Tribblix: manual page: TIFFGetField.3tiff

TIFFGetField(3TIFF) TIFFGetField(3TIFF)

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 opened 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(3TIFF). 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 TIFFGetField returns 1.

TIFFVGetField is functionally equivalent to TIFFGetField except that
it takes a pointer to a variable argument list. TIFFVGetField is
useful 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(3TIFF), 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 values to TIFFSetField(3TIFF). 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 (or relevant industry specification) for
information on the meaning of each tag and their possible values.

Tag Name Count TypesNotes
TIFFTAG_ARTIST 1 const char**
TIFFTAG_BADFAXLINES 1 uint32_t*
TIFFTAG_BITSPERSAMPLE 1 uint16_t*
TIFFTAG_CLEANFAXDATA 1 uint16_t*
TIFFTAG_COLORMAP 3 const uint16_t**1<<BitsPerSample arrays
TIFFTAG_COMPRESSION 1 uint16_t*
TIFFTAG_CONSECUTIVEBADFAXLINES 1 uint32_t*
TIFFTAG_COPYRIGHT 1 const char**
TIFFTAG_DATATYPE 1 uint16_t*
TIFFTAG_DATETIME 1 const char**
TIFFTAG_DOCUMENTNAME 1 const char**
TIFFTAG_DOTRANGE 2 uint16_t*
TIFFTAG_EXTRASAMPLES 2 uint16_t*,const uint16_t**count & types array
TIFFTAG_FAXFILLFUNC 1 TIFFFaxFillFunc*G3/G4 compression pseudo-tag
TIFFTAG_FAXMODE 1 int* G3/G4 compression pseudo-tag
TIFFTAG_FILLORDER 1 uint16_t*
TIFFTAG_GROUP3OPTIONS 1 uint32_t*
TIFFTAG_GROUP4OPTIONS 1 uint32_t*
TIFFTAG_HALFTONEHINTS 2 uint16_t*
TIFFTAG_HOSTCOMPUTER 1 const char**
TIFFTAG_ICCPROFILE 2 const uint32_t*,const void**count, profile data
TIFFTAG_IMAGEDEPTH 1 uint32_t*
TIFFTAG_IMAGEDESCRIPTION 1 const char**
TIFFTAG_IMAGELENGTH 1 uint32_t*
TIFFTAG_IMAGEWIDTH 1 uint32_t*
TIFFTAG_INKNAMES 1 const char**
TIFFTAG_INKSET 1 uint16_t*
TIFFTAG_JPEGCOLORMODE 1 int* JPEG pseudo-tag
TIFFTAG_JPEGQUALITY 1 int* JPEG pseudo-tag
TIFFTAG_JPEGTABLES 2 uint32_t*,const void**count & tables
TIFFTAG_JPEGTABLESMODE 1 int* JPEG pseudo-tag
TIFFTAG_MAKE 1 const char**
TIFFTAG_MATTEING 1 uint16_t*
TIFFTAG_MAXSAMPLEVALUE 1 uint16_t*
TIFFTAG_MINSAMPLEVALUE 1 uint16_t*
TIFFTAG_MODEL 1 const char**
TIFFTAG_ORIENTATION 1 uint16_t*
TIFFTAG_PAGENAME 1 const char**
TIFFTAG_PAGENUMBER 2 uint16_t*
TIFFTAG_PHOTOMETRIC 1 uint16_t*
TIFFTAG_PHOTOSHOP 2 uint32_t*,const void**count, data
TIFFTAG_PLANARCONFIG 1 uint16_t*
TIFFTAG_PREDICTOR 1 uint16_t*
TIFFTAG_PRIMARYCHROMATICITIES 1 const float** 6-entry array
TIFFTAG_REFERENCEBLACKWHITE 1 const float** 6-entry array
TIFFTAG_RESOLUTIONUNIT 1 uint16_t*
TIFFTAG_RICHTIFFIPTC 2 uint32_t*,const void**count, data
TIFFTAG_ROWSPERSTRIP 1 uint32_t*
TIFFTAG_SAMPLEFORMAT 1 uint16_t*
TIFFTAG_SAMPLESPERPIXEL 1 uint16_t*
TIFFTAG_SMAXSAMPLEVALUE 1 double*
TIFFTAG_SMINSAMPLEVALUE 1 double*
TIFFTAG_SOFTWARE 1 const char**
TIFFTAG_STONITS 1 const double**
TIFFTAG_STRIPBYTECOUNTS 1 const uint64_t**
TIFFTAG_STRIPOFFSETS 1 const uint64_t**
TIFFTAG_SUBFILETYPE 1 uint32_t*
TIFFTAG_SUBIFD 2 uint16_t*,const uint64_t**count & offsets array
TIFFTAG_TARGETPRINTER 1 const char**
TIFFTAG_THRESHHOLDING 1 uint16_t*
TIFFTAG_TILEBYTECOUNTS 1 const uint64_t**
TIFFTAG_TILEDEPTH 1 uint32_t*
TIFFTAG_TILELENGTH 1 uint32_t*
TIFFTAG_TILEOFFSETS 1 const uint64_t**
TIFFTAG_TILEWIDTH 1 uint32_t*
TIFFTAG_TRANSFERFUNCTION 1 or 3<*> const uint16_t**1<<BitsPerSample entry arrays
TIFFTAG_WHITEPOINT 1 const float** 2-entry array
TIFFTAG_XMLPACKET 2 uint32_t*,const void**count, data
TIFFTAG_XPOSITION 1 float*
TIFFTAG_XRESOLUTION 1 float*
TIFFTAG_YCBCRCOEFFICIENTS 1 const float** 3-entry array
TIFFTAG_YCBCRPOSITIONING 1 uint16_t*
TIFFTAG_YCBCRSUBSAMPLING 2 uint16_t*
TIFFTAG_YPOSITION 1 float*
TIFFTAG_YRESOLUTION 1 float*<**>
<*> If SamplesPerPixel is one, then a single array is returned;
otherwise 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.

AUTOREGISTERED TAGS

If you can't find the tag in the table above that means this is an
unsupported tag and is not directly supported by libtiff(3TIFF)
library. You will still be able to read it's value if you know the
data type of that tag. For example, if you want to read the LONG
value from the tag 33424 and ASCII string from the tag 36867 you can
use the following code:

uint32_t count;
void *data;

TIFFGetField(tiff, 33424, &count, &data);
printf("Tag %d: %d, count %d0, 33424, *(uint32_t *)data, count);
TIFFGetField(tiff, 36867, &count, &data);
printf("Tag %d: %s, count %d0, 36867, (char *)data, count);

RETURN VALUES

1 is returned if the tag is defined in the current directory;
otherwise a 0 is returned.

DIAGNOSTICS