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TIFF and LibTiff Mail List Archive

Thread

2003.01.31 16:52 "Opening compressed images in "update" mode.", by Frank Warmerdam
2003.02.03 07:54 "RE: Opening compressed images in "update" mode.", by Rainer Wiesenfarth

2003.02.03 07:54 "RE: Opening compressed images in "update" mode.", by Rainer Wiesenfarth

I have removed the restriction in tif_open.c that prevented compressed images from being opened in update mode. I have added a check in TIFFWriteCheck() (called before imagery can be written on a directory) to fail if an attempt is made to write to an existing compressed image.

I do not think that this causes any harm. However, the best - and probably most welcome - solution would be to incorporate full support for the two tags FreeOffsets / FreeByteCounts into libtiff. Once this is in the library, there should be the possibility to open whatever image in update mode.

However, there are backdrops of it: as soon as private tags reference to content the references might get dangling. But for "standard" image it might be a big improvement.

Ok, you gave me the little finger, and I ask for the whole arm. I am totally satisfied with what libtiff currently offers, but if you are searching for tasks for your spare time, this might be one ;-)

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