libtiff(3) C Library Functions libtiff(3)NAMElibtiff - introduction to libtiff, a library for reading and writing
TIFF files
SYNOPSIS
#include <tiffio.h>
cc [ flag ...] -I/usr/sfw/include file [ library ... ]
-L/usr/sfw/lib -R/usr/sfw/lib -ltiff
DESCRIPTIONlibtiff is a library for reading and writing data files encoded with
the Tag Image File format, Revision 4.0 or later. The TIFF file format
is suitable for archiving multicolor and monochromatic image data.
EXTENDED DESCRIPTION
The libtiff library supports several compression algorithms, as indi‐
cated by the Compression field, including:
· No compression (1)
· CCITT 1D Huffman compression (2)
· CCITT Group 3 Facsimile compression (3)
· CCITT Group 4 Facsimile compression (4)
· Lempel-Ziv & Welch compression (5)
· Baseline JPEG compression (7)
· Word-aligned 1D Huffman compression (32771)
· PackBits compression (32773)
In addition, several nonstandard compression algorithms are supported:
· 4-bit compression algorithm used by the ThunderScan program
(32809) (decompression only)
· NeXT's 2-bit compression algorithm (32766) (decompression only)
· Experimental LZ-style algorithm known as Deflate (32946)
· Experimental CIE LogLuv compression scheme designed for images
with high dynamic range (32845 for LogL and 32845 for LogLuv)
Directory information may be in either little- or big-endian byte
order. Byte swapping is automatically done by the library.
Data bit ordering may be either Most Significant Bit (MSB) to Least
Significant Bit (LSB), or LSB to MSB.
The library does not support files in which the BitsPerSample, Compres‐
sion, MinSampleValue, or MaxSampleValue fields are defined differently
on a per-sample basis. In Revision 6.0, the Compression tag is not
defined on a per-sample basis, so this is immaterial.
Data Types
The libtiff library makes extensive use of C typedefs to promote porta‐
bility. Two sets of typedefs are used, one for communication with
clients of the library and one for internal data structures and parsing
of the TIFF format. The following typedefs are exposed to users either
through function definitions or through parameters passed through the
varargs interfaces.
· typedef unsigned short uint16; — 16-bit unsigned integer
· typedef unsigned <thing> uint32; — 32-bit unsigned integer
· typedef unsigned int ttag_t; — directory tag
· typedef uint16 tdir_t; — directory index
· typedef uint16 tsample_t; — sample number
· typedef uint32 tstrip_t; — strip number
· typedef uint32 ttile_t; — tile number
· typedef int32 tsize_t; — i/o size in bytes
· typedef void* tdata_t; — image data ref
· typedef void* thandle_t; — client data handle
· typedef int32 toff_t; — file offset
tstrip_t, ttile_t, and tsize_t are limited to 32-bit quantities because
they are stored in 32-bit fields in the TIFF image. Similarly, tsam‐
ple_t is limited by the 16-bit field used to store the SamplesPerPixel
tag. tdir_t constrains the maximum number of IFDs that may appear in an
image and may be an arbitrary size without penalty.
ttag_t must be int, unsigned int, pointer, or double because the
library uses a varargs interface and ANSI C restricts the type of the
parameter before an ellipsis to be a promoted type.
toff_t is defined as int32 because TIFF file offsets are unsigned
32-bit quantities. A signed value is used because some interfaces
return -1 on error.
User-specified data references are passed as opaque handles and only
cast at the lowest layers where their type is presumed.
Library Routines
The following routines are part of the libtiff library. Consult spe‐
cific reference pages for details on their operation. The reference
page names listed below are for systems where the full function names
cannot be encoded in the file system. On most systems, the command man
function-name will work.
_TIFFfree Release allocated memory. See
TIFFmemory(3tiff).
_TIFFmalloc Dynamically allocate memory.
See TIFFmemory(3tiff).
_TIFFmemcmp Compare allocated memory. See
TIFFmemory(3tiff).
