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<!-- Creator : groff version 1.19.2 -->
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<title>TIFFOpen</title>
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<body>
<h1 align=center>TIFFOpen</h1>
<a href="#NAME">NAME</a><br>
<a href="#SYNOPSIS">SYNOPSIS</a><br>
<a href="#DESCRIPTION">DESCRIPTION</a><br>
<a href="#OPTIONS">OPTIONS</a><br>
<a href="#BYTE ORDER">BYTE ORDER</a><br>
<a href="#RETURN VALUES">RETURN VALUES</a><br>
<a href="#DIAGNOSTICS">DIAGNOSTICS</a><br>
<a href="#SEE ALSO">SEE ALSO</a><br>
<hr>
<a name="NAME"></a>
<h2>NAME</h2>
<p style="margin-left:11%; margin-top: 1em">TIFFOpen,
TIFFFdOpen, TIFFClientOpen − open a
<small>TIFF</small> file for reading or writing</p>
<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>
<p style="margin-left:11%; margin-top: 1em"><b>#include
<tiffio.h></b></p>
<p style="margin-left:11%; margin-top: 1em"><b>TIFF*
TIFFOpen(const char *</b><i>filename</i><b>, const char
*</b><i>mode</i><b>) <br>
TIFF* TIFFFdOpen(const int</b> <i>fd</i><b>, const char
*</b><i>filename</i><b>, const char
*</b><i>mode</i><b>)</b></p>
<p style="margin-left:11%; margin-top: 1em"><b>typedef
tsize_t (*TIFFReadWriteProc)(thandle_t, tdata_t, tsize_t);
<br>
typedef toff_t (*TIFFSeekProc)(thandle_t, toff_t, int); <br>
typedef int (*TIFFCloseProc)(thandle_t); <br>
typedef toff_t (*TIFFSizeProc)(thandle_t); <br>
typedef int (*TIFFMapFileProc)(thandle_t, tdata_t*,
toff_t*); <br>
typedef void (*TIFFUnmapFileProc)(thandle_t, tdata_t,
toff_t);</b></p>
<p style="margin-left:11%; margin-top: 1em"><b>TIFF*
TIFFClientOpen(const char *</b><i>filename</i><b>, const
char *</b><i>mode</i><b>, thandle_t</b>
<i>clientdata</i><b>, TIFFReadWriteProc</b>
<i>readproc</i><b>, TIFFReadWriteProc</b>
<i>writeproc</i><b>, TIFFSeekProc</b> <i>seekproc</i><b>,
TIFFCloseProc</b> <i>closeproc</i><b>, TIFFSizeProc</b>
<i>sizeproc</i><b>, TIFFMapFileProc</b> <i>mapproc</i><b>,
TIFFUnmapFileProc</b> <i>unmapproc</i><b>)</b></p>
<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>
<p style="margin-left:11%; margin-top: 1em"><i>TIFFOpen</i>
opens a <small>TIFF</small> file whose name is
<i>filename</i> and returns a handle to be used in
subsequent calls to routines in <i>libtiff</i>. If the open
operation fails, then zero is returned. The <i>mode</i>
parameter specifies if the file is to be opened for reading
(‘‘r’’), writing
(‘‘w’’), or appending
(‘‘a’’) and, optionally, whether to
override certain default aspects of library operation (see
below). 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.</p>
<p style="margin-left:11%; margin-top: 1em">If a file is
opened for reading, the first <small>TIFF</small> directory
in the file is automatically read (also see
<i>TIFFSetDirectory</i>(3TIFF) for reading directories other
than the first). If a file is opened for writing or
appending, a default directory is automatically created for
writing subsequent data. This directory has all the default
values specified in <small>TIFF</small> Revision 6.0:
<i>BitsPerSample</i>=1, <i>ThreshHolding</i>=bilevel art
scan, <i>FillOrder</i>=1 (most significant bit of each data
byte is filled first), <i>Orientation</i>=1 (the 0th row
represents the visual top of the image, and the 0th column
represents the visual left hand side),
<i>SamplesPerPixel</i>=1, <i>RowsPerStrip</i>=infinity,
<i>ResolutionUnit</i>=2 (inches), and <i>Compression</i>=1
(no compression). To alter these values, or to define values
for additional fields, <i>TIFFSetField</i>(3TIFF) must be
used.</p>
<p style="margin-left:11%; margin-top: 1em"><i>TIFFFdOpen</i>
is like <i>TIFFOpen</i> except that it opens a
<small>TIFF</small> file given an open file descriptor
<i>fd</i>. The file’s name and mode must reflect that
of the open descriptor. The object associated with the file
descriptor <b>must support random access</b>.</p>
<p style="margin-left:11%; margin-top: 1em"><i>TIFFClientOpen</i>
is like <i>TIFFOpen</i> except that the caller supplies a
collection of functions that the library will use to do
<small>UNIX</small> -like I/O operations. The
<i>readproc</i> and <i>writeproc</i> are called to read and
write data at the current file position. <i>seekproc</i> is
called to change the current file position a la
<i>lseek</i>(2). <i>closeproc</i> is invoked to release any
resources associated with an open file. <i>sizeproc</i> is
invoked to obtain the size in bytes of a file.
