INTRO(3T) Image Format Library C++ Reference Manual INTRO(3T)
NAME
libtiff - introduction to libtiff, a library for reading and writing TIFF
files
SYNOPSIS
#include <tiffio.h>
cc file.c -ltiff
DESCRIPTION
libtiff is a library for reading and writing data files encoded with the
Tag Image File format, Revision 6.0 (or revision 5.0 or revision 4.0).
This file format is suitable for archiving multi-color and monochromatic
image data.
The library supports several compression algorithms, as indicated 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), and
PackBits compression (32773). In addition, several nonstandard
compression algorithms are supported: the 4-bit compression algorithm
used by the ThunderScan program (32809) (decompression only), NeXT's 2-
bit compression algorithm (32766) (decompression only), and an
experimental LZ-style algorithm known as Deflate (32946). 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. Finally, the library does not support files in which the
BitsPerSample, Compression, MinSampleValue, or MaxSampleValue fields are
defined differently on a per-sample basis (in Rev. 6.0 the Compression
tag is not defined on a per-sample basis, so this is immaterial).
DATA TYPES
The library makes extensive use of C typedefs to promote portability.
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
Note that tstrip_t, ttile_t, and tsize_t are constrained to be no more
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INTRO(3T) Image Format Library C++ Reference Manual INTRO(3T)
than 32-bit quantities by 32-bit fields they are stored in in the TIFF
image. Likewise tsample_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 (w/o penalty).
ttag_t must be either 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.
Finally, note that user-specified data references are passed as opaque
handles and only cast at the lowest layers where their type is presumed.
LIST OF ROUTINES
The following routines are part of the library. Consult specific manual
pages for details on their operation. The manual page names listed below
are for systems where the full function names can not be encoded in the
filesystem; on most systems doing ``man function-name'' will work.
Name Appears on Page Description
TIFFCheckTile tile.3t very x,y,z,sample is within image
TIFFClientOpen open.3t open a file for reading or writing
TIFFClose close.3t close an open file
TIFFComputeStrip strip.3t return strip containing y,sample
TIFFComputeTile tile.3t return tile containing x,y,z,sample
TIFFCurrentDirectory query.3t return index of current directory
TIFFCurrentRow query.3t return index of current scanline
TIFFCurrentStrip query.3t return index of current strip
TIFFCurrentTile query.3t return index of current tile
TIFFError error.3t library error handler
TIFFFdOpen open.3t open a file for reading or writing
TIFFFileName query.3t return name of open file
TIFFFileno query.3t return open file descriptor
TIFFFlush flush.3t flush all pending writes
TIFFFlushData flush.3t flush pending data writes
TIFFGetBitRevTable swab.3t return bit reversal table
TIFFGetField getfield.3t return tag value in current directory
TIFFGetFieldDefaulted getfield.3t return tag value in current directory
TIFFGetMode query.3t return open file mode
TIFFGetVersion query.3t return library version string
TIFFIsTiled query.3t return true if image data is tiled
TIFFIsByteSwapped query.3t return true if image data is byte-swapped
TIFFNumberOfStrips strip.3t return number of strips in an image
TIFFNumberOfTiles tile.3t return number of tiles in an image
TIFFOpen open.3t open a file for reading or writing
TIFFPrintDirectory print.3t print description of the current directory
TIFFReadBufferSetup rdbuf.3t specify i/o buffer for reading
TIFFReadDirectory readdir.3t read the next directory
TIFFReadEncodedStrip rdestrip.3t read and decode a strip of data
TIFFReadEncodedTile rdetile.3t read and decode a tile of data
TIFFReadRawStrip rdrstrip.3t read a raw strip of data
TIFFReadRawTile rdrtile.3t read a raw tile of data
TIFFReadRGBAImage rdimage.3t read an image into a fixed format raster
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TIFFReadScanline readline.3t read and decode a row of data
TIFFReadTile readtile.3t read and decode a tile of data
TIFFReverseBits swab.3t reverse bits in an array of bytes
TIFFRGBAImageBegin rgbaimage.3t setup decoder state for TIFFRGBAImageGet
TIFFRGBAImageEnd rgbaimage.3t release TIFFRGBAImage decoder state
TIFFRGBAImageGet rgbaimage.3t read and decode an image
