[Digikam-devel] [Bug 146337] Tag regions of an image

Braiam Yesid braiam.yesid at yahoo.com
Fri Dec 14 13:02:38 GMT 2007

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------- Additional Comments From braiam.yesid yahoo com  2007-12-14 14:02 -------
I agree with Christian: rectangles are sufficient.

Systems with region tagging (i.e. Facebook) have always the same image size. Since digikam organizes local collections, where there are lots of images with disparate aspect ratios (this is more true to pro photographers, they cut the image just as a step of making the pic), what should be the size of the region? 

One approach would be use a default fixed size, I think 20% of the image size (20% of the shorter side of the image). The other approach would be a user defined size.

(next paragraph is IMHO. I have not seen a single line of digikam. and have never written a single line of QT)
But note that both approaches have in practice, custom square size. So I think it could be implemented using a class with following attribs:  x, y, length, comment, tags. Explaining it a little more:
- x, y: could be the center of the area. alternatively, it could be the up-left corner.
- length: is the length of the side of the square
- comment: is a string with a custom comment for the region
- tags: is the collection of tags associated to this region
- and possibly, an ID field. I dont know what could be the next step in organizing photos, but a public region id could be useful in the future.

It could also be useful a list of regions in the side bar (QListView?). Some systems like Flickr let tag, but one should search with the pointer for regions. Some other systems, like Facebook, have the list of tagged items, and it's very handy. The mentioned list should not be a mere list, but some kind of a regions administrator. I think that below the list there would be a box to write/view the comment, and the tag selector.

For the user, I think the flow would go like this
- select the "create region" ("tag region", or any other name) button.
the pointer changes to crosshair, the sidebar gives the "click or drag to make a region" instruction. Possibly a more flashy behavior to reflect this "creating region" state could be a thick colored border for the image (ideally, a beautiful and sober highlighting frame).
- create the region by clicking or dragging
- if clicked or dragged a little, create the region with the default region size, and centered in the clicked point.
- if dragged more than (let's say) 4 or 5 px, begin making an area.
- When finished creating the region popup or focus to the frame containing the comment box and tags selector.
- if the popup was used, click ok and go to the normal state. If focus was used, just go to the normal state.

With this digikam would be ready to export to flickr with regions, to facebook with tags, and obviously, helping a little with bug #146288

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