[wxWidgets.git] / src / tiff / html / man / TIFFOpen.3tiff.html

<!-- Creator     : groff version 1.18.1 -->
<!-- CreationDate: Mon Mar 13 18:03:08 2006 -->
<html>
<head>
<meta name="generator" content="groff -Thtml, see www.gnu.org">
<meta name="Content-Style" content="text/css">
<title>TIFFOpen</title>
</head>
<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>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p>TIFFOpen, TIFFFdOpen, TIFFClientOpen &minus; open a
<small>TIFF</small> file for reading or writing</p>
</td>
</table>
<a name="SYNOPSIS"></a>
<h2>SYNOPSIS</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p><b>#include &lt;tiffio.h&gt;</b></p>
<!-- INDENTATION -->
<p><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>
<!-- INDENTATION -->
<p><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>
<!-- INDENTATION -->
<p><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>
</td>
</table>
<a name="DESCRIPTION"></a>
<h2>DESCRIPTION</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p><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
(&lsquo;&lsquo;r&rsquo;&rsquo;), writing
(&lsquo;&lsquo;w&rsquo;&rsquo;), or appending
(&lsquo;&lsquo;a&rsquo;&rsquo;) 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>
<!-- INDENTATION -->
<p>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>
<!-- INDENTATION -->
<p><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&rsquo;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>
<!-- INDENTATION -->
<p><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&rsquo;s contents in memory; c.f.
<i>mmap</i>(2) and <i>munmap</i>(2). The <i>clientdata</i>
parameter is an opaque &lsquo;&lsquo;handle&rsquo;&rsquo;
passed to the client-specified routines passed as parameters
to <i>TIFFClientOpen</i>.</p>
</td>
</table>
<a name="OPTIONS"></a>
<h2>OPTIONS</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p>The open mode parameter can include the following flags
in addition to the &lsquo;&lsquo;r&rsquo;&rsquo;,
&lsquo;&lsquo;w&rsquo;&rsquo;, and
&lsquo;&lsquo;a&rsquo;&rsquo; flags. Note however that
option flags must follow the read-write-append
specification.</p>
</td>
</table>
<!-- TABS -->
<table width="100%" border=0 rules="none" frame="void"
       cols="5" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>l</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>b</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>L</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>B</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>H</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>M</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>m</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>Disable the use of memory-mapped files.</p>
</td>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>C</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>Enable the use of &lsquo;&lsquo;strip
chopping&rsquo;&rsquo; 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>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>c</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>Disable the use of strip chopping when reading
images.</p>
</td>
<td width="0%">
</td>
<tr valign="top" align="left">
<td width="10%"></td>
<td width="2%">

<p><b>h</b></p>
</td>
<td width="6%"></td>
<td width="80%">

<p>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>
<td width="0%">
</td>
</table>
<a name="BYTE ORDER"></a>
<h2>BYTE ORDER</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p>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
&lsquo;&lsquo;b&rsquo;&rsquo; and
&lsquo;&lsquo;l&rsquo;&rsquo; option flags may be included
in the call to open a file; for example,
