2006.01.10 17:54 "Re: [Tiff] Incorrect IFD???", by Antoine

ich have ab problem creating a multipage tiff image. The 8 byte image file header is ok, but something is going wrong in the IFD. The beginning of the IFD consists of a 2-byte count of the number of directory (i. e., the number of fields). My image has 16 tags and the value has to be (in hex) "10 00", hasn't it?

I need these images for a special import process. I have a full funcionally sample (which is not created by me) where the IFD design is correct. But when I create an multipage tiff image with the lifftib library I get other values at this postion. Sometimes it is for example FF FF. By checking these images for the special import process it returns a failure. It can't read the correct count of the tags (FF FF instead of 10 00).

If you have some specific placement requirement (like a lot of tiff subsets) then there is nothing like rolling your own. After a bit of frustration with understanding a specifications document (which I have since learned to appreciate as a very good one...), I decided to roll my own (programme that is...). If you don't need to do anything else with libtiff then there is basically no need to use it. If you do (which I do), then use libtiff and write a basic interpreter which will reconstruct the tiff according to your requirements.

It is not hard. The specification (do a google for tiff6.pdf) is excellent, and byte-level access easy even in vb6 (which I used).

Cheers
Antoine

ps. you get a great sense of accomplishment after reading (and understanding) the guts of tiff6!