TIFFQUERY(3tiff) LibTIFF TIFFQUERY(3tiff)
NAME
TIFFquery - query routines
SYNOPSIS
#include <tiffio.h>
tdir_t TIFFCurrentDirectory(TIFF *tif)
uint64_t TIFFCurrentDirOffset(TIFF *tif)
int TIFFLastDirectory(TIFF *tif)
tdir_t TIFFNumberOfDirectories(TIFF *tif)
uint32_t TIFFCurrentRow(TIFF *tif)
tstrip_t TIFFCurrentStrip(TIFF *tif)
ttile_t TIFFCurrentTile(TIFF *tif)
int TIFFFileno(TIFF *tif)
char *TIFFFileName(TIFF *tif)
int TIFFGetMode(TIFF *tif)
int TIFFIsTiled(TIFF *tif)
int TIFFIsBigEndian(TIFF *tif)
int TIFFIsBigTIFF(TIFF *tif)
int TIFFIsByteSwapped(TIFF *tif)
int TIFFIsMSB2LSB(TIFF *tif)
int TIFFIsUpSampled(TIFF *tif)
const char *TIFFGetVersion(void)
DESCRIPTION
The following query routines return status information about the direc-
tory structure of an open TIFF file.
TIFFCurrentDirectory() returns the index of the current directory (di-
rectories are numbered starting at 0). This number is suitable for use
with the TIFFSetDirectory() routine. A value of 65535 (non-existing
directory) is returned if the directory has not yet been written to the
file after opening it.
TIFFCurrentDirOffset() returns the file offset of the current directory
(instead of an index). The file offset is suitable for use with the
TIFFSetSubDirectory() routine. This is required for accessing subdirec-
tories linked through a SubIFD tag.
TIFFLastDirectory() returns a non-zero value if the current directory
is the last directory in the file; otherwise zero is returned.
TIFFNumberOfDirectories() returns the number of directories in a file.
Be aware that just created directories, which are not "written" to file
do not count.
NOTE:
Be aware that the return value of the above directory query func-
tions is not valid until the directory is "written" to file AND read
back e.g. TIFFSetDirectory() or TIFFReadDirectory().
The following query routines return information about an open TIFF file
and its image data.
TIFFCurrentRow(), TIFFCurrentStrip(), and TIFFCurrentTile() return the
current row, strip, and tile, respectively, that is being read or writ-
ten. These values are updated each time a read or write is done.
TIFFFileno() returns the underlying file descriptor used to access the
TIFF image in the filesystem.
TIFFFileName() returns the pathname argument passed to TIFFOpen() or
TIFFFdOpen().
TIFFGetMode() returns the mode with which the underlying file was
opened. On UNIX systems, this is the value passed to the open() (2)
system call.
TIFFIsTiled() returns a non-zero value if the image data has a tiled
organization. Zero is returned if the image data is organized in
strips.
TIFFIsBigEndian() returns a non-zero value if the file is BigEndian and
zero if the file is LittleEndian.
TIFFIsBigTIFF() returns a non-zero value if the file is in BigTIFF
style.
TIFFIsByteSwapped() returns a non-zero value if the image data was in a
different byte-order than the host machine. Zero is returned if the
TIFF file and local host byte-orders are the same. Note that
TIFFReadTile(), TIFFReadEncodedStrip() and TIFFReadScanline() functions
already normally perform byte swapping to local host order if needed.
TIFFIsMSB2LSB() returns a non-zero value if the image data is being re-
turned with bit 0 as the most significant bit.
TIFFIsUpSampled() returns a non-zero value if image data returned
through the read interface routines is being up-sampled. This can be
useful to applications that want to calculate I/O buffer sizes to re-
flect this usage (though the usual strip and tile size routines already
do this).
TIFFGetVersion() returns an ASCII string that has a version stamp for
the TIFF library software.
DIAGNOSTICS
None.
SEE ALSO
libtiff (3tiff), TIFFOpen (3tiff)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2023, LibTIFF contributors
4.5 Nov 23, 2023 TIFFQUERY(3tiff)
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