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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 compres-
sion (1), CCITT 1D Huffman compression (2), CCITT Group 3
Facsimile compression (3), CCITT Group 4 Facsimile compres-
sion (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 pro-
gram (32809) (decompression only), NeXT's 2-bit compression
algorithm (32766) (decompression only), an experimental LZ-
style algorithm known as Deflate (32946), and an experimen-
tal 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.
Finally, the library does not support files in which the
BitsPerSample, Compression, MinSampleValue, or MaxSam-
pleValue 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 commun-
ication with clients of the library and one for internal
data structures and parsing of the TIFF format. The follow-
ing 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 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 res-
tricts 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
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
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
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 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
TIFFTAG_ZIPQUALITY Deflate R/Wcompression quality level
TIFFTAG_PIXARLOGDATAFMT PixarLog R/Wuser data format
TIFFTAG_PIXARLOGQUALITY PixarLog R/Wcompression quality level
TIFFTAG_SGILOGDATAFMT SGILog R/W user data format
TIFFTAG_FAXMODE
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.
TIFFTAG_FAXFILLFUNC
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 ras-
ters (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.
TIFFTAG_JPEGQUALITY
Control the compression quality level used in the base-
line algorithm. Note that quality levels are in the
range 0-100 with a default value of 75.
TIFFTAG_JPEGCOLORMODE
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.
TIFFTAG_JPEGTABLESMODE
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.
TIFFTAG_ZIPQUALITY
Control the compression technique used by the Deflate
codec. Quality levels are in the range 1-9 with larger
numbers yielding better compression at the cost of more
computation. The default quality level is 6 which
yields a good time-space tradeoff.
TIFFTAG_PIXARLOGDATAFMT
Control the format of user data passed in to the Pixar-
Log codec when encoding and passed out from when decod-
ing. Possible values are: PIXARLOGDATAFMT_8BIT for
8-bit unsigned pixels, PIXARLOGDATAFMT_8BITABGR for 8-
bit unsigned ABGR-ordered pixels,
PIXARLOGDATAFMT_11BITLOG for 11-bit log-encoded raw
data, PIXARLOGDATAFMT_12BITPICIO for 12-bit PICIO-
compatible data, PIXARLOGDATAFMT_16BIT for 16-bit
signed samples, and PIXARLOGDATAFMT_FLOAT for 32-bit
IEEE floating point samples.
TIFFTAG_PIXARLOGQUALITY
Control the compression technique used by the PixarLog
codec. This value is treated identically to
TIFFTAG_ZIPQUALITY; see the above description.
TIFFTAG_SGILOGDATAFMT
Control the format of client data passed in to the SGI-
Log codec when encoding and passed out from when decod-
ing. Possible values 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 conversion 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, and SGILOGDATAFMT_8BITGRY
for returning 8-bit greyscale data (valid only when
decoding LogL-encoded data).
DIAGNOSTICS
All error messages are directed through the TIFFError rou-
tine. 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), tiff-
dither(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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