LibTiff Mailing List

FYI: I solved the problem by creating a new TIFF on the fly.

It seems that libtiff doesn't handle extending a directory without
overwriting data at all. If a directory size increases, libtiff would
have to relocate the entire directory entry with all existing tags to
e.g. the end of the file. It doesn't do that now, but writes the new
tag to the file right after the end of the current directory, thereby
destroying whatever is there.

That's just my observation without looking into libtiff's source.

Juergen


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		TIFF and LibTiff Mailing List Archive
	LibTiff Mailing List TIFF and LibTiff Mailing List Archive November 2009 Previous Thread Next Thread Previous by Thread Next by Thread Previous by Date Next by Date Contact The TIFF Mailing List Homepage This list is run by Frank Warmerdam Archive maintained by AWare Systems	Thread 2009.11.30 11:26 "Adding tags to a broken(?) TIFF", by Juergen Buchmueller 2009.12.06 15:02 "Re: Adding tags to a broken(?) TIFF", by Juergen Buchmueller 2009.12.06 15:57 "Re: Adding tags to a broken(?) TIFF", by Bob Friesenhahn 2009.12.06 15:02 "Re: Adding tags to a broken(?) TIFF", by Juergen Buchmueller FYI: I solved the problem by creating a new TIFF on the fly. It seems that libtiff doesn't handle extending a directory without overwriting data at all. If a directory size increases, libtiff would have to relocate the entire directory entry with all existing tags to e.g. the end of the file. It doesn't do that now, but writes the new tag to the file right after the end of the current directory, thereby destroying whatever is there. That's just my observation without looking into libtiff's source. Juergen

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2009.12.06 15:02 "Re: Adding tags to a broken(?) TIFF", by Juergen Buchmueller