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TIFFReadEncodedTile - read and decode a tile
of data from an open TIFF
file
#include <tiffio.h>
int TIFFReadEncodedTile(TIFF
*tif, u_long tile, u_char *buf, u_long size)
Read the specified
tile of data and place up to size bytes of decompressed information in
the (user supplied) data buffer.
The value of tile is a ‘‘raw tile number.’’
That is, the caller must take into account whether or not the data are
organized in separate planes (PlanarConfiguration=2). TIFFComputeTile automatically
does this when converting an (x,y,z,sample) coordinate quadruple to a tile
number. To read a full tile of data the data buffer should be at least as
large as the value returned by TIFFTileSize.
The library attempts to hide
bit- and byte-ordering differences between the image and the native machine
by converting data to the native machine order. Bit reversal is done if
the FillOrder tag is opposite to the native machine bit order. 16- and 32-bit
samples are automatically byte-swapped if the file was written with a byte
order opposite to the native machine byte order,
The actual
number of bytes of data that were placed in buf is returned; TIFFReadEncodedTile
returns -1 if an error was encountered.
All error messages are
directed to the TIFFError(3TIFF)
routine.
TIFFOpen(3TIFF)
, TIFFReadRawTile(3TIFF)
,
TIFFReadTile(3TIFF)
, libtiff(3TIFF)
Libtiff library home page: http://www.remotesensing.org/libtiff/
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