[Insight-users] Tiff Tag Warning on image load

[Michael Jackson]

Taking that information and looking around some more on the internet I came across this page:

http://www.remotesensing.org/libtiff/addingtags.html

Which on a cursory glance may be what is needed to figure out how to add a custom tag to be read.
___________________________________________________________
Mike Jackson                      www.bluequartz.net
Principal Software Engineer       mike.jackson at bluequartz.net 
BlueQuartz Software               Dayton, Ohio   

On Oct 17, 2010, at 9:16 AM, Luis Ibanez wrote:

> 
> Hi Michael,
> 
> I'm browsing through the TIFF code looking
> for a place where such a callback could be
> inserted.
> 
> So, far I have not found a clear place where
> this could be done, but there are many hints
> that lead to think that it is indeed possible to
> do it.
> 
> Let me list what I have found so far, in the 
> hope that other people can follow the trail
> or find additional hits.
> 
> ---
>  
> Here are some functions and variables in
> the TIFF library that seem to be related to
> a potential management of custom tags:
> 
> 
> A) tif->tif_nfields :  number of known tags
> 
> if we could insert the id of that custom tag
> in the structure for which nfields counts,
> then it could be accepted during the initial
> parsing in line 283 of tif_dirread.c
> 
> 
> B) TIFFTagValue: struct in tif_dir.c
> 
>    In particular, its appearances in lines
>    526-543 give us some hope:
> 
>    namely:
> 
>              /*
>              * Grow the custom list if the entry was not found.
>              */
>             if( tv == NULL )
>             {
>     TIFFTagValue  *new_customValues;
>     
>     td->td_customValueCount++;
>     new_customValues = (TIFFTagValue *)
>       _TIFFrealloc(td->td_customValues,
>              sizeof(TIFFTagValue) * td->td_customValueCount);
>     if (!new_customValues) {
>       TIFFError(module,
>     "%s: Failed to allocate space for list of custom values",
>           tif->tif_name);
>       status = 0;
>       goto end;
>     }
> 
> 
> -----
> 
> 
> Once we figure out how to do this at the
> level of the TIFF library, we will be able
> to expose that functionality at the level
> of the TIFFImageIO class.
> 
> 
>     Regards,
> 
> 
>           Luis
> 
> 
> 
> ----------------------------------------------------------
> On Thu, Sep 30, 2010 at 2:07 PM, Michael Jackson <mike.jackson at bluequartz.net> wrote:
> I get the following warning when I open some of my Tiff files:
> 
> TIFFReadDirectory: Warning, 7001.tif: unknown field with tag 34681 (0x8779) encountered.
> 
> I know what the field is and I know how to parse it. Are there any facilities for setting a callback function or anything like that to the Tiff file reader?
> 
> Thanks
> ___________________________________________________________
> Mike Jackson                      www.bluequartz.net
> Principal Software Engineer       mike.jackson at bluequartz.net
> BlueQuartz Software               Dayton, Ohio
> 
> 
> 
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