&lsquo;&lsquo;wb&rsquo;&rsquo; or
&lsquo;&lsquo;wl&rsquo;&rsquo;.</p>
</td>
</table>
<a name="RETURN VALUES"></a>
<h2>RETURN VALUES</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p>Upon successful completion <i>TIFFOpen</i>,
<i>TIFFFdOpen</i>, and <i>TIFFClientOpen</i> return a
<small>TIFF</small> pointer. Otherwise, NULL is
returned.</p>
</td>
</table>
<a name="DIAGNOSTICS"></a>
<h2>DIAGNOSTICS</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p>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>
<!-- INDENTATION -->
<p><b>&quot;%s&quot;: Bad mode</b>. The specified
<i>mode</i> parameter was not one of
&lsquo;&lsquo;r&rsquo;&rsquo; (read),
&lsquo;&lsquo;w&rsquo;&rsquo; (write), or
&lsquo;&lsquo;a&rsquo;&rsquo; (append).</p>
<!-- INDENTATION -->
<p><b>%s: Cannot open</b>. <i>TIFFOpen</i>() was unable to
open the specified filename for read/writing.</p>
<!-- INDENTATION -->
<p><b>Cannot read TIFF header</b>. An error occurred while
attempting to read the header information.</p>
<!-- INDENTATION -->
<p><b>Error writing TIFF header</b>. An error occurred while
writing the default header information for a new file.</p>
<!-- INDENTATION -->
<p><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>
<!-- INDENTATION -->
<p><b>Not a TIFF file, bad version number %d (0x%x)</b>. The
version field in the header was not 42 (decimal).</p>
<!-- INDENTATION -->
<p><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 (&lsquo;&lsquo;a&rsquo;&rsquo;). This is a
limitation of the library.</p>
</td>
</table>
<a name="SEE ALSO"></a>
<h2>SEE ALSO</h2>
<!-- INDENTATION -->
<table width="100%" border=0 rules="none" frame="void"
       cols="2" cellspacing="0" cellpadding="0">
<tr valign="top" align="left">
<td width="8%"></td>
<td width="91%">
<p><i>libtiff</i>(3TIFF), <i>TIFFClose</i>(3TIFF)</p>
</td>
</table>
<hr>
</body>
</html>
Commit	Line	Data
8414a40c VZ	1	<!-- Creator : groff version 1.18.1 -->
	2	<!-- CreationDate: Mon Mar 13 18:03:08 2006 -->
	3	<html>
	4	<head>
	5	<meta name="generator" content="groff -Thtml, see www.gnu.org">
	6	<meta name="Content-Style" content="text/css">
	7	<title>TIFFOpen</title>
	8	</head>
	9	<body>
	10
	11	<h1 align=center>TIFFOpen</h1>
	12	<a href="#NAME">NAME</a><br>
	13	<a href="#SYNOPSIS">SYNOPSIS</a><br>
	14	<a href="#DESCRIPTION">DESCRIPTION</a><br>
	15	<a href="#OPTIONS">OPTIONS</a><br>
	16	<a href="#BYTE ORDER">BYTE ORDER</a><br>
	17	<a href="#RETURN VALUES">RETURN VALUES</a><br>
	18	<a href="#DIAGNOSTICS">DIAGNOSTICS</a><br>
	19	<a href="#SEE ALSO">SEE ALSO</a><br>
	20
	21	<hr>
	22	<a name="NAME"></a>
	23	<h2>NAME</h2>
	24	<!-- INDENTATION -->
	25	<table width="100%" border=0 rules="none" frame="void"
	26	cols="2" cellspacing="0" cellpadding="0">
	27	<tr valign="top" align="left">
	28	<td width="8%"></td>
	29	<td width="91%">
	30	<p>TIFFOpen, TIFFFdOpen, TIFFClientOpen − open a
	31	<small>TIFF</small> file for reading or writing</p>
	32	</td>
	33	</table>
	34	<a name="SYNOPSIS"></a>
	35	<h2>SYNOPSIS</h2>
	36	<!-- INDENTATION -->
	37	<table width="100%" border=0 rules="none" frame="void"
	38	cols="2" cellspacing="0" cellpadding="0">
	39	<tr valign="top" align="left">
	40	<td width="8%"></td>
	41	<td width="91%">
	42	<p><b>#include <tiffio.h></b></p>
	43	<!-- INDENTATION -->
	44	<p><b>TIFF* TIFFOpen(const char *</b><i>filename</i><b>,
	45	const char *</b><i>mode</i><b>)<br>
	46	TIFF* TIFFFdOpen(const int</b> <i>fd</i><b>, const char
	47	*</b><i>filename</i><b>, const char
	48	*</b><i>mode</i><b>)</b></p>
	49	<!-- INDENTATION -->
	50	<p><b>typedef tsize_t (*TIFFReadWriteProc)(thandle_t,
	51	tdata_t, tsize_t);<br>
	52	typedef toff_t (*TIFFSeekProc)(thandle_t, toff_t, int);<br>
