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 approximately 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(3TIFF) routine. All
warning messages are directed to the
TIFFWarning(3TIFF) routine.
Seek error accessing TIFF directory. An error occurred while positioning
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.
BitsPerSample. 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 encountered
in the directory; the library ignores all such tags.
TIFF directory is missing required "ImageLength" field. The
image violates the specification by not having a necessary field. There is no
way for the library to recover from this error.
TIFF directory is missing required "PlanarConfig" field. The
image violates the specification by not having a necessary field. There is no
way for the library to recover from this error.
TIFF directory is missing required "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 required "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
imagelength. 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¶
TIFFOpen(3TIFF),
TIFFWriteDirectory(3TIFF),
TIFFSetDirectory(3TIFF),
TIFFSetSubDirectory(3TIFF),
libtiff(3TIFF)
Libtiff library home page:
http://www.remotesensing.org/libtiff/