the reversibility of the wavelet transform for the specified component and tile. A wavelet transform is reversible when it is suitable for lossless and lossy-to-lossless compression.