TIFFGetField
TIFFGetField(3T) TIFFGetField(3T)
NAME
TIFFGetField, TIFFVGetField - get the value(s) of a tag in an open
TIFF file
SYNOPSIS
#include <tiffio.h>
int TIFFGetField(TIFF* tif, ttag_t tag, ...)
#include <stdarg.h>
int TIFFVGetField(TIFF* tif, ttag_t tag, va_list ap)
int TIFFGetFieldDefaulted(TIFF* tif, ttag_t tag, ...)
int TIFFVGetFieldDefaulted(TIFF* tif, ttag_t tag, va_list ap)
DESCRIPTION
TIFFGetField returns the value of a tag or pseudo-tag associated with
the the current directory of the open TIFF file tif. (A pseudo-tag is
a parameter that is used to control the operation of the TIFF library
but whose value is not read or written to the underlying file.) The
file must have been previously opened with TIFFOpen(3T). The tag is
identified by tag, one of the values defined in the include file
tiff.h (see also the table below). The type and number of values
returned is dependent on the tag being requested. The programming
interface uses a variable argument list as prescribed by the stdarg(3)
interface. The returned values should only be interpreted if TIFFGet-
Field returns 1.
TIFFVGetField is functionally equivalent to TIFFGetField except that
it takes a pointer to a variable argument list. TIFFVGetField is use-
ful for layering interfaces on top of the functionality provided by
TIFFGetField.
TIFFGetFieldDefaulted and TIFFVGetFieldDefaulted are identical to
TIFFGetField and TIFFVGetField, except that if a tag is not defined in
the current directory and it has a default value, then the default
value is returned.
The tags understood by libtiff, the number of parameter values, and
the types for the returned values are shown below. The data types are
specified as in C and correspond to the types used to specify tag val-
ues to TIFFSetField(3T). Remember that TIFFGetField returns parameter
values, so all the listed data types are pointers to storage where
values should be returned. Consult the TIFF specification for infor-
mation on the meaning of each tag and their possible values.
Tag Name Count Types Notes
TIFFTAG_ARTIST 1 char**
TIFFTAG_BADFAXLINES 1 uint32*
TIFFTAG_BITSPERSAMPLE 1 uint16*
TIFFTAG_CLEANFAXDATA 1 uint16*
TIFFTAG_COLORMAP 3 uint16** 1<<BitsPerSample arrays
TIFFTAG_COMPRESSION 1 uint16*
TIFFTAG_CONSECUTIVEBADFAXLINES 1 uint32*
TIFFTAG_COPYRIGHT 1 char**
TIFFTAG_DATATYPE 1 uint16*
TIFFTAG_DATETIME 1 char**
TIFFTAG_DOCUMENTNAME 1 char**
TIFFTAG_DOTRANGE 2 uint16*
TIFFTAG_EXTRASAMPLES 2 uint16*,uint16** count & types array
TIFFTAG_FAXMODE 1 int* G3/G4 compression pseudo-tag
TIFFTAG_FAXFILLFUNC 1 TIFFFaxFillFunc* G3/G4 compression pseudo-tag
TIFFTAG_FILLORDER 1 uint16*
TIFFTAG_GROUP3OPTIONS 1 uint32*
TIFFTAG_GROUP4OPTIONS 1 uint32*
TIFFTAG_HALFTONEHINTS 2 uint16*
TIFFTAG_HOSTCOMPUTER 1 char**
TIFFTAG_IMAGEDEPTH 1 uint32*
TIFFTAG_IMAGEDESCRIPTION 1 char**
TIFFTAG_IMAGELENGTH 1 uint32*
TIFFTAG_IMAGEWIDTH 1 uint32*
TIFFTAG_INKNAMES 1 char**
TIFFTAG_INKSET 1 uint16*
TIFFTAG_JPEGTABLES 2 u_short*,void** count & tables
TIFFTAG_JPEGQUALITY 1 int* JPEG pseudo-tag
TIFFTAG_JPEGCOLORMODE 1 int* JPEG pseudo-tag
TIFFTAG_JPEGTABLESMODE 1 int* JPEG pseudo-tag
TIFFTAG_MAKE 1 char**
TIFFTAG_MATTEING 1 uint16*
TIFFTAG_MAXSAMPLEVALUE 1 uint16*
TIFFTAG_MINSAMPLEVALUE 1 uint16*
TIFFTAG_MODEL 1 char**
TIFFTAG_ORIENTATION 1 uint16*
TIFFTAG_PAGENAME 1 char**
TIFFTAG_PAGENUMBER 2 uint16*
TIFFTAG_PHOTOMETRIC 1 uint16*
TIFFTAG_PLANARCONFIG 1 uint16*
TIFFTAG_PREDICTOR 1 uint16*
TIFFTAG_PRIMARYCHROMATICITIES 1 float** 6-entry array
TIFFTAG_REFERENCEBLACKWHITE 1 float** 2*SamplesPerPixel array
TIFFTAG_RESOLUTIONUNIT 1 uint16*
TIFFTAG_ROWSPERSTRIP 1 uint32*
TIFFTAG_SAMPLEFORMAT 1 uint16*
TIFFTAG_SAMPLESPERPIXEL 1 uint16*
TIFFTAG_SMAXSAMPLEVALUE 1 double*
TIFFTAG_SMINSAMPLEVALUE 1 double*
TIFFTAG_SOFTWARE 1 char**
TIFFTAG_STONITS 1 double**
TIFFTAG_STRIPBYTECOUNTS 1 uint32**
TIFFTAG_STRIPOFFSETS 1 uint32**
TIFFTAG_SUBFILETYPE 1 uint32*
TIFFTAG_SUBIFD 2 uint16*,uint32** count & offsets array
TIFFTAG_TARGETPRINTER 1 char**
TIFFTAG_THRESHHOLDING 1 uint16*
TIFFTAG_TILEBYTECOUNTS 1 uint32**
TIFFTAG_TILEDEPTH 1 uint32*
TIFFTAG_TILELENGTH 1 uint32*
TIFFTAG_TILEOFFSETS 1 uint32**
TIFFTAG_TILEWIDTH 1 uint32*
TIFFTAG_TRANSFERFUNCTION 1 or 3† uint16**1<<BitsPerSample entry arrays
TIFFTAG_WHITEPOINT 1 float** 2-entry array
TIFFTAG_XPOSITION 1 float*
TIFFTAG_XRESOLUTION 1 float*
TIFFTAG_YCBCRCOEFFICIENTS 1 float** 3-entry array
TIFFTAG_YCBCRPOSITIONING 1 uint16*
TIFFTAG_YCBCRSUBSAMPLING 2 uint16*
TIFFTAG_YPOSITION 1 float*
TIFFTAG_YRESOLUTION 1 float*
TIFFTAG_ICCPROFILE 2 uint32*,void** count, profile data‡
† If SamplesPerPixel is one, then a single array is returned; other-
wise three arrays are returned.
‡ The contents of this field are quite complex. See The ICC Profile
Format Specification, Annex B.3 "Embedding ICC Profiles in TIFF Files"
(available at http://www.color.org) for an explanation.
RETURN VALUES
1 is returned if the tag is defined in the current directory; other-
wise a 0 is returned.
DIAGNOSTICS
All error messages are directed to the TIFFError(3T) routine.
Unknown field, tag 0x%x. An unknown tag was supplied.
SEE ALSO
libtiff(3T), TIFFOpen(3T), TIFFSetField(3T), TIFFSetDirectory(3T),
TIFFReadDirectory(3T), TIFFWriteDirectory(3T)
August 22, 1997 TIFFGetField(3T)