_TIFFmemcpy Copy allocated memory to
another memory location. See
TIFFmemory(3tiff).
_TIFFmemset Set allocated memory to known
value. See TIFFmemory(3tiff).
_TIFFrealloc Dynamically reallocate memory.
See TIFFmemory(3tiff).
TIFFbuffer Specify i/o buffer for reading
or writing. See TIFF‐
buffer(3tiff).
TIFFCheckTile Every x,y,z,sample is within
image. See TIFFtile(3tiff).
TIFFClientOpen Open a file for reading or
writing. See TIFFOpen(3tiff).
TIFFClose Close an open file. See TIFF‐
Close(3tiff).
TIFFcodec Work with codecs. See TIFF‐
codec(3tiff).
TIFFComputeStrip Return strip containing
x,y,z,sample. See TIFF‐
strip(3tiff).
TIFFComputeTile Return tile containing y,sam‐
ple. See TIFFtile(3tiff).
TIFFCurrentDirectory Return index of current direc‐
tory. See TIFFquery(3tiff).
TIFFCurrentRow Return index of current scan‐
line. See TIFFquery(3tiff).
TIFFCurrentStrip Return index of current strip.
See TIFFquery(3tiff).
TIFFCurrentTile Return index of current tile.
See TIFFquery(3tiff).
TIFFDefaultStripSize Return size of a strip. See
TIFFstrip(3tiff).
TIFFDefaultTileSize Return size of a tile. See
TIFFtile(3tiff).
TIFFError Library error handler. See TIF‐
FError(3tiff).
TIFFFdOpen Open a file for reading or
writing. See TIFFOpen(3tiff).
TIFFFileName Return name of open file. See
TIFFquery(3tiff).
TIFFFileno Return open file descriptor.
See TIFFquery(3tiff).
TIFFFindCODEC Find a codec. See TIFF‐
codec(3tiff).
TIFFFlush Flush all pending writes. See
TIFFFlush(3tiff).
TIFFFlushData Flush pending data writes. See
TIFFFlush(3tiff).
TIFFGetBitRevTable Return bit reversal table. See
TIFFswab(3tiff).
TIFFGetField Return tag value in current
directory. See TIFFGet‐
Field(3tiff).
TIFFGetFieldDefaulted Return tag value in current
directory. See TIFFGet‐
Field(3tiff).
TIFFGetMode Return open file mode. See
TIFFquery(3tiff).
TIFFGetVersion Return library version string.
See TIFFquery(3tiff).
TIFFIsByteSwapped Return true if image data is
byte-swapped. See TIFF‐
query(3tiff).
TIFFIsMSB2LSB Return true if image data is
returned with bit 0 as the most
significant bit. See TIFF‐
query(3tiff).
TIFFIsTiled Return true if image data is
tiled. See TIFFquery(3tiff).
TIFFIsUpSampled Return true if image data is
up-sampled. See TIFF‐
query(3tiff).
TIFFLastDirectory Return a non-zero value if the
current directory is the last
directory in the file. See
TIFFquery(3tiff).
TIFFmemory Manage memory. See TIFFmem‐
ory(3tiff).
TIFFNumberOfStrips Return number of strips in an
image. See TIFFstrip(3tiff).
TIFFNumberOfTiles Return number of tiles in an
image. See TIFFtile(3tiff).
TIFFOpen Open a file for reading or
writing. See TIFFOpen(3tiff).
TIFFPrintDirectory Print description of the cur‐
rent directory. See TIFFPrint‐
Directory(3tiff).
TIFFquery Return information about image.
See TIFFquery(3tiff).
TIFFRasterScanlineSize Return size of a raster scan‐
line. See TIFFsize(3tiff).
TIFFReadBufferSetup Specify i/o buffer for reading.
See TIFFbuffer(3tiff).
TIFFReadDirectory Read the next directory. See
TIFFReadDirectory(3tiff).
TIFFReadEncodedStrip Read and decode a strip of
data. See TIFFReadEncoded‐
Strip(3tiff).
