src/tiff/man/TIFFGetField.3tiff

.\" $Id: TIFFGetField.3tiff,v 1.4 2006/01/02 23:50:44 bfriesen Exp $
.\"
.\" Copyright (c) 1988-1997 Sam Leffler
.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
.\"
.\" Permission to use, copy, modify, distribute, and sell this software and
.\" its documentation for any purpose is hereby granted without fee, provided
.\" that (i) the above copyright notices and this permission notice appear in
.\" all copies of the software and related documentation, and (ii) the names of
.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
.\" publicity relating to the software without the specific, prior written
.\" permission of Sam Leffler and Silicon Graphics.
.\"
.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
.\"
.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
.\" OF THIS SOFTWARE.
.\"
.if n .po 0
.TH TIFFGetField 3TIFF "March 18, 2005" "libtiff"
.SH NAME
TIFFGetField, TIFFVGetField \- get the value(s) of a tag in an open
.SM TIFF
file
.SH SYNOPSIS
.B "#include <tiffio.h>"
.sp
.BI "int TIFFGetField(TIFF *" tif ", ttag_t " tag ", " ... ")"
.sp
.B "#include <stdarg.h>"
.sp
.BI "int TIFFVGetField(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
.br
.BI "int TIFFGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", " ... ")"
.br
.BI "int TIFFVGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
.SH DESCRIPTION
.IR TIFFGetField
returns the value of a tag or pseudo-tag associated with the the current
directory of the opened
.SM TIFF
file
.IR tif .
(A
.I pseudo-tag
is a parameter that is used to control the operation of the
.SM TIFF
library but whose value is not read or written to the underlying file.) The
file must have been previously opened with
.IR TIFFOpen (3TIFF).
The tag is identified by
.IR tag ,
one of the values defined in the include file
.B 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 argument list as prescribed by the
.IR stdarg (3)
interface. The returned values should only be interpreted if
.IR TIFFGetField
returns 1.
.PP
.IR TIFFVGetField
is functionally equivalent to
.IR TIFFGetField
except that it takes a pointer to a variable argument list.
.I TIFFVGetField
is useful for layering interfaces on top of the functionality provided by
.IR TIFFGetField .
.PP
.IR TIFFGetFieldDefaulted
and
.IR TIFFVGetFieldDefaulted
are identical to
.IR TIFFGetField
and
.IR 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.
.PP
The tags understood by
.IR libtiff(3TIFF),
the number of parameter 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
.IR TIFFSetField (3TIFF).
Remember that
.IR TIFFGetField
returns parameter values, so all the listed data types are pointers to storage
where values should be returned.
Consult the
.SM TIFF
specification (or relevant industry specification) for information on the
meaning of each tag and their possible values.
.PP
.nf
.ta \w'TIFFTAG_CONSECUTIVEBADFAXLINES'u+2n +\w'Count'u+2n +\w'TIFFFaxFillFunc*'u+2n
\fITag Name\fP	\fICount\fP	\fITypes\fP	\fINotes\fP
.sp 5p
TIFFTAG_ARTIST	1	char**
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_FAXFILLFUNC	1	TIFFFaxFillFunc*	G3/G4 compression pseudo-tag
TIFFTAG_FAXMODE	1	int*	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_ICCPROFILE	2	uint32*,void**	count, profile data
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_JPEGCOLORMODE	1	int*	JPEG pseudo-tag
TIFFTAG_JPEGQUALITY	1	int*	JPEG pseudo-tag
TIFFTAG_JPEGTABLES	2	uint32*,void**	count & tables
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_PHOTOSHOP	2	uint32*,void**	count, data
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_RICHTIFFIPTC	2	uint32*,void**	count, data
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**
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\(dg	uint16**1<<BitsPerSample entry arrays
TIFFTAG_WHITEPOINT	1	float**	2-entry array
TIFFTAG_XMLPACKET	2	uint32*,void**	count, data
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*\(dd
.fi
\(dg If
.I SamplesPerPixel
is one, then a single array is returned; otherwise three arrays are returned.
.fi
\(dd The contents of this field are quite complex.  See
.IR "The ICC Profile Format Specification" ,
Annex B.3 "Embedding ICC Profiles in TIFF Files" (available at
http://www.color.org) for an explanation.
