NAME

TIFFFieldQuery - routines to query TIFF field information

SYNOPSIS

#include <tiffio.h>

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().

All three functions return NULL, when the tag is not registered within libtiff (see also Default Tag Auto-registration ).

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 an 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. See also description of TIFFFieldReadCount().

DIAGNOSTICS

None.

SEE ALSO

TIFFFieldDataType (3tiff), TIFFFieldName (3tiff), TIFFFieldPassCount (3tiff), TIFFFieldReadCount (3tiff), TIFFFieldTag (3tiff), TIFFFieldWriteCount (3tiff), libtiff (3tiff)

AUTHOR

LibTIFF contributors

COPYRIGHT

1988-2022, LibTIFF contributors