<i>mapproc</i> and <i>unmapproc</i> are called to map and
unmap a file’s contents in memory; c.f. <i>mmap</i>(2)
and <i>munmap</i>(2). The <i>clientdata</i> parameter is an
opaque ‘‘handle’’ passed to the
client-specified routines passed as parameters to
<i>TIFFClientOpen</i>.</p>
<a name="OPTIONS"></a>
<h2>OPTIONS</h2>
<p style="margin-left:11%; margin-top: 1em">The open mode
parameter can include the following flags in addition to the
‘‘r’’,
‘‘w’’, and
‘‘a’’ flags. Note however that
option flags must follow the read-write-append
specification.</p>
<table width="100%" border=0 rules="none" frame="void"
cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>l</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">When creating a new
file force information be written with Little-Endian byte
order (but see below). By default the library will create
new files using the native <small>CPU</small> byte
order.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>b</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">When creating a new
file force information be written with Big-Endian byte order
(but see below). By default the library will create new
files using the native <small>CPU</small> byte order.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>L</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Force image data
that is read or written to be treated with bits filled from
Least Significant Bit ( <small>LSB</small> ) to Most
Significant Bit ( <small>MSB</small> ). Note that this is
the opposite to the way the library has worked from its
inception.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>B</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Force image data
that is read or written to be treated with bits filled from
Most Significant Bit ( <small>MSB</small> ) to Least
Significant Bit ( <small>LSB</small> ); this is the
default.</p> </td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>H</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Force image data
that is read or written to be treated with bits filled in
the same order as the native <small>CPU.</small></p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>M</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Enable the use of
memory-mapped files for images opened read-only. If the
underlying system does not support memory-mapped files or if
the specific image being opened cannot be memory-mapped then
the library will fallback to using the normal system
interface for reading information. By default the library
will attempt to use memory-mapped files.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>m</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Disable the use of
memory-mapped files.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>C</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Enable the use of
‘‘strip chopping’’ when reading
images that are comprised of a single strip or tile of
uncompressed data. Strip chopping is a mechanism by which
the library will automatically convert the single-strip
image to multiple strips, each of which has about 8
Kilobytes of data. This facility can be useful in reducing
the amount of memory used to read an image because the
library normally reads each strip in its entirety. Strip
chopping does however alter the apparent contents of the
image because when an image is divided into multiple strips
it looks as though the underlying file contains multiple
separate strips. Finally, note that default handling of
strip chopping is a compile-time configuration parameter.
The default behaviour, for backwards compatibility, is to
enable strip chopping.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>c</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Disable the use of
strip chopping when reading images.</p></td>
<tr valign="top" align="left">
<td width="11%"></td>
<td width="1%">
<p style="margin-top: 1em" valign="top"><b>h</b></p></td>
<td width="10%"></td>
<td width="78%">
<p style="margin-top: 1em" valign="top">Read TIFF header
only, do not load the first image directory. That could be
useful in case of the broken first directory. We can open
the file and proceed to the other directories.</p></td>
</table>
<a name="BYTE ORDER"></a>
<h2>BYTE ORDER</h2>
<p style="margin-left:11%; margin-top: 1em">The
<small>TIFF</small> specification (<b>all versions</b>)
states that compliant readers <i>must be capable of reading
images written in either byte order</i>. Nonetheless some
software that claims to support the reading of
<small>TIFF</small> images is incapable of reading images in
anything but the native <small>CPU</small> byte order on
which the software was written. (Especially notorious are
applications written to run on Intel-based machines.) By
default the library will create new files with the native
byte-order of the <small>CPU</small> on which the
application is run. This ensures optimal performance and is
portable to any application that conforms to the TIFF
specification. To force the library to use a specific
byte-order when creating a new file the
‘‘b’’ and
‘‘l’’ option flags may be included
in the call to open a file; for example,
‘‘wb’’ or
‘‘wl’’.</p>
<a name="RETURN VALUES"></a>
<h2>RETURN VALUES</h2>
<p style="margin-left:11%; margin-top: 1em">Upon successful
completion <i>TIFFOpen</i>, <i>TIFFFdOpen</i>, and
<i>TIFFClientOpen</i> return a <small>TIFF</small> pointer.
Otherwise, NULL is returned.</p>
<a name="DIAGNOSTICS"></a>
<h2>DIAGNOSTICS</h2>
<p style="margin-left:11%; margin-top: 1em">All error
messages are directed to the <i>TIFFError</i>(3TIFF)
routine. Likewise, warning messages are directed to the
<i>TIFFWarning</i>(3TIFF) routine.</p>
<p style="margin-left:11%; margin-top: 1em"><b>"%s":
Bad mode</b>. The specified <i>mode</i> parameter was not
one of ‘‘r’’ (read),
‘‘w’’ (write), or
‘‘a’’ (append).</p>
<p style="margin-left:11%; margin-top: 1em"><b>%s: Cannot
open</b>. <i>TIFFOpen</i>() was unable to open the specified
filename for read/writing.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Cannot read
TIFF header</b>. An error occurred while attempting to read
the header information.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Error
writing TIFF header</b>. An error occurred while writing the
default header information for a new file.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Not a TIFF
file, bad magic number %d (0x%x)</b>. The magic number in
the header was not (hex) 0x4d4d or (hex) 0x4949.</p>
<p style="margin-left:11%; margin-top: 1em"><b>Not a TIFF
file, bad version number %d (0x%x)</b>. The version field in
the header was not 42 (decimal).</p>
<p style="margin-left:11%; margin-top: 1em"><b>Cannot
append to file that has opposite byte ordering</b>. A file
with a byte ordering opposite to the native byte ordering of
the current machine was opened for appending
(‘‘a’’). This is a limitation of the
library.</p>
<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>
<p style="margin-left:11%; margin-top: 1em"><i>libtiff</i>(3TIFF),
<i>TIFFClose</i>(3TIFF)</p>
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