.SH 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:
.PP
.RS
.nf
uint16  count;
void    *data;

TIFFGetField(tiff, 33424, &count, &data);
printf("Tag %d: %d, count %d\n", 33424, *(uint32 *)data, count);
TIFFGetField(tiff, 36867, &count, &data);
printf("Tag %d: %s, count %d\n", 36867, (char *)data, count);
.fi
.RE
.PP


is not supported by
.BR libtiff(3TIFF),
library
.SH RETURN VALUES
1 is returned if the tag is defined in the current directory; otherwise a 0 is
returned.
.SH DIAGNOSTICS
All error messages are directed to the
.BR TIFFError (3TIFF)
routine.
.PP
.BR "Unknown field, tag 0x%x" .
An unknown tag was supplied.
.SH "SEE ALSO"
.BR TIFFOpen (3TIFF),
.BR TIFFSetField (3TIFF),
.BR TIFFSetDirectory (3TIFF),
.BR TIFFReadDirectory (3TIFF),
.BR TIFFWriteDirectory (3TIFF)
.BR libtiff (3TIFF),
.PP
Libtiff library home page:
.BR http://www.remotesensing.org/libtiff/
Commit	Line	Data
	1	.\" $Id: TIFFGetField.3tiff,v 1.4 2006/01/02 23:50:44 bfriesen Exp $
	2	.\"
	3	.\" Copyright (c) 1988-1997 Sam Leffler
	4	.\" Copyright (c) 1991-1997 Silicon Graphics, Inc.
	5	.\"
	6	.\" Permission to use, copy, modify, distribute, and sell this software and
	7	.\" its documentation for any purpose is hereby granted without fee, provided
	8	.\" that (i) the above copyright notices and this permission notice appear in
	9	.\" all copies of the software and related documentation, and (ii) the names of
	10	.\" Sam Leffler and Silicon Graphics may not be used in any advertising or
	11	.\" publicity relating to the software without the specific, prior written
	12	.\" permission of Sam Leffler and Silicon Graphics.
	13	.\"
	14	.\" THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
	15	.\" EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
	16	.\" WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	17	.\"
	18	.\" IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
	19	.\" ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
	20	.\" OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
	21	.\" WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
	22	.\" LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
	23	.\" OF THIS SOFTWARE.
	24	.\"
	25	.if n .po 0
	26	.TH TIFFGetField 3TIFF "March 18, 2005" "libtiff"
	27	.SH NAME
	28	TIFFGetField, TIFFVGetField \- get the value(s) of a tag in an open
	29	.SM TIFF
	30	file
	31	.SH SYNOPSIS
	32	.B "#include <tiffio.h>"
	33	.sp
	34	.BI "int TIFFGetField(TIFF *" tif ", ttag_t " tag ", " ... ")"
	35	.sp
	36	.B "#include <stdarg.h>"
	37	.sp
	38	.BI "int TIFFVGetField(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
	39	.br
	40	.BI "int TIFFGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", " ... ")"
	41	.br
	42	.BI "int TIFFVGetFieldDefaulted(TIFF *" tif ", ttag_t " tag ", va_list " ap ")"
	43	.SH DESCRIPTION
	44	.IR TIFFGetField
	45	returns the value of a tag or pseudo-tag associated with the the current
	46	directory of the opened
	47	.SM TIFF
	48	file
	49	.IR tif .
	50	(A
	51	.I pseudo-tag
	52	is a parameter that is used to control the operation of the
	53	.SM TIFF
	54	library but whose value is not read or written to the underlying file.) The
	55	file must have been previously opened with
	56	.IR TIFFOpen (3TIFF).
	57	The tag is identified by
	58	.IR tag ,
	59	one of the values defined in the include file
	60	.B tiff.h
	61	(see also the table below). The type and number of values returned is
	62	dependent on the tag being requested. The programming interface uses a
	63	variable argument list as prescribed by the
	64	.IR stdarg (3)
	65	interface. The returned values should only be interpreted if
	66	.IR TIFFGetField
	67	returns 1.
	68	.PP
	69	.IR TIFFVGetField
	70	is functionally equivalent to
	71	.IR TIFFGetField
	72	except that it takes a pointer to a variable argument list.
	73	.I TIFFVGetField
	74	is useful for layering interfaces on top of the functionality provided by
	75	.IR TIFFGetField .
	76	.PP
	77	.IR TIFFGetFieldDefaulted
	78	and
	79	.IR TIFFVGetFieldDefaulted
	80	are identical to
	81	.IR TIFFGetField
	82	and
	83	.IR TIFFVGetField ,
	84	except that if a tag is not defined in the current directory and it has a
	85	default value, then the default value is returned.
