2022.12.09 01:29 "[Tiff] How to write multi-file TIFFs", by L. E. Segovia

2022.12.10 20:44 "Re: [Tiff] How to write multi-file TIFFs", by L. E. Segovia

Update: I've enhanced your gist with our use of QFile:

https://gist.github.com/amyspark/deb7fee06ff5144028865269c8fb9967

So the issue boiled down to LibTiff requiring read+write (and not just write) access to the file. The documentation says it but sort of eliptically:

> TIFFFdOpen is like TIFFOpen except that it opens a TIFF file given an open file descriptor fd. The file's name and mode must reflect that of the open descriptor. The object associated with the file descriptor must support random access.

We thought that was just random seeking + writing, but the directory link actually reads back the partially written TIFF when creating subsequent IFDs.

Thanks again for your help!

amyspark

amyspark 🌸 https://www.amyspark.me