Verifying correct tag info (not value) from tag name in -listx output

[Phil Harvey]

Ok, so the updated -listx will show new tag names, but not new groups (g1) when they are created and existing tags are 'put in them'?

Exactly.

I guess part of my confusion is that since tags with the same name can be in several groups, I tend to think of a tag as a specific tag in a specific group.

Yes.  That would have been simpler, but would have resulted in a potentially infinite duplication of tags, which is why I needed to use the dynamic group names.  (ie. there is no limit on the maxumum number of IFD's in a TIFF image.)

For the third situation, PreviewImage, it looks like the -listx info for this tag is defined the same in both places in -listx (Composite table and the Extra table) so I will use the Extra one since I already have the table and id values from my -X -t output to use to look up the tag info in my -listx output.

The PreviewImage tag exists in many tables.  Extra and Composite are just 2 of them.  Your confusion came from the fact that the groups specified in the -listx output are usually "File" and "Composite" respectively for these tags.  However, the family 0 and 1 group names are overridden for the MPF PreviewImage, and are set to "Composite" instead of "File".  I hope this is clear now.

- Phil

[Curtis]

Yes, as long as the table, id (and index) given in the -X -t output points me to a valid table, id  (and index) in my -listx output I will use that info from the -listx output even though this info has a different g1 and tag name  from what I got from my -X -t output.  And I will show (to user in my program) the group1:tag name I get from the -X -t output.

My head is spinning.... but I believe all is clear now!

Thanks again!
Curtis