[Digikam-devel] First steps with the new features: face recognition and versioning

[Sven Burmeister]

Hi!

Today I compiled digikam2 against KDE 4.4 and the libk* from trunk. So I would 
like to share my first steps with the new features in case that might be 
interesting to those developing them.

Face recognition:
I knew that there were new features. If I had not known I would not have come 
across the face recognition since it is only a little icon in the tab bar at 
the left. I would suggest to check whether face recognition was ever run and 
ask the user whether he wants to start scanning the collection or not, 
including a checkbox "never show this again".

In fact I found the little icon in the preview before finding the tab that 
allows to scan the whole collection. So my first impression was: "why do I 
have to mark faces on photos if picasa does this automatically?". The latter 
also indicates my bias, I know picasa's face recognition so I expected it to 
work in a similar way, i.e. start to scan and group the photos and give the 
user the possibility to tell which pictures were false positives.

So I tried to add some face recognition, i.e. clicked on the small icon in the 
preview of a picture.

Why is there a "show face tags" icon if the picture does not have any face 
tags? would it not make more sense to show the "add face tag" if there are 
none yet?

When adding a face tag I tried to name it and typed Ol <- L which opened the 
light table although the cursor was in the line edit for the tag name.

I closed the light table and clicked on another image where I had to click on 
the "show face tags" again in order to add one. Yet now one has to click twice 
on it to get the "add face tag" icon. After restarting digikam one has to only 
click once for the first time again.

If one moves the red square one gets some grey or black lines that remain on 
the picture but that might be a NVIDIA graphics driver issue.

If one enters a name for the tag but does not click on the tick, the tag is 
not saved. I think that entering the name should be enough.

Having a look at the people tags shows a preview of the picture the tag was 
added to. Yet the bit shown as preview is not the part of the image the red 
square marked, i.e. not the face.

If one opens the preview of the marked photo again the red square is gone and 
clicking on "show people tags" does not seem to do anything. Where is the red 
square gone? Or is it just a one off? I think I thought that "add people tag" 
meant the red square including the name and tag are added to the picture. But 
it only means "use the red square to pick a face". So for me the red square 
was part of the tag rather than a tool to add it. What about calling it 
"select face", "mark face", "mark person" or "link face to person"? Then it 
would be clear that nothing is added to the picture but only a face marked as 
person xy.

So after searching a bit I found that one could scan the whole collection from 
within the people tag tab. Yet somehow it stops after a few images, i.e. it 
created an "unknown" tag and then gets stuck at some picture.

I tried several times yet I never got more than one "unknown" tag, I thought I 
should get something like "person 1", "person 2" and then mark the false 
positives for each tag.

Versioning:
I found versioning when saving an image, so everything fine here, since one 
does not need that feature if one does not save images. However since I did 
not find a "save" item anymore in the file menu I thought that "new version" 
replaces "save". Thus I was surprised to see that the digikam album view 
showed both versions since I expected "new version" to "overwrite" the 
original, i.e. that the album view would only show the new picture.

Thinking about it it does make sense though to be able to have multiple 
visible versions a picture, e.g. for comparing them on the light table. 
However I think that "overwriting" is a valid use case as well because I do 
not want to see the original in the album view if I corrected some colour or 
contrast in the picture or resized it. I just want to see the final version.

Thus I think that there should be a "save" item which "overwrites" the 
previous version, i.e. hides it in the album view and there should be the "new 
version" item which does exactly what it does now, i.e. duplicate the picture 
and create a separate version of it.

The album view just showed a "?" as icon at the bottom-right of the thumbnail 
for the new versions. And I think that the versioning tab is too hidden, i.e. 
clicking on that little new icon or right-clicking the image should give 
access to the versions or open the versioning tab. At least "revert to 
original" should be available from the right-click menu. There is a toolbar 
button in the image editor but the album view lacks that feature.

Within the image editor I found the following:
- the text next to the thumbnails in the "versions" tab is black even for the 
dark theme, so it's black text on black background. (The same is true for the 
album view's standard toolbar btw)
- if one creates a new version of the picture the new thumbnail is not added 
to the "versions" tab until one clicks on another picture in the preview pane 
and back.
- if one right clicks on one of the applied filters it shows a "remove filter" 
pop-up yet one cannot click it, i.e. nothing happens.
- clicking on the version thumbnails does not show them in the main editor 
window
- saving a new version will add that thumbnail to the bottom of the preview 
pane instead of where it belongs according to the sorting.

That's it until now. I'll keep on using and testing and provide feedback if 
it's wanted.

Sven