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TIFFGetField(3T)  Image Format Library C++ Reference Manual   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, ttagt tag, ...)

#include <stdarg.h>
int TIFFVGetField(TIFF* tif, ttagt tag, valist ap)
int TIFFGetFieldDefaulted(TIFF* tif, ttagt tag, ...) int TIFFVGetFieldDefaulted(TIFF* tif, ttagt tag, valist 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 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, 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(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 information 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_DATATYPE 1 uint16*
TIFFTAG_DATETIME 1 char**
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TIFFGetField(3T)  Image Format Library C++ Reference Manual   TIFFGetField(3T)



     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_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



                                                                        Page 2





TIFFGetField(3T)  Image Format Library C++ Reference Manual   TIFFGetField(3T)



     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; 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.

RETURN VALUES
     1 is returned if the tag is defined in the current directory; otherwise 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)




























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