2003.04.30 10:29 "How use SubIFD TIFF tag", by Julien Demaria

Hello,

I would have some help about the SubIFD TIFF tag.

1. To set the SubIFD TIFF tag I need the number of subifd and their offset... How can I know the subifds offsets ?
2. I want to use the SubIFD tag to add some subsampled images to an existing IFD.

I wouldn't recopy existing data ; I want append subfid to the ifd of an existing TIFF image.

My idea is:

• open the TIFF file in append mode ;
• TIFFSetDirectory(tif, 0) ;
• set the tag of this directory with their existing value ;
• set the SubIFD tag ;
• call TIFFRewriteDirectory ;
• then write the next subfids as standards directories.

Do you think it's the good way to do that? (in my little tests it seams currently work...)

Many thanks in advance for your help,

Julien