	86	.PP
	87	The tags understood by
	88	.IR libtiff(3TIFF),
	89	the number of parameter values, and the types for the returned values are
	90	shown below. The data types are specified as in C and correspond to the types
	91	used to specify tag values to
	92	.IR TIFFSetField (3TIFF).
	93	Remember that
	94	.IR TIFFGetField
	95	returns parameter values, so all the listed data types are pointers to storage
	96	where values should be returned.
	97	Consult the
	98	.SM TIFF
	99	specification (or relevant industry specification) for information on the
	100	meaning of each tag and their possible values.
	101	.PP
	102	.nf
	103	.ta \w'TIFFTAG_CONSECUTIVEBADFAXLINES'u+2n +\w'Count'u+2n +\w'TIFFFaxFillFunc*'u+2n
	104	\fITag Name\fP \fICount\fP \fITypes\fP \fINotes\fP
	105	.sp 5p
	106	TIFFTAG_ARTIST 1 char**
	107	TIFFTAG_BADFAXLINES 1 uint32*
	108	TIFFTAG_BITSPERSAMPLE 1 uint16*
	109	TIFFTAG_CLEANFAXDATA 1 uint16*
	110	TIFFTAG_COLORMAP 3 uint16** 1<<BitsPerSample arrays
	111	TIFFTAG_COMPRESSION 1 uint16*
	112	TIFFTAG_CONSECUTIVEBADFAXLINES 1 uint32*
	113	TIFFTAG_COPYRIGHT 1 char**
	114	TIFFTAG_DATATYPE 1 uint16*
	115	TIFFTAG_DATETIME 1 char**
	116	TIFFTAG_DOCUMENTNAME 1 char**
	117	TIFFTAG_DOTRANGE 2 uint16*
	118	TIFFTAG_EXTRASAMPLES 2 uint16,uint16* count & types array
	119	TIFFTAG_FAXFILLFUNC 1 TIFFFaxFillFunc* G3/G4 compression pseudo-tag
	120	TIFFTAG_FAXMODE 1 int* G3/G4 compression pseudo-tag
	121	TIFFTAG_FILLORDER 1 uint16*
	122	TIFFTAG_GROUP3OPTIONS 1 uint32*
	123	TIFFTAG_GROUP4OPTIONS 1 uint32*
	124	TIFFTAG_HALFTONEHINTS 2 uint16*
	125	TIFFTAG_HOSTCOMPUTER 1 char**
	126	TIFFTAG_ICCPROFILE 2 uint32,void* count, profile data
	127	TIFFTAG_IMAGEDEPTH 1 uint32*
	128	TIFFTAG_IMAGEDESCRIPTION 1 char**
	129	TIFFTAG_IMAGELENGTH 1 uint32*
	130	TIFFTAG_IMAGEWIDTH 1 uint32*
	131	TIFFTAG_INKNAMES 1 char**
	132	TIFFTAG_INKSET 1 uint16*
	133	TIFFTAG_JPEGCOLORMODE 1 int* JPEG pseudo-tag
	134	TIFFTAG_JPEGQUALITY 1 int* JPEG pseudo-tag
	135	TIFFTAG_JPEGTABLES 2 uint32,void* count & tables
	136	TIFFTAG_JPEGTABLESMODE 1 int* JPEG pseudo-tag
	137	TIFFTAG_MAKE 1 char**
	138	TIFFTAG_MATTEING 1 uint16*
	139	TIFFTAG_MAXSAMPLEVALUE 1 uint16*
	140	TIFFTAG_MINSAMPLEVALUE 1 uint16*
	141	TIFFTAG_MODEL 1 char**
	142	TIFFTAG_ORIENTATION 1 uint16*
	143	TIFFTAG_PAGENAME 1 char**
	144	TIFFTAG_PAGENUMBER 2 uint16*
	145	TIFFTAG_PHOTOMETRIC 1 uint16*
	146	TIFFTAG_PHOTOSHOP 2 uint32,void* count, data
	147	TIFFTAG_PLANARCONFIG 1 uint16*
	148	TIFFTAG_PREDICTOR 1 uint16*
	149	TIFFTAG_PRIMARYCHROMATICITIES 1 float** 6-entry array
	150	TIFFTAG_REFERENCEBLACKWHITE 1 float** 2*SamplesPerPixel array
	151	TIFFTAG_RESOLUTIONUNIT 1 uint16*
	152	TIFFTAG_RICHTIFFIPTC 2 uint32,void* count, data
	153	TIFFTAG_ROWSPERSTRIP 1 uint32*
	154	TIFFTAG_SAMPLEFORMAT 1 uint16*