	53	typedef int (*TIFFCloseProc)(thandle_t);<br>
	54	typedef toff_t (*TIFFSizeProc)(thandle_t);<br>
	55	typedef int (TIFFMapFileProc)(thandle_t, tdata_t,
	56	toff_t*);<br>
	57	typedef void (*TIFFUnmapFileProc)(thandle_t, tdata_t,
	58	toff_t);</b></p>
	59	<!-- INDENTATION -->
	60	<p><b>TIFF* TIFFClientOpen(const char
	61	</b><i>filename</i><b>, const char </b><i>mode</i><b>,
	62	thandle_t</b> <i>clientdata</i><b>, TIFFReadWriteProc</b>
	63	<i>readproc</i><b>, TIFFReadWriteProc</b>
	64	<i>writeproc</i><b>, TIFFSeekProc</b> <i>seekproc</i><b>,
65	TIFFCloseProc</b> <i>closeproc</i><b>, TIFFSizeProc</b>
66	<i>sizeproc</i><b>, TIFFMapFileProc</b> <i>mapproc</i><b>,
67	TIFFUnmapFileProc</b> <i>unmapproc</i><b>)</b></p>
68	</td>
69	</table>
70	<a name="DESCRIPTION"></a>
71	<h2>DESCRIPTION</h2>
72	<!-- INDENTATION -->
73	<table width="100%" border=0 rules="none" frame="void"
74	cols="2" cellspacing="0" cellpadding="0">
75	<tr valign="top" align="left">
76	<td width="8%"></td>
77	<td width="91%">
78	<p><i>TIFFOpen</i> opens a <small>TIFF</small> file whose
79	name is <i>filename</i> and returns a handle to be used in
80	subsequent calls to routines in <i>libtiff</i>. If the open
81	operation fails, then zero is returned. The <i>mode</i>
82	parameter specifies if the file is to be opened for reading
83	(‘‘r’’), writing
84	(‘‘w’’), or appending
85	(‘‘a’’) and, optionally, whether to
86	override certain default aspects of library operation (see
87	below). When a file is opened for appending, existing data
88	will not be touched; instead new data will be written as
89	additional subfiles. If an existing file is opened for
90	writing, all previous data is overwritten.</p>
91	<!-- INDENTATION -->
92	<p>If a file is opened for reading, the first
93	<small>TIFF</small> directory in the file is automatically
94	read (also see <i>TIFFSetDirectory</i>(3TIFF) for reading
95	directories other than the first). If a file is opened for
96	writing or appending, a default directory is automatically
97	created for writing subsequent data. This directory has all
98	the default values specified in <small>TIFF</small> Revision
99	6.0: <i>BitsPerSample</i>=1, <i>ThreshHolding</i>=bilevel
100	art scan, <i>FillOrder</i>=1 (most significant bit of each
101	data byte is filled first), <i>Orientation</i>=1 (the 0th
102	row represents the visual top of the image, and the 0th
103	column represents the visual left hand side),
104	<i>SamplesPerPixel</i>=1, <i>RowsPerStrip</i>=infinity,
105	<i>ResolutionUnit</i>=2 (inches), and <i>Compression</i>=1
106	(no compression). To alter these values, or to define values
107	for additional fields, <i>TIFFSetField</i>(3TIFF) must be
108	used.</p>
109	<!-- INDENTATION -->
110	<p><i>TIFFFdOpen</i> is like <i>TIFFOpen</i> except that it
111	opens a <small>TIFF</small> file given an open file
112	descriptor <i>fd</i>. The file’s name and mode must
113	reflect that of the open descriptor. The object associated
114	with the file descriptor <b>must support random
115	access</b>.</p>
116	<!-- INDENTATION -->
117	<p><i>TIFFClientOpen</i> is like <i>TIFFOpen</i> except that
118	the caller supplies a collection of functions that the
119	library will use to do <small>UNIX</small> -like I/O
120	operations. The <i>readproc</i> and <i>writeproc</i> are
121	called to read and write data at the current file position.
122	<i>seekproc</i> is called to change the current file
123	position a la <i>lseek</i>(2). <i>closeproc</i> is invoked
124	to release any resources associated with an open file.
125	<i>sizeproc</i> is invoked to obtain the size in bytes of a
126	file. <i>mapproc</i> and <i>unmapproc</i> are called to map
127	and unmap a file’s contents in memory; c.f.