TIFFReadEncodedTile Read and decode a tile of data.
See TIFFReadEncodedTile(3tiff).
TIFFReadRawStrip Read a raw strip of data. See
TIFFReadRawStrip(3tiff).
TIFFReadRawTile Read a raw tile of data. See
TIFFReadRawTile(3tiff).
TIFFReadRGBAImage Read an image into a fixed for‐
mat raster. See TIFFReadRGBAIm‐
age(3tiff).
TIFFReadRGBAStrip Read an image strip into a
fixed format raster. See TIFF‐
ReadRGBAStrip(3tiff).
TIFFReadRGBATile Read an image tile into a fixed
format raster. See TIFFReadRG‐
BATile(3tiff).
TIFFReadScanline Read and decode a row of data.
See TIFFReadScanline(3tiff).
TIFFReadTile Read and decode a tile of data.
See TIFFReadTile(3tiff).
TIFFRegisterCODEC Register a codec. See TIFF‐
codec(3tiff).
TIFFReverseBits Reverse bits in an array of
bytes. See TIFFswab(3tiff).
TIFFRGBAImage Read and decode an image into a
raster. See TIFFRGBAIm‐
age(3tiff).
TIFFRGBAImageBegin Set up decoder state for
TIFFRGBAImageGet. See TIFFRG‐
BAImage(3tiff).
TIFFRGBAImageEnd Release TIFFRGBAImage decoder
state. See TIFFRGBAIm‐
age(3tiff).
TIFFRGBAImageGet Read and decode an image. See
TIFFRGBAImage(3tiff).
TIFFRGBAImageOK Determine whether image is
readable by TIFFRGBAImageGet.
See TIFFRGBAImage(3tiff).
TIFFScanlineSize Return size of a scanline. See
TIFFsize(3tiff).
TIFFSetDirectory Set the current directory. See
TIFFSetDirectory(3tiff).
TIFFSetSubDirectory Set the current directory. See
TIFFSetDirectory(3tiff).
TIFFSetErrorHandler Set error handler function. See
TIFFError(3tiff).
TIFFSetField Set tag value in the current
directory. See TIFFSet‐
Field(3tiff).
TIFFSetWarningHandler Set warning handler function.
See TIFFWarning(3tiff).
TIFFsize Return the size. See TIFF‐
size(3tiff).
TIFFstrip Work with strips. See TIFF‐
strip(3tiff).
TIFFStripSize Return size of a strip. See
TIFFstrip(3tiff).
TIFFswab Swap bytes. See TIFF‐
swab(3tiff).
TIFFSwabShort Swap bytes of short. See TIFF‐
swab(3tiff).
TIFFSwabLong Swap bytes of long. See TIFF‐
swab(3tiff).
TIFFSwabArrayOfShort Swap bytes of an array of
shorts. See TIFFswab(3tiff).
TIFFSwabArrayOfLong Swap bytes of an array of
longs. See TIFFswab(3tiff).
TIFFtile Return tile information. See
TIFFtile(3tiff).
TIFFTileRowSize Return size of a row in a tile.
See TIFFtile(3tiff).
TIFFTileSize Return size of a tile. See
TIFFtile(3tiff).
TIFFUnregisterCODEC Unregister a codec. See TIFF‐
codec(3tiff).
TIFFVGetField Return tag value in current
directory. See TIFFGet‐
Field(3tiff).
TIFFVGetFieldDefaulted Return tag value in current
directory. See TIFFGet‐
Field(3tiff).
TIFFVSetField Set tag value in current direc‐
tory. See TIFFSetField(3tiff).
TIFFVStripSize Return size of a strip. See
TIFFstrip(3tiff).
TIFFVTileSize Return size of a tile. See
TIFFtile(3tiff).
TIFFWarning Library warning handler. See
TIFFWarning(3tiff).
TIFFWriteBufferSetup Specify i/o buffer for writing.
See TIFFbuffer(3tiff).
