TIFFOpen(3T) MISC. REFERENCE MANUAL PAGES TIFFOpen(3T)
NAME
TIFFOpen, TIFFFdOpen, TIFFClientOpen - open a TIFF file for
reading or writing
SYNOPSIS
#include <tiffio.h>
TIFF* TIFFOpen(const char* filename, const char* mode)
TIFF* TIFFFdOpen(const int fd, const char* filename, const char* mode)
typedef tsize_t (*TIFFReadWriteProc)(thandle_t, tdata_t, tsize_t);
typedef toff_t (*TIFFSeekProc)(thandle_t, toff_t, int);
typedef int (*TIFFCloseProc)(thandle_t);
typedef toff_t (*TIFFSizeProc)(thandle_t);
typedef int (*TIFFMapFileProc)(thandle_t, tdata_t*, toff_t*);
typedef void (*TIFFUnmapFileProc)(thandle_t, tdata_t, toff_t);
TIFF* TIFFClientOpen(const char* filename, const char* mode, thandle_t clientdata,
TIFFReadWriteProc readproc, TIFFReadWriteProc writeproc, TIFFSeekProc seekproc,
TIFFCloseProc closeproc, TIFFSizeProc sizeproc, TIFFMapFileProc mapproc,
TIFFUnmapFileProc unmapproc)
DESCRIPTION
TIFFOpen opens a TIFF file whose name is filename and
returns a handle to be used in subsequent calls to routines
in libtiff. If the open operation fails, then zero is
returned. The mode parameter specifies if the file is to be
opened for reading (``r''), writing (``w''), or appending
(``a''). When a file is opened for appending, existing data
will not be touched; instead new data will be written as
additional subfiles. If an existing file is opened for
writing, all previous data is overwritten.
If a file is opened for reading, the first TIFF directory in
the file is automatically read (also see
TIFFSetDirectory(3T) for reading directories other than the
first). If a file is opened for writing or appending, a
default directory is automatically created for writing sub-
sequent data. This directory has all the default values
specified in TIFF Revision 6.0: BitsPerSample=1,
ThreshHolding=bilevel art scan, FillOrder=1 (most signifi-
cant bit of each data byte is filled first), Orientation=1
(the 0th row represents the visual top of the image, and the
0th column represents the visual left hand side), Sam-
plesPerPixel=1, RowsPerStrip=infinity, ResolutionUnit=2
(inches), and Compression=1 (no compression). To alter
these values, or to define values for additional fields,
TIFFSetField(3T) must be used.
It is not possible to append data to a file that has a byte
ordering opposite to the native byte ordering of a machine.
That is, for example, the library will not allow a file with
little-endian byte ordering to be appended to on a machine
that has a native big-endian byte ordering.
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TIFFOpen(3T) MISC. REFERENCE MANUAL PAGES TIFFOpen(3T)
TIFFFdOpen is like TIFFOpen except that it opens a TIFF file
given an open file descriptor fd. The file's name and mode
must reflect that of the open descriptor. The object asso-
ciated with the file descriptor must support random access.
TIFFClientOpen is like TIFFOpen except that the caller sup-
plies a collection of functions that the library will use to
do UNIX-like I/O operations. The readproc and writeproc are
called to read and write data at the current file position.
seekproc is called to change the current file position a la
lseek(2). closeproc is invoked to release any resources
associated with an open file. sizeproc is invoked to obtain
the size in bytes of a file. mapproc and unmapproc are
called to map and unmap a file's contents in memory; c.f.
mmap(2) and munmap(2). The clientdata parameter is an
opaque ``handle'' passed to the client-specified routines
passed as parameters to TIFFClientOpen.
RETURN VALUES
Upon successful completion TIFFOpen, TIFFFdOpen, and
TIFFClientOpen return a TIFF pointer. Otherwise, NULL is
returned.
DIAGNOSTICS
All error messages are directed to the TIFFError(3T) rou-
tine. Likewise, warning messages are directed to the
TIFFWarning(3T) routine.
"%s": Bad mode. The specified mode parameter was not one of
``r'' (read), ``w'' (write), or ``a'' (append).
%s: Cannot open. TIFFOpen() was unable to open the speci-
fied filename for read/writing.
Cannot read TIFF header. An error occurred while attempting
to read the header information.
Error writing TIFF header. An error occurred while writing
the default header information for a new file.
Not a TIFF file, bad magic number %d (0x%x). The magic
number in the header was not (hex) 0x4d4d or (hex) 0x4949.
Not a TIFF file, bad version number %d (0x%x). The version
field in the header was not 42 (decimal).
Cannot append to file that has opposite byte ordering. A
file with a byte ordering opposite to the native byte order-
ing of the current machine was opened for appending (``a'').
This is a limitation of the library.
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TIFFOpen(3T) MISC. REFERENCE MANUAL PAGES TIFFOpen(3T)
SEE ALSO
intro(3T), TIFFClose(3T)
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