libtiff.3t

tiff文件开发库

CleanFaxData	327	R/W
ColorMap	320	R/W
ColorResponseUnit	300		parsed but ignored
Compression	259	R/W	choosing codec
ConsecutiveBadFaxLines	328	R/W
Copyright       33432   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
.SH "PSEUDO TAGS"
In addition to the normal
.SM TIFF
tags the library supports a collection of 
tags whose values lie in a range outside the valid range of 
.SM TIFF
tags.
These tags are termed
.I pseud-tags
and are used to control various codec-specific functions within the library.
The table below summarizes the defined pseudo-tags.
.sp 5p
.nf
.ta \w'TIFFTAG_JPEGTABLESMODE'u+2n +\w'Codec'u+2n +\w'R/W'u+2n
\fITag Name\fP	\fICodec\fP	\fIR/W\fP	\fILibrary Use/Notes\fP
.sp 5p
.nf
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 \fIJPEGTables\fP 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
.fi
.TP
.B 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
.SM 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 
.SM 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.
.TP
.B 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 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.
.TP
.B TIFFTAG_IPTCNEWSPHOTO
Tag contaings image metadata per the IPTC newsphoto spec: Headline, 
captioning, credit, etc... Used by most wire services. 
.TP
.B TIFFTAG_PHOTOSHOP
Tag contains Photoshop captioning information and metadata. Photoshop 
uses in parallel and redundantly alongside IPTCNEWSPHOTO information. 
.TP
.B TIFFTAG_JPEGQUALITY
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.
.TP
.B 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.
.TP
.B TIFFTAG_JPEGTABLESMODE
Control the information written in the 
.I 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.
.TP
.B 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.
.TP
.B TIFFTAG_PIXARLOGDATAFMT
Control the format of user data passed
.I in
to the PixarLog codec when encoding and passed
.I out
from when decoding.
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.
.TP
.B TIFFTAG_PIXARLOGQUALITY
Control the compression technique used by the PixarLog codec.
This value is treated identically to TIFFTAG_ZIPQUALITY; see the
above description.
.TP
.B TIFFTAG_SGILOGDATAFMT
Control the format of client data passed 
.I in
to the SGILog codec when encoding and passed
.I out
from when decoding.
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).
.SH DIAGNOSTICS
All error messages are directed through the
.IR TIFFError
routine.
By default messages are directed to
.B stderr
in the form:
.IR "module: message\en."
Warning messages are likewise directed through the
.IR TIFFWarning
routine.
.SH "SEE ALSO"
.IR fax2tiff (1),
.IR gif2tiff (1),
.IR pal2rgb (1),
.IR ppm2tiff (1),
.IR rgb2ycbcr (1),
.IR ras2tiff (1),
.IR raw2tiff (1),
.IR sgi2tiff (1),
.IR tiff2bw (1),
.IR tiffdither (1),
.IR tiffdump (1),
.IR tiffcp (1),
.IR tiffcmp (1),
.IR tiffgt (1),
.IR tiffinfo (1),
.IR tiffmedian (1),
.IR tiffsplit (1),
.IR tiffsv (1),
.PP
.IR "Tag Image File Format Specification \(em Revision 6.0" ,
an Aldus Technical Memorandum.
.PP
.IR "The Spirit of TIFF Class F" ,
an appendix to the TIFF 5.0 specification prepared by Cygnet Technologies.
.SH BUGS
The library does not support multi-sample images
where some samples have different bits/sample.
.PP
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.