1TIFFGetField(3TIFF)                                        TIFFGetField(3TIFF)
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NAME

6       TIFFGetField, TIFFVGetField - get the value(s) of a tag in an open TIFF
7       file
8

SYNOPSIS

10       #include <tiffio.h>
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12       int TIFFGetField(TIFF *tif, ttag_t tag, ...)
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14       #include <stdarg.h>
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16       int TIFFVGetField(TIFF *tif, ttag_t tag, va_list ap)
17       int TIFFGetFieldDefaulted(TIFF *tif, ttag_t tag, ...)
18       int TIFFVGetFieldDefaulted(TIFF *tif, ttag_t tag, va_list ap)
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DESCRIPTION

21       TIFFGetField returns the value of a tag or pseudo-tag  associated  with
22       the  the  current directory of the opened TIFF file tif.  (A pseudo-tag
23       is a parameter that is used  to  control  the  operation  of  the  TIFF
24       library but whose value is not read or written to the underlying file.)
25       The file must have been previously opened  with  TIFFOpen(3TIFF).   The
26       tag is identified by tag, one of the values defined in the include file
27       tiff.h (see also the table  below).  The  type  and  number  of  values
28       returned  is  dependent  on  the  tag  being requested. The programming
29       interface uses a variable argument list as prescribed by the  stdarg(3)
30       interface.  The  returned values should only be interpreted if TIFFGet‐
31       Field returns 1.
32
33       TIFFVGetField is functionally equivalent to TIFFGetField except that it
34       takes  a  pointer to a variable argument list.  TIFFVGetField is useful
35       for layering  interfaces  on  top  of  the  functionality  provided  by
36       TIFFGetField.
37
38       TIFFGetFieldDefaulted   and  TIFFVGetFieldDefaulted  are  identical  to
39       TIFFGetField and TIFFVGetField, except that if a tag is not defined  in
40       the  current  directory  and  it  has a default value, then the default
41       value is returned.
42
43       The tags understood by libtiff(3TIFF), the number of parameter  values,
44       and  the  types for the returned values are shown below. The data types
45       are specified as in C and correspond to the types used to  specify  tag
46       values  to  TIFFSetField(3TIFF).   Remember  that  TIFFGetField returns
47       parameter values, so all the listed data types are pointers to  storage
48       where  values  should  be returned.  Consult the TIFF specification (or
49       relevant industry specification) for information on the meaning of each
50       tag and their possible values.
51
52       Tag Name                        Count  Types             Notes
53       TIFFTAG_ARTIST                  1      char**
54       TIFFTAG_BADFAXLINES             1      uint32*
55       TIFFTAG_BITSPERSAMPLE           1      uint16*
56       TIFFTAG_CLEANFAXDATA            1      uint16*
57       TIFFTAG_COLORMAP                3      uint16**          1<<BitsPerSample arrays
58       TIFFTAG_COMPRESSION             1      uint16*
59       TIFFTAG_CONSECUTIVEBADFAXLINES  1      uint32*
60       TIFFTAG_COPYRIGHT               1      char**
61       TIFFTAG_DATATYPE                1      uint16*
62       TIFFTAG_DATETIME                1      char**
63       TIFFTAG_DOCUMENTNAME            1      char**
64       TIFFTAG_DOTRANGE                2      uint16*
65       TIFFTAG_EXTRASAMPLES            2      uint16*,uint16**  count & types array
66       TIFFTAG_FAXFILLFUNC             1      TIFFFaxFillFunc*  G3/G4 compression pseudo-tag
67       TIFFTAG_FAXMODE                 1      int*              G3/G4 compression pseudo-tag
68       TIFFTAG_FILLORDER               1      uint16*
69       TIFFTAG_GROUP3OPTIONS           1      uint32*
70       TIFFTAG_GROUP4OPTIONS           1      uint32*
71       TIFFTAG_HALFTONEHINTS           2      uint16*
72       TIFFTAG_HOSTCOMPUTER            1      char**
73       TIFFTAG_ICCPROFILE              2      uint32*,void**    count, profile data
74       TIFFTAG_IMAGEDEPTH              1      uint32*
75       TIFFTAG_IMAGEDESCRIPTION        1      char**
76       TIFFTAG_IMAGELENGTH             1      uint32*
77       TIFFTAG_IMAGEWIDTH              1      uint32*
78       TIFFTAG_INKNAMES                1      char**
79       TIFFTAG_INKSET                  1      uint16*
80       TIFFTAG_JPEGCOLORMODE           1      int*              JPEG pseudo-tag
81       TIFFTAG_JPEGQUALITY             1      int*              JPEG pseudo-tag
82       TIFFTAG_JPEGTABLES              2      uint32*,void**    count & tables
83       TIFFTAG_JPEGTABLESMODE          1      int*              JPEG pseudo-tag
84       TIFFTAG_MAKE                    1      char**
85       TIFFTAG_MATTEING                1      uint16*
86       TIFFTAG_MAXSAMPLEVALUE          1      uint16*
87       TIFFTAG_MINSAMPLEVALUE          1      uint16*
88       TIFFTAG_MODEL                   1      char**
89       TIFFTAG_ORIENTATION             1      uint16*
90       TIFFTAG_PAGENAME                1      char**
91       TIFFTAG_PAGENUMBER              2      uint16*
92       TIFFTAG_PHOTOMETRIC             1      uint16*
93       TIFFTAG_PHOTOSHOP               2      uint32*,void**    count, data
94       TIFFTAG_PLANARCONFIG            1      uint16*
95       TIFFTAG_PREDICTOR               1      uint16*
96       TIFFTAG_PRIMARYCHROMATICITIES   1      float**           6-entry array
97       TIFFTAG_REFERENCEBLACKWHITE     1      float**           2*SamplesPerPixel array
98       TIFFTAG_RESOLUTIONUNIT          1      uint16*
99       TIFFTAG_RICHTIFFIPTC            2      uint32*,void**    count, data
100       TIFFTAG_ROWSPERSTRIP            1      uint32*
101       TIFFTAG_SAMPLEFORMAT            1      uint16*
102       TIFFTAG_SAMPLESPERPIXEL         1      uint16*
103       TIFFTAG_SMAXSAMPLEVALUE         1      double*
104       TIFFTAG_SMINSAMPLEVALUE         1      double*
105       TIFFTAG_SOFTWARE                1      char**
106       TIFFTAG_STONITS                 1      double**
107       TIFFTAG_STRIPBYTECOUNTS         1      uint32**
108       TIFFTAG_STRIPOFFSETS            1      uint32**
109       TIFFTAG_SUBFILETYPE             1      uint32*
110       TIFFTAG_SUBIFD                  2      uint16*,uint32**  count & offsets array
111       TIFFTAG_TARGETPRINTER           1      char**
112       TIFFTAG_THRESHHOLDING           1      uint16*
113       TIFFTAG_TILEBYTECOUNTS          1      uint32**
114       TIFFTAG_TILEDEPTH               1      uint32*
115       TIFFTAG_TILELENGTH              1      uint32*
116       TIFFTAG_TILEOFFSETS             1      uint32**
117       TIFFTAG_TILEWIDTH               1      uint32*
118       TIFFTAG_TRANSFERFUNCTION        1 or 3†                  uint16**1<<BitsPerSample entry arrays
119       TIFFTAG_WHITEPOINT              1      float**           2-entry array
120       TIFFTAG_XMLPACKET               2      uint32*,void**    count, data
121       TIFFTAG_XPOSITION               1      float*
122       TIFFTAG_XRESOLUTION             1      float*
123       TIFFTAG_YCBCRCOEFFICIENTS       1      float**           3-entry array
124       TIFFTAG_YCBCRPOSITIONING        1      uint16*
125       TIFFTAG_YCBCRSUBSAMPLING        2      uint16*
126       TIFFTAG_YPOSITION               1      float*
127       TIFFTAG_YRESOLUTION             1      float*‡
128       † If SamplesPerPixel is one, then a single array is returned; otherwise
129       three arrays are returned.
130       ‡ The contents of this field are quite complex.  See  The  ICC  Profile
131       Format  Specification, Annex B.3 "Embedding ICC Profiles in TIFF Files"
132       (available at http://www.color.org) for an explanation.
133

