2015.12.09 15:52 "[Tiff] Creating private IFD", by Mat Maher

Hi all,

Can anyone advise a 'proper' way to create private IFD's within an image TIFF?

I've been using the tif_dir.h routines: TIFFCreateCustomDirectory(), TIFFWriteCustomDirectory(); but I'm a little concerned that, because they need private header includes, this might not be the proper way to do things.

My current implementation does:

1. Create TIFF file
2. Complete the 'normal' metadata
3. Write the image data
4. Create the custom IFD
5. Write the IFD index into the normal tag area
6. Close the file

Unfortunately, it's getting stumped at step (5), whereby I'm getting a pair of exceptions:

"Cannot modify tag "Compression" whilst writing"
"Unknown tag 330"

- The first one is just bonkers, as I'm neither writing data nor modifying compression tags at the time

The second one relates to the TIFFTAG_SUBIFD tag write (step5): Which again is a little strange since this tag is defined by the library (so is not unknown).

Any help, suggestions or advice greatly appreciated!!

Mat

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