TIFFSetField

Synopsis

#include <tiffio.h>
#include <stdarg.h>"
int TIFFSetField(TIFF *tif, ttag_t tag, ...)
int TIFFVSetField(TIFF *tif, ttag_t tag, va_list ap)
int TIFFUnsetField(TIFF *tif, uint32_t tag)

Description

TIFFSetField() sets the value of a field or pseudo-tag in the current directory associated with the open 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.) To set the value of a field the file must have been previously opened for writing with TIFFOpen(). Pseudo-tags can be set whether the file was opened for reading or writing. 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.h interface.

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().

TIFFUnsetField() clears the contents of the field in the internal structure. If it is a custom field, it is removed from the list of known tags.

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:

Tag data types

Type

Description

char*

a null-terminated string corresponding to the ASCII data type

uint16_t

an unsigned 16-bit value

uint32_t

an unsigned 32-bit value;

uint16_t*

an array of unsigned 16-bit values.

void*

an array of data values of unspecified type.

Consult the TIFF specification for information on the meaning of each tag.

Tag properties

Tag name

Count

Types

Notes

TIFFTAG_ARTIST

1

char*

TIFFTAG_BADFAXLINES

1

uint32_t

TIFFTAG_BITSPERSAMPLE

1

uint16_t

TIFFTAG_CLEANFAXDATA

1

uint16_t

TIFFTAG_COLORMAP

3

uint16_t*

1 << BitsPerSample arrays

TIFFTAG_COMPRESSION

1

uint16_t

TIFFTAG_CONSECUTIVEBADFAXLINES

1

uint32_t

TIFFTAG_COPYRIGHT

1

char*

TIFFTAG_DATETIME

1

char*

TIFFTAG_DOCUMENTNAME

1

char*

TIFFTAG_DOTRANGE

2

uint16_t

TIFFTAG_EXTRASAMPLES

2

uint16_t, uint16_t*

† 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_t

TIFFTAG_GROUP3OPTIONS

1

uint32_t

TIFFTAG_GROUP4OPTIONS

1

uint32_t

TIFFTAG_HALFTONEHINTS

2

uint16_t

TIFFTAG_HOSTCOMPUTER

1

char*

TIFFTAG_ICCPROFILE

2

uint32_t, void*

count, profile data*

TIFFTAG_IMAGEDEPTH

1

uint32_t

TIFFTAG_IMAGEDESCRIPTION

1

char*

TIFFTAG_IMAGELENGTH

1

uint32_t

TIFFTAG_IMAGEWIDTH

1

uint32_t

TIFFTAG_INKNAMES

2

uint16_t, char*

TIFFTAG_INKSET

1

uint16_t

TIFFTAG_JPEGCOLORMODE

1

int

† JPEG pseudo-tag

TIFFTAG_JPEGQUALITY

1

int

JPEG pseudo-tag

TIFFTAG_JPEGTABLES

2

uint32_t*, void*

† count, tables

TIFFTAG_JPEGTABLESMODE

1

int

† JPEG pseudo-tag

TIFFTAG_MAKE

1

char*

TIFFTAG_MATTEING

1

uint16_t

TIFFTAG_MAXSAMPLEVALUE

1

uint16_t

TIFFTAG_MINSAMPLEVALUE

1

uint16_t

TIFFTAG_MODEL

1

char*

TIFFTAG_ORIENTATION

1

uint16_t

TIFFTAG_PAGENAME

1

char*

TIFFTAG_PAGENUMBER

2

uint16_t

TIFFTAG_PHOTOMETRIC

1

uint16_t

TIFFTAG_PHOTOSHOP

?

uint32_t, void*

count, data

TIFFTAG_PLANARCONFIG

1

uint16_t

TIFFTAG_PREDICTOR

1

uint16_t

TIFFTAG_PRIMARYCHROMATICITIES

1

float*

6-entry array

TIFFTAG_REFERENCEBLACKWHITE

1

float*

† 6-entry array

TIFFTAG_RESOLUTIONUNIT

1

uint16_t

TIFFTAG_RICHTIFFIPTC

2

uint32_t, void*

count, data

TIFFTAG_ROWSPERSTRIP

1

uint32_t

† must be > 0

TIFFTAG_SAMPLEFORMAT

1

uint16_t

TIFFTAG_SAMPLESPERPIXEL

1

uint16_t

† value must be ≤ 4

TIFFTAG_SMAXSAMPLEVALUE

1

double

TIFFTAG_SMINSAMPLEVALUE

1

double

TIFFTAG_SOFTWARE

1

char*

TIFFTAG_STONITS

1

double

TIFFTAG_SUBFILETYPE

1

uint32_t

TIFFTAG_SUBIFD

2

uint16_t, uint64_t*

count, offsets array

TIFFTAG_TARGETPRINTER

1

char*

TIFFTAG_THRESHHOLDING

1

uint16_t

TIFFTAG_TILEDEPTH

1

uint32_t

TIFFTAG_TILELENGTH

1

uint32_t

† must be a multiple of 8

TIFFTAG_TILEWIDTH

1

uint32_t

† must be a multiple of 8

TIFFTAG_TRANSFERFUNCTION

1 or 3‡

uint16_t*

1 << BitsPerSample entry arrays

TIFFTAG_WHITEPOINT

1

float*

2-entry array

TIFFTAG_XMLPACKET

2

uint32_t, void*

count, data

TIFFTAG_XPOSITION

1

float

TIFFTAG_XRESOLUTION

1

float

TIFFTAG_YCBCRCOEFFICIENTS

1

float*

† 3-entry array

TIFFTAG_YCBCRPOSITIONING

1

uint16_t

TIFFTAG_YCBCRSAMPLING

2

uint16_t

TIFFTAG_YPOSITION

1

float

TIFFTAG_YRESOLUTION

1

float

†:

Tag may not have its values changed once data is written.

‡:

If SamplesPerPixel is one, then a single array is passed; otherwise three arrays should be passed.

*:

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.

Return values

1 is returned if the operation was successful. Otherwise, 0 is returned if an error was detected.

Diagnostics

All error messages are directed to the TIFFError() 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.

%d: Bad value for "%s":

An invalid value was supplied for the named tag.

See also

TIFFOpen (3tiff), TIFFGetField (3tiff), TIFFSetDirectory (3tiff), TIFFWriteDirectory (3tiff), TIFFReadDirectory (3tiff), libtiff (3tiff)