TIFFWriteDirectory Write the current directory.
See TIFFWriteDirectory(3tiff).
TIFFWriteEncodedStrip Compress and write a strip of
data. See TIFFWriteEncoded‐
Strip(3tiff).
TIFFWriteEncodedTile Compress and write a tile of
data. See TIFFWriteEncod‐
edTile(3tiff).
TIFFWriteRawStrip Write a raw strip of data. See
TIFFWriteRawStrip(3tiff).
TIFFWriteRawTile Write a raw tile of data. See
TIFFWriteRawTile(3tiff).
TIFFWriteScanline Write a scanline of data. See
TIFFWriteScanline(3tiff).
TIFFWriteTile Compress and write a tile of
data. See TIFFWriteTile(3tiff).
Tag Usage
The table below lists the TIFF tags that are recognized and supported
by the libtiff library. If no use is indicated in the table, then the
library reads and writes the tag, but does not use the tag internally.
Note that some tags are meaningful only when a particular compression
scheme is used. For example, Group3Options is only useful if Compres‐
sion is set to CCITT Group 3 encoding. Tags of this sort are considered
codec-specific tags and the library does not recognize them except when
the Compression tag has been previously set to the relevant compression
scheme.
┌────────────────────────────┬────────────────┬────────────────┬───────────────────────────────┐
│TAG NAME │ VALUE │ R/W │LIBRARY USE / NOTES │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Artist │ 315 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│BadFaxLines │ 326 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│BitsPerSample │ 258 │ R/W │Lots. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│CellLength │ 265 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│CellWidth │ 264 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│CleanFaxData │ 327 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ColorMap │ 320 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ColorResponseUnit │ 300 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Compression │ 259 │ R/W │Choosing codec. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ConsecutiveBadFaxLines │ 328 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│DataType │ 32996 │ R │Obsoleted by SampleFormat tag. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│DateTime │ 306 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│DocumentName │ 269 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│DotRange │ 336 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ExtraSamples │ 338 │ R/W │Lots. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FaxRecvParams │ 34908 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FaxSubAddress │ 34909 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FaxRecvTime │ 34910 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FillOrder │ 266 │ R/W │Control bit order. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FreeByteCounts │ 289 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│FreeOffsets │ 288 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│GrayResponseCurve │ 291 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│GrayResponseUnit │ 290 │ │Parsed but ignored. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Group3Options │ 292 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by Group 3 codec. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Group4Options │ 293 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│HostComputer │ 316 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ImageDepth │ 32997 │ R/W │Tile/strip │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│calculations. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ImageDescription │ 270 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ImageLength │ 257 │ R/W │Lots. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ImageWidth │ 256 │ R/W │Lots. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│InkNames │ 333 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│InkSet │ 332 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│JPEGTables │ 347 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by JPEG codec. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Make │ 271 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Matteing │ 32995 │ R │Obsoleted │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by ExtraSamples tag. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│MaxSampleValue │ 281 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│MinSampleValue │ 280 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Model │ 272 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│NewSubFileType │ 254 │ R/W │Called SubFileType in spec. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│NumberOfInks │ 334 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Orientation │ 274 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│PageName │ 285 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│PageNumber │ 297 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│PhotometricInterpretation │ 262 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by Group 3 and JPEG codecs. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│PlanarConfiguration │ 284 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Predictor │ 317 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by LZW and Deflate codecs. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│PrimaryChromacities │ 319 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ReferenceBlackWhite │ 532 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│ResolutionUnit │ 296 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by Group 3 codec. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│RowsPerStrip │ 278 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│SampleFormat │ 339 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│SamplesPerPixel │ 277 │ R/W │Lots. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│SMinSampleValue │ 340 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│SMaxSampleValue │ 341 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Software │ 305 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│StoNits │ 37439 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│StripByteCounts │ 279 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│StripOffsets │ 273 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│SubFileType │ 255 │ R/W │Called OSubFileType in spec. │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TargetPrinter │ 337 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│Thresholding │ 263 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TileByteCounts │ 324 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TileDepth │ 32998 │ R/W │Tile/strip │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│calculations. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TileLength │ 323 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TileOffsets │ 324 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TileWidth │ 322 │ R/W │Data │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│i/o. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│TransferFunction │ 301 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│WhitePoint │ 318 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│XPosition │ 286 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│XResolution │ 282 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│YCbCrCoefficients │ 529 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by TIFFRGBAImage support. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│YCbCrPositioning │ 531 │ R/W │Tile/strip │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│size calulcations. │ │ │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│YCbCrSubsampling │ 530 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│YPosition │ 286 │ R/W │ │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│YResolution │ 283 │ R/W │Used │
├────────────────────────────┼────────────────┼────────────────┼───────────────────────────────┤
│by Group 3 codec. │ │ │ │
└────────────────────────────┴────────────────┴────────────────┴───────────────────────────────┘
Pseudo Tags
In addition to the normal TIFF tags, the libtiff library supports a
collection of tags whose values lie in a range outside the valid range
of TIFF tags. These tags are termed pseudo-tags and are used to control
various codec-specific functions within the library. The table below
summarizes the defined pseudo-tags.
