Returns, in the blk argument, the 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.
After being read the coefficients are level shifted by subtracting 2^(nominal bit range - 1)
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.
If the data array in blk is null, 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 blk 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 blk after the method has returned.
The returned data always has its 'progressive' attribute unset (i.e. false).
When an I/O exception is encountered the JJ2KExceptionHandler is used. The exception is passed to its handleException method. The action that is taken depends on the action that has been registered in JJ2KExceptionHandler. See JJ2KExceptionHandler for details.
This method implements buffering for the 3 components: When the first one is asked, all the 3 components are read and stored until they are needed.