2006.09.26 14:22 "[Tiff] 2003.08.07 16:40 "Custom tags", by Andrey Kiselev", by Robert Scheck

I tried to run this example program,
but after each "TIFFSetField()" I got errormessage like this:
   _TIFFVSetField: test.tif: Invalid tag "MyTag" (not supported by codec).

I'm using LIBTIFF, Version 3.8.2 for Windows.
Do You know, what's the problem?

Test-Code:

#include <tiffio.h>
#include <stdio.h>

#define TIFFTAG_ASCIITAG 666
#define TIFFTAG_LONGTAG 667
#define TIFFTAG_SHORTTAG 668
#define TIFFTAG_RATIONALTAG 669
#define TIFFTAG_FLOATTAG 670
#define TIFFTAG_DOUBLETAG 671
#define TIFFTAG_BYTE 672

static void TagExtender(TIFF *tiff)
{
    static const TIFFFieldInfo xtiffFieldInfo[] = {
        { TIFFTAG_ASCIITAG, -1,-1, TIFF_ASCII, FIELD_CUSTOM,
          1, 0, "MyTag" },
        { TIFFTAG_SHORTTAG, 1, 1, TIFF_SHORT, FIELD_CUSTOM, 0, 1,
            "ShortTag" },
        { TIFFTAG_LONGTAG, 1, 1, TIFF_LONG, FIELD_CUSTOM, 0, 1,
            "LongTag" },
        { TIFFTAG_RATIONALTAG, 1, 1, TIFF_RATIONAL, FIELD_CUSTOM, 0, 1,
            "RationalTag" },
        { TIFFTAG_FLOATTAG, 1, 1, TIFF_FLOAT, FIELD_CUSTOM, 0, 1,
            "FloatTag" },
        { TIFFTAG_DOUBLETAG, 1, 1, TIFF_DOUBLE, FIELD_CUSTOM, 0, 1,
            "DoubleTag" },
        { TIFFTAG_BYTE, 1, 1, TIFF_BYTE, FIELD_CUSTOM, 0, 1,
            "DoubleTag" },
    };

    TIFFMergeFieldInfo( tiff, xtiffFieldInfo,
                                         sizeof(xtiffFieldInfo) /
sizeof(xtiffFieldInfo[0]) );
}

int main()
{

    TIFF    *tiff;
    char    *pszString;
    long    iLong, *paiLong;
    short   iShort, *paiShort;
    float   fFloat, *pafFloat;
    double  dfDouble, *padfDouble;
    char    iByte, *paiByte;

unsigned short iCount;

TIFFSetTagExtender(TagExtender);

tiff = TIFFOpen("test.tif", "r+"); TIFFSetField(tiff, TIFFTAG_ASCIITAG, "Tag contents"); iShort = 263; TIFFSetField(tiff, TIFFTAG_SHORTTAG, 1, &iShort); iLong = 117; TIFFSetField(tiff, TIFFTAG_LONGTAG, 1, &iLong); fFloat = 0.333333; TIFFSetField(tiff, TIFFTAG_RATIONALTAG, 1, &fFloat); fFloat = 0.666666; TIFFSetField(tiff, TIFFTAG_FLOATTAG, 1, &fFloat); dfDouble = 0.1234567; TIFFSetField(tiff, TIFFTAG_DOUBLETAG, 1, &dfDouble); iByte = 89; TIFFSetField(tiff, TIFFTAG_BYTE, 1, &iByte); TIFFRewriteDirectory(tiff); TIFFClose(tiff);

tiff = TIFFOpen("test.tif", "r"); TIFFGetField(tiff, TIFFTAG_ASCIITAG, &pszString); printf("ASCII tag: %s\n", pszString); TIFFGetField(tiff, TIFFTAG_SHORTTAG, &iCount, &paiShort); if (iCount == 1)

        printf("Short tag: %d\n", paiShort[0]);
TIFFGetField(tiff, TIFFTAG_LONGTAG, &iCount, &paiLong);
if (iCount == 1)
        printf("Long tag: %ld\n", paiLong[0]);
TIFFGetField(tiff, TIFFTAG_RATIONALTAG, &iCount, &pafFloat);
if (iCount == 1)
        printf("Rational tag: %f\n", pafFloat[0]);
TIFFGetField(tiff, TIFFTAG_FLOATTAG, &iCount, &pafFloat);
if (iCount == 1)
        printf("Float tag: %f\n", pafFloat[0]);
TIFFGetField(tiff, TIFFTAG_DOUBLETAG, &iCount, &padfDouble);
if (iCount == 1)
        printf("Double tag: %lf\n", padfDouble[0]);
TIFFGetField(tiff, TIFFTAG_BYTE, &iCount, &paiByte);
if (iCount == 1)
        printf("Byte tag: %d\n", paiByte[0]);
TIFFClose(tiff);

    return 0;
}

Robert Scheck
Senior Software Engineer
----------------------------------------
Beta Systems Software AG
Business Line ECM
Hübnerstraße 3, D-86150 Augsburg
Phone +49 (0) 821 - 7941 - 215
Fax +49 (0) 821 - 7941 - 353
Email: robert.scheck@betasystems.com
http://www.betasystems.com

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