AUTOREGISTERED TAGS

135       If you can't find the tag in the table above that means this is  unsup‐
136       ported  tag.  But  you still be able to read it's value if you know the
137       data type of that tag. For example, if you want to read the LONG  value
138       from  the tag 33424 and ASCII string from the tag 36867 you can use the
139       following code:
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141              uint16  count;
142              void    *data;
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144              TIFFGetField(tiff, 33424, &count, &data);
145              printf("Tag %d: %d, count %d0, 33424, *(uint32 *)data, count);
146              TIFFGetField(tiff, 36867, &count, &data);
147              printf("Tag %d: %s, count %d0, 36867, (char *)data, count);
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149       is not supported by libtiff(3TIFF), library
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RETURN VALUES

152       1 is returned if the tag is defined in the current directory; otherwise
153       a 0 is returned.
154

DIAGNOSTICS

156       All error messages are directed to the TIFFError(3TIFF) routine.
157
158       Unknown field, tag 0x%x.  An unknown tag was supplied.
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SEE ALSO

161       TIFFOpen(3TIFF),  TIFFSetField(3TIFF),  TIFFSetDirectory(3TIFF),  TIFF‐
162       ReadDirectory(3TIFF), TIFFWriteDirectory(3TIFF) libtiff(3TIFF),
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164       Libtiff library home page: http://www.remotesensing.org/libtiff/
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168libtiff                         March 18, 2005             TIFFGetField(3TIFF)
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