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  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_FAXFILLFUNC             1      TIFFFaxFillFunc*  G3/G4 compression pseudo-tag
       TIFFTAG_FAXMODE                 1      int*              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_ICCPROFILE              2      uint32*,void**    count, profile data
       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_JPEGCOLORMODE           1      int*              JPEG pseudo-tag
       TIFFTAG_JPEGQUALITY             1      int*              JPEG pseudo-tag
       TIFFTAG_JPEGTABLES              2      uint32*,void**    count & tables
       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_PHOTOSHOP               2      uint32*,void**    count, data
       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_RICHTIFFIPTC            2      uint32*,void**    count, data
       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_XMLPACKET               2      uint32*,void**    count, data
       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*
         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 unsupported tag. But you 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:

              uint16  count;
              void    *data;

              TIFFGetField(tiff, 33424, &count, &data);
              printf("Tag %d: %d, count %d0, 33424, *(uint32 *)data, count);
              TIFFGetField(tiff, 36867, &count, &data);
              printf("Tag %d: %s, count %d0, 36867, (char *)data, count);



       is not supported by libtiff(3TIFF), library

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
       TIFFOpen(3TIFF),   TIFFSetField(3TIFF),    TIFFSetDirec-
       tory(3TIFF),  TIFFReadDirectory(3TIFF),  TIFFWriteDirec-
       tory(3TIFF) libtiff(3TIFF),

       Libtiff  library   home   page:   http://www.remotesens-
       ing.org/libtiff/



libtiff                  March 18, 2005     TIFFGetField(3TIFF)
