TIFFSetField(3T)

NAME
TIFFSetField - set the value(s) of a tag in a TIFF file open for writing

SYNOPSIS
#include <tiffio.h>
int TIFFSetField(TIFF* tif, int tag, ...)
#include <stdarg.h>
int TIFFVSetField(TIFF* tif, int tag, va_list ap)

DESCRIPTION
TIFFSetField() sets the value of a field in the current directory associated with the open TIFF file tif. The file must have been previously opened for writing with TIFFOpen(3T). The field is identified by tag, one of the values defined in the include file tiff.h (see also the table below). The actual value is specified using a variable argument list, as prescribed by the stdarg(3) interface (or, on some machines, the varargs(3) interface.) A 1 is returned if the operation was successful, or 0 if an error was detected.

TIFFVSetField() is functionally equivalent to TIFFSetField(); except that it takes a pointer to a variable argument list. TIFFVSetField is useful for writing routines that are layered on top of the functionality provided by TIFFSetField.

The tags understood by libtiff, the number of parameter values, and the expected types for the parameter values are shown below. The data types are specified as in C: char* is null-terminated string and corresponds to the ASCII data type; u_short is an unsigned 16-bit value; u_long is an unsigned 32-bit value; u_short* is an array of unsigned 16-bit values. Consult the TIFF specification for information on the meaning of each tag.

Tag Name	Count	Types	Notes

TIFFTAG_ARTIST	1	char*
TIFFTAG_BADFAXLINES	1	u_long
TIFFTAG_BITSPERSAMPLE	1	u_short	†
TIFFTAG_CLEANFAXDATA	1	u_short
TIFFTAG_COLORMAP	3	u_short*	1<<BitsPerSample arrays
TIFFTAG_COMPRESSION	1	u_short	†
TIFFTAG_CONSECUTIVEBADFAXLINES	1	u_long
TIFFTAG_DATETIME	1	char*
TIFFTAG_DOCUMENTNAME	1	char*
TIFFTAG_DOTRANGE	2	u_short
TIFFTAG_FILLORDER	1	u_short	†
TIFFTAG_GROUP3OPTIONS	1	u_long	†
TIFFTAG_GROUP4OPTIONS	1	u_long	†
TIFFTAG_HALFTONEHINTS	2	u_short
TIFFTAG_HOSTCOMPUTER	1	char*
TIFFTAG_IMAGEDESCRIPTION	1	char*
TIFFTAG_IMAGEDEPTH	1	u_long	†
TIFFTAG_IMAGELENGTH	1	u_long
TIFFTAG_IMAGEWIDTH	1	u_long	†
TIFFTAG_INKNAMES	1	char*
TIFFTAG_INKSET	1	u_short	†
TIFFTAG_JPEGPROC	1	u_short	†
TIFFTAG_JPEGRESTARTINTERVAL	1	u_short	†
TIFFTAG_JPEGACTABLES	1	u_char**	† SamplesPerPixel arrays
TIFFTAG_JPEGDCTABLES	1	u_char**	† SamplesPerPixel arrays
TIFFTAG_JPEGQTABLES	1	u_short**	† SamplesPerPixel 64-entry arrays
TIFFTAG_MAKE	1	char*
TIFFTAG_MATTEING	1	u_short	†
TIFFTAG_MAXSAMPLEVALUE	1	u_short
TIFFTAG_MINSAMPLEVALUE	1	u_short
TIFFTAG_MODEL	1	char*
TIFFTAG_ORIENTATION	1	u_short
TIFFTAG_PAGENAME	1	char*
TIFFTAG_PAGENUMBER	2	u_short
TIFFTAG_PHOTOMETRIC	1	u_short
TIFFTAG_PLANARCONFIG	1	u_short	†
TIFFTAG_PREDICTOR	1	u_short	†
TIFFTAG_PRIMARYCHROMATICITIES	1	float	6-entry array
TIFFTAG_REFERENCEBLACKWHITE	1	float*	† 2*SamplesPerPixel array
TIFFTAG_RESOLUTIONUNIT	1	u_short
TIFFTAG_ROWSPERSTRIP	1	u_long	† must be > 0
TIFFTAG_SAMPLEFORMAT	1	u_short	†
TIFFTAG_SAMPLESPERPIXEL	1	u_short	† value must be <= 4
TIFFTAG_SOFTWARE	1	char*
TIFFTAG_SUBFILETYPE	1	u_long
TIFFTAG_TARGETPRINTER	1	char*
TIFFTAG_THRESHHOLDING	1	u_short
TIFFTAG_TILEDEPTH	1	u_long	†
TIFFTAG_TILELENGTH	1	u_long	† must be a multiple of 8
TIFFTAG_TILEWIDTH	1	u_long	† must be a multiple of 8
TIFFTAG_TRANSFERFUNCTION	S‡	u_short*	1<<BitsPerSample entry arrays
TIFFTAG_XPOSITION	1	float
TIFFTAG_XRESOLUTION	1	float
TIFFTAG_WHITEPOINT	1	float	2-entry array
TIFFTAG_YCBCRCOEFFICIENTS	1	float*	† 3-entry array
TIFFTAG_YCBCRPOSITIONING	1	u_short	†
TIFFTAG_YCBCRSAMPLING	2	u_short	†
TIFFTAG_YPOSITION	1	float
TIFFTAG_YRESOLUTION	1	float

(† Tag may not have its values changed once data is written.) (‡ S indicates SamplesPerPixels parameters.)

DIAGNOSTICS
All error messages are directed to the TIFFError(3T) routine.

%s: Cannot modify tag "%s" while writing. Data has already been written to the file, so the specified tag's value can not be changed. This restriction is applied to all tags that affect the format of written data.

Cannot handle %d-channel data A value greater than 4 was specified for the SamplesPerPixel tag. The library handles at most 4 channel images.

%d: Bad value for "%s". An invalid value was supplied for the named tag.

SEE ALSO
intro(3T), TIFFOpen(3T), TIFFGetField(3T), TIFFSetDirectory(3T), TIFFWriteDirectory(3T), TIFFReadDirectory(3T)