230 lines
7.7 KiB
Plaintext
230 lines
7.7 KiB
Plaintext
.\" $Id: TIFFGetField.3tiff,v 1.6 2012-05-19 23:15:22 bfriesen Exp $
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.\"
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.\" Copyright (c) 1988-1997 Sam Leffler
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.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
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.\"
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.\" Permission to use, copy, modify, distribute, and sell this software and
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.\" its documentation for any purpose is hereby granted without fee, provided
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.\" that (i) the above copyright notices and this permission notice appear in
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.\" all copies of the software and related documentation, and (ii) the names of
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.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
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.\" publicity relating to the software without the specific, prior written
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.\" permission of Sam Leffler and Silicon Graphics.
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.\"
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.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
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.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
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.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
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.\"
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.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
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.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
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.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
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.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
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.\" OF THIS SOFTWARE.
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.\"
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.if n .po 0
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.TH TIFFGetField 3TIFF "March 18, 2005" "libtiff"
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.SH NAME
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TIFFGetField, TIFFVGetField \- get the value(s) of a tag in an open
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.SM TIFF
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file
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.SH SYNOPSIS
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.B "#include <tiffio.h>"
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.sp
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.BI "int TIFFGetField(TIFF *" tif ", ttag_t " tag ", " ... ")"
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.sp
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.B "#include <stdarg.h>"
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.sp
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.BI "int TIFFVGetField(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
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.br
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.BI "int TIFFGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", " ... ")"
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.br
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.BI "int TIFFVGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
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.SH DESCRIPTION
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.IR TIFFGetField
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returns the value of a tag or pseudo-tag associated with the the current
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directory of the opened
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.SM TIFF
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file
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.IR tif .
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(A
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.I pseudo-tag
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is a parameter that is used to control the operation of the
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.SM TIFF
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library but whose value is not read or written to the underlying file.) The
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file must have been previously opened with
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.IR TIFFOpen (3TIFF).
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The tag is identified by
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.IR tag ,
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one of the values defined in the include file
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.B tiff.h
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(see also the table below). The type and number of values returned is
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dependent on the tag being requested. The programming interface uses a
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variable argument list as prescribed by the
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.IR stdarg (3)
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interface. The returned values should only be interpreted if
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.IR TIFFGetField
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returns 1.
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.PP
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.IR TIFFVGetField
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is functionally equivalent to
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.IR TIFFGetField
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except that it takes a pointer to a variable argument list.
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.I TIFFVGetField
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is useful for layering interfaces on top of the functionality provided by
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.IR TIFFGetField .
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.PP
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.IR TIFFGetFieldDefaulted
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and
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.IR TIFFVGetFieldDefaulted
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are identical to
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.IR TIFFGetField
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and
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.IR TIFFVGetField ,
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except that if a tag is not defined in the current directory and it has a
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default value, then the default value is returned.
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.PP
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The tags understood by
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.IR libtiff(3TIFF),
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the number of parameter values, and the types for the returned values are
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shown below. The data types are specified as in C and correspond to the types
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used to specify tag values to
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.IR TIFFSetField (3TIFF).
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Remember that
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.IR TIFFGetField
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returns parameter values, so all the listed data types are pointers to storage
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where values should be returned.
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Consult the
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.SM TIFF
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specification (or relevant industry specification) for information on the
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meaning of each tag and their possible values.
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.PP
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.nf
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.ta \w'TIFFTAG_CONSECUTIVEBADFAXLINES'u+2n +\w'Count'u+2n +\w'TIFFFaxFillFunc*'u+2n
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\fITag Name\fP \fICount\fP \fITypes\fP \fINotes\fP
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.sp 5p
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TIFFTAG_ARTIST 1 char**
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TIFFTAG_BADFAXLINES 1 uint32*
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TIFFTAG_BITSPERSAMPLE 1 uint16*
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TIFFTAG_CLEANFAXDATA 1 uint16*
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TIFFTAG_COLORMAP 3 uint16** 1<<BitsPerSample arrays
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TIFFTAG_COMPRESSION 1 uint16*
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TIFFTAG_CONSECUTIVEBADFAXLINES 1 uint32*
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TIFFTAG_COPYRIGHT 1 char**
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TIFFTAG_DATATYPE 1 uint16*
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TIFFTAG_DATETIME 1 char**
