XP image properties category - which exif tag ?

[R.Wieser]

Hello All,

Under XPsp3, when I look at an image -> properties -> summary (simple mode)
there is a field named "Category" which currently grayed out (I've not seen
an image where it wasn't). As I've been writing some code to show &
alter EXIF info I would like to be able to use that field too (hey its
there, so why not ? :-) ).

The problem is that I can't seem to find any info about this "Category"
field. Not its index#/tag/ID, nor what contents it should have (I've found
ID 0x0023, but providing it with two dwords doesn't change the above field).

So, the question is: Can anybody tell me which EXIF index#/tag/ID is
attached to that "Category" field (and possibly what kind of data is needed
for to make something show up in it).

Regards,
Rudy Wieser

[David Lowndes]

Post by R.Wieser
Under XPsp3, when I look at an image -> properties -> summary (simple mode)
there is a field named "Category" which currently grayed out (I've not seen
an image where it wasn't). As I've been writing some code to show &
alter EXIF info I would like to be able to use that field too (hey its
there, so why not ? :-) ).

I suspect it's System.Category (PKEY_Category): https://docs.microsoft.com/en-us/windows/desktop/properties/props-system-category
defined in the Windows header propkey.h.

You'll see from the documentation it's now deprecated and only works on OLE documents (such as old Word .doc files), so that might
explain why it's shown as disabled for images.

Dave

[R.Wieser]

David,

Post by David Lowndes
https://docs.microsoft.com/en-us/windows/desktop/properties/props-system-category
defined in the Windows header propkey.h.

... I don't think so.

The Category ID/index#/Tag I'm looking for is an EXIF one, with a size of
two just bytes. Looking thru that above page and on as well as that
"propkey.h" (the ones google returned I mean) seems to shows it works with
GUIDS.

Thanks for trying though. :-)

Regards,
Rudy Wieser

[David Lowndes]

Post by R.Wieser
... I don't think so.

Check how the UI behaves for a Word .doc file.

Dave

[R.Wieser]

Dave,

Post by David Lowndes
Check how the UI behaves for a Word .doc file.

Its enabled there.

That might mean that the "Category" field is disabled for an image simply
because its not part what EXIF has to offer. Is that what you tried to
tell me ? (I was/am not sure why it was disabled to begin with).

Regards,
Rudy Wieser

[David Lowndes]

Post by R.Wieser

Post by David Lowndes
Check how the UI behaves for a Word .doc file.

Its enabled there.
That might mean that the "Category" field is disabled for an image simply
because its not part what EXIF has to offer. Is that what you tried to
tell me ?

Yes, that's what the documentation says and it matches the behaviour I see with one of my applications. For a jpg files I got the
following error when I tried to set that property:

Unable to set the value for the System.Category property.
Error: 0x88982f41: The bitmap codec does not support the bitmap property.

When I tried setting it on a .doc file, it worked, and showed up in the file's property page as the "Categories" property.

Dave

[R.Wieser]

David,

Post by David Lowndes
Yes, that's what the documentation says

My apologies. My mind was tuned to finding the EXIF code for that field
(and assumed your response was about that code) and I must have missed that
part as a result.

Post by David Lowndes
Unable to set the value for the System.Category property.
Error: 0x88982f41: The bitmap codec does not support the bitmap property.

Yep, that is makes it a lot clearer (I take it that the "bitmap property" is
a mistype, and should have been "category property". I mean, a bitmap codec
which does not support a bitmap ? :-) ).

Thanks for the explanation.

Regards,
Rudy Wieser

[David Lowndes]

Post by R.Wieser
Yep, that is makes it a lot clearer (I take it that the "bitmap property" is
a mistype, and should have been "category property". I mean, a bitmap codec
which does not support a bitmap ? :-) ).

You'd think so, but that's the text of the error returned by Windows itself, not my application :)

Dave