libtiff.3t

tiff文件开发库

.\" $Header: /cvsroot/osrs/libtiff/man/libtiff.3t,v 1.8 2003/12/21 22:04:53 dron Exp $
.\"
.\" Copyright (c) 1988-1997 Sam Leffler
.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
.\"
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.\"
.if n .po 0
.TH INTRO 3T "August 21, 1997"
.SH NAME
libtiff \- introduction to
.IR libtiff ,
a library for reading and writing
.SM TIFF
files
.SH SYNOPSIS
.B "#include <tiffio.h>"
.br
cc file.c
.B -ltiff
.SH DESCRIPTION
.I libtiff
is a library for reading and writing data files encoded with the
.I "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.
.PP
The library supports several compression algorithms, as indicated
by the
.I Compression
field, including:
no compression (1),
.SM CCITT
1D Huffman compression (2),
.SM CCITT
Group 3 Facsimile compression (3),
.SM 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
.I ThunderScan
program (32809) (decompression only),
NeXT's 2-bit compression algorithm (32766) (decompression only),
an experimental LZ-style algorithm known as Deflate (32946), and
an 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 (\c
.SM MSB\c
) to Least Significant Bit (\c
.SM LSB\c
) or
.SM LSB
to
.SM MSB.
Finally, the library does not support files in which the
.IR BitsPerSample ,
.IR Compression ,
.IR MinSampleValue ,
or
.IR MaxSampleValue
fields are defined differently on a per-sample basis
(in Rev. 6.0 the
.I Compression
tag is not defined on a per-sample basis, so this is immaterial).
.SH "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
.SM TIFF
format.
The following typedefs are exposed to users either through
function definitions or through parameters passed through the
varargs interfaces.
.in +.5i
.sp 5p
.ta +\w'typedef unsigned <\fIthing\fP> uint32;    'u
.nf
typedef unsigned short uint16;	16-bit unsigned integer
typedef unsigned <\fIthing\fP> uint32;	32-bit unsigned integer
.sp 5p
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
.fi
.sp 5p
.in -.5i
Note that
.IR tstrip_t ,
.IR ttile_t ,
and
.I tsize_t
are constrained to be no more than 32-bit quantities by
32-bit fields they are stored in in the
.SM TIFF
image.
Likewise
.I tsample_t
is limited by the 16-bit field used to store the
.I SamplesPerPixel
tag.
.I tdir_t
constrains the maximum number of
.SM IFDs
that may appear in an image and may be an arbitrary size (w/o penalty). 
.I ttag_t
must be either int, unsigned int, pointer, or double because
the library uses a varargs interface and
.SM "ANSI C"
restricts the type of the parameter before an ellipsis to be a
promoted type.
.I 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.
.SH "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.
.sp 5p
.nf
.ta \w'TIFFWriteEncodedStrip'u+2n +\w'Appears on Page'u+2n
\fIName\fP	\fIAppears on Page\fP	\fIDescription\fP
.sp 5p
TIFFCheckpointDirectory writedir.3t	writes the current state of the directory
TIFFCheckTile	tile.3t	very x,y,z,sample is within image
TIFFCIELabToRGBInit	color.3t	initialize CIE L*a*b* 1976 to RGB conversion state
TIFFCIELabToXYZ	color.3t	perform CIE L*a*b* 1976 to CIE XYZ conversion
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
TIFFDataWidth 	width.3t	return the size of TIFF data types
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
TIFFFindCODEC	codec.3t	find standard codec for the specific scheme
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
TIFFIsCODECConfigured	codec.3t	check, whether we have working codec
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
TIFFRegisterCODEC	codec.3t	override standard codec for the specific scheme
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	strip.3t	returns size of a strip
TIFFRawStripSize	strip.3t	returns the number of bytes in a raw 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
TIFFUnRegisterCODEC	codec.3t	unregisters the codec
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
TIFFVStripSize	strip.3t	returns the number of bytes in a strip
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
TIFFXYZToRGB	color.3t	perform CIE XYZ to RGB conversion
TIFFYCbCrToRGBInit	color.3t	initialize YCbCr to RGB conversion state
TIFFYCbCrtoRGB	color.3t	perform YCbCr to RGB conversion
.fi
.SH "TAG USAGE"
The table below lists the
.SM 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.
.I Group3Options
is only useful if 
.I Compression
is set to
.SM CCITT
Group 3 encoding.
Tags of this sort are considered
.I codec-specific
tags and the library does not recognize them except when the
.I Compression
tag has been previously set to the relevant compression scheme.
.sp 5p
.nf
.ta \w'TIFFTAG_JPEGTABLESMODE'u+2n +\w'Value'u+2n +\w'R/W'u+2n
\fITag Name\fP	\fIValue\fP	\fIR/W\fP	\fILibrary Use/Notes\fP
.sp 5p
.nf
Artist	315	R/W
BadFaxLines	326	R/W
BitsPerSample	258	R/W	lots
CellLength	265		parsed but ignored
CellWidth	264		parsed but ignored