TIFFReadDirectory
TIFFReadDirectory(3T) TIFFReadDirectory(3T)
NAME
TIFFReadDirectory - get the contents of the next directory in an open
TIFF file
SYNOPSIS
#include <tiffio.h>
int TIFFReadDirectory(TIFF* tif)
DESCRIPTION
Read the next directory in the specified file and make it the current
directory. Applications only need to call TIFFReadDirectory to read
multiple subfiles in a single TIFF file¿ the first directory in a file
is automatically read when TIFFOpen is called.
NOTES
If the library is compiled with STRIPCHOP_SUPPORT enabled, then images
that have a single uncompressed strip or tile of data are automatically
treated as if they were made up of multiple strips or tiles of approxi-
mately 8 kilobytes each. This operation is done only in-memory; it
does not alter the contents of the file. However, the construction of
the ``chopped strips'' is visible to the application through the number
of strips [tiles] returned by TIFFNumberOfStrips [TIFFNumberOfTiles].
RETURN VALUES
If the next directory was successfully read, 1 is returned. Otherwise,
0 is returned if an error was encountered, or if there are no more
directories to be read.
DIAGNOSTICS
All error messages are directed to the TIFFError(3T) routine. All
warning messages are directed to the TIFFWarning(3T) routine.
Seek error accessing TIFF directory. An error occurred while position-
ing to the location of the directory.
Wrong data type %d for field "%s". The tag entry in the directory had
an incorrect data type. For example, an ImageDescription tag with a
SHORT data type.
TIFF directory is missing required "%s" field. The specified tag is
required to be present by the TIFF 5.0 specification, but is missing.
The directory is (usually) unusable.
%s: Rational with zero denominator. A directory tag has a RATIONAL
value whose denominator is zero.
Incorrect count %d for field "%s" (%lu, expecting %lu); tag ignored.
The specified tag's count field is bad. For example, a count other
than 1 for a SubFileType tag.
Cannot handle different per-sample values for field "%s". The tag has
SamplesPerPixel values and they are not all the same; e.g. BitsPerSam-
ple. The library is unable to handle images of this sort.
Count mismatch for field "%s"; expecting %d, got %d. The count field
in a tag does not agree with the number expected by the library. This
should never happen, so if it does, the library refuses to read the
directory.
Invalid TIFF directory; tags are not sorted in ascending order. The
directory tags are not properly sorted as specified in the TIFF 5.0
specification. This error is not fatal.
Ignoring unknown field with tag %d (0x%x). An unknown tag was encoun-
tered in the directory; the library ignores all such tags.
TIFF directory is missing requred "ImageLength" field. The image vio-
lates the specification by not having a necessary field. There is no
way for the library to recover from this error.
TIFF directory is missing requred "PlanarConfig" field. The image vio-
lates the specification by not having a necessary field. There is no
way for the library to recover from this error.
TIFF directory is missing requred "StripOffsets" field. The image has
multiple strips, but is missing the tag that specifies the file offset
to each strip of data. There is no way for the library to recover from
this error.
TIFF directory is missing requred "TileOffsets" field. The image has
multiple tiles, but is missing the tag that specifies the file offset
to each tile of data. There is no way for the library to recover from
this error.
TIFF directory is missing required "StripByteCounts" field. The image
has multiple strips, but is missing the tag that specifies the size of
each strip of data. There is no way for the library to recover from
this error.
TIFF directory is missing required "StripByteCounts" field, calculating
from imagelength. The image violates the specification by not having a
necessary field. However, when the image is comprised of only one
strip or tile, the library will estimate the missing value based on the
file size.
Bogus "StripByteCounts" field, ignoring and calculating from image-
length. Certain vendors violate the specification by writing zero for
the StripByteCounts tag when they want to leave the value unspecified.
If the image has a single strip, the library will estimate the missing
value based on the file size.
SEE ALSO
libtiff(3T), TIFFOpen(3T), TIFFWriteDirectory(3T), TIFFSetDirec-
tory(3T), TIFFSetSubDirectory(3T)
October 15, 1995 TIFFReadDirectory(3T)
