TIFFWRITEDIRECTORY(3tiff) LibTIFF TIFFWRITEDIRECTORY(3tiff)
NAME
TIFFWriteDirectory - write the current directory in an open TIFF file
SYNOPSIS
#include <tiffio.h>
TIFFWriteDirectory(3) *tif)
int TIFFRewriteDirectory(TIFF *tif)
int TIFFCheckpointDirectory(TIFF *tif)
void TIFFSetWriteOffset(TIFF *tif, toff_t off)
int TIFFWriteCheck(TIFF *tif, int tiles, const char *module)
DESCRIPTION
TIFFWriteDirectory() will write the contents of the current directory
(IFD) to the file and setup to create a new directory (IFD) using
TIFFCreateDirectory(). Applications only need to call
TIFFWriteDirectory() when writing multiple subfiles (images) to a
single TIFF file. This is called "multi-page TIFF" or "multi-image
TIFF" (see Multi Page / Multi Image TIFF). TIFFWriteDirectory() is
automatically called by TIFFClose() and TIFFFlush() to write a modified
directory if the file is open for writing.
The TIFFRewriteDirectory() function operates similarly to
TIFFWriteDirectory(), but can be called with directories previously
read or written that already have an established location in the file.
It will rewrite the directory, but instead of placing it at its old
location (as TIFFWriteDirectory() would, if the size of the directory
has not grown) it will place them at the end of the file, correcting
the pointer from the preceding directory or file header to point to
it's new location. This is particularly important in cases where the
size of the directory and pointed to data has grown, so it won't fit in
the space available at the old location.
The TIFFCheckpointDirectory() writes the current state of the tiff
directory into the file to make what is currently in the file readable.
Unlike TIFFWriteDirectory(), TIFFCheckpointDirectory() does not free up
the directory data structures in memory, so they can be updated (as
strips/tiles are written) and written again. Reading such a partial
file you will at worst get a tiff read error for the first strip/tile
encountered that is incomplete, but you will at least get all the valid
data in the file before that. When the file is complete, just use
TIFFWriteDirectory() as usual to finish it off cleanly.
The TIFFSetWriteOffset() sets the current write offset. This should
only be used to set the offset to a known previous location (very
carefully), or to 0 so that the next write gets appended to the end of
the file.
The TIFFWriteCheck() verify file is writable and that the directory
information is setup properly. In doing the latter we also "freeze"
the state of the directory so that important information is not
changed.
RETURN VALUES
1 is returned when the contents are successfully written to the file.
Otherwise, 0 is returned if an error was encountered when writing the
directory contents.
DIAGNOSTICS
All error messages are directed to the TIFFErrorExtR() routine.
"Error post-encoding before directory write":
Before writing the contents of the current directory, any pending
data are flushed. This message indicates that an error occurred
while doing this.
"Error flushing data before directory write":
Before writing the contents of the current directory, any pending
data are flushed. This message indicates that an error occurred
while doing this.
"Cannot write directory, out of space":
There was not enough space to allocate a temporary area for the
directory that was to be written.
"Error writing directory count":
A write error occurred when writing the count of fields in the
directory.
"Error writing directory contents":
A write error occurred when writing the directory fields.
"Error writing directory link":
A write error occurred when writing the link to the next directory.
Error writing data for field "%s":
A write error occurred when writing indirect data for the specified
field.
"Error writing TIFF header":
A write error occurred when re-writing header at the front of the
file.
"Error fetching directory count":
A read error occurred when fetching the directory count field for a
previous directory. This can occur when setting up a link to the
directory that is being written.
"Error fetching directory link":
A read error occurred when fetching the directory link field for a
previous directory. This can occur when setting up a link to the
directory that is being written.
SEE ALSO
TIFFquery(3), TIFFOpen(3), TIFFCreateDirectory(3),
TIFFCustomDirectory(3), TIFFSetDirectory(3),
TIFFReadDirectory(3), TIFFError(3), Multi Page / Multi Image
TIFF, libtiff(3)
AUTHOR
LibTIFF contributors
COPYRIGHT
1988-2022, LibTIFF contributors
4.7 September 11, 2024 TIFFWRITEDIRECTORY(3tiff)
tiff 4.7.0 - Generated Thu Oct 3 14:36:08 CDT 2024