NAME

       TIFFFieldQuery - routines to query TIFF field information

SYNOPSIS

          #include <tiffio.h>

       const TIFFField *TIFFFieldWithName(TIFF *tif, const char *field_name)

       const TIFFField *TIFFFieldWithTag(TIFF *tif, uint32_t tag)

       const TIFFField *TIFFFindField(TIFF *tif, uint32_t tag, TIFFDataType dt)

       int TIFFFieldIsAnonymous(const TIFFField *fip)

       int TIFFFieldSetGetSize(const TIFFField *fip)

       int TIFFFieldSetGetCountSize(const TIFFField *fip)

DESCRIPTION

       TIFFFieldWithName()  and  TIFFFieldWithTag()  return  a  pointer to TIFF field information
       structure fip by the tag's field_name or its tag number.

       TIFFFindField() searches for the TIFF field information  structure  fip  of  a  given  tag
       number  and a specific TIFFDataType dt.  With dt== TIFF_ANY the behaviour is the same than
       for TIFFFieldWithTag().
          Such a TIFFDataType dependent search could be useful when the same tag is defined twice
          but    with   different   data   types,   which   is   true   for   rare   cases   like
          TIFFTAG_XCLIPPATHUNITS. However,  the  libtiff  does  currently  not  support  multiple
          definitions of the same tag.

       The following routines return status information about TIFF fields.
          fip   is   a   field   information  pointer  previously  returned  by  TIFFFindField(),
          TIFFFieldWithTag(), TIFFFieldWithName().

       TIFFFieldIsAnonymous() returns true (nonzero) if the field, read from file, is unknown  to
       libtiff  and  a  anonymous  field has been auto-registered. Return is zero "0" if field is
       known to libtiff.  See  Default Tag Auto-registration   for more information.

       TIFFFieldSetGetSize() returns the data size in bytes of  the  field  data  type  used  for
       libtiff  internal  storage.  This is also the data size of the parameter to be provided to
       TIFFSetField() and TIFFGetField(). Custom TIFF_RATIONAL values can  be  stored  internally
       either   as  float  or  double.  TIFFFieldSetGetSize()  would  then  return  "4"  or  "8",
       respectively.

       TIFFFieldSetGetCountSize()  returns  size  of  count  parameter  of   TIFFSetField()   and
       TIFFGetField() and also if it is required:  0=none, 2= uint16_t, 4= uint32_t

DIAGNOSTICS

       None.

SEE ALSO

       libtiff (3tiff)

AUTHOR

       LibTIFF contributors

COPYRIGHT

       1988-2024, LibTIFF contributors