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TIFFGetField(3tiff)





TIFFGetField(3TIFF)MISC. REFERENCE MANUAL PAGETIFFGetField(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  asso-
     ciated  with  the  the  current directory of the opened TIFF
     file tif.  (A pseudo-tag is a parameter that is used to con-
     trol  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 argu-
     ment 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 identi-
     cal  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 parame-
     ter  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  for  information on the meaning of each
     tag and their possible values.

     Tag Name                        Count  Types             Notes
     TIFFTAG_ARTIST                  1      char**

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TIFFGetField(3TIFF)MISC. REFERENCE MANUAL PAGETIFFGetField(3TIFF)


     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**

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     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 Pro-
     files 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  direc-
     tory; otherwise a 0 is returned.


DIAGNOSTICS

     All error messages are directed to the TIFFError(3TIFF) rou-
     tine.

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TIFFGetField(3TIFF)MISC. REFERENCE MANUAL PAGETIFFGetField(3TIFF)


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


SEE ALSO

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

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