	155	TIFFTAG_SAMPLESPERPIXEL 1 uint16*
	156	TIFFTAG_SMAXSAMPLEVALUE 1 double*
	157	TIFFTAG_SMINSAMPLEVALUE 1 double*
	158	TIFFTAG_SOFTWARE 1 char**
	159	TIFFTAG_STONITS 1 double**
	160	TIFFTAG_STRIPBYTECOUNTS 1 uint32**
	161	TIFFTAG_STRIPOFFSETS 1 uint32**
	162	TIFFTAG_SUBFILETYPE 1 uint32*
	163	TIFFTAG_SUBIFD 2 uint16,uint32* count & offsets array
	164	TIFFTAG_TARGETPRINTER 1 char**
	165	TIFFTAG_THRESHHOLDING 1 uint16*
	166	TIFFTAG_TILEBYTECOUNTS 1 uint32**
	167	TIFFTAG_TILEDEPTH 1 uint32*
	168	TIFFTAG_TILELENGTH 1 uint32*
	169	TIFFTAG_TILEOFFSETS 1 uint32**
	170	TIFFTAG_TILEWIDTH 1 uint32*
	171	TIFFTAG_TRANSFERFUNCTION 1 or 3\(dg uint16**1<<BitsPerSample entry arrays
	172	TIFFTAG_WHITEPOINT 1 float** 2-entry array
	173	TIFFTAG_XMLPACKET 2 uint32,void* count, data
	174	TIFFTAG_XPOSITION 1 float*
	175	TIFFTAG_XRESOLUTION 1 float*
	176	TIFFTAG_YCBCRCOEFFICIENTS 1 float** 3-entry array
	177	TIFFTAG_YCBCRPOSITIONING 1 uint16*
	178	TIFFTAG_YCBCRSUBSAMPLING 2 uint16*
	179	TIFFTAG_YPOSITION 1 float*
	180	TIFFTAG_YRESOLUTION 1 float*\(dd
	181	.fi
	182	\(dg If
	183	.I SamplesPerPixel
	184	is one, then a single array is returned; otherwise three arrays are returned.
	185	.fi
	186	\(dd The contents of this field are quite complex. See
	187	.IR "The ICC Profile Format Specification" ,
	188	Annex B.3 "Embedding ICC Profiles in TIFF Files" (available at
	189	http://www.color.org) for an explanation.
	190	.SH AUTOREGISTERED TAGS
	191	If you can't find the tag in the table above that means this is unsupported
	192	tag. But you still be able to read it's value if you know the data type of
	193	that tag. For example, if you want to read the LONG value from the tag 33424
	194	and ASCII string from the tag 36867 you can use the following code:
	195	.PP
	196	.RS
	197	.nf
	198	uint16 count;
	199	void *data;
	200
	201	TIFFGetField(tiff, 33424, &count, &data);
	202	printf("Tag %d: %d, count %d\n", 33424, (uint32 )data, count);
	203	TIFFGetField(tiff, 36867, &count, &data);
	204	printf("Tag %d: %s, count %d\n", 36867, (char *)data, count);
	205	.fi
	206	.RE
	207	.PP
	208
	209
	210	is not supported by
	211	.BR libtiff(3TIFF),
	212	library
	213	.SH RETURN VALUES
	214	1 is returned if the tag is defined in the current directory; otherwise a 0 is
	215	returned.
	216	.SH DIAGNOSTICS
	217	All error messages are directed to the
	218	.BR TIFFError (3TIFF)
	219	routine.
	220	.PP
	221	.BR "Unknown field, tag 0x%x" .
	222	An unknown tag was supplied.
	223	.SH "SEE ALSO"
	224	.BR TIFFOpen (3TIFF),
	225	.BR TIFFSetField (3TIFF),
	226	.BR TIFFSetDirectory (3TIFF),
	227	.BR TIFFReadDirectory (3TIFF),
	228	.BR TIFFWriteDirectory (3TIFF)
	229	.BR libtiff (3TIFF),
	230	.PP
	231	Libtiff library home page:
	232	.BR http://www.remotesensing.org/libtiff/