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October 2006
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2006.10.14 12:58 "Re: Handling Of SubIFD in Libtiff Ver 3.8.3", by Anurag Singh
Hello All Sebastian thanks a lot!!! I got updated code, i compiled it, it's working fine but i didnt check for subIFD. There are some confusion about subIFD and your code snippet. In your code , you are setting TIFFTAG_PRIVATE_OFFSET for SubIFD offset. Is there any use of it??. we can get the offset of any subIFD with this tag only TIFFTAG_SUBIFD. But whtever i knw that any IFD can have more than one SubIFD, in that case we have to use SubIFD offsets, which is the feature of our tiff image architecture. how do we deal with the image which have 2 oe more SubIFDs. what i earlier used to do generally we use TIFFSetSubDirectory(input_tiff,subifdoffset) function to read SubIFD, i think this should also be modified. One important question , wht is the flow of reading and writing when a image have one aur more subIFD's. i am writing over here wht i have done with my code, please do correction if any 1) Read main IFD ( for example IFD 0) 2) Get offset of subIFD if any 3) read subIFD by using TIFFReadPrivateDirectory(TIFF* tif, toff_t diroff) if we have more than one subIFD then all the entries goes in tif->tif_privateFieldInfo. And at the time of writing we are not able diffrenciate which entris belongs to which subIFD. am i right?? So we have to read n write one by one subIFD ( act my aim is just reading n writing any tiff image) and wht about the offsets of subIFD, we have to finally set all the offset of subIFD before writing main IFD or libtiff will take care of it. please suggest me. Thanks Anurag Singh On 10/11/06, Sebastian Boehmer <sebastian.boehmer@web.de> wrote: > > Hello folks, > > This Problem could be solved with the patch in the bugzilla report 1320 > http://bugzilla.remotesensing.org/show_bug.cgi?id=1320 > > It add the following interface for private sub IFD support: > extern void TIFFMergePrivateFieldInfo(TIFF*, const > TIFFFieldInfo[],unsigned int); > extern const TIFFFieldInfo* TIFFFindPrivateFieldInfo(TIFF*, ttag_t, > TIFFDataType); > extern const TIFFFieldInfo* TIFFPrivateFieldWithTag(TIFF*, ttag_t); > > extern int TIFFSetPrivateField(TIFF*, ttag_t, ...); > extern int TIFFVSetPrivateField(TIFF*, ttag_t, va_list); > extern int TIFFGetPrivateField(TIFF*, ttag_t, ...); > extern int TIFFVGetPrivateField(TIFF*, ttag_t, va_list); > extern int TIFFWritePrivateDirectory(TIFF*, toff_t*); > extern int TIFFReadPrivateDirectory(TIFF*, toff_t); > extern int TIFFReadPrivateDirectoryWithFieldInfo(TIFF*, toff_t, const > TIFFFieldInfo[], size_t); > > > In the attachment is an example Interface for the ATR private tags. > The code below comes from this files. > greets, Sebastian > > > Here is a draft of an example: > > Use the code for custom tags from > http://www.remotesensing.org/libtiff/addingtags.html > The essenctial changes are marked with //!!! > > File: private_tags.h > --- > > #include <tiffio.h> > #include <tiff.h> > > #define TIFFTAG_PRIVATE_OFFSET 0xB10A // !!! > > > // !!! > static const TIFFFieldInfo tiffIFDOffset[] = { > /* TIFF_IFD is actual not correct implemented in libtiff. */ > //{ TIFFTAG_PRIVATE_OFFSET, 1,1, TIFF_IFD, FIELD_CUSTOM, > // TRUE, FALSE, "IMTEK ATR2 IFD" } > /* BUG: libtiff 06-09-26: TIFF_IFD didn't work correct > date:06-09-26 */ > { TIFFTAG_PRIVATE_OFFSET, 1,1, TIFF_LONG, FIELD_CUSTOM, > TRUE, FALSE, "IMTEK ATR2 IFD" } > }; > > static const TIFFFieldInfo xtiffFieldInfo[] = { > > /* XXX Insert Your tags here */ > { TIFFTAG_GEOPIXELSCALE, -1,-1, TIFF_DOUBLE, FIELD_CUSTOM, > TRUE, TRUE, "GeoPixelScale" }, > { TIFFTAG_GEOTRANSMATRIX, -1,-1, TIFF_DOUBLE, FIELD_CUSTOM, > TRUE, TRUE, "GeoTransformationMatrix" }, > { TIFFTAG_GEOTIEPOINTS, -1,-1, TIFF_DOUBLE, FIELD_CUSTOM, > TRUE, TRUE, "GeoTiePoints" }, > { TIFFTAG_GEOKEYDIRECTORY, -1,-1, TIFF_SHORT, FIELD_CUSTOM, > TRUE, TRUE, "GeoKeyDirectory" }, > { TIFFTAG_GEODOUBLEPARAMS, -1,-1, TIFF_DOUBLE, FIELD_CUSTOM, > TRUE, TRUE, "GeoDoubleParams" }, > { TIFFTAG_GEOASCIIPARAMS, -1,-1, TIFF_ASCII, FIELD_CUSTOM, > TRUE, FALSE, "GeoASCIIParams" } > }; > > #define N(a) (sizeof (a) / sizeof (a[0])) > > static TIFFExtendProc _ParentExtender = NULL; > > static > void _XTIFFInitialize(void) > { > static int first_time=1; > > if (! first_time) return; /* Been there. Done that. */ > first_time = 0; > > /* Grab the inherited method and install */ > _ParentExtender = TIFFSetTagExtender(_XTIFFDefaultDirectory); > } > > static void > _XTIFFDefaultDirectory(TIFF *tif) > { > /* Install the extended Tag field info */ > TIFFMergeFieldInfo(tif, tiffIFDOffset, > N(tiffIFDOffset)); // !!! > TIFFMergePrivateFieldInfo(tif, xtiffFieldInfo, > N(xtiffFieldInfo)); // !!! > > /* Since an XTIFF client module may have overridden > * the default directory method, we call it now to > * allow it to set up the rest of its own methods. > */ > > if (_ParentExtender) > (*_ParentExtender)(tif); > } > > --- > > > File: application.cc > --- > #include <tiffio.h> // the libtiff > > > int main() { > char filename[] = "test.tiff"; > unsinged int length=100, width=100; > uint16 bps=8, spp=1; > unsigned char* imageBuffer = new unsigned char[2*length*width]; > > _XTIFFInitialize(); > TIFF* image; > if (( image = TIFFOpen(filename,"w")) == NULL) { > printf("Could not open %s for \n",filename); > return -1; > } > > /* > * Write the Image > */ > // Check that it is of a type that we support > if(TIFFSetField(image, TIFFTAG_BITSPERSAMPLE, bps) == 0){ > printf("Couldn't write the bits per sample. It is not > possible to write the image."); > TIFFClose(image); > return -1; > } > if(TIFFSetField(image, TIFFTAG_SAMPLESPERPIXEL, spp) == 0){ > printf("Couldn't write number of samples per pixel (last > time %i)",spp); > TIFFClose(image); > return -1; > } > if(TIFFSetField(image, TIFFTAG_IMAGEWIDTH, width) == 0){ > printf("Couldn't write the width (last time %i)",width); > TIFFClose(image); > return -1; > } > > ... see attachment > > /* write the image data */ > if ( bps == 8 ) { > if ( TIFFWriteEncodedStrip(image, 0, imageBuffer, width * > length) == 0 ) { > printf("Write error: TIFF image writing. \nPerhaps > not enought memory?"); > TIFFClose(image); > return -2; > } > > } else > if ( TIFFWriteEncodedStrip(image, 0, imageBuffer, width * > length * 2) == 0) { > printf("Write error: TIFF image writing. \nPerhaps > not enought memory?"); > TIFFClose(image); > return -2; > } > > > /* > * Write the Offset > */ > // with pseudo value for calculating offset > if (!TIFFSetField(image, TIFFTAG_PRIVATE_OFFSET, 0 )) > printf("Couldn't write the offset tag to 0"); > if (!TIFFCheckpointDirectory(image)) > printf("Couldn't write the checkpoint"); > tiff_ifd_offset = TIFFCurrentDirOffset(image); > if (!TIFFSetField(image, TIFFTAGSPEC_OFFSET_V1, tiff_ifd_offset)) { > printf("Couldn't write the offset tag > (offset=%d)",TIFFCurrentDirOffset(image)); > } > if (!TIFFWriteDirectory(image)) { > printf("Couldn't write the directory"); > TIFFClose(image); > return -5; > } > > > /* > * Write the private values > */ > if (! TIFFSetPrivateField(image, TIFFTAG_GEOPIXELSCALE, 0.3 ) { > printf("Error at writing private field\n"); > return -2; > } > > ... > > /* > * Write the private Sub IFD > */ > toff_t tiff_ref_offset = 0; > if (!TIFFWritePrivateCustomDirectory(image,&tiff_ref_offset)) { > printf("Couldn't write the custom directory\n"); > TIFFClose(image); > return -8; > } > > TIFFClose(image); > > /* > * now we read the file > */ > > if ( (image = TIFFOpen(filename,"r")) == NULL ) { > printf("Could not open %s for reading \n",filename); > return -3; > } > > /* > * Get the Image > */ > // Check that it is of a type that we support > if((TIFFGetField(image, TIFFTAG_BITSPERSAMPLE, &bps) == 0) || > !((bps == 8) || (bps == 16))){ > printf("Either undefined or unsupported number of bits per > sample (should be 8 or 16)"); > TIFFClose(image); > return -1; > } > > if((TIFFGetField(image, TIFFTAG_SAMPLESPERPIXEL, &spp) == 0) || > (spp != 1)){ > printf("Either undefined or unsupported number of samples > per pixel (should be 1)"); > TIFFClose(image); > return -1; > } > > ... > > /* read the image */ > for (row = 0; row < length; row++) > if ( TIFFReadScanline(image, > &imageBuffer[row*scanLineSize], row, 0) == -1 ) { > sprintf(error_str,"Read error on input > \nscanLineSize=%i row=%i",scanLineSize,row); > setError(error_str); > closeFile(image); > return -1; > } > > ... > /* > * Read the private subIFD > */ > > toff_t tiff_ifd_offset; > // get the offset to the directory > if ( ! TIFFGetField(image, TIFFTAG_PRIVATE_OFFSET, > &tiff_ifd_offset) ) { > printf("Couldn't find the private IFD Offset to the ATR > tags."); > return -2; > } > // read directory from offset > if ( ! TIFFReadPrivateCustomDirectory(image, tiff_ifd_offset) ) { > printf("Couldn't read the private ATR tags."); > return -2; > } > > > /* > * Read the private values > */ > > float f; > if (TIFFGetPrivateField(image, TIFFTAG_GEOPIXELSCALE, &f) == 0) { > printf("Couldn't read the private value geo pixel scale"); > } > ... > > TIFFClose(image); > > return 0; > } > > > > > > > _______________________________________________ > Tiff mailing list: Tiff@lists.maptools.org > http://lists.maptools.org/mailman/listinfo/tiff > http://www.remotesensing.org/libtiff/ > > >