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  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(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 val-
       ues  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 corre-
       spond to the types used to specify tag values  to  TIFF-
       SetField(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 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_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      uint32*,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; 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(3TIFF)
       routine.

       Unknown field, tag 0x%x.  An unknown tag was supplied.

SEE ALSO
       libtiff(3TIFF),   TIFFOpen(3TIFF),  TIFFSetField(3TIFF),
       TIFFSetDirectory(3TIFF),       TIFFReadDirectory(3TIFF),
       TIFFWriteDirectory(3TIFF)



libtiff                November 04, 2004    TIFFGetField(3TIFF)