TIFFRGBAImageOK rgbaimage.3t is image readable by TIFFRGBAImageGet
TIFFScanlineSize size.3t return size of a scanline
TIFFSetDirectory setdir.3t set the current directory
TIFFSetSubDirectory setdir.3t set the current directory
TIFFSetErrorHandler error.3t set error handler function
TIFFSetField setfield.3t set a tag's value in the current directory
TIFFSetWarningHandler error.3t set warning handler function
TIFFStripSize size.3t return size of a strip
TIFFSwabShort swab.3t swap bytes of short
TIFFSwabLong swab.3t swap bytes of long
TIFFSwabArrayOfShort swab.3t swap bytes of an array of shorts
TIFFSwabArrayOfLong swab.3t swap bytes of an array of longs
TIFFTileRowSize size.3t return size of a row in a tile
TIFFTileSize size.3t return size of a tile
TIFFVGetField getfield.3t return tag value in current directory
TIFFVGetFieldDefaulted getfield.3t return tag value in current directory
TIFFVSetField setfield.3t set a tag's value in the current directory
TIFFWarning warning.3t library warning handler
TIFFWriteDirectory writedir.3t write the current directory
TIFFWriteEncodedStrip wrestrip.3t compress and write a strip of data
TIFFWriteEncodedTile wretile.3t compress and write a tile of data
TIFFWriteRawStrip wrrstrip.3t write a raw strip of data
TIFFWriteRawTile wrrtile.3t write a raw tile of data
TIFFWriteScanline writeline.3t write a scanline of data
TIFFWriteTile wrrtile.3t compress and write a tile of data
TAG USAGE
The table below lists the TIFF tags that are recognized and handled by
the library. If no use is indicated in the table, then the library reads
and writes the tag, but does not use it internally. Note that some tags
are meaningful only when a particular compression scheme is being used;
e.g. Group3Options is only useful if Compression 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
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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/Wused 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
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
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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 library supports a collection of
tags whose values lie in a range outside the valid range of TIFF tags.
These tags are termed pseud-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
TIFFTAGFAXMODE
Control the operation of the Group 3 codec. Possible values
(independent bits that can be combined by or'ing them together) are:
FAXMODE_CLASSIC (enable old-style format in which the RTC is written
at the end of the last strip), FAXMODE_NORTC (opposite of
FAXMODE_CLASSIC; also called FAXMODE_CLASSF), FAXMODE_NOEOL (do not
write EOL codes at the start of each row of data), FAXMODE_BYTEALIGN
(align each encoded row to an 8-bit boundary), FAXMODE_WORDALIGN
(align each encoded row to an 16-bit boundary), The default value is
dependent on the compression scheme; this pseudo-tag is used by the
various G3 and G4 codecs to share code.
TIFFTAGFAXFILLFUNC
Control 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 (e.g. for display in colormap
mode) or for other purposes. The default value is a pointer to a
builtin function that images packed bilevel data.
TIFFTAGJPEGQUALITY
Control 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.
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TIFFTAGJPEGCOLORMODE
Control whether or not conversion is done between RGB and YCbCr
colorspaces. Possible values are: JPEGCOLORMODE_RAW (do not
convert), and JPEGCOLORMODE_RGB (convert to/from RGB) The default
value is JPEGCOLORMODE_RAW.
TIFFTAGJPEGTABLESMODE
Control 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 JPEGTABLESMODE_HUFF (include Huffman encoding tables). The
default value is JPEGTABLESMODE_QUANT|JPEGTABLESMODE_HUFF.
DIAGNOSTICS
All error messages are directed through the TIFFError routine. By
default messages are directed to stderr in the form: module: message\n.
Warning messages are likewise directed through the TIFFWarning routine.
SEE ALSO
fax2tiff(1), gif2tiff(1), pal2rgb(1), ppm2tiff(1), rgb2ycbcr(1),
ras2tiff(1), sgi2tiff(1), tiff2bw(1), tiffdither(1), tiffdump(1),
tiffcp(1), tiffcmp(1), tiffgt(1), tiffinfo(1), tiffmedian(1),
tiffsplit(1), tiffsv(1),
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.
BUGS
The library does not support multi-sample images where some samples 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 discards
unknown tags. The library should do more validity checking of a
directory's contents.
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