128	<i>mmap</i>(2) and <i>munmap</i>(2). The <i>clientdata</i>
129	parameter is an opaque ‘‘handle’’
130	passed to the client-specified routines passed as parameters
131	to <i>TIFFClientOpen</i>.</p>
132	</td>
133	</table>
134	<a name="OPTIONS"></a>
135	<h2>OPTIONS</h2>
136	<!-- INDENTATION -->
137	<table width="100%" border=0 rules="none" frame="void"
138	cols="2" cellspacing="0" cellpadding="0">
139	<tr valign="top" align="left">
140	<td width="8%"></td>
141	<td width="91%">
142	<p>The open mode parameter can include the following flags
143	in addition to the ‘‘r’’,
144	‘‘w’’, and
145	‘‘a’’ flags. Note however that
146	option flags must follow the read-write-append
147	specification.</p>
148	</td>
149	</table>
150	<!-- TABS -->
151	<table width="100%" border=0 rules="none" frame="void"
152	cols="5" cellspacing="0" cellpadding="0">
153	<tr valign="top" align="left">
154	<td width="10%"></td>
155	<td width="2%">
156
157	<p><b>l</b></p>
158	</td>
159	<td width="6%"></td>
160	<td width="80%">
161
162	<p>When creating a new file force information be written
163	with Little-Endian byte order (but see below). By default
164	the library will create new files using the native
165	<small>CPU</small> byte order.</p>
166	</td>
167	<td width="0%">
168	</td>
169	<tr valign="top" align="left">
170	<td width="10%"></td>
171	<td width="2%">
172
173	<p><b>b</b></p>
174	</td>
175	<td width="6%"></td>
176	<td width="80%">
177
178	<p>When creating a new file force information be written
179	with Big-Endian byte order (but see below). By default the
180	library will create new files using the native
181	<small>CPU</small> byte order.</p>
182	</td>
183	<td width="0%">
184	</td>
185	<tr valign="top" align="left">
186	<td width="10%"></td>
187	<td width="2%">
188
189	<p><b>L</b></p>
190	</td>
191	<td width="6%"></td>
192	<td width="80%">
193
194	<p>Force image data that is read or written to be treated
195	with bits filled from Least Significant Bit (
196	<small>LSB</small> ) to Most Significant Bit (
197	<small>MSB</small> ). Note that this is the opposite to the
198	way the library has worked from its inception.</p>
199	</td>
200	<td width="0%">
201	</td>
202	<tr valign="top" align="left">
203	<td width="10%"></td>
204	<td width="2%">
205
206	<p><b>B</b></p>
207	</td>
208	<td width="6%"></td>
209	<td width="80%">
210
211	<p>Force image data that is read or written to be treated
212	with bits filled from Most Significant Bit (
213	<small>MSB</small> ) to Least Significant Bit (
214	<small>LSB</small> ); this is the default.</p>
215	</td>
216	<td width="0%">
217	</td>
218	<tr valign="top" align="left">
219	<td width="10%"></td>
220	<td width="2%">
221
222	<p><b>H</b></p>
223	</td>
224	<td width="6%"></td>
225	<td width="80%">
226
227	<p>Force image data that is read or written to be treated
228	with bits filled in the same order as the native
229	<small>CPU.</small></p>
230	</td>
231	<td width="0%">
232	</td>
233	<tr valign="top" align="left">
234	<td width="10%"></td>
235	<td width="2%">
236
237	<p><b>M</b></p>
238	</td>
239	<td width="6%"></td>
240	<td width="80%">
241
242	<p>Enable the use of memory-mapped files for images opened
243	read-only. If the underlying system does not support
244	memory-mapped files or if the specific image being opened
245	cannot be memory-mapped then the library will fallback to
246	using the normal system interface for reading information.
247	By default the library will attempt to use memory-mapped
248	files.</p>
249	</td>
250	<td width="0%">
251	</td>
252	<tr valign="top" align="left">
253	<td width="10%"></td>
254	<td width="2%">
255
256	<p><b>m</b></p>
257	</td>
258	<td width="6%"></td>
259	<td width="80%">
260
261	<p>Disable the use of memory-mapped files.</p>
262	</td>
263	<td width="0%">
264	</td>
265	<tr valign="top" align="left">
266	<td width="10%"></td>
267	<td width="2%">
268
269	<p><b>C</b></p>
270	</td>
271	<td width="6%"></td>
272	<td width="80%">
273
274	<p>Enable the use of ‘‘strip
275	chopping’’ when reading images that are
276	comprised of a single strip or tile of uncompressed data.
277	Strip chopping is a mechanism by which the library will
278	automatically convert the single-strip image to multiple
279	strips, each of which has about 8 Kilobytes of data. This
280	facility can be useful in reducing the amount of memory used
281	to read an image because the library normally reads each
282	strip in its entirety. Strip chopping does however alter the
283	apparent contents of the image because when an image is
284	divided into multiple strips it looks as though the
285	underlying file contains multiple separate strips. Finally,
286	note that default handling of strip chopping is a
287	compile-time configuration parameter. The default behaviour,
288	for backwards compatibility, is to enable strip
289	chopping.</p>
290	</td>
291	<td width="0%">
292	</td>
293	<tr valign="top" align="left">
294	<td width="10%"></td>
295	<td width="2%">
296
297	<p><b>c</b></p>
298	</td>
299	<td width="6%"></td>
300	<td width="80%">
301
302	<p>Disable the use of strip chopping when reading
303	images.</p>
304	</td>
305	<td width="0%">
306	</td>
307	<tr valign="top" align="left">
308	<td width="10%"></td>
309	<td width="2%">
310
311	<p><b>h</b></p>
312	</td>
313	<td width="6%"></td>
314	<td width="80%">
315
316	<p>Read TIFF header only, do not load the first image
317	directory. That could be useful in case of the broken first
318	directory. We can open the file and proceed to the other
319	directories.</p>
320	</td>
321	<td width="0%">
322	</td>
323	</table>
324	<a name="BYTE ORDER"></a>
325	<h2>BYTE ORDER</h2>
326	<!-- INDENTATION -->
327	<table width="100%" border=0 rules="none" frame="void"
328	cols="2" cellspacing="0" cellpadding="0">
329	<tr valign="top" align="left">
330	<td width="8%"></td>
331	<td width="91%">
332	<p>The <small>TIFF</small> specification (<b>all
333	versions</b>) states that compliant readers <i>must be
334	capable of reading images written in either byte order</i>.
