2 .\" Copyright (c) 1988-1997 Sam Leffler
3 .\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
5 .\" Permission to use, copy, modify, distribute, and sell this software and
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25 .TH TIFFOpen 3TIFF "July 1, 2005" "libtiff"
27 TIFFOpen, TIFFFdOpen, TIFFClientOpen \- open a
29 file for reading or writing
31 .B "#include <tiffio.h>"
33 .BI "TIFF* TIFFOpen(const char *" filename ", const char *" mode ")"
35 .BI "TIFF* TIFFFdOpen(const int " fd ", const char *" filename ", const char *" mode ")"
37 .B "typedef tsize_t (*TIFFReadWriteProc)(thandle_t, tdata_t, tsize_t);"
39 .B "typedef toff_t (*TIFFSeekProc)(thandle_t, toff_t, int);"
41 .B "typedef int (*TIFFCloseProc)(thandle_t);"
43 .B "typedef toff_t (*TIFFSizeProc)(thandle_t);"
45 .B "typedef int (*TIFFMapFileProc)(thandle_t, tdata_t*, toff_t*);"
47 .B "typedef void (*TIFFUnmapFileProc)(thandle_t, tdata_t, toff_t);"
49 .BI "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 ")"
56 and returns a handle to be used in subsequent calls to routines in
58 If the open operation fails, then zero is returned.
61 parameter specifies if the file is to be opened for reading (``r''),
62 writing (``w''), or appending (``a'') and, optionally, whether
63 to override certain default aspects of library operation (see below).
64 When a file is opened for appending, existing data will not
65 be touched; instead new data will be written as additional subfiles.
66 If an existing file is opened for writing, all previous data is
69 If a file is opened for reading, the first
71 directory in the file is automatically read
73 .IR TIFFSetDirectory (3TIFF)
74 for reading directories other than the first).
75 If a file is opened for writing or appending, a default directory
76 is automatically created for writing subsequent data.
77 This directory has all the default values specified in
81 .IR ThreshHolding "=bilevel art scan,"
83 (most significant bit of each data byte is filled first),
85 (the 0th row represents the visual top of the image, and the 0th
86 column represents the visual left hand side),
87 .IR SamplesPerPixel =1,
88 .IR RowsPerStrip =infinity,
93 To alter these values, or to define values for additional fields,
94 .IR TIFFSetField (3TIFF)
100 except that it opens a
102 file given an open file descriptor
104 The file's name and mode must reflect that of the open descriptor.
105 The object associated with the file descriptor
106 .BR "must support random access" .
111 except that the caller supplies a collection of functions that the
112 library will use to do \s-1UNIX\s+1-like I/O operations.
117 are called to read and write data at the current file position.
119 is called to change the current file position a la
122 is invoked to release any resources associated with an open file.
124 is invoked to obtain the size in bytes of a file.
128 are called to map and unmap a file's contents in memory; c.f.
134 parameter is an opaque ``handle'' passed to the client-specified
135 routines passed as parameters to
138 The open mode parameter can include the following flags in
139 addition to the ``r'', ``w'', and ``a'' flags.
140 Note however that option flags must follow the read-write-append
144 When creating a new file force information be written with
145 Little-Endian byte order (but see below).
146 By default the library will create new files using the native
151 When creating a new file force information be written with
152 Big-Endian byte order (but see below).
153 By default the library will create new files using the native
158 Force image data that is read or written to be treated with
159 bits filled from Least Significant Bit (\s-1LSB\s+1) to
160 Most Significant Bit (\s-1MSB\s+1).
161 Note that this is the opposite to the way the library has
162 worked from its inception.
165 Force image data that is read or written to be treated with
166 bits filled from Most Significant Bit (\s-1MSB\s+1) to
167 Least Significant Bit (\s-1LSB\s+1); this is the default.
170 Force image data that is read or written to be treated with
171 bits filled in the same order as the native
175 Enable the use of memory-mapped files for images opened read-only.
176 If the underlying system does not support memory-mapped files
177 or if the specific image being opened cannot be memory-mapped
178 then the library will fallback to using the normal system interface
179 for reading information.
180 By default the library will attempt to use memory-mapped files.
183 Disable the use of memory-mapped files.
186 Enable the use of ``strip chopping'' when reading images
187 that are comprised of a single strip or tile of uncompressed data.
188 Strip chopping is a mechanism by which the library will automatically
189 convert the single-strip image to multiple strips,
190 each of which has about 8 Kilobytes of data.
191 This facility can be useful in reducing the amount of memory used
192 to read an image because the library normally reads each strip
194 Strip chopping does however alter the apparent contents of the
195 image because when an image is divided into multiple strips it
196 looks as though the underlying file contains multiple separate
198 Finally, note that default handling of strip chopping is a compile-time
199 configuration parameter.
200 The default behaviour, for backwards compatibility, is to enable
204 Disable the use of strip chopping when reading images.
207 Read TIFF header only, do not load the first image directory. That could be
208 useful in case of the broken first directory. We can open the file and proceed
209 to the other directories.
213 specification (\fBall versions\fP) states that compliant readers
214 .IR "must be capable of reading images written in either byte order" .
215 Nonetheless some software that claims to support the reading of
217 images is incapable of reading images in anything but the native
219 byte order on which the software was written.
220 (Especially notorious
221 are applications written to run on Intel-based machines.)
222 By default the library will create new files with the native
225 on which the application is run.
226 This ensures optimal performance and is portable to any application
227 that conforms to the TIFF specification.
228 To force the library to use a specific byte-order when creating
229 a new file the ``b'' and ``l'' option flags may be included in
230 the call to open a file; for example, ``wb'' or ``wl''.
232 Upon successful completion
240 Otherwise, NULL is returned.
242 All error messages are directed to the
243 .IR TIFFError (3TIFF)
245 Likewise, warning messages are directed to the
246 .IR TIFFWarning (3TIFF)
249 \fB"%s": Bad mode\fP.
252 parameter was not one of ``r'' (read), ``w'' (write), or ``a'' (append).
254 .BR "%s: Cannot open" .
256 was unable to open the specified filename for read/writing.
258 .BR "Cannot read TIFF header" .
259 An error occurred while attempting to read the header information.
261 .BR "Error writing TIFF header" .
262 An error occurred while writing the default header information
265 .BR "Not a TIFF file, bad magic number %d (0x%x)" .
266 The magic number in the header was not (hex)
267 0x4d4d or (hex) 0x4949.
269 .BR "Not a TIFF file, bad version number %d (0x%x)" .
270 The version field in the header was not 42 (decimal).
272 .BR "Cannot append to file that has opposite byte ordering" .
273 A file with a byte ordering opposite to the native byte
274 ordering of the current machine was opened for appending (``a'').
275 This is a limitation of the library.
278 .IR TIFFClose (3TIFF)
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