| java.lang.Object
 jj2000.j2k.image.input.ImgReader
jj2000.j2k.image.input.ImgReaderPGM
| ImgReaderPGM | | public class ImgReaderPGM extends ImgReader (Code) | | This class implements the ImgData interface for reading 8 bit unsigned data
from a binary PGM file.
After being read the coefficients are level shifted by subtracting
2^(nominal bit range-1)
The TransferType (see ImgData) of this class is TYPE_INT.
NOTE: This class is not thread safe, for reasons of internal buffering.
See Also: jj2000.j2k.image.ImgData |
| Constructor Summary | |
| public | ImgReaderPGM(File file)
Creates a new PGM file reader from the specified file. | | public | ImgReaderPGM(String fname)
Creates a new PGM file reader from the specified file name. | | public | ImgReaderPGM(RandomAccessFile in)
Creates a new PGM file reader from the specified RandomAccessFile
object. |
| Method Summary | |
| public void | close()
Closes the underlying RandomAccessFile from where the image data is
being read. | | public DataBlk | getCompData(DataBlk blk, int c)
Returns, in the blk argument, a block of image data containing the
specifed rectangular area, in the specified component. | | public int | getFixedPoint(int c)
Returns the position of the fixed point in the specified component
(i.e. | | final public DataBlk | getInternCompData(DataBlk blk, int c)
Returns, in the blk argument, the block of image data containing the
specifed rectangular area, in the specified component. | | public int | getNomRangeBits(int c)
Returns the number of bits corresponding to the nominal range of the
data in the specified component. | | public boolean | isOrigSigned(int c)
Returns true if the data read was originally signed in the specified
component, false if not. | | public String | toString()
Returns a string of information about the object, more than 1 line
long. |
| DC_OFFSET | | public static int DC_OFFSET(Code) | | DC offset value used when reading image
|
| ImgReaderPGM | | public ImgReaderPGM(File file) throws IOException(Code) | | Creates a new PGM file reader from the specified file.
Parameters:
file - The input file.
exception:
IOException - If an error occurs while opening the file. |
| ImgReaderPGM | | public ImgReaderPGM(String fname) throws IOException(Code) | | Creates a new PGM file reader from the specified file name.
Parameters:
fname - The input file name.
exception:
IOException - If an error occurs while opening the file. |
| ImgReaderPGM | | public ImgReaderPGM(RandomAccessFile in) throws EOFException, IOException(Code) | | Creates a new PGM file reader from the specified RandomAccessFile
object. The file header is read to acquire the image size.
Parameters:
in - From where to read the data
exception:
EOFException - if an EOF is read
exception:
IOException - if an error occurs when opening the file |
| close | | public void close() throws IOException(Code) | | Closes the underlying RandomAccessFile from where the image data is
being read. No operations are possible after a call to this method.
exception:
IOException - If an I/O error occurs. |
| getCompData | | public DataBlk getCompData(DataBlk blk, int c)(Code) | | 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".
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' of
the returned data is 0, and the 'scanw' is the same as the block's
width. See the 'DataBlk' class.
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.
The returned data has its 'progressive' attribute unset
(i.e. false).
This method just calls 'getInternCompData(blk, n)'.
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.
Parameters:
blk - Its coordinates and dimensions specify the area toreturn. If it contains a non-null data array, then it must have thecorrect dimensions. If it contains a null data array a new one iscreated. The fields in this object are modified to return the data.
Parameters:
c - The index of the component from which to get the data. Only 0is valid. The requested DataBlk
See Also: ImgReaderPGM.getInternCompData
See Also: JJ2KExceptionHandler |
| getFixedPoint | | public int getFixedPoint(int c)(Code) | | Returns the position of the fixed point in the specified component
(i.e. the number of fractional bits), which is always 0 for this
ImgReader.
Parameters:
c - The index of the component. The position of the fixed-point (i.e. the number of fractionalbits). Always 0 for this ImgReader. |
| getInternCompData | | final public DataBlk getInternCompData(DataBlk blk, int c)(Code) | | 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.
Parameters:
blk - Its coordinates and dimensions specify the area toreturn. Some fields in this object are modified to return the data.
Parameters:
c - The index of the component from which to get the data. Only 0is valid. The requested DataBlk
See Also: ImgReaderPGM.getCompData
See Also: JJ2KExceptionHandler |
| getNomRangeBits | | public int getNomRangeBits(int c)(Code) | | Returns the number of bits corresponding to the nominal range of the
data in the specified component. This is the value rb (range bits) that
was specified in the constructor, which normally is 8 for non bilevel
data, and 1 for bilevel data.
If this number is b then the nominal range is between
-2^(b-1) and 2^(b-1)-1, since unsigned data is level shifted to have a
nominal average of 0.
Parameters:
c - The index of the component. The number of bits corresponding to the nominal range of thedata. Fro floating-point data this value is not applicable and thereturn value is undefined. |
| isOrigSigned | | public boolean isOrigSigned(int c)(Code) | | Returns true if the data read was originally signed in the specified
component, false if not. This method returns always false since PGM
data is always unsigned.
Parameters:
c - The index of the component, from 0 to N-1. always false, since PGM data is always unsigned. |
| toString | | public String toString()(Code) | | Returns a string of information about the object, more than 1 line
long. The information string includes information from the underlying
RandomAccessIO (its toString() method is called in turn).
A string of information about the object. |
|
|