┌────────────────────────┬────────────────┬────────────────┬────────────────────────────────────┐
│TAG NAME │ CODEC │ R/W │LIBRARY USE / NOTES │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_FAXMODE │ G3 │ R/W │General codec operation. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_FAXFILLFUNC │ G3/G4 │ R/W │Bitmap fill function. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_JPEGQUALITY │ JPEG │ R/W │Compression quality control. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_JPEGCOLORMODE │ JPEG │ R/W │Control colorspace conversions. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_JPEGTABLESMODE │ JPEG │ R/W │Control contents of JPEGTables tag. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_ZIPQUALITY │ Deflate │ R/W │Compression quality level. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_PIXARLOGDATAFMT │ PixarLog │ R/W │User data format. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_PIXARLOGQUALITY │ PixarLog │ R/W │Compression quality level. │
├────────────────────────┼────────────────┼────────────────┼────────────────────────────────────┤
│TIFFTAG_SGILOGDATAFMT │ SGILog │ R/W │User data format. │
└────────────────────────┴────────────────┴────────────────┴────────────────────────────────────┘
TIFFTAG_FAXMODE
Controls the operation of the Group 3 codec. Possible values (indepen‐
dent bits that can be combined by or'ing them together) are:
FAXMODE_BYTEALIGN Align each encoded row to an 8-bit boundary.
FAXMODE_CLASSIC Enable old-style format in which the RTC is
written at the end of the last strip.
FAXMODE_NOEOL Do not write EOL codes at the start of each row
of data.
FAXMODE_NORTC, also callOppositeDofCFAXMODE_CLASSIC.
FAXMODE_WORDALIGN Align each encoded row to a 16-bit boundary.
The default value depends on the compression scheme. This pseudo-tag
is used by the various G3 and G4 codecs to share code.
TIFFTAG_FAXFILLFUNC
Controls the function used to convert arrays of black and white runs to
packed bit arrays. This hook can be used to image decoded scanlines in
multi-bit depth rasters (for example, for display in colormap mode) or
for other purposes. The default value is a pointer to a builtin func‐
tion that images packed bilevel data.
TIFFTAG_IPTCNEWSPHOTO
Contains image metadata per the IPTC newsphoto specification: Headline,
captioning, credit, and so on. Used by most wire services.
TIFFTAG_PHOTOSHOP
Contains Photoshop captioning information and metadata. Photoshop uses
in parallel and redundantly alongside IPTCNEWSPHOTO information.
TIFFTAG_JPEGQUALITY
Controls the compression quality level used in the baseline algorithm.
Note that quality levels are in the range 0-100 with a default value of
75.