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TIFFTAG_DOCUMENTNAME 1 char**
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TIFFTAG_DOTRANGE 2 uint16*
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TIFFTAG_EXTRASAMPLES 2 uint16*,uint16** count & types array
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TIFFTAG_FAXFILLFUNC 1 TIFFFaxFillFunc* G3/G4 compression pseudo-tag
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TIFFTAG_FAXMODE 1 int* G3/G4 compression pseudo-tag
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TIFFTAG_FILLORDER 1 uint16*
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TIFFTAG_GROUP3OPTIONS 1 uint32*
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TIFFTAG_GROUP4OPTIONS 1 uint32*
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TIFFTAG_HALFTONEHINTS 2 uint16*
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TIFFTAG_HOSTCOMPUTER 1 char**
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TIFFTAG_ICCPROFILE 2 uint32*,void** count, profile data
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TIFFTAG_IMAGEDEPTH 1 uint32*
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TIFFTAG_IMAGEDESCRIPTION 1 char**
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TIFFTAG_IMAGELENGTH 1 uint32*
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TIFFTAG_IMAGEWIDTH 1 uint32*
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TIFFTAG_INKNAMES 1 char**
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TIFFTAG_INKSET 1 uint16*
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TIFFTAG_JPEGCOLORMODE 1 int* JPEG pseudo-tag
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TIFFTAG_JPEGQUALITY 1 int* JPEG pseudo-tag
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TIFFTAG_JPEGTABLES 2 uint32*,void** count & tables
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TIFFTAG_JPEGTABLESMODE 1 int* JPEG pseudo-tag
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TIFFTAG_MAKE 1 char**
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TIFFTAG_MATTEING 1 uint16*
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TIFFTAG_MAXSAMPLEVALUE 1 uint16*
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TIFFTAG_MINSAMPLEVALUE 1 uint16*
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TIFFTAG_MODEL 1 char**
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TIFFTAG_ORIENTATION 1 uint16*
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TIFFTAG_PAGENAME 1 char**
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TIFFTAG_PAGENUMBER 2 uint16*
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TIFFTAG_PHOTOMETRIC 1 uint16*
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TIFFTAG_PHOTOSHOP 2 uint32*,void** count, data
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TIFFTAG_PLANARCONFIG 1 uint16*
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TIFFTAG_PREDICTOR 1 uint16*
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TIFFTAG_PRIMARYCHROMATICITIES 1 float** 6-entry array
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TIFFTAG_REFERENCEBLACKWHITE 1 float** 6-entry array
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TIFFTAG_RESOLUTIONUNIT 1 uint16*
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TIFFTAG_RICHTIFFIPTC 2 uint32*,void** count, data
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TIFFTAG_ROWSPERSTRIP 1 uint32*
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TIFFTAG_SAMPLEFORMAT 1 uint16*
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TIFFTAG_SAMPLESPERPIXEL 1 uint16*
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TIFFTAG_SMAXSAMPLEVALUE 1 double*
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TIFFTAG_SMINSAMPLEVALUE 1 double*
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TIFFTAG_SOFTWARE 1 char**
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TIFFTAG_STONITS 1 double**
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TIFFTAG_STRIPBYTECOUNTS 1 uint32**
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TIFFTAG_STRIPOFFSETS 1 uint32**
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TIFFTAG_SUBFILETYPE 1 uint32*
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TIFFTAG_SUBIFD 2 uint16*,uint32** count & offsets array
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TIFFTAG_TARGETPRINTER 1 char**
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TIFFTAG_THRESHHOLDING 1 uint16*
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TIFFTAG_TILEBYTECOUNTS 1 uint32**
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TIFFTAG_TILEDEPTH 1 uint32*
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TIFFTAG_TILELENGTH 1 uint32*
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TIFFTAG_TILEOFFSETS 1 uint32**
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TIFFTAG_TILEWIDTH 1 uint32*
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TIFFTAG_TRANSFERFUNCTION 1 or 3\(dg uint16**1<<BitsPerSample entry arrays
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TIFFTAG_WHITEPOINT 1 float** 2-entry array
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TIFFTAG_XMLPACKET 2 uint32*,void** count, data
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TIFFTAG_XPOSITION 1 float*
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TIFFTAG_XRESOLUTION 1 float*
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TIFFTAG_YCBCRCOEFFICIENTS 1 float** 3-entry array
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TIFFTAG_YCBCRPOSITIONING 1 uint16*
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TIFFTAG_YCBCRSUBSAMPLING 2 uint16*
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TIFFTAG_YPOSITION 1 float*
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TIFFTAG_YRESOLUTION 1 float*\(dd
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.fi
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\(dg If
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.I SamplesPerPixel
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is one, then a single array is returned; otherwise three arrays are returned.
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.fi
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\(dd The contents of this field are quite complex. See
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.IR "The ICC Profile Format Specification" ,
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Annex B.3 "Embedding ICC Profiles in TIFF Files" (available at
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http://www.color.org) for an explanation.
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.SH AUTOREGISTERED TAGS
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If you can't find the tag in the table above that means this is an unsupported
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tag and is not directly supported by
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.BR libtiff(3TIFF)
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library. You will still be able to read it's value if you know the data type of
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that tag. For example, if you want to read the LONG value from the tag 33424
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and ASCII string from the tag 36867 you can use the following code:
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.PP
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.RS
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.nf
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uint32 count;
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void *data;
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TIFFGetField(tiff, 33424, &count, &data);
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printf("Tag %d: %d, count %d\n", 33424, *(uint32 *)data, count);
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TIFFGetField(tiff, 36867, &count, &data);
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printf("Tag %d: %s, count %d\n", 36867, (char *)data, count);
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.fi
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.RE
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.PP
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.SH RETURN VALUES
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1 is returned if the tag is defined in the current directory; otherwise a 0 is
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returned.
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.SH DIAGNOSTICS
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All error messages are directed to the
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.BR TIFFError (3TIFF)
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routine.
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.PP
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.BR "Unknown field, tag 0x%x" .
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An unknown tag was supplied.
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.SH "SEE ALSO"
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.BR TIFFOpen (3TIFF),
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.BR TIFFSetField (3TIFF),
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.BR TIFFSetDirectory (3TIFF),
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.BR TIFFReadDirectory (3TIFF),
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.BR TIFFWriteDirectory (3TIFF)
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.BR libtiff (3TIFF),
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.PP
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Libtiff library home page:
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.BR http://www.remotesensing.org/libtiff/
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