335	Nonetheless some software that claims to support the reading
336	of <small>TIFF</small> images is incapable of reading images
337	in anything but the native <small>CPU</small> byte order on
338	which the software was written. (Especially notorious are
339	applications written to run on Intel-based machines.) By
340	default the library will create new files with the native
341	byte-order of the <small>CPU</small> on which the
342	application is run. This ensures optimal performance and is
343	portable to any application that conforms to the TIFF
344	specification. To force the library to use a specific
345	byte-order when creating a new file the
346	‘‘b’’ and
347	‘‘l’’ option flags may be included
348	in the call to open a file; for example,
349	‘‘wb’’ or
350	‘‘wl’’.</p>
351	</td>
352	</table>
353	<a name="RETURN VALUES"></a>
354	<h2>RETURN VALUES</h2>
355	<!-- INDENTATION -->
356	<table width="100%" border=0 rules="none" frame="void"
357	cols="2" cellspacing="0" cellpadding="0">
358	<tr valign="top" align="left">
359	<td width="8%"></td>
360	<td width="91%">
361	<p>Upon successful completion <i>TIFFOpen</i>,
362	<i>TIFFFdOpen</i>, and <i>TIFFClientOpen</i> return a
363	<small>TIFF</small> pointer. Otherwise, NULL is
364	returned.</p>
365	</td>
366	</table>
367	<a name="DIAGNOSTICS"></a>
368	<h2>DIAGNOSTICS</h2>
369	<!-- INDENTATION -->
370	<table width="100%" border=0 rules="none" frame="void"
371	cols="2" cellspacing="0" cellpadding="0">
372	<tr valign="top" align="left">
373	<td width="8%"></td>
374	<td width="91%">
375	<p>All error messages are directed to the
376	<i>TIFFError</i>(3TIFF) routine. Likewise, warning messages
377	are directed to the <i>TIFFWarning</i>(3TIFF) routine.</p>
378	<!-- INDENTATION -->
379	<p><b>"%s": Bad mode</b>. The specified
380	<i>mode</i> parameter was not one of
381	‘‘r’’ (read),
382	‘‘w’’ (write), or
383	‘‘a’’ (append).</p>
384	<!-- INDENTATION -->
385	<p><b>%s: Cannot open</b>. <i>TIFFOpen</i>() was unable to
386	open the specified filename for read/writing.</p>
387	<!-- INDENTATION -->
388	<p><b>Cannot read TIFF header</b>. An error occurred while
389	attempting to read the header information.</p>
390	<!-- INDENTATION -->
391	<p><b>Error writing TIFF header</b>. An error occurred while
392	writing the default header information for a new file.</p>
393	<!-- INDENTATION -->
394	<p><b>Not a TIFF file, bad magic number %d (0x%x)</b>. The
395	magic number in the header was not (hex) 0x4d4d or (hex)
396	0x4949.</p>
397	<!-- INDENTATION -->
398	<p><b>Not a TIFF file, bad version number %d (0x%x)</b>. The
399	version field in the header was not 42 (decimal).</p>
400	<!-- INDENTATION -->
401	<p><b>Cannot append to file that has opposite byte
402	ordering</b>. A file with a byte ordering opposite to the
403	native byte ordering of the current machine was opened for
404	appending (‘‘a’’). This is a
405	limitation of the library.</p>
406	</td>
407	</table>
408	<a name="SEE ALSO"></a>
409	<h2>SEE ALSO</h2>
410	<!-- INDENTATION -->
411	<table width="100%" border=0 rules="none" frame="void"
412	cols="2" cellspacing="0" cellpadding="0">
413	<tr valign="top" align="left">
414	<td width="8%"></td>
415	<td width="91%">
416	<p><i>libtiff</i>(3TIFF), <i>TIFFClose</i>(3TIFF)</p>
417	</td>
418	</table>
419	<hr>
420	</body>
421	</html>