TIFFTAG_JPEGCOLORMODE
Controls whether or not conversion is done between RGB and YCbCr col‐
orspaces. Possible values are: JPEGCOLORMODE_RAW (do not convert), and
JPEGCOLORMODE_RGB (convert to/from RGB). The default value is JPEGCOL‐
ORMODE_RAW.
TIFFTAG_JPEGTABLESMODE
Controls the information written in the JPEGTables tag. Possible values
(independent bits that can be combined by or'ing them together) are:
JPEGTABLESMODE_QUANT (include quantization tables), and JPEGTA‐
BLESMODE_HUFF (include Huffman encoding tables).
TIFFTAG_ZIPQUALITY
Controls the compression technique used by the Deflate codec. Quality
levels are in the range 1-9 with larger numbers yielding better com‐
pression at the cost of more computation. The default quality level is
6 which yields a good time-space tradeoff.
TIFFTAG_PIXARLOGDATAFMT
Controls the format of user data passed to the PixarLog codec when
encoding and passed from the PixarLog codec when decoding. Possible
values are:
· PIXARLOGDATAFMT_8BIT for 8-bit unsigned pixels
· PIXARLOGDATAFMT_8BITABGR for 8-bit unsigned ABGR-orderedpixels
· PIXARLOGDATAFMT_11BITLOG for 11-bit log-encoded raw data
· PIXARLOGDATAFMT_12BITPICIO for 12-bit PICIO-compatible data
· PIXARLOGDATAFMT_16BIT for 16-bit signed samples
· PIXARLOGDATAFMT_FLOAT for 32-bit IEEE floating point samples
TIFFTAG_PIXARLOGQUALITY
Controls the compression technique used by the PixarLog codec. This
value is treated identically to TIFFTAG_ZIPQUALITY.
TIFFTAG_SGILOGDATAFMT
Controls the format of client data passed to the SGILog codec when
encoding and passed from the SGILog codec when decoding. Possible val‐
ues are:
· SGILOGDATAFMT_FLTXYZ for converting between LogLuv and 32-bit IEEE
floating valued XYZ pixels
· SGILOGDATAFMT_16BITLUV for 16-bit encoded Luv pixels
· SGILOGDATAFMT_32BITRAW and SGILOGDATAFMT_24BITRAW for no conver‐
sion of data
· SGILOGDATAFMT_8BITRGB for returning 8-bit RGB data (valid only
when decoding LogLuv-encoded data)
· SGILOGDATAFMT_FLTY for converting between LogL and 32-bit IEEE
floating valued Y pixels
· SGILOGDATAFMT_16BITL for 16-bit encoded L pixels
· SGILOGDATAFMT_8BITGRY for returning 8-bit greyscale data (valid
only when decoding LogL-encoded data)
Diagnostics
All error messages are directed through the TIFFError routine. By
default, messages are directed to stderr in the form: module: mes‐
sage\n. Warning messages are likewise directed through the TIFFWarning
routine.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │image/library/libtiff │
├─────────────────────────────┼─────────────────────────────┤
│Interface stability │Uncommitted │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOfax2tiff(1), gif2tiff(1), pal2rgb(1), ppm2tiff(1), ras2tiff(1),
rgb2ycbcr(1), sgi2tiff(1), tiff2bw(1), tiffcmp(1), tiffcp(1),
tiffdither(1), tiffdump(1), tiffgt(1), tiffinfo(1), tiffmedian(1),
tiffsplit(1), tiffsv(1), attributes(5)
Tag Image File Format Specification Revision 6.0, an Aldus Technical
Memorandum.
The Spirit of TIFF Class F an appendix to the TIFF 5.0 specification
prepared by Cygnet Technologies.
NOTES
The libtiff library does not support multisample images where some sam‐
ples have different bits/sample.
The library does not support random access to compressed data that is
organized with more than one row per tile or strip. The library dis‐
cards unknown tags. The library should do more validity checking of a
directory's contents.
This man page was originally written by Sam Leffler. Updated by Breda
McColgan, Sun Microsystems Inc., 2004.
SunOS 5.11 06 Apr 